JP2019215310A - Angle calculation device - Google Patents

Abstract

To provide an angle calculation device capable of determining abnormality in rotational speed information.SOLUTION: An angle calculation device 30 includes a microcomputer 31 and a rotation monitoring unit 32. A counter circuit 101 of the rotation monitoring part 32 calculates a count value C used for calculating a rotation angle of a multi-turn of a motor based on a detection signal from a rotation angle sensor 41. The microcomputer 31 includes a relative angle calculation unit 33 and a determination unit 35. The determination unit 35 stores a first map M1 indicating a first determination area shifted by a predetermined amount relative to a second determination area for calculating the count value C. Using the first map M1, the determination unit 35 determines abnormality of the count value C based on a relative angle d calculated by the relative angle calculation unit 33 and quadrant information Q calculated by a quadrant determination unit 105.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an angle calculation device.

  The angle calculation device of Patent Document 1 includes a rotation detector that counts the number of multi-turns of a motor based on a detection signal from a rotation angle sensor, and a multi-turn number calculated by the rotation detector and detection from the rotation angle sensor. An MPU (Micro Processing Unit) for calculating a multi-turn rotation angle of the motor based on the signal is provided. The MPU calculates the rotation angle of the motor as a relative angle based on the detection signal detected through the rotation angle sensor, and obtains the number of multi-turns calculated based on the detection signal. The MPU obtains the relative angle and the number of multi-turns in a predetermined calculation cycle, and calculates the multi-turn rotation angle of the motor using the relative angle and the number of multi-turns obtained in the predetermined calculation cycle. Accordingly, the MPU calculates the multi-turn rotation angle of the motor using the relative angle and the number of multi-turns which are basically calculated within a predetermined calculation cycle, that is, based on the detection signal which can be said to be the same timing. are doing.

JP-A-2006-191702

  There may be a delay in transmission of various signals, a shift in processing using the signals, and the like. For example, transmission of a detection signal from the rotation angle sensor to the MPU may be delayed, or transmission of a signal indicating the number of multi-turns from the rotation detector to the MPU may be delayed. In addition, for example, since the circuit characteristics of the rotation detector and the MPU that perform the arithmetic processing of the detection signal are different, there may occur a shift in the processing of delaying the arithmetic processing of the multi-turn number by the rotation detector and the arithmetic processing of the relative angle by the MPU. is there. In such a case, the MPU calculates the multi-turn rotation angle of the motor based on the relative angle and the multi-turn number calculated based on the detection signals at different timings. For this reason, the MPU may not be able to appropriately calculate the multi-turn rotation angle of the motor.

  An angle calculation device that solves the above-mentioned problem includes a first calculation unit that calculates a multi-turn rotation angle of a motor based on a detection signal from a detection unit, and the rotation angle based on the detection signal from the detection unit. And a second calculating unit for calculating rotation speed information that is information indicating the number of multi-turns of the motor, the second calculating unit comprising three or more angular regions. And a quadrant information, which is information indicating an angular area where the rotational position of the motor exists in the second determination area, based on the detection signal. Wherein the first calculation unit stores a first determination area including three or more angle areas shifted by a predetermined amount with respect to the second determination area, and stores the first determination area. 1 is the second operation unit. It said quadrant information obtained from parts, based on the angular region the rotational position of the motor in the first determination area exists based on the detection signal, determines an abnormality of the rotation speed information.

  Due to a delay in transmission of various signals or a deviation in processing using various signals, a deviation may occur between the number of multi-turns indicated by the rotation speed information and the actual number of multi-turns. According to the above configuration, the first calculation unit determines the abnormality of the rotation speed information using the first determination region shifted by a predetermined amount with respect to the second determination region for calculating the rotation speed information. ing. Since the abnormality of the rotation speed information can be determined using the first determination region and the second determination region, the first calculation unit calculates the multi-turn rotation angle of the motor using the abnormal rotation speed information. Can be suppressed.

  In the above angle calculation device, if the first calculation unit does not determine that the rotation speed information is abnormal, the first calculation unit changes the rotation speed information obtained from the second calculation unit based on the detection signal. Is preferred.

  In the above angle calculation device, if the first calculation unit does not determine that the rotation speed information is abnormal, the first calculation unit calculates the rotation speed information stored in the second calculation unit based on the detection signal. It is preferable to change.

  When the first arithmetic unit does not determine the rotation speed information as abnormal, there is no difference between the multi-turn number indicated by the rotation speed information and the actual multi-turn number, which is determined to be abnormal. However, the content of the information held by the first calculation unit may not match the content of the information held by the second calculation unit. According to the above configuration, the first calculation unit calculates the rotation speed information calculated by the second calculation unit based on the detection signal from the detection unit used for calculating the rotation angle in the first calculation unit. Have changed. From this, it is possible to match the content of the rotation speed information calculated by the second calculation unit with the content of the detection signal used for calculating the rotation angle by the first calculation unit.

  In the above angle calculation device, the first calculation unit stores the second determination region, and the first calculation unit is configured to control the motor in the second determination region based on the quadrant information. It is preferable that the rotation speed information is changed such that the angle region where the rotation position exists is the same as the angle region where the rotation position of the motor exists in the second determination region based on the detection signal.

  According to the above configuration, by changing the rotation speed information, the second determination region based on the changed rotation speed information has the angle region where the motor rotational position exists, and the second determination based on the detection signal. The rotation position of the motor in the region can be matched with the angle region where the motor exists. From this, it is possible to match the content of the rotation speed information and the content of the detection signal to be obtained by the first arithmetic unit.

  In the above-described angle calculation device, the number of the angle regions in the first determination region and the number of the angle regions in the second determination region are the same, and the number of the first determination region with respect to the second determination region is It is preferable that the shift of the predetermined amount is a shift of half of one angular area of the second determination area.

  According to the above configuration, the angle area of the first determination area is configured to correspond to the angle area where the rotational position of the motor exists in the second determination area based on the rotation speed information and the adjacent angle area. are doing. From this, if the rotation position of the motor exists in a certain angle region of the first determination region based on the detection signal, and if there is no abnormality in the rotation speed information, the certain rotation region of the first determination region The rotational position of the motor exists in one of the two angle regions of the second determination region corresponding to the above. In setting the first determination area and the second determination area, the number of the angle areas is set to the same number, and further, the correspondence between the angle areas based on the shift of the angle areas is equalized, thereby obtaining the first determination area. The setting of the determination region and the second determination region can be made appropriate.

  In the above-described angle calculation device, the rotation angle and the rotation number information are calculated at a predetermined calculation cycle, and the first calculation unit calculates the current value of the rotation angle and the previous value of the rotation angle. If the amount of change from the value does not exceed a predetermined amount of change determined to be able to calculate the rotation speed information normally, it is determined that the rotation speed information is not abnormal, and the previous rotation angle of the current value of the rotation angle is determined. If the amount of change from the value exceeds a predetermined amount of change that determines that the rotation speed information can be calculated normally, it is preferable to determine that the rotation speed information is abnormal.

  The rotation shaft of the motor may rotate at a high speed due to a large reverse input due to a curb climbing or the like. In such a case, the rotation speed information may not be appropriately transmitted to the first calculation unit. Therefore, according to the configuration described above, the first calculation unit determines that the rotation speed information is abnormal when the change amount of the rotation angle exceeds the predetermined change amount. In some cases, the previous value of the rotation speed information is not adopted as the official rotation speed information. On the other hand, if the change amount of the rotation angle does not exceed the predetermined change amount, the first calculation unit determines that the rotation speed information is not abnormal. The previous value of the information is adopted as formal rotation speed information. This makes it possible to further improve the accuracy of the rotation speed information used for calculating the multi-turn rotation angle of the motor.

  In the above-described angle calculation device, the first calculation unit may determine a change in a current value of the rotation speed information from a previous value of the rotation speed information and a change in a current value of the quadrant information from a previous value of the quadrant information. It is preferable to determine the abnormality of the quadrant information based on the relationship with the change.

  When the rotation speed information changes from the previous value to the current value, the quadrant information should change from the previous value to the current value in a predetermined relationship according to the change in the rotation speed information. Therefore, according to the above configuration, the first arithmetic unit determines that the quadrant information is not abnormal when the quadrant information changes in a predetermined manner with respect to the change in the rotation speed information. If the quadrant information does not change in accordance with the change, it can be determined that the quadrant information is abnormal. Thereby, the accuracy of the quadrant information can be improved.

  According to the angle calculation device of the present invention, it is possible to determine the abnormality of the rotation speed information.

FIG. 2 is a block diagram showing a schematic configuration of a steering device. FIG. 2 is a block diagram showing an electrical configuration of the angle calculation device in the first embodiment. 7 is a graph showing a specific example of a second determination area. 7 is a graph showing a specific example of a first determination area. Relationship between the angle area where the rotation position of the motor rotation axis exists in the first determination area based on the detection signal and the quadrant where the rotation position of the motor rotation axis exists in the second determination area based on the quadrant information FIG. The figure which shows the relationship between the relative angle of the motor calculated based on a detection signal, the quadrant in which the rotational position of the rotating shaft of the motor exists based on quadrant information, and the count correction value which is a correction value with respect to a count value. The figure which shows the relationship between a count value and quadrant information. The figure which shows the relationship between a count value, quadrant information, and a relative angle. When the relative angle is 20 degrees, there is an angle region where the rotation position of the motor rotation axis exists in the first determination region and a rotation position of the motor rotation shaft in the second determination region based on the count value. The figure which shows the relationship with the quadrant which performs. FIG. 9 is a block diagram showing an electrical configuration of an angle calculation device according to the second embodiment. 9 is a graph showing a specific example of a second determination area according to another embodiment. 7 is a graph showing a specific example of a first determination area according to another embodiment. In another embodiment, the rotation angle of the rotation axis of the motor in the first determination area based on the detection signal and the rotation area of the rotation axis of the motor in the second determination area based on the quadrant information are different. The figure which shows the relationship with the existing quadrant. In another embodiment, the relationship between the relative angle of the motor calculated based on the detection signal, the quadrant where the rotational position of the rotation axis of the motor is based on the quadrant information, and the count correction value that is a correction value for the count value. FIG. 9 is a graph showing a specific example of a second determination area according to another embodiment. In another embodiment, the rotation angle of the rotation axis of the motor in the first determination area based on the detection signal and the rotation area of the rotation axis of the motor in the second determination area based on the quadrant information are different. The figure which shows the relationship with the existing quadrant. In another embodiment, the relationship between the relative angle of the motor calculated based on the detection signal, the quadrant where the rotational position of the rotation axis of the motor is based on the quadrant information, and the count correction value that is a correction value for the count value. FIG. FIG. 13 is a block diagram showing an electrical configuration of an angle calculation device according to another embodiment.

<First Embodiment>
Hereinafter, a first embodiment of an angle calculation device mounted on an electric power steering device (hereinafter, referred to as “EPS”) will be described.

  As shown in FIG. 1, the EPS includes a steering mechanism 1 that turns a steered wheel 15 based on an operation of a steering wheel 10 by a driver, and a motor that generates an assisting force for assisting the steering mechanism 1 in steering operation. An actuator 3 having an actuator 20 and an angle calculation device 30 that detects the rotation angle θ of the motor 20 and controls the motor 20 are provided.

