JP2019199197A - Arithmetic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable arithmetic device. An interface group 41 detects a voltage abnormality detection circuit 71 that detects an abnormality of a power supply circuit 61, an arithmetic rotation direction comparison circuit 72 that detects an abnormality of a rotation direction detection circuit 65, and an abnormality of detection signals Sd1 and Sd2. A sensor rotation direction comparison circuit 73 for detecting and a counter comparison circuit 74 for detecting abnormality of the counter 68 are provided. The interface group 41 includes a power supply BIST circuit 81 for diagnosing the voltage abnormality detection circuit 71, a calculation BIST circuit 82 for diagnosing the calculation rotation direction comparison circuit 72, and a sensor BIST circuit 83 for diagnosing the sensor rotation direction comparison circuit 73. , A counter BIST circuit 84 for diagnosing the counter comparison circuit 74. [Selection diagram] Figure 2

Description

  The present invention relates to a calculation device that calculates rotation information for detecting a rotation angle.

  Conventionally, a steering device such as an electric power steering device (EPS) that applies an assist force for assisting steering using a motor as a drive source detects the steering angle of the steering wheel with an absolute angle including a range exceeding 360 °. Some have a rotation angle detector. As such a rotation angle detection device, a device that detects a steering angle based on a rotation angle of a motor detected at a relative angle within a range of 360 ° and, for example, the rotation speed of the motor from a steering neutral position is known. (For example, Patent Document 1).

  In the rotation angle detection device of Patent Document 1, based on the detection signal from the rotation angle sensor that detects the rotation angle of the motor, the rotation angle of the motor is in a quadrant (first to fourth quadrants) in which the rotation range is divided into four. An arithmetic unit that detects the position of the motor, detects the rotation direction of the motor based on the quadrant transition of the rotation angle, and counts the count value indicating the rotation speed of the motor is provided. The steering angle calculation device (microcomputer) detects a steering angle indicated by an absolute angle based on the rotation angle and count value of the motor output from the calculation device.

  Further, in the rotation angle detection device of the same document, for example, the calculation device is configured based on whether or not the difference between the count value in the latest calculation cycle and the previous value is a value corresponding to the rotation direction. An abnormality detection circuit for detecting whether or not an abnormality has occurred in each circuit is provided. Thus, it is possible to prevent the steering angle from being detected based on the rotation information erroneously calculated in a state where an abnormality has occurred.

Japanese Patent Laid-Open No. 2006-5918

  By the way, in recent years, higher reliability has been demanded in rotation angle detection devices. However, in the above-described conventional configuration, if any abnormality occurs in the abnormality detection circuit, even if the rotation information calculated by the arithmetic device is abnormal, this cannot be detected, and there is a possibility that an accurate steering angle cannot be detected. there were.

  Such a problem is not limited to the detection of the steering angle. For example, in a steer-by-wire type steering device, the steered wheel is based on the rotation angle of the motor that is the drive source of the steered actuator that steers the steered wheel. This can also occur in the case where the rotation angle of the rotation shaft that can be converted into the turning angle is detected as an absolute angle.

  An object of the present invention is to provide a highly reliable arithmetic device.

  An arithmetic unit that solves the above problem is based on a detection signal from a rotation angle sensor that detects a rotation angle of a motor connected to a rotation shaft that can be converted into a turning angle of a steered wheel as a relative angle. A main circuit that calculates rotation information indicating a rotation state, an abnormality detection circuit that detects an abnormality of the main circuit, and a BIST circuit that diagnoses the abnormality detection circuit.

  According to the above configuration, it is possible to detect that an abnormality has occurred in the abnormality detection circuit by the BIST circuit. Therefore, when the rotation information calculated by the main circuit is abnormal, it can be prevented that the rotation information is output without being detected by the abnormality detection circuit. Thereby, the reliability of the rotation information output from the main circuit can be improved.

  In the above arithmetic device, the BIST circuit calculates a rotational angle of the rotary shaft indicated by an absolute angle based on the rotational information output from the main circuit after turning on a start switch of a vehicle. It is preferable that the abnormality detection circuit is diagnosed during an initial period until the control voltage supplied to is stabilized.

  According to the above configuration, the abnormality detection circuit is diagnosed by the BIST circuit before the control voltage is stably supplied to the steering angle calculation device, that is, before the steering angle calculation device starts the calculation process. It can suppress that the diagnosis by a circuit affects the calculation process of a steering angle calculating device.

  In the arithmetic device, the main circuit intermittently obtains the detection signal from the rotation angle sensor to calculate the rotation information when the start switch of the vehicle is off, and the abnormality detection circuit calculates the rotation of the start switch. When off, the main circuit detects an abnormality in the main circuit, and when the start switch is off, the BIST circuit does not calculate the rotation information. It is preferable to diagnose the abnormality detection circuit.

  According to the above configuration, the abnormality detection circuit is diagnosed by the BIST circuit when the main circuit and the abnormality detection circuit are not performing the process of calculating the rotation information based on the detection signal detected by the rotation angle sensor. It is possible to suppress the diagnosis by the BIST circuit from affecting the calculation of the rotation information.

  In the arithmetic device, the main circuit includes a power supply circuit that generates a control voltage to be supplied to another circuit based on a power supply voltage, and the abnormality detection circuit has a control voltage within a predetermined voltage range set in advance. A voltage abnormality detection circuit for detecting an abnormality based on whether or not there is an abnormality, wherein the BIST circuit detects an abnormality by the voltage abnormality detection circuit when the upper and lower limit values defining the predetermined voltage range are changed; It is preferable to include a power supply BIST circuit for diagnosing the voltage abnormality detection circuit based on whether or not.

  According to the above configuration, since the voltage abnormality detection circuit for detecting abnormality of the power supply circuit is diagnosed by the power supply BIST circuit, rotation information calculated by the main circuit is output in a state where the normal control voltage is not supplied. Can be suppressed.

  In the above arithmetic device, the main circuit detects whether the rotation angle is located in a quadrant obtained by dividing the rotation range of the motor based on a detection signal from the rotation angle sensor, and A rotation direction detection circuit that detects a rotation direction of the motor based on a quadrant transition; and a detection signal from the rotation angle sensor that detects whether the rotation angle is located in the quadrant; A redundant circuit for detecting the rotational direction of the motor based on the quadrant transition, and the abnormality detection circuit is configured to detect the rotational direction detected by the rotational direction detection circuit and the rotational speed detected by the computational redundant circuit. A calculation rotation direction comparison circuit for detecting an abnormality based on a comparison with the direction, wherein the BIST circuit transmits a test signal indicating the rotation direction to the calculation rotation direction comparison circuit. If, on the basis of whether or not abnormal by calculating the rotation direction comparing circuit is detected, it is preferable to include operational BIST circuit for diagnosing the operational direction of rotation comparator circuit.

  According to the above configuration, the rotation direction detection circuit and the calculation redundancy circuit detect the rotation direction based on the detection signal from the rotation angle sensor, respectively, and the calculation rotation direction comparison circuit compares these rotation directions, thereby rotating the rotation direction detection circuit. Anomaly detection is performed. And since this calculation rotation direction comparison circuit is diagnosed by the calculation BIST circuit, it can suppress that the rotation direction detected by the abnormal calculation is output.

  In the above arithmetic device, the main circuit detects whether the rotation angle is located in a quadrant obtained by dividing the rotation range of the motor based on a detection signal from the rotation angle sensor, and A detection signal from a rotation direction detection circuit that detects the rotation direction of the motor based on a quadrant transition and a redundant rotation angle sensor that detects a rotation angle of the motor provided as a relative angle separately from the rotation angle sensor. A redundant circuit for detecting the rotation angle of the motor based on a transition of the quadrant of the rotation angle, detecting whether the rotation angle is located in the quadrant based on the abnormality detection circuit, A sensor rotation direction comparison circuit for detecting an abnormality based on a comparison between the rotation direction detected by the rotation direction detection circuit and the rotation direction detected by the sensor redundancy circuit; The T circuit, when transmitting a test signal indicating the rotation direction to the sensor rotation direction comparison circuit, based on whether or not an abnormality is detected by the sensor rotation direction comparison circuit, the sensor rotation direction comparison circuit It is preferable to include a sensor BIST circuit for diagnosing the above.