  The steering mechanism 1 has a steering shaft 11 to which a steering wheel 10 is connected, and a rack shaft 12 that reciprocates in the axial direction according to the rotation of the steering shaft 11. The steering shaft 11 includes a column shaft 11a connected to the steering wheel 10, an intermediate shaft 11b connected to a lower end of the column shaft 11a, and a pinion shaft 11c connected to a lower end of the intermediate shaft 11b. I have. The rack shaft 12 and the pinion shaft 11c are arranged at a predetermined intersection angle, and the rack and pinion mechanism is formed by meshing the rack teeth formed on the rack shaft 12 with the pinion teeth formed on the pinion shaft 11c. 13 are constituted. A tie rod 14 is connected to both ends of the rack shaft 12, and a tip of the tie rod 14 is connected to a knuckle (not shown) to which the steered wheels 15 are attached. Therefore, in the EPS, the rotational motion of the steering shaft 11 accompanying the steering operation is converted into the axial reciprocating linear motion of the rack shaft 12 via the rack and pinion mechanism 13. The reciprocating linear motion in the axial direction is transmitted to the knuckle via the tie rod 14, whereby the steered angle of the steered wheels 15, that is, the traveling direction of the vehicle is changed.

  The actuator 3 includes a motor 20 and a speed reduction mechanism 21. The rotation shaft 20a of the motor 20 is connected to the column shaft 11a via a speed reduction mechanism 21. The rotation shaft 20a of the motor 20 can make multiple rotations. The reduction mechanism 21 reduces the rotation of the motor 20, and transmits the reduced rotation force to the column shaft 11a. That is, the driver's steering operation is assisted by applying the torque of the motor 20 to the steering shaft 11 as an assisting force (assisting force).

  The angle calculation device 30 controls the motor 20 based on the detection results of various sensors provided on the vehicle. As various sensors, for example, a torque sensor 40 and a rotation angle sensor 41 are provided. The torque sensor 40 is provided on the column shaft 11a. The torque sensor 40 detects a steering torque Th applied to the steering shaft 11 in response to a driver's steering operation. The rotation angle sensor 41 is provided in the motor 20. The rotation angle sensor 41 generates a detection signal for calculating the actual rotation angle θ of the rotation shaft 20a of the motor 20, and outputs the signal as a voltage value. A battery 50, which is a power source of power supplied to the motor 20, is connected to the angle calculation device 30. The angle calculation device 30 calculates the actual rotation angle θ of the motor 20 based on the detection signal generated by the rotation angle sensor 41. As the rotation angle sensor 41, a magnetic sensor that generates a detection signal by detecting magnetism that changes according to the rotation of the rotation shaft 20a of the motor 20 is employed. As the magnetic sensor, for example, an MR sensor (magnetoresistive sensor) is employed. The rotation angle sensor 41 has a bridge circuit composed of two magnetic sensor elements, and each of these magnetic sensor elements generates an electric signal (voltage). The phase of the electric signal generated by one magnetic sensor element is shifted by 90 degrees from the phase of the electric signal generated by the other magnetic sensor element. Therefore, in the first embodiment, the electric signal generated by one magnetic sensor element is regarded as a sine wave signal Ssin, and the electric signal generated by the other magnetic sensor element is regarded as a cosine wave signal Scos. The sine wave signal Ssin and the cosine wave signal Scos are detection signals of the rotation angle sensor 41. The angle calculation device 30 calculates a multi-turn (multi-rotation) rotation angle θ of the motor 20 based on the detection signals (sine wave signal Ssin and cosine wave signal Scos) detected by the rotation angle sensor 41. The angle calculation device 30 sets a target torque to be applied to the steering mechanism 1 based on the output value of each sensor, and supplies the target torque to the motor 20 so that the actual torque of the motor 20 becomes the target torque. Control the power

The configuration of the angle calculation device 30 will be described.
As shown in FIG. 2, the angle calculation device 30 includes a microcomputer 31 and a rotation monitoring unit 32. Note that the microcomputer 31 is an example of a first calculation unit, and the rotation monitoring unit 32 is an example of a second calculation unit. The rotation angle sensor 41 is an example of a detection unit.

  When the ignition switch 51 is turned on, the microcomputer 31 calculates the multi-turn rotation angle θ of the motor 20 and controls the power supplied to the motor 20. The microcomputer 31 calculates the rotation angle θ of the motor 20 at a predetermined calculation cycle. The calculation cycle of the microcomputer 31 is set to a short cycle such that the rotation of the rotating shaft 20a of the motor 20 can be quickly detected. The microcomputer 31 includes, for example, a microprocessing unit or the like. The rotation monitoring unit 32 is connected to the microcomputer 31. The rotation monitoring unit 32 is configured by packaging a logic circuit combining an electronic circuit and a flip-flop. The rotation monitoring unit 32 is a so-called ASIC (application specific integrated circuit). The microcomputer 31 reads a program stored in the storage unit and executes an operation according to the program. The rotation monitoring unit 32 performs a predetermined output with respect to a specific input (here, a detection signal of the rotation angle sensor 41).

  The rotation monitoring unit 32 is provided with a power supply circuit 100 that steps down a supply voltage which is power supplied from the battery 50 and supplies a constant voltage. Between the battery 50 and the power supply circuit 100, an ignition switch 51 for switching between energization and cutoff of power supplied from the battery 50 is provided. When the driver operates a switch provided on the vehicle, the ignition switch 51 is switched on and off. When the ignition switch 51 is turned on, an ON signal is input to the power supply circuit 100, and power is supplied between the battery 50 and the power supply circuit 100 through the ignition switch 51. When the ignition switch 51 is turned off, an off signal is input to the power supply circuit 100, and power is cut off between the battery 50 and the power supply circuit 100 through the ignition switch 51.

  When electric power is supplied between the battery 50 and the power supply circuit 100 through the ignition switch 51, the electric power is supplied to the microcomputer 31. That is, when the ignition switch 51 is turned on, power is supplied to the microcomputer 31 and the microcomputer 31 operates. On the other hand, when power is cut off between the battery 50 and the power supply circuit 100 through the ignition switch 51, no power is supplied to the microcomputer 31. That is, when the ignition switch 51 is turned off, power is not supplied to the microcomputer 31 and the microcomputer 31 stops operating.

  The battery 50 is directly connected to the power supply circuit 100. That is, power is constantly supplied to the rotation monitoring unit 32 from the battery 50 regardless of whether the ignition switch 51 is on or off. A rotation angle sensor 41 is connected to the rotation monitoring unit 32. The rotation angle sensor 41 is also connected to the microcomputer 31.

  The rotation monitoring unit 32 includes a counter circuit 101 and a communication interface 102. The counter circuit 101 is always supplied with power from the battery 50 regardless of whether the ignition switch 51 is on or off. When the ignition switch 51 is turned on, power is supplied from the battery 50 to the communication interface 102.

  The counter circuit 101 acquires detection signals (sine wave signal Ssin and cosine wave signal Scos) generated by the rotation angle sensor 41 as voltage values. The counter circuit 101 calculates a count value C used for calculating a multi-turn rotation angle θ of the motor 20 based on the detection signal. The count value C is rotation number information indicating a multi-turn number (multi-rotation number) of the motor 20. In the first embodiment, the count value C is information indicating how many times the rotation position of the rotation shaft 20a of the motor 20 has rotated with respect to its reference position (neutral position).

  The counter circuit 101 includes an amplifier 103, a comparator 104, a quadrant determination unit 105, a counter 106, a previous count output circuit 107, and a counter comparison circuit 108.

  The amplifier 103 acquires detection signals (sine wave signal Ssin and cosine wave signal Scos) generated by the rotation angle sensor 41 as voltage values. The amplifier 103 amplifies the voltage value acquired from the rotation angle sensor 41, and outputs the amplified voltage value to the comparator 104.

  The comparator 104 outputs a Hi-level signal when the voltage value generated by the rotation angle sensor 41 (a voltage value amplified by the amplifier 103) is higher than a set threshold value, and outputs a Lo level signal when the voltage value is lower than the set threshold value. Generate. This threshold is set to, for example, “0”. That is, the comparator 104 generates a Hi level signal when the voltage value (the voltage value amplified by the amplifier 103) is positive, and generates a Lo level signal when the voltage value is negative.

  The quadrant judging unit 105 determines, based on a combination of the Hi-level signal and the Lo-level signal generated by the comparator 104, in which of the four possible quadrants the rotational position of the rotation shaft 20a of the motor 20 is located. Is determined. The reference position of the rotation shaft 20a of the motor 20 is, for example, the rotation position of the rotation shaft 20a of the motor 20 when the steering wheel 10 is at the neutral position, and the rotation angle θ at this time is, for example, “0” degrees.

  As shown in FIG. 3, one rotation (360 degrees) of the rotation shaft 20 a of the motor 20 is divided into four rotations by 90 degrees from a combination of the Hi-level signal and the Lo-level signal, that is, a positive / negative combination of the detection signals. Divided into quadrants. The rotation monitoring unit 32 stores a second determination area A2 including these four quadrants. The second determination area A2 is specifically as follows.

  The first quadrant is a quadrant when both the sine wave signal Ssin and the cosine wave signal Scos are at the Hi level. When the rotation position of the rotation shaft 20a of the motor 20 is in the first quadrant, the rotation angle θ of the motor 20 is in the range of 0 to 90 degrees.

  The second quadrant is a quadrant when the sine wave signal Ssin is at the Hi level and the cosine wave signal Scos is at the Lo level. When the rotation position of the rotation shaft 20a of the motor 20 is in the second quadrant, the rotation angle θ of the motor 20 is in the range of 90 to 180 degrees.

  The third quadrant is a quadrant when both the sine wave signal Ssin and the cosine wave signal Scos are at the Lo level. When the rotation position of the rotation shaft 20a of the motor 20 is in the third quadrant, the rotation angle θ of the motor 20 is in the range of 180 to 270 degrees.

  The fourth quadrant is a quadrant when the sine wave signal Ssin is at the Lo level and the cosine wave signal Scos is at the Hi level. When the rotation position of the rotation shaft 20a of the motor 20 is in the fourth quadrant, the rotation angle θ of the motor 20 is in the range of 270 to 360 degrees.

  As shown in FIG. 2, the quadrant determination unit 105 uses the information indicating the quadrant where the rotation position of the rotation shaft 20 a of the motor 20 exists based on the Hi-level signal and the Lo-level signal generated by the comparator 104. Generate certain quadrant information Q. The quadrant determination unit 105 generates the left rotation flag Fl or the right rotation flag Fr based on a change in the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 indicated by the quadrant information Q exists. It is assumed that the quadrant determining unit 105 has rotated by a unit rotation amount (90 degrees) each time the quadrant in which the rotational position of the rotation shaft 20a of the motor 20 is present changes to an adjacent quadrant. The rotation direction of the rotation shaft 20a of the motor 20 is determined based on the relationship between the quadrant where the rotation position of the rotation shaft 20a of the motor 20 exists before the rotation of the motor 20 and the quadrant that exists after the rotation of the motor 20. To identify. If the quadrant in which the rotational position of the rotation shaft 20a of the motor 20 is present changes from the first quadrant to the second quadrant, for example, the quadrant changes in the counterclockwise direction, the quadrant determination unit 105 Generate Fl. When the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 is present changes from the first quadrant to the fourth quadrant, for example, the quadrant changes in the clockwise direction, the quadrant determination unit 105 outputs the right rotation flag Fr. Generate

  The counter 106 calculates the count value C based on the left rotation flag Fl or the right rotation flag Fr acquired by the quadrant determination unit 105. The counter 106 is a logic circuit combining flip-flops and the like. The count value C indicates the number of times the rotation position of the rotation shaft 20a of the motor 20 has rotated by a unit rotation amount (90 degrees) with respect to the reference position. The counter 106 increments (increases the count value C by 1) each time the left rotation flag Fl is obtained from the quadrant determination unit 105, and decrements (counts 1 by 1) each time the right rotation flag Fr is obtained from the quadrant determination unit 105. Subtraction). As described above, the counter 106 calculates the count value C every time a detection signal is generated from the rotation angle sensor 41, and stores the count value C. The count value C calculated by the counter 106 is output to the previous count output circuit 107, the counter comparison circuit 108, and the communication interface 102.

  The previous count output circuit 107 holds the input count value C for at least two calculation cycles. That is, the previous count value output circuit 107 holds not only the count present value Cn, which is the count value C of the current calculation cycle, but also the count last value Cn-1, which is the count value C of the previous calculation cycle. Then, each time the count value C of the current calculation cycle is input, the previous count value output circuit 107 outputs the previous count value Cn-1 of the previous calculation cycle to the counter comparison circuit 108.

  The counter comparison circuit 108 outputs the left rotation flag Fl or the right rotation flag Fr obtained by the quadrant determination unit 105, the count value C (the current count value Cn) calculated by the counter 106, and the count previous value output circuit 107. An abnormality of the counter 106 is determined based on the previous count value Cn-1. Specifically, the counter comparing circuit 108 determines whether the difference between the current count value Cn and the previous count value Cn−1 is the motor 20 indicated by the left rotation flag Fl or the right rotation flag Fr acquired by the quadrant determination unit 105. When the counter 106 does not match the rotation direction, a counter error flag Fc indicating that an error has occurred in the counter 106 is generated. For example, when there is a difference between the current count value Cn and the previous count value Cn−1 even though the motor 20 is not rotating, the counter comparison circuit 108 generates the counter abnormality flag Fc. On the other hand, if the difference between the current count value Cn and the previous count value Cn−1 is in accordance with the rotation direction of the motor 20 indicated by the left rotation flag Fl or the right rotation flag Fr, the counter comparison circuit 108 No abnormality flag Fc is generated.

  Each time the ignition switch 51 is turned on, the communication interface 102 outputs the count value C stored in the counter 106, the quadrant information Q generated by the quadrant determination unit 105, and the counter abnormality flag Fc to the microcomputer 31. On the other hand, the communication interface 102 does not operate when the ignition switch 51 is turned off.

  The power supply circuit 100 grasps on / off of the ignition switch 51 based on the input ON signal or OFF signal. When the ignition switch 51 is turned on, the power supply circuit 100 intermittently supplies power to the rotation angle sensor 41 and the counter circuit 101 using electric power constantly supplied from the battery 50. On the other hand, when the ignition switch 51 is turned on, the power supply circuit 100 uses the power that is constantly supplied from the battery 50, as compared with the case where the ignition switch 51 is turned off. The current is intermittently applied to the 101 at a short cycle. As a result, the power supply circuit 100 operates the rotation angle sensor 41 and the counter circuit 101 intermittently at a predetermined cycle to intermittently calculate the count value C. This predetermined cycle is set to a size that does not overlook that the rotation shaft 20a of the motor 20 has rotated by the unit rotation amount (90 degrees).

  The microcomputer 31 acquires the count value C calculated by the rotation monitoring unit 32 every time the ignition switch 51 is turned on. The microcomputer 31 calculates the count value C acquired when the ignition switch 51 is turned on until the ignition switch 51 is turned off, based on a change in the detection signal generated by the rotation angle sensor 41, and determines whether or not the microcomputer 31 itself has been turned on. Is updated at a predetermined calculation cycle. The microcomputer 31 updates the count value C by incrementing the count value C (adding the count value C by 1) every time the relative angle d calculated using the detection signal changes in the counterclockwise direction by a unit rotation amount (90 degrees). Each time the relative angle d changes in the clockwise direction by the unit rotation amount (90 degrees), the count value C is decremented (the count value C is decremented by 1) and updated. That is, in the present embodiment, the count value C is individually updated by the microcomputer 31 and the rotation monitoring unit 32 while the ignition switch 51 is turned on. Further, the microcomputer 31 acquires a detection signal generated by the rotation angle sensor 41 at a predetermined calculation cycle. The microcomputer 31 calculates a multi-turn rotation angle θ of the motor 20 based on the acquired count value C and the detection signal. More specifically, the microcomputer 31 has a relative angle calculation unit 33 that calculates an arc tangent from two detection signals generated by the rotation angle sensor 41 to calculate the rotation angle of the motor 20 with the relative angle d. The relative angle d represents the rotation angle of the motor 20 within a range of 0 to 360 degrees. Further, the microcomputer 31 performs a multi-turn operation of the motor 20 based on the count value C calculated by the rotation monitoring unit 32 (specifically, a changed count value Cc described later) and the relative angle d calculated by the relative angle calculation unit 33. Has a rotation angle calculation unit 34 for calculating the rotation angle θ. The rotation angle calculation unit 34 determines how many rotations of the rotation shaft 20a of the motor 20 are performed in one rotation (360 degrees) based on the count value C (specifically, a changed count value Cc described later). The rotation angle calculation unit 34 adds a value obtained by multiplying the multi-turn number of the rotation shaft 20a of the motor 20 based on the count value C (the changed count value Cc) by 360 degrees to the relative angle d. , The multi-turn rotation angle θ (absolute angle) of the motor 20 is calculated. The microcomputer 31 can also calculate the steering absolute rotation angle from the multi-turn rotation angle θ of the motor 20 in consideration of the reduction ratio of the reduction mechanism 21 interposed between the motor 20 and the steering shaft 11. it can. The angle calculation device 30 controls the power supplied to the motor 20 by using the multi-turn rotation angle θ of the motor 20 obtained in this manner.

  Incidentally, transmission of various signals may be delayed, and processing using various signals may be shifted. For example, transmission of the detection signal from the rotation angle sensor 41 to the microcomputer 31 may be delayed, or transmission of the count value C from the rotation monitoring unit 32 to the microcomputer 31 may be delayed. Further, there are variations in circuit characteristics of the microcomputer 31 and the rotation monitoring unit 32, that is, characteristics of hardware. As a result, there may be a shift in processing such as a delay in the calculation processing of the count value C by the rotation monitoring unit 32 and the calculation processing of the relative angle d by the microcomputer 31. In such a case, the microcomputer 31 receives the count value C of a calculation cycle different from the detection signal generated by the rotation angle sensor 41, and may calculate the multi-turn rotation angle θ of the motor 20. Therefore, the microcomputer 31 is provided with a determination unit 35 that determines the abnormality of the count value C each time the count value C is obtained, and changes the count value C based on the relative angle d calculated using the detection signal. ing.

  The determination unit 35 acquires the relative angle d calculated by the relative angle calculation unit 33, the quadrant information Q calculated by the quadrant determination unit 105, the count value C calculated by the counter circuit 101, and the counter abnormality flag Fc. The timing at which the determination unit 35 of the microcomputer 31 acquires the quadrant information Q and the count value C from the rotation monitoring unit 32 is the same. The determination unit 35 determines whether the count value C is abnormal based on the relative angle d and the quadrant information Q. Specifically, the determination unit 35 determines the abnormality of the count current value Cn of the current calculation cycle based on the relative angle current value dn of the current calculation cycle and the quadrant information current value Qn. The determination unit 35 stores a first map M1 indicating a first determination area A1 including four angle areas.

  FIG. 4 shows the first determination area A1. From the combination of the sine wave signal Ssin and the cosine wave signal Scos, that is, the combination of the detection signals, the first determination area A1 determines one rotation (360 degrees) of the rotation shaft 20a of the motor 20 by four angles every 90 degrees. It is divided into regions. The determination unit 35 determines that the rotation shaft 20a of the motor 20 is rotated by a unit rotation amount (90 degrees) each time the angle region where the rotation position of the rotation shaft 20a of the motor 20 is present changes to an adjacent angle region. Shall be. The first determination area A1 is shifted from the second determination area A2 by a predetermined amount. The predetermined amount is set in consideration of an allowable shift of the count value C and the quadrant information Q due to a shift between transmission of various signals (information) and processing using the various signals. The count value C calculated by the counter circuit 101 and the quadrant information Q calculated by the quadrant determination unit 105 are converted into a relative angle calculation unit due to a delay in transmission of various signals and a shift in processing using various signals. The angle calculation device 30 is designed so as to allow the count value and the quadrant information when the angle is shifted by not more than 45 degrees from the relative angle d calculated by 33. Therefore, in the first embodiment, the first determination area A1 is configured to be shifted clockwise by 45 degrees with respect to the second determination area A2. The four angle areas of the first determination area A1 are specifically as follows.

  The first angle region is a quadrant when the relative angle d of the motor 20 is in a range of 315 to 45 degrees. In this case, the sine wave signal Ssin is equal to or less than the negative threshold value -Ths and the cosine wave signal Scos is equal to or greater than the positive threshold value Thc, and the sine wave signal Ssin is less than the positive threshold value Ths and the cosine wave signal Scos is greater than the positive threshold value Thc. . When the relative angle d of the motor 20 is in the range of 315 to 45 degrees, the rotation position of the rotation shaft 20a of the motor 20 is within the first angle region.

  Note that the positive threshold Ths is a voltage value as a sine wave signal Ssin to be detected when the relative angle d is 45 degrees, and the negative threshold Ths is detected when the relative angle d is -45 degrees. This is a voltage value as a sine wave signal Ssin to be obtained. The positive threshold Thc is a voltage value as the cosine wave signal Scos to be detected when the relative angle d is 45 degrees, and the negative threshold Thc is detected when the relative angle d is 135 degrees. This is a voltage value as a power cosine wave signal Scos. Each of these thresholds is obtained experimentally or theoretically.

  The second angle region is a quadrant when the relative angle d of the motor 20 is in a range of 45 to 135 degrees. In this case, the sine wave signal Ssin is greater than or equal to the positive threshold Ths and the cosine wave signal Scos is less than or equal to the positive threshold Thc, and the sine wave signal Ssin is greater than the positive threshold Ths and the cosine wave signal Scos is greater than the negative threshold -Thc. Is also big. When the relative angle d of the motor 20 is in the range of 45 to 135 degrees, the rotation position of the rotation shaft 20a of the motor 20 is within the second angle range.

  The third angle region is a quadrant when the relative angle d of the motor 20 is in the range of 135 to 225 degrees. In this case, the sine wave signal Ssin is equal to or less than the positive threshold value Ths and the cosine wave signal Scos is equal to or less than the negative threshold value -Thc, and the sine wave signal Ssin is larger than the negative threshold value -Ths and the cosine wave signal Scos is the negative threshold value. It is smaller than Thc. When the relative angle d of the motor 20 is in the range of 135 to 225 degrees, the rotation position of the rotation shaft 20a of the motor 20 is within the third angle range.

  The fourth angle area is a quadrant when the relative angle d of the motor 20 is in the range of 225 to 315 degrees. In this case, the sine wave signal Ssin is less than the negative threshold value -Ths and the cosine wave signal Scos is more than the negative threshold value -Thc, and the sine wave signal Ssin is less than the negative threshold value -Ths and the cosine wave signal Scos is greater than the positive threshold value Thc. small. When the relative angle d of the motor 20 is in the range of 225 to 315 degrees, the rotation position of the rotation shaft 20a of the motor 20 is within the fourth angle range.

  As shown in FIG. 2, the determination unit 35 of the microcomputer 31 stores a first map M1 shown in FIG. 5 and a second map M2 shown in FIG. The second map M2 has the same angle region as the second determination region A2. That is, since the determination unit 35 stores the second map M2, the determination unit 35 also stores the second determination area A2 included in the second map M2. The quadrant information Q is closely related to the count value C. When the quadrant information Q is abnormal, it can be said that the count value C is also abnormal. For this reason, the determination unit 35 determines abnormality of the count value C based on the quadrant information Q using the first map M1. When the determination unit 35 does not determine the abnormality of the count value C, the count value acquired from the counter circuit 101 of the rotation monitoring unit 32 based on the relative angle d (detection signal) using the second map M2. Change C.

  FIG. 5 shows the first map M1. The first map M1 includes an angle area where the rotation position of the rotation shaft 20a of the motor 20 exists in the first determination area A1 based on the relative angle d (detection signal), and a second determination based on the quadrant information Q. The relationship between the rotation position of the rotation shaft 20a of the motor 20 in the area A2 and the existing quadrant is shown. The determination unit 35 stores a combination that is not abnormal in the angle area and the quadrant and a combination that is abnormal in the angle area and the quadrant. The relationship between the angle regions and the quadrants shown in the first map M1 is specifically as follows.

  When the relative angle d of the motor 20 is in a range of 315 to 45 degrees (0 degree ≦ d <45 degrees, 315 degrees ≦ d <360 degrees), that is, the rotation position of the rotation shaft 20a of the motor 20 is within the first angle range. , The non-abnormal quadrants are the first and fourth quadrants, and the abnormal quadrants are the second and third quadrants. The non-abnormal quadrant is a quadrant corresponding to the quadrant information Q when the quadrant determining section 105 generates the non-abnormal quadrant information Q. An abnormal quadrant is a quadrant that is not a quadrant corresponding to the quadrant information Q when the quadrant information Q that is not abnormal is calculated by the quadrant determination unit 105, and the rotational position of the rotating shaft 20a of the motor 20 exists. It is a quadrant that cannot be obtained. The count value C and the quadrant information Q are allowed to include a deviation of less than 45 degrees as a predetermined amount of deviation from the relative angle d. In this case, the rotation position of the rotating shaft 20a of the motor 20 is located in the quadrant where the rotation is abnormal.

  When the relative angle d of the motor 20 is in the range of 45 to 135 degrees (45 degrees ≦ d <135 degrees), that is, when the rotation position of the rotation shaft 20a of the motor 20 is within the second angle range, the abnormality is abnormal. The missing quadrants are the first and second quadrants, and the abnormal quadrants are the third and fourth quadrants.

  When the relative angle d of the motor 20 is in the range of 135 to 225 degrees (135 degrees d <225 degrees), that is, when the rotation position of the rotation shaft 20a of the motor 20 is within the third angle range, an abnormality is determined. The missing quadrants are the second and third quadrants, and the abnormal quadrants are the first and fourth quadrants.

  When the relative angle d of the motor 20 is in the range of 225 to 315 degrees (225 degrees d <315 degrees), that is, when the rotation position of the rotation shaft 20a of the motor 20 is within the fourth quadrant, it is not abnormal. The quadrants are the third and fourth quadrants, and the abnormal quadrants are the first and second quadrants.

  As shown in FIG. 2, the microcomputer 31 has a previous value output circuit 36 and a relative angle previous value output circuit 37. The previous value output circuit 36 holds the count value C and the quadrant information Q input to the microcomputer 31 for at least two calculation cycles. That is, the previous value output circuit 36 holds not only the count present value Cn, which is the count value C of the current calculation cycle, but also the count previous value Cn-1, which is the count value C of the previous calculation cycle. The previous value output circuit 36 outputs the previous value of the count Cn−1, which is the previous value, to the determination unit 35 each time the count value C of the current calculation cycle is input. The previous value output circuit 36 holds not only the quadrant information current value Qn, which is the quadrant information Q of the current calculation cycle, but also the previous quadrant information Qn-1, which is the quadrant information Q of the previous calculation cycle. The previous value output circuit 36 outputs the previous value of the previous quadrant information Qn-1 to the determination unit 35 each time the quadrant information Q of the current calculation cycle is input.

  The relative angle previous value output circuit 37 holds the relative angle d calculated by the relative angle calculation unit 33 for at least two calculation cycles. That is, the relative angle previous value output circuit 37 holds not only the relative angle present value dn which is the relative angle d of the current calculation cycle but also the relative angle previous value dn-1 which is the relative angle d of the previous calculation cycle. . Then, the relative angle previous value output circuit 37 outputs the previous relative angle value dn-1, which is the previous value, to the determination unit 35 each time the relative angle d in the current calculation cycle is input.

  The determination unit 35 includes a count current value Cn that is a count value C of the current calculation cycle calculated by the counter 106, a quadrant information current value Qn that is quadrant information Q of the current calculation cycle calculated by the quadrant determination unit 105, And the counter abnormality flag Fc. Further, the determination unit 35 calculates the relative angle current value dn, which is the relative angle d of the current calculation cycle calculated by the relative angle calculation unit 33, the count previous value Cn−1 output by the previous value output circuit 36, and the quadrant The previous information value Qn-1 and the previous relative angle value dn-1 output by the previous relative angle output circuit 37 are acquired.

  FIG. 7 shows a third map M3 stored in the determination unit 35. The third map M3 shows the relationship between the change of the current count value Cn from the previous count value Cn-1 and the change of the current quadrant information value Qn from the previous quadrant information value Qn-1. The determination unit 35 stores a combination of abnormal quadrant information Q corresponding to a change in the current count value Cn from the previous count value Cn-1. The relationship between the change in the count value C and the change in the quadrant information Q shown in the third map M3 is specifically as follows.

  When the previous count value Cn-1 which is the count value C of the previous calculation cycle is "4R + 1" (R is an arbitrary integer), the current count value Cn of the next cycle is "(4R + 1) +1", It takes one of the values “4R + 1” and “(4R + 1) −1”. When the current count value Cn is “(4R + 1) +1” and the previous count value Cn−1 is “4R + 1”, the quadrant of the previous calculation cycle is the first quadrant, and the quadrant that is not abnormal in the current calculation cycle is The quadrant that is the second quadrant and is abnormal in the current operation cycle is the first quadrant, the third quadrant, and the fourth quadrant. The non-abnormal quadrant corresponds to, for example, a quadrant where the quadrant corresponding to the quadrant information Q has not changed when the count value C has not changed, or a quadrant information Q where the count value C has changed. This is a quadrant when the quadrant is located at a position corresponding to the change in the count value C. The abnormal quadrant is, for example, a quadrant when the quadrant corresponding to the quadrant information Q has changed from the previous cycle even though the count value C has not changed, or even though the count value C has changed. First, the quadrant corresponding to the quadrant information Q has not changed from the previous cycle. When the current count value Cn is “4R + 1” and the previous count value Cn−1 is “4R + 1”, the quadrant of the previous calculation cycle is the first quadrant, and the quadrant that is not abnormal in the current calculation cycle is the fourth quadrant. The quadrant that is one quadrant and is abnormal in the current operation cycle is the second quadrant, the third quadrant, and the fourth quadrant. When the current count value Cn is "(4R + 1) -1" and the previous count value Cn-1 is "4R + 1", the quadrant of the previous calculation cycle is the first quadrant. The missing quadrant is the fourth quadrant, and the quadrants that are abnormal in the current operation cycle are the first quadrant, the second quadrant, and the third quadrant.

  When the count previous value Cn-1 of the previous calculation cycle is "4R + 2", the count present value Cn of the next cycle is any one of "(4R + 2) +1", "4R + 2", and "(4R + 2) -1". Value. When the current count value Cn is “(4R + 2) +1” and the previous count value Cn−1 is “4R + 2”, the quadrant of the previous computation cycle is the second quadrant, and the quadrant that is not abnormal in the current computation cycle is The third quadrant, in which the current operation cycle is abnormal, is the first quadrant, the second quadrant, and the fourth quadrant. If the current count value Cn is “4R + 2” and the previous count value Cn−1 is “4R + 2”, the quadrant of the previous calculation cycle is the second quadrant, and the quadrant that is not abnormal in the current calculation cycle is the second quadrant. The quadrants in which the current operation cycle is abnormal are the first quadrant, the third quadrant, and the fourth quadrant. When the current count value Cn is “(4R + 2) −1” and the previous count value Cn−1 is “4R + 2”, the quadrant of the previous calculation cycle is the second quadrant, which is not an abnormality of the current calculation cycle. Is the first quadrant, and the quadrants in which the current calculation cycle is abnormal are the second, third, and fourth quadrants.

  When the count previous value Cn-1 of the previous calculation cycle is "4R + 3", the count present value Cn of the next cycle is any one of "(4R + 3) +1", "4R + 3", and "(4R + 3) -1". Value. If the current count value Cn is “(4R + 3) +1” and the previous count value Cn−1 is “4R + 3”, the quadrant of the previous computation cycle is the third quadrant, and the quadrant that is not abnormal in the current computation cycle is The fourth quadrant, in which the current operation cycle is abnormal, is a first quadrant, a second quadrant, and a third quadrant. If the current count value Cn is “4R + 3” and the previous count value Cn−1 is “4R + 3”, the quadrant of the previous calculation cycle is the third quadrant, and the quadrant that is not abnormal this time is the third quadrant. The quadrants in which the current calculation cycle is abnormal are the first quadrant, the second quadrant, and the fourth quadrant. When the current count value Cn is “(4R + 3) −1” and the previous count value Cn−1 is “4R + 3”, the quadrant of the previous calculation cycle is the third quadrant, which is not abnormal in the current calculation cycle. Is the second quadrant, and the quadrants in which the current calculation cycle is abnormal are the first quadrant, the third quadrant, and the fourth quadrant.

  If the previous count value Cn-1 of the previous calculation cycle is "4R", the current count value Cn of the next cycle takes one of "4R + 1", "4R", and "4R-1". Become. When the current count value Cn is “4R + 1” and the previous count value Cn−1 is “4R”, the quadrant of the previous calculation cycle is the fourth quadrant, and the quadrant that is not abnormal in the current calculation cycle is the first quadrant. And the quadrants in which the current calculation cycle is abnormal are the second quadrant, the third quadrant, and the fourth quadrant. When the current count value Cn is “4R” and the previous count value Cn−1 is “4R”, the quadrant of the previous calculation cycle is the fourth quadrant, and the quadrant that is not abnormal in the current calculation cycle is the fourth quadrant. The quadrants in which the current operation cycle is abnormal are the first quadrant, the second quadrant, and the third quadrant. When the current count value Cn is “4R−1” and the previous count value Cn−1 is “4R”, the quadrant of the previous computation cycle is the fourth quadrant, and the quadrant that is not abnormal in the current computation cycle is the fourth quadrant. There are three quadrants, and the quadrants in which the current calculation cycle is abnormal are a first quadrant, a second quadrant, and a fourth quadrant.

  As shown in FIG. 2, the determination unit 35 uses such a third map M3 to count the current value Cn, the previous value Cn-1, the current quadrant information value Qn, and the previous quadrant information value Qn-1. , It is determined whether or not the count value C and the quadrant information Q have an appropriate relationship. When the count value C and the quadrant information Q are not in an appropriate relationship, it is considered that either the count value C or the quadrant information Q is abnormal. Even when the count value C and the quadrant information Q are not in an appropriate relationship, when the counter abnormality flag Fc is not generated, the counter comparison circuit 108 confirms that the counter 106 has no abnormality. Therefore, there is a higher possibility that the abnormality has occurred in the quadrant information Q than the possibility that the count value C has an abnormality. Therefore, when the counter abnormality flag Fc is not generated, the determination unit 35 determines that the quadrant information Q is abnormal when the count value C and the quadrant information Q are not in a proper relationship, and determines that the count value C and the quadrant information When Q has a proper relationship, it is determined that the quadrant information Q is not abnormal.

  Specifically, the determination unit 35 determines that the change in the current count value Cn from the previous count value Cn-1 does not correspond to the change in the current quadrant information value Qn from the previous quadrant information value Qn-1. It is determined that an abnormality has occurred in the information Q. On the other hand, if the change of the current count value Cn from the previous count value Cn−1 is in accordance with the change of the current quadrant information value Qn from the previous quadrant information value Qn−1, the determination unit 35 It is determined that no abnormality has occurred. For example, when there is a difference between the current count value Cn and the previous count value Cn−1, the determination unit 35 determines that the current quadrant information value Qn has not changed from the previous quadrant information value Qn−1. It is determined that an abnormality has occurred in the quadrant information Q.

  The determination unit 35 calculates the relative angle current value dn, which is the relative angle d of the current calculation cycle calculated by the relative angle calculation unit 33, and the relative angle previous value dn-1 output by the relative angle previous value output circuit 37. Based on this, the amount of change in the relative angle current value dn from the previous relative angle value dn-1 is calculated. The determination unit 35 determines that the count current value Cn is not abnormal when the change amount of the relative angle current value dn from the previous relative angle value dn-1 does not exceed a predetermined change amount determined that the count value C can be normally calculated. Is determined. On the other hand, the determination unit 35 determines that the current count value Cn is abnormal when the change amount of the current relative angle value dn from the previous relative angle value dn-1 exceeds a predetermined change amount. The determination unit 35 determines whether or not the change amount of the relative angle previous value dn-1 from the relative angle last time value which is the relative angle d of the last two calculation periods in the previous calculation period exceeds a predetermined change amount. The abnormality of the previous count value Cn-1 is determined. Therefore, when the amount of change of the relative angle current value dn from the previous relative angle value dn-1 exceeds the predetermined amount of change, the amount of change of the relative angle previous value dn-1 from the previous relative angle value is changed by the predetermined amount. If not, it is possible to determine that the relative angle current value dn is abnormal, not the relative angle previous value dn-1.

  As shown in FIGS. 2 and 8, the determination unit 35 determines whether the quadrant information Q is abnormal based on the count value C and the quadrant information Q (arrow A1 in FIG. 8), and based on the relative angle d and the quadrant information Q. 8 (arrow A2 in FIG. 8), determination of high-speed rotation of the rotating shaft 20a of the motor 20 based on the current relative angle value dn and the previous relative angle value dn-1 (arrow in FIG. 8). Execute A3). Note that the predetermined change amount is set to 45 degrees corresponding to a shift of 45 degrees at which the count value C and the quadrant information Q are allowed to deviate from the relative angle d. The predetermined amount of change is set based on the amount of change of the relative angle d corresponding to the rotation speed of the rotation shaft 20a of the motor 20 such that the count value C and the quadrant information Q can be appropriately transmitted from the rotation monitoring unit 32 to the microcomputer 31. ing. In addition, when the above-described three abnormalities are repeatedly determined at predetermined intervals, the specified change amount is determined by the rotation axis of the motor 20 that can correctly transmit the count value C and the quadrant information Q from the rotation monitoring unit 32 to the microcomputer 31. The setting is made in consideration of the viewpoint of the rotation speed of 20a. For example, in the determination of the abnormality of the count value C based on the relative angle d and the quadrant information Q, even if it is determined that the count value C is not abnormal when the rotation shaft 20a of the motor 20 is not rotating, This is because the count value C may be determined to be abnormal in a situation where the rotating shaft 20a is rotating. Therefore, even if it is temporarily determined that the count value C is not abnormal in the determination of the count value C based on the relative angle d and the quadrant information Q, the predetermined change amount is determined by the rotational speed of the rotating shaft 20a of the motor 20. In consideration of the above, the setting is made from the viewpoint of determining whether there is a situation where it is determined that there is no abnormality continuously in all calculation cycles. The predetermined amount of change is experimentally obtained based on these viewpoints.

  If the determination unit 35 determines that no abnormality has occurred in the count value C and the quadrant information Q in any of the three abnormality determinations, the determination unit 35 adopts the previous count value Cn-1 as the official count value C, and The count value C is changed using the second map M2.

  When the count value C needs to be changed, the quadrant information Q also needs to be changed. Therefore, the determination unit 35 also changes the quadrant information Q using the second map M2, similarly to the count value C.

  FIG. 6 shows a second map M2. The second map M2 includes a correction for the relative angle d of the motor 20 calculated based on the detection signal, a quadrant in which the rotation position of the rotary shaft 20a of the motor 20 exists based on the quadrant information Q, and a count value C. The relationship with the count correction value as a value is shown. The relationship between the relative angle d, the quadrant, and the count correction value shown in the second map M2 is specifically as follows.

  When the relative angle d of the motor 20 is within the range of the first quadrant referred to in the second determination area A2 (0 degrees d <90 degrees), the rotational position of the rotation shaft 20a of the motor 20 based on the quadrant information Q is located. If the quadrant information Q is not abnormal, the quadrant is one of the first quadrant, the second quadrant, and the fourth quadrant. When the relative angle d is 0 to 90 degrees, when the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the fourth quadrant, the correction value for increasing or decreasing the count value C is used. A certain count correction value is “1”. In this case, the quadrant information correction value, which is a correction value for increasing or decreasing the quadrant information Q, is a value that changes the quadrant in which the rotational position of the rotary shaft 20a of the motor 20 based on the quadrant information Q exists in a counterclockwise direction. Become. When the relative angle d is 0 to 90 degrees and the quadrant information Q indicates that the rotation position of the rotating shaft 20a of the motor 20 is located in the first quadrant, the count correction value is “0”. It becomes. In this case, the quadrant information correction value is a value that does not directly change the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists. When the relative angle d is 0 to 90 degrees and the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the second quadrant, the count correction value is “−1”. ". In this case, the quadrant information correction value is a value that changes the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists in the clockwise direction.

  When the relative angle d of the motor 20 is in the range of the second quadrant in the second determination area A2 (90 degrees ≦ d <180 degrees), the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q is located. If the quadrant information Q is not abnormal, the quadrant is one of the first quadrant, the second quadrant, and the third quadrant. When the relative angle d is 90 to 180 degrees and the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the first quadrant, the count correction value is “1”. . In this case, the quadrant information correction value is a value that changes the quadrant where the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists in the counterclockwise direction. When the relative angle d is 90 to 180 degrees and the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the second quadrant, the count correction value is “0”. Becomes In this case, the quadrant information correction value is a value that does not directly change the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists. When the relative angle d is 90 to 180 degrees and the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the third quadrant, the count correction value is “−1”. ". In this case, the quadrant information correction value is a value that changes the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists in the clockwise direction.

  When the relative angle d of the motor 20 is in the range of the third quadrant in the second determination area A2 (180 degrees ≦ d <270 degrees), the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q is located. If the quadrant information Q is not abnormal, the quadrant is one of three quadrants, a second quadrant, a third quadrant, and a fourth quadrant. When the relative angle d is 180 to 270 degrees, when the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the second quadrant, the count correction value is “1”. . In this case, the quadrant information correction value is a value that changes the quadrant where the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists in the counterclockwise direction. When the relative angle d is 180 to 270 degrees, when the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the third quadrant, the count correction value is “0”. Becomes In this case, the quadrant information correction value is a value that does not directly change the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists. When the relative angle d is 180 to 270 degrees and the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the fourth quadrant, the count correction value is "-1". ". In this case, the quadrant information correction value is a value that changes the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists in the clockwise direction.

  When the relative angle d of the motor 20 is in the range of the fourth quadrant in the second determination area A2 (270 degrees ≦ d <360 degrees), the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q is located. If the quadrant information Q is not abnormal, the quadrant is one of the first quadrant, the third quadrant, and the fourth quadrant. When the relative angle d is 270 to 360 degrees, when the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the third quadrant, the count correction value is “1”. . In this case, the quadrant information correction value is a value that changes the quadrant where the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists in the counterclockwise direction. When the relative angle d is 270 to 360 degrees, when the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the fourth quadrant, the count correction value is “0”. It becomes. In this case, the quadrant information correction value is a value that does not directly change the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists. When the relative angle d is 270 to 360 degrees and the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is located in the first quadrant, the count correction value is “−1”. ". In this case, the quadrant information correction value is a value that changes the quadrant in which the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists in the clockwise direction.

  As illustrated in FIG. 2, the determination unit 35 calculates the post-change count value Cc using such a second map M2. When the count correction value is “1”, the determination unit 35 calculates the changed count value Cc by incrementing the count value C, and outputs the changed count value Cc to the rotation angle calculator 34. When the count correction value is “0”, the determination unit 35 outputs the count value C as it is to the rotation angle calculation unit 34 as a changed count value Cc. When the count correction value is “−1”, the determination unit 35 calculates the changed count value Cc by decrementing the count value C, and outputs the changed count value Cc to the rotation angle calculator 34.

  The rotation angle calculator 34 acquires the relative angle d calculated by the relative angle calculator 33 and the post-change count value Cc calculated by the determiner 35. The rotation angle calculation unit 34 adds the value obtained by multiplying the multi-turn number of the rotation shaft 20a of the motor 20 based on the post-change count value Cc by 360 degrees to the relative angle d, thereby multi-turning the motor 20. Is calculated.

  On the other hand, the determination unit 35 determines the abnormality of the quadrant information Q based on the count value C and the quadrant information Q, determines the abnormality of the count value C based on the relative angle d and the quadrant information Q, and determines the relative angle current value dn and the relative angle dn. If it is determined that the count value C or the quadrant information Q is abnormal in any of the high-speed rotation determinations of the rotation shaft 20a of the motor 20 based on the previous angle value dn-1, the rotation angle calculation unit 34 In this case, the count value C (change count value Cc) necessary for calculating the multi-turn rotation angle θ cannot be obtained with an appropriate value. Therefore, when the determination unit 35 determines that the count value C or the quadrant information Q is abnormal, the rotation angle calculation unit 34 cannot calculate the multi-turn rotation angle θ of the motor 20. Execute fail-safe such as stopping operation assistance. Further, even when the determination unit 35 obtains the counter abnormality flag Fc, the microcomputer 31 cannot obtain the count value C necessary for calculating the multi-turn rotation angle θ of the motor 20 with an appropriate value. Execute fail-safe such as stopping the assist of the steering operation.

The operation and effect of the first embodiment will be described.
(1) Due to a delay in transmission of various signals and a deviation in processing using various signals, a deviation may occur between the number of multi-turns indicated by the count value C and the actual number of multi-turns. Therefore, the contents of the relative angle d calculated by the relative angle calculation unit 33 of the microcomputer 31 and the contents of the count value C calculated by the counter circuit 101 of the rotation monitoring unit 32 may not match.

  For example, FIG. 9 shows the rotation position of the rotation shaft 20a of the motor 20 in the first determination area A1 when the relative angle calculation unit 33 calculates the relative angle d as 20 degrees based on the detection signal from the rotation angle sensor 41. And the quadrant in which the rotational position of the rotating shaft 20a of the motor 20 in the second determination area A2 based on the quadrant information Q exists. In this regard, even if the count value C which is not abnormal is calculated by the counter circuit 101, the count value C obtained by the microcomputer 31 deviates by at most 45 degrees from the relative angle d calculated by the relative angle calculator 33. It may be a count value when it is an angle. That is, the count value C calculated by the counter circuit 101 is a value that can be taken when the relative angle d is in the range of 335 degrees to 65 degrees. At this time, the quadrant information Q acquired by the microcomputer 31 indicates that the rotational position of the rotating shaft 20a of the motor 20 in the second determination area A2 exists in the first quadrant or the fourth quadrant. From this, when the relative angle d calculated by the relative angle calculation unit 33 is 20 degrees, the quadrant where the rotation position of the rotary shaft 20a of the motor 20 exists in the second determination area A2 based on the quadrant information Q exists. In the case of the first quadrant or the fourth quadrant, the count value C is not abnormal. On the other hand, when the relative angle d calculated by the relative angle calculator 33 is 20 degrees, the quadrant where the rotation position of the rotation shaft 20a of the motor 20 exists in the second determination area A2 based on the quadrant information Q is the second quadrant. In the case of the quadrant or the third quadrant, the count value C is abnormal. In this manner, for the relative angle d calculated by the relative angle calculation unit 33 based on the detection signal from the rotation angle sensor 41, it is possible to determine the relationship between the abnormal count value C and the non-abnormal count value C. it can.

  In the first embodiment, the determination unit 35 of the microcomputer 31 uses the first determination area A1 shifted by 45 degrees as a predetermined amount with respect to the second determination area A2 for calculating the count value C, and calculates the count value. C abnormality is determined. When the relative angle d calculated by the relative angle calculation unit 33 is 20 degrees, that is, when the relative angle d is in the range of the first angle area (315 to 45 degrees), the determination unit 35 determines based on the quadrant information Q. The count value C is not abnormal if the quadrant where the rotation position of the rotation shaft 20a of the motor 20 exists in the second determination area A2 is the first quadrant or the fourth quadrant, and if the quadrant is the second quadrant or the third quadrant. The count value C can be determined to be abnormal. Considering that the count value C has a deviation of up to 45 degrees, when the count value C is not abnormal, the quadrant information Q when the relative angle d is in the range of the first angle area is the relative angle This is because it indicates that d is in the range of 270 to 90 degrees (first quadrant or fourth quadrant).

  From this, the rotation position of the rotation shaft 20a of the motor 20 based on the quadrant information Q exists in the first to fourth angle regions where the rotation position of the rotation shaft 20a of the motor 20 based on the relative angle d exists. A first map M1 for determining whether or not the count value C is abnormal can be generated based on the combination of the first to fourth quadrants. As described above, the determination unit 35 stores the first map M1 indicating the relationship of the first determination area A1 shifted by 45 degrees as the predetermined amount with respect to the second determination area A2 for calculating the count value C. Then, the abnormality of the count value C can be determined using the first map M1. For this reason, the microcomputer 31 can suppress the calculation of the multi-turn rotation angle θ of the motor 20 using the abnormal count value C.

  (2) Even when the count value C is not abnormal, since the count value C includes a maximum deviation of 45 degrees, the content of the relative angle d calculated by the relative angle calculation unit 33 of the microcomputer 31 and the rotation The contents of the count value C (quadrant information Q) calculated by the counter circuit 101 of the monitoring unit 32 may not match. For example, in the case of FIG. 9, while the relative angle d calculated by the relative angle calculation unit 33 is 20 degrees, the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 in the second determination area A2 is the third position. If it indicates that the object exists in the quadrant, the calculation is performed using the content of the relative angle d calculated by the relative angle calculation unit 33 of the microcomputer 31, the quadrant information Q calculated by the quadrant determination unit 105, and the quadrant information Q. Does not match the content of the counted value C. Therefore, in the first embodiment, when the determination unit 35 does not determine that the count value C is abnormal, the determination unit 35 changes the count value C using the second map M2. For example, in the case of FIG. 9, the determination unit 35 sets the count correction value to “1” based on the relative angle d and the quadrant information Q using the second map M2, and increments the count value C, thereby changing the count value after the change. The value Cc is output to the rotation angle calculation unit 34 as “+4”. Accordingly, the content of the relative angle d calculated by the relative angle calculation unit 33 of the microcomputer 31 and the content of the changed count value Cc calculated by the determination unit 35 can be matched.

  (3) The determination unit 35 changes the count value C based on the detection signal, so that the rotation area of the rotation shaft 20a of the motor 20 in the second determination area A2 based on the changed count value Cc exists. And the angle region where the rotational position of the rotation shaft 20a of the motor 20 exists in the second determination region A2 based on the relative angle d calculated using the detection signal. From this, it is possible to match the contents of the post-change count value Cc with the contents of the relative angle d.

  (4) The number of the angle areas included in the first determination area A1 is the same as the number of the quadrants included in the second determination area A2, and the first determination area A1 is 45 times the second determination area A2. It is staggered. Thus, the angle area of the first determination area A1 is configured to correspond to a certain angle area and an adjacent angle area in the second determination area A2. For example, the first angle area of the first determination area A1 corresponds to a half angle area of the first quadrant and a half angle area of the fourth quadrant of the second determination area A2. From this, if the rotation position of the rotation shaft 20a of the motor 20 exists in an angle region of the first determination region A1 based on the relative angle d (detection signal), if the count value C is not abnormal, The rotational position of the rotation shaft 20a of the motor 20 is present in one of the two angle regions of the second determination region A2 corresponding to a certain angle region of the first determination region A1. As described above, in the setting of the first determination area A1 and the second determination area A2, the number of the angle areas is set to the same number, and the correspondence between the angle areas based on the shift of the angle areas is equalized. Thus, the setting of the first determination area A1 and the second determination area A2 can be made appropriate.

  (5) If the first determination area A1 is shifted from the second determination area A2 by more than half (45 degrees) or less than half of one angle area of the second determination area A2, Two quadrants of the second determination area A2 non-uniformly correspond to one angle area of one determination area A1. For example, if the first determination area A1 is configured to be shifted by 60 degrees in the clockwise direction with respect to the second determination area A2, the first angle area of the first determination area A1 is different from that of the second determination area A2. An angle area of 30 degrees in the first quadrant corresponds to an angle area of 60 degrees in the second quadrant. In this case, the process of determining the abnormality of the count value C may be complicated, and the accuracy of the abnormality determination of the count value C may differ depending on the rotation direction of the rotating shaft 20a of the motor 20. In this regard, in the first embodiment, the first determination area A1 is configured to be shifted from the second determination area A2 by half (45 degrees) of one angle area of the second determination area A2. Therefore, two quadrants of the second determination area A2 equally correspond to one angle area of the first determination area A1. From this, it is possible to simply configure the abnormality determination processing of the count value C. Further, it is possible to suppress a difference in the accuracy of the abnormality determination of the count value C depending on the rotation direction of the rotation shaft 20a of the motor 20.

  (6) Since the count value C and the quadrant information Q are allowed to be shifted up to 45 degrees with respect to the relative angle d, the determination unit 35 determines that the count value C exceeds 45 degrees with respect to the relative angle d. What is necessary is just to be able to determine whether it is shifted. That is, the determination accuracy of the determination process of the abnormality of the count value C may be any value that corresponds to the calculation accuracy of the count value C. Therefore, the determination unit 35 stores the first determination area A1 which is configured to be shifted by 45 degrees with respect to the second determination area A2 in consideration of the shift of the count value C and the quadrant information Q, and stores the first determination area A1. The abnormality of the count value C is determined using the determination area A1. From this, it is possible to determine the abnormality of the count value C as an appropriate calculation load determination process corresponding to the calculation accuracy of the count value C.

  (7) The rotation shaft 20a of the motor 20 may rotate at a high speed due to a large reverse input due to a curb climbing or the like. In such a case, the count value C may not be properly transmitted from the rotation monitoring unit 32 to the microcomputer 31. Therefore, in the present embodiment, when the change amount of the relative angle d exceeds the predetermined change amount, the determination unit 35 of the microcomputer 31 determines that the count current value Cn is abnormal, and thereby determines the count current value Cn and the count current value Cn. The previous value Cn-1 is not adopted as the official count value C. On the other hand, when the change amount of the relative angle d does not exceed the predetermined change amount, the determination unit 35 determines that the current count value Cn and the previous count value Cn-1 are not abnormal, and determines the previous count value Cn-1. This is adopted as the official count value C. The reason why the previous count value Cn-1 is adopted as the formal count value C is that the previous count value Cn-1 is not only determined not to be abnormal in the current calculation cycle but also used in the previous calculation cycle. This is because it is determined that there is no abnormality even in the cycle. Thus, the accuracy of the count value C used for calculating the multi-turn rotation angle θ of the motor 20 can be further increased.

  (8) When the count value Cn changes from the previous count value Cn-1 to the present count value Cn, the quadrant information Q changes from the previous quadrant information value Qn-1 to the current quadrant information Qn according to the change in the count value C. And should change in a predetermined relationship. For example, when the previous count value Cn-1 changes from "4R + 1" to the current count value Cn "(4R + 1) +1", the quadrant information indicating the first quadrant indicates the second quadrant from the previous value Qn-1. The quadrant information should change to the current value Qn. Despite this, when the current value does not change to the current quadrant information Qn indicating the second quadrant, it is considered that either the count value C or the quadrant information Q is abnormal. However, even in the case where the count value C and the quadrant information Q are not in an appropriate relationship, the counter comparison circuit 108 of the rotation monitoring unit 32 confirms that the counter 106 has no abnormality. The possibility that an abnormality has occurred in the quadrant information Q is higher than the possibility that an abnormality has occurred in the value C. Therefore, in the present embodiment, when the quadrant information Q changes as predetermined with respect to the change in the count value C, the determination unit 35 determines that the quadrant information Q is not abnormal, and On the other hand, when the quadrant information Q does not change as predetermined, it can be determined that the quadrant information Q is abnormal. Further, if it is determined in the previous calculation cycle that the previous quadrant information value Qn−1 is not abnormal, the quadrant information Q changes as predetermined with respect to the change in the count value C. If not, it can be determined that the quadrant information current value Qn is abnormal.

  (9) In the counter comparison circuit 108, the abnormality of the counter 106 is determined based on a comparison between the current count value Cn and the previous count value Cn-1 while considering the left rotation flag Fl or the right rotation flag Fr. Thus, generation of an abnormal count value C from the counter 106 can be suppressed.

Second Embodiment
Hereinafter, a second embodiment of the angle calculation device mounted on the EPS will be described. Here, the description will focus on the differences from the first embodiment.

  As shown in FIG. 10, the determination unit 35 obtains the relative angle d calculated by the relative angle calculation unit 33, the quadrant information Q calculated by the quadrant determination unit 105, and the count value C calculated by the counter circuit 101. I do. If the determination unit 35 does not determine that the count value C is abnormal using the first map M1, the determination unit 35 determines the counter value of the counter circuit 101 based on the relative angle d (detection signal) using the second map M2. The count value C stored in 106 is changed. The determination unit 35 generates the left rotation flag Fl when the count correction value is “1”, and generates the right rotation flag Fr when the count correction value is “−1”. The counter 106 is incremented each time the left rotation flag Fl is obtained from the quadrant determination unit 105 and the determination unit 35, and decremented each time the right rotation flag Fr is obtained from the quadrant determination unit 105 and the determination unit 35.

  The rotation angle calculator 34 of the microcomputer 31 obtains the relative angle d calculated by the relative angle calculator 33 and the changed count value Cc calculated by the determiner 35. The rotation angle calculation unit 34 adds the value obtained by multiplying the multi-turn number of the rotation shaft 20a of the motor 20 based on the post-change count value Cc by 360 degrees to the relative angle d, thereby multi-turning the motor 20. Is calculated.

The operation and effect of the second embodiment will be described.
(10) Since the count value C stored in the counter 106 of the counter circuit 101 is changed, the contents of the relative angle d calculated by the relative angle calculator 33 of the microcomputer 31 and the count stored in the counter 106 are changed. The content of the value C can be matched. In addition, the process of acquiring the count value C from the counter 106 and executing using the count value C (for example, calculation of the multi-turn rotation angle θ of the motor 20) can be made appropriate.

Each embodiment may be changed as follows. The following other embodiments can be combined with each other within a technically consistent range.
In each embodiment, the first determination area A1 is configured from four angle areas, but may be configured from three angle areas, or may be configured from five or more angle areas. Further, the second determination area A2 is configured from four quadrants, but may be configured from three quadrants, or may be configured from five or more quadrants. That is, the first determination area A1 may be configured by three or more angle areas. Further, the second determination area A2 may be composed of three or more quadrants.

  For example, as shown in FIGS. 11 and 12, the first determination area A1 may be configured from three angle areas, and the second determination area A2 may be configured from three quadrants. From the combination of the sine wave signal Ssin and the cosine wave signal Scos, that is, the combination of the detection signals, one rotation (360 degrees) of the rotation shaft 20a of the motor 20 is divided into three quadrants every 120 degrees. Is divided into The first quadrant is a quadrant when the relative angle d of the motor 20 is in the range of 0 to 120 degrees. The second quadrant is a quadrant when the relative angle d of the motor 20 is in the range of 120 to 240 degrees. The third quadrant is a quadrant when the relative angle d of the motor 20 is in the range of 240 to 360 degrees.

  From the combination of the sine wave signal Ssin and the cosine wave signal Scos, that is, the combination of the detection signals, the first determination area A1 determines one rotation (360 degrees) of the rotation shaft 20a of the motor 20 by three angles every 120 degrees. It is divided into regions. The first determination area A1 is configured to be shifted by a predetermined amount by 60 degrees from the second determination area A2. This predetermined amount is a half angle (60 degrees) of one angle area of the second determination area A2. In this case, the count value C and the quadrant information Q are converted from the relative angle d calculated by the relative angle calculator 33 by 60 degrees due to a delay in transmission of various signals and a shift in processing using various signals. The angle calculation device 30 is designed to allow the count value and the quadrant information when the angle is shifted so as not to exceed. The first angle area is a quadrant when the relative angle d of the motor 20 is in a range of 300 to 60 degrees. The second angle region is a quadrant when the relative angle d of the motor 20 is in the range of 60 to 180 degrees. The third angle region is a quadrant when the relative angle d of the motor 20 is in the range of 180 to 300 degrees.

  The determination unit 35 stores a first map M1 shown in FIG. 13 and a second map M2 shown in FIG. The determination unit 35 determines the abnormality of the count value C using the first map M1, and changes the count value C using the second map M2.

  FIG. 13 shows a first map M1 in a case where the first determination area A1 and the second determination area A2 include three angle areas. When the relative angle d of the motor 20 is in the range of 300 to 60 degrees (0 degree ≦ d <60 degrees, 300 degrees ≦ d <360 degrees), that is, the rotation position of the rotation shaft 20a of the motor 20 is within the first angle range. , The non-abnormal quadrants are the first and third quadrants, and the abnormal quadrant is the second quadrant. When the relative angle d of the motor 20 is in the range of 60 to 120 degrees (60 degrees ≦ d <120 degrees), that is, when the rotation position of the rotation shaft 20a of the motor 20 is within the second angle region, an abnormality is determined. The missing quadrants are the first and second quadrants, and the abnormal quadrant is the third quadrant. If the relative angle d of the motor 20 is in the range of 120 to 240 degrees (120 degrees d <240 degrees), that is, if the rotation position of the rotation shaft 20a of the motor 20 is within the third angle range, an abnormality is determined. The missing quadrants are the second and third quadrants, and the abnormal quadrant is the first quadrant.

  FIG. 14 shows a second map M2 in a case where the first determination area A1 and the second determination area A2 include three angle areas. If the relative angle d of the motor 20 is within the range of the first quadrant in the second determination area A2 (0 degrees ≦ d <120 degrees), the quadrant information Q indicates that the rotational position of the rotating shaft 20a of the motor 20 is in the third quadrant. , The count correction value is “1”, and the quadrant information Q indicates that the rotational position of the rotating shaft 20 a of the motor 20 is located in the first quadrant. At this time, the count correction value becomes “0”. When the relative angle d of the motor 20 is within the range of the second quadrant in the second determination area A2 (120 degrees ≦ d <240 degrees), the quadrant information Q indicates that the rotational position of the rotary shaft 20a of the motor 20 is in the first quadrant. , The count correction value is “1”, and the quadrant information Q indicates that the rotational position of the rotating shaft 20 a of the motor 20 is in the second quadrant. At this time, the count correction value becomes “0”. If the relative angle d of the motor 20 is within the range of the third quadrant in the second determination area A2 (240 degrees ≦ d <360 degrees), the quadrant information Q indicates that the rotational position of the rotating shaft 20a of the motor 20 is in the second quadrant. , The count correction value is “1”, and the quadrant information Q indicates that the rotational position of the rotating shaft 20 a of the motor 20 is located in the third quadrant. At this time, the count correction value becomes “0”. The determination unit 35 changes the count value C using such a count correction value.

  -In each embodiment, the number of angle regions of the first determination region A1 may be different from the number of quadrants of the second determination region A2. For example, the second determination area A2 may be composed of four quadrants as shown in FIG. 3, and the first determination area A1 may be composed of eight angle areas as shown in FIG.

  FIG. 15 illustrates a first determination area A1 including eight angle areas. The first determination area A1 performs one rotation (360 degrees) of the rotation shaft 20a of the motor 20 based on a combination of the sine wave signal Ssin and the cosine wave signal Scos, that is, based on the relative angle d, every eight 45 degrees. It is divided into angle areas. The first determination area A1 is configured to be shifted from the second determination area A2 by a predetermined amount by 22.5 degrees. This predetermined amount is a half angle (22.5 degrees) of one angle area of the second determination area A2. In this case, the count value C and the quadrant information Q are calculated based on the relative angle d calculated by the relative angle calculator 33 by 22.5 due to a delay in transmission of various signals and a shift in processing using various signals. The angle calculation device 30 is designed to allow the count value and the quadrant information when the angle is shifted so as not to exceed the degree. The first angle region is an angle region when the relative angle d of the motor 20 is in a range of 337.5 to 22.5 degrees. The second angle area is an angle area when the relative angle d of the motor 20 is in the range of 22.5 to 67.5 degrees. The third angle region is an angle region when the relative angle d of the motor 20 is in the range of 67.5 to 112.5 degrees. Hereinafter, the fourth to eighth angle regions are also constituted by angle regions at 45-degree intervals, similarly to the first to third angle regions.

  The determination unit 35 stores a first map M1 shown in FIG. 16 and a second map M2 shown in FIG. The determination unit 35 determines the abnormality of the count value C using the first map M1, and changes the count value C using the second map M2.

  FIG. 16 shows a first map M1 in a case where the first determination area A1 includes eight angle areas and the second determination area A2 includes four quadrants. When the relative angle d of the motor 20 is in a range of 337.5 to 22.5 degrees (0 degree d <22.5 degrees, 337.5 degrees ≦ d <360 degrees), that is, when the rotation axis 20a of the motor 20 is When the rotation position is within the range of the first angle region, the non-abnormal quadrants are the first and fourth quadrants, and the abnormal quadrants are the second and third quadrants. When the relative angle d of the motor 20 is in the range of 22.5 to 67.5 degrees (22.5 degrees ≦ d <67.5 degrees), that is, the rotation position of the rotation shaft 20a of the motor 20 is in the second angle region. If it is within the range, the non-abnormal quadrant is the first quadrant, and the abnormal quadrant is the second to fourth quadrants. When the relative angle d of the motor 20 is in the range of 67.5 to 112.5 degrees (67.5 degrees ≦ d <112.5 degrees), that is, the rotation position of the rotation shaft 20a of the motor 20 is in the third angle range. If within the range, the non-abnormal quadrants are the first and second quadrants, and the abnormal quadrants are the third and fourth quadrants. Thereafter, even when the rotation position of the rotation shaft 20a of the motor 20 is within the range of the fourth to eighth angle regions, a quadrant that is not abnormal and a quadrant that is abnormal are determined similarly to the first to third angle regions. ing.

  FIG. 17 shows a second map M2 in a case where the first determination area A1 is composed of eight angle areas and the second determination area A2 is composed of four quadrants. When the relative angle d of the motor 20 is within the range of the first quadrant in the second determination area A2 (0 degrees ≦ d <90 degrees), the quadrant information Q indicates that the rotation position of the rotation shaft 20a of the motor 20 is the fourth position. The count correction value is "1" when the signal indicates that it exists in the quadrant, and the count correction value is "0" when the signal indicates that it exists in the first quadrant. When it indicates that it is present, the count correction value is “−1”. Even when the relative angle d of the motor 20 is in the second to fourth quadrants in the second determination area A2, the relationship between the quadrant information Q and the count correction value is determined. The determination unit 35 changes the count value C using such a count correction value.

  In each of the embodiments, the counter circuit 101 determines that the rotation axis 20a of the motor 20 has a cycle that does not overlook that the rotation axis 20a of the motor 20 has rotated by the unit rotation amount (90 degrees), that is, in the second determination area A2. Although the count value C is calculated in a cycle that does not miss the fact that the rotation position has changed from one quadrant to an adjacent quadrant, the present invention is not limited to this. For example, when the first determination area A1 is configured from eight angle areas and the second determination area A2 is configured from eight angle areas, the counter circuit 101 determines that the rotational position of the rotation shaft 20a of the motor 20 exists. The count value C may be calculated in a cycle that does not miss the fact that the quadrant has changed from a certain quadrant to two adjacent quadrants. In this case, the counter 106 may increment or decrement the count value C by “2” at a time in accordance with a change in the quadrant of the second determination area A2. Note that the calculation cycle of the count value C can be changed as appropriate. The determination unit 35 determines the angle region where the rotation position of the rotation shaft 20a of the motor 20 is present in the second determination region A2 based on the count value C by using the motor in the second determination region A2 based on the relative angle d. The count value C may be changed so that the rotation position of the 20 rotation shafts 20a coincides with the angle region where the rotation axis exists, or the count value C may be changed so as to approach the angle region.

  In each embodiment, the determination unit 35 obtains the relative angle d calculated by the relative angle calculation unit 33, but obtains a detection signal from the rotation angle sensor 41, and performs the first determination based on the detection signal. An angle region where the rotation position of the rotation shaft 20a of the motor 20 in the region A1 exists may be determined.

  In each embodiment, when the count value C is not abnormal, the determination unit 35 changes the count value C using the second map M2, but the count value C need not be changed. The determination unit 35 performs fail-safe when it is determined that the count value C is abnormal. The execution of various processes using the rotation angle θ can be suppressed.

In the embodiments, the direction in which the first determination area A1 is shifted with respect to the second determination area A2 is the clockwise direction, but may be the counterclockwise direction.
The difference between the first determination area A1 and the second determination area A2 by a predetermined amount is set in consideration of a difference between transmission of various signals and processing using various signals, but is not limited thereto. For example, the predetermined amount may be set from the viewpoint of ensuring the accuracy of the determination of the abnormality of the count value C, or may be set from the viewpoint of easily designing each angle region of the first determination region A1. Good.

  In each embodiment, the determination unit 35 determines the abnormality of the quadrant information Q based on the count value C and the quadrant information Q, determines the abnormality of the count value C based on the relative angle d and the quadrant information Q, and determines the relative angle In the determination of the high-speed rotation of the rotating shaft 20a of the motor 20 based on the value dn and the relative angle previous value dn-1, if neither the count value C nor the quadrant information Q is determined to be abnormal, the count previous value Cn-1 is adopted as the official count value C, but is not limited to this. That is, the determination unit 35 may adopt the current count value Cn as the official count value C when none of the three determinations indicates that an abnormality has occurred in the count value C and the quadrant information Q. .

  In each embodiment, the determination unit 35 determines the abnormality of the quadrant information Q based on the count value C and the quadrant information Q, and determines the abnormality of the count value C based on the relative angle d and the quadrant information Q for each calculation cycle. The determination and the determination of the high-speed rotation of the rotating shaft 20a of the motor 20 based on the relative angle current value dn and the previous relative angle value dn-1 are executed, but the invention is not limited thereto. For example, the determination unit 35 may execute the determination of the abnormality of the quadrant information Q only in a specific one of the ten calculation cycles. In this case, when the change of the current count value Cn from the previous count value Cn-1 does not correspond to the change of the quadrant information current value Qn from the previous quadrant information value Qn-1, the quadrant information current value Qn or the quadrant It is determined that at least one of the information previous value Qn-1 is abnormal.

  -In each embodiment, although the predetermined change amount was set corresponding to the shift of 45 degrees where the count value C and the quadrant information Q were allowed to deviate from the relative angle d, the present invention is not limited to this. For example, the predetermined amount of change may be an angle smaller than 45 degrees in order to further restrict the rotation speed of the rotation shaft 20a of the motor 20, or the rotation speed of the rotation shaft 20a of the motor 20 is obviously abnormal. The angle may be larger than 45 degrees from the viewpoint of restricting the value. That is, the predetermined change amount may be set from any viewpoint as long as the abnormality of the change amount of the relative angle d can be determined.

  -In each embodiment, although the judgment part 35 performed judgment of high-speed rotation of the rotating shaft 20a of the motor 20, based on the current relative angle value dn and the previous relative angle value dn-1, it is not limited to this. For example, the determination unit 35 determines the rotation axis of the motor 20 based on the relative angle d of the calculation cycle prior to the previous relative angle value dn-1 in addition to the current relative angle value dn and the previous relative angle value dn-1. The determination of the high-speed rotation of 20a may be executed.

  In each embodiment, the determination unit 35 determines whether the change of the current count value Cn from the previous count value Cn-1 is in accordance with the change of the current quadrant information value Qn from the previous quadrant information value Qn-1. Although the abnormality of the quadrant information Q is determined, the present invention is not limited to this. For example, the determination unit 35 uses the count value C of the calculation cycle earlier than the count previous value Cn-1 in addition to the count current value Cn and the count previous value Cn-1 to calculate the quadrant information current value Qn and the quadrant information previous value. The abnormality of the quadrant information Q may be determined using the quadrant information Q of the calculation cycle before the previous quadrant information Qn-1 in addition to Qn-1.

  In each embodiment, the determination unit 35 determines the abnormality of the quadrant information Q based on the count value C and the quadrant information Q, determines the abnormality of the count value C based on the relative angle d and the quadrant information Q, and determines the relative angle The determination of the high-speed rotation of the rotating shaft 20a of the motor 20 based on the value dn and the previous relative angle value dn-1 has been performed, but is not limited thereto. The determination unit 35 may determine whether the count value C is abnormal based on at least the relative angle d and the quadrant information Q. When the determination unit 35 only determines the abnormality of the count value C based on the relative angle d and the quadrant information Q, as shown in FIG. 18, the angle calculation device 30 includes a previous count output circuit 107, a counter comparison circuit 108, the previous value output circuit 36, and the relative angle previous value output circuit 37 are omitted.

  In each embodiment, the rotation monitoring unit 32 is an ASIC that executes a predetermined calculation for a specific input, but is not limited to this. For example, the rotation monitoring unit 32 may be realized by a microcomputer including a microprocessing unit or the like. Further, the rotation monitoring unit 32 may read out a program stored in the storage unit and execute an operation according to the program. Even in these cases, the configuration of the rotation monitoring unit 32 is simpler than the configuration of the microcomputer 31 because the count value C that is smaller than the calculation load of the multi-turn rotation angle θ is calculated. It can be. Further, the rotation monitoring unit 32 may be realized by a low power consumption microcomputer specialized for a specific function such as calculation of a multi-turn rotation angle θ. Even in this case, the configuration of the rotation monitoring unit 32 can be made simpler than that of the microcomputer 31 by the amount specialized for the specific function.

The rotation angle sensor 41 may be, for example, a sensor using a Hall element or a sensor using a resolver.
The rotation angle sensor 41 may detect, for example, the rotation angle of the steering shaft 11. The rotation angle of the steering shaft 11 can be converted into a multi-turn rotation angle θ of the motor 20 in consideration of the reduction ratio of the reduction mechanism 21 interposed between the motor 20 and the steering shaft 11.

The rotation angle sensor 41 is provided on the motor 20, but may be provided on the steering shaft 11, which is the rotation shaft of the steering wheel 10.
The rotation monitoring unit 32 calculates the count value C intermittently even when the ignition switch 51 is turned on, but does not calculate the count value C when the ignition switch 51 is turned on. You may. In this case, when the ignition switch 51 is switched from on to off, for example, the microcomputer 31 stores the current rotation angle θ, and the rotation monitoring unit 32 intermittently calculates and stores the count value C after the operation starts. I do. Then, when the ignition switch 51 is switched from off to on, the microcomputer 31 reads out the count value C calculated by the rotation monitoring unit 32 and the stored rotation angle θ while the ignition switch 51 is off, and reads the rotation of the motor 20. Calculate the angle θ.

  The determination unit 35 takes in the quadrant information Q calculated by the quadrant determination unit 105 and uses this quadrant information Q to determine and change the abnormality of the count value C, but the present invention is not limited to this. For example, when the calculation of the count value C is continued even while the ignition switch 51 is turned on by the rotation monitoring unit 32, the determination unit 35 generates the quadrant information Q from the count value C acquired from the counter 106. The determination and change of the count value C may be performed using the quadrant information Q.

  When the determination unit 35 determines that the count value C is not abnormal, the determination unit 35 changes the quadrant information Q in addition to the change in the count value C. However, the determination unit 35 only needs to change at least the count value C. The information Q need not be changed.

  The previous value output circuit 36 outputs the count value Cc after the change of the current calculation cycle changed based on the count correction value in the determination unit 35 and the count value Cc after the change of the current calculation cycle changed based on the quadrant information correction value. The quadrant information Q may be held. That is, in the present embodiment, the count value C and the quadrant information Q that have been changed in consideration of the communication delay and the like are stored in the previous value output circuit 36 as the previous count value Cn-1 and the previous quadrant information Qn-1. Is done. Each time the current count value Cc after the change of the current calculation cycle and the quadrant information Q after the change of the current calculation cycle are input, the previous value output circuit 36 outputs the count value Cc after the change of the previous calculation cycle and the count value Cc. The quadrant information Q after the change of the previous calculation cycle is output to the determination unit 35. Thus, the determination unit 35 can determine the abnormality of the count value C and the quadrant information Q using the information corrected in the previous calculation cycle.

  The first map M1 is based on the angle area where the rotation position of the rotating shaft 20a of the motor 20 exists in the first determination area A1 based on the relative angle d, and the second area based on the quadrant information Q and the count value C. It may indicate the relationship between the rotation position of the rotation shaft 20a of the motor 20 in the determination area A2 and the existing quadrant. Further, the second map M2 includes a relative angle d of the motor 20, a quadrant in which the rotational position of the rotary shaft 20a of the motor 20 is based on the quadrant information Q and the count value C, and a correction value for the count value C. May be shown in relation to the count correction value.

  The quadrant determination unit 105 generates the left rotation flag Fl or the right rotation flag Fr based on the change in the combination of the Hi level signal and the Lo level signal generated by the comparator 104, The quadrant information Q may be generated in parallel with the generation of the rotation flag Fr. That is, the counter circuit 101 may execute the calculation of the count value C and the calculation of the quadrant information Q in parallel.

  The microcomputer 31 may capture the detection signal of the rotation angle sensor 41 via the rotation monitoring unit 32 (the counter circuit 101 and the communication interface 102). In this case, the rotation angle sensor 41 is energized in the same manner as the microcomputer 31 while the ignition switch 51 is on.

  The EPS of each embodiment may be embodied as an EPS in which the rotation axis 20a of the motor 20 and the axis of the rack shaft 12 are parallel to each other, or may be applied to an EPS in which the rotation axis 20a and the rack axis 12 are coaxial. You may. Further, the present invention is not limited to the EPS, and may be embodied in, for example, a steer-by-wire steering device.

  The vehicle on which the EPS of each embodiment is mounted may be a vehicle having a so-called internal combustion engine that employs an engine as a vehicle drive source, or a so-called electric vehicle that employs a motor as a vehicle drive source. . The ignition switch in the case of an electric vehicle is a switch for starting a motor as a vehicle drive source.

  DESCRIPTION OF SYMBOLS 1 ... Steering mechanism, 3 ... Actuator, 10 ... Steering wheel, 11 ... Steering shaft, 12 ... Rack shaft, 15 ... Steered wheel, 20 ... Motor, 20a ... Rotating shaft, 21 ... Reduction mechanism, 30 ... Angle calculation device, 31 .. Microcomputer, 32 rotation monitoring section, 33 relative angle calculation section, 34 rotation angle calculation section, 35 determination section, 36 previous value output circuit, 37 relative angle previous value output circuit, 40 torque sensor, 41 ... Rotation angle sensor, 50 ... Battery, 51 ... Ignition switch, 100 ... Power circuit, 101 ... Counter circuit, 102 ... Communication interface, 103 ... Amplifier, 104 ... Comparator, 105 ... Quadrant judging unit, 106 ... Counter, 107 ... Count Previous value output circuit, 108: counter comparison circuit, θ: rotation angle, A1: first determination area, A2: second determination area , C: count value, Cc: count value after change, Cn: count current value, Cn-1: count previous value, d: relative angle, dn: relative angle current value, dn-1: relative angle current value, Fc ... Counter abnormality flag, Fl left rotation flag, Fr right rotation flag, M1 first map, M2 second map, M3 third map, Q quadrant information, Qn quadrant information current value, Qn -1: previous value of quadrant information, Ssin: sine wave signal, Scos: cosine wave signal, Th: steering torque.

Claims (7)

A first calculation unit for calculating a multi-turn rotation angle of the motor based on a detection signal from the detection unit; and information used for calculating the rotation angle based on the detection signal from the detection unit. A second calculation unit that calculates rotation speed information that is information indicating the number of multi-turns of the motor,
The second calculation unit stores a second determination region including three or more angle regions, and based on the detection signal, the rotation speed information and the rotation speed of the motor in the second determination region. Calculating quadrant information which is information indicating an angle area where the position exists,
The first calculation unit stores a first determination area including three or more angle areas shifted by a predetermined amount with respect to the second determination area,
The first calculation unit is configured to determine, based on the quadrant information acquired from the second calculation unit, and an angle region where the rotational position of the motor in the first determination region is based on the detection signal, An angle calculation device for determining an abnormality in the rotation speed information.   The angle according to claim 1, wherein the first calculation unit changes the rotation speed information acquired from the second calculation unit based on the detection signal when the rotation speed information is not determined to be abnormal. Arithmetic unit.   The said 1st calculation part changes the said rotation speed information memorize | stored by the said 2nd calculation part based on the said detection signal, when not determining the said rotation speed information as abnormal. Angle calculation device. The first calculation unit stores the second determination area,
The first arithmetic unit determines that the angle region where the rotation position of the motor is present in the second determination region based on the quadrant information is the rotation position of the motor in the second determination region based on the detection signal. The angle calculation device according to claim 2, wherein the rotation speed information is changed so as to match an existing angle region. The number of angle regions in the first determination region and the number of angle regions in the second determination region are the same,
The shift of the predetermined amount of the first determination area with respect to the second determination area is a shift of half of one angle area of the second determination area. Angle calculation device. The rotation angle and the rotation speed information are calculated at a predetermined calculation cycle,
The first computing unit is
If the amount of change of the current value of the rotation angle from the previous value of the rotation angle does not exceed a predetermined amount of change determined to be able to calculate the rotation information normally, it is determined that the rotation information is not abnormal,
If the amount of change of the current value of the rotation angle from the previous value of the rotation angle exceeds a predetermined amount of change determined to be able to normally calculate the rotation speed information, it is determined that the rotation speed information is abnormal. Item 6. The angle calculation device according to any one of Items 1 to 5. The first computing unit is
An abnormality in the quadrant information is determined based on a relationship between a change in a current value of the rotation speed information from a previous value of the rotation speed information and a change in a current value of the quadrant information from a previous value of the quadrant information. The angle calculation device according to claim 1.