  According to the above configuration, the rotation direction detection circuit and the sensor redundancy circuit detect the rotation direction based on the detection signals from the different rotation angle sensors, and the sensor rotation direction comparison circuit compares these rotation directions to detect the detection signal. Anomaly detection is performed. And since this sensor rotation direction comparison circuit is diagnosed by the sensor BIST circuit, it can suppress that the rotation direction detected based on the abnormal detection signal is output.

  In the above arithmetic device, the main circuit detects whether the rotation angle is located in a quadrant obtained by dividing the rotation range of the motor based on a detection signal from the rotation angle sensor, and A rotation direction detection circuit for detecting the rotation direction of the motor based on quadrant transition, a counter for counting a count value as the rotation information indicating the rotation speed of the motor based on the rotation direction of the motor, and the counter A previous value output circuit that outputs the previous value of the count value output from the counter, wherein the abnormality detection circuit detects an abnormality based on a comparison between the count value in consideration of the rotation direction and the previous value. The BIST circuit includes a comparison circuit, and transmits a test signal indicating the rotation direction and the count value to the counter comparison circuit. Abnormality based on whether detected by motor comparator circuit preferably includes a counter BIST circuit for diagnosing the counter comparator circuit.

  According to the above configuration, the counter BIST circuit diagnoses the counter comparison circuit that detects the abnormality of the counter based on the comparison between the count value and the previous value while considering the rotation direction. For this reason, output of an abnormal count value (rotation information) can be suppressed.

  According to the present invention, the reliability of the arithmetic device can be improved.

The schematic block diagram of an electric power steering apparatus. The block diagram of a steering control apparatus. The timing chart which shows the relationship between the ON / OFF state of a start switch, the control voltage of a microcomputer, and the operation timing of a main circuit.

Hereinafter, an embodiment of an arithmetic device will be described with reference to the drawings.
As shown in FIG. 1, an electric power steering device (EPS) 1 as a steering device includes a steering mechanism 4 that steers steered wheels 3 based on an operation of a steering wheel 2 by a driver. The EPS 1 also includes an EPS actuator 5 that applies an assist force for assisting the steering operation to the steering mechanism 4, and a steering control device 6 as a rotation angle detection device that controls the operation of the EPS actuator 5.

  The steering mechanism 4 includes a steering shaft 11 to which the steering wheel 2 is fixed, a rack shaft 12 that reciprocates in the axial direction according to the rotation of the steering shaft 11, and a substantially cylindrical shape through which the rack shaft 12 is reciprocally inserted. Rack housing 13. The steering shaft 11 is configured by connecting a column shaft 14, an intermediate shaft 15, and a pinion shaft 16 in this order from the steering wheel 2 side.

  The rack shaft 12 and the pinion shaft 16 are arranged in the rack housing 13 with a predetermined crossing angle, and the rack teeth 12a formed on the rack shaft 12 and the pinion teeth 16a formed on the pinion shaft 16 are meshed with each other. Thus, the rack and pinion mechanism 17 is configured. Further, both ends of the rack shaft 12 are connected to knuckle (not shown) in which the steered wheels 3 are assembled via tie rods 18. Therefore, in EPS 1, the rotation of the steering shaft 11 accompanying the steering operation is converted into the axial movement of the rack shaft 12 by the rack and pinion mechanism 17, and this axial movement is transmitted to the knuckle via the tie rod 18. The turning angle of the steered wheels 3, that is, the traveling direction of the vehicle is changed.

  The EPS actuator 5 includes a motor 21 as a drive source, a transmission mechanism 22 that transmits the rotation of the motor 21, and a conversion mechanism 23 that converts the rotation transmitted through the transmission mechanism 22 into a reciprocating motion of the rack shaft 12. I have. The EPS actuator 5 transmits the rotation of the motor 21 to the conversion mechanism 23 via the transmission mechanism 22, and converts the reciprocation of the rack shaft 12 by the conversion mechanism 23, thereby giving assist force to the steering mechanism 4. . For example, a three-phase brushless motor is employed as the motor 21 of the present embodiment, a belt mechanism is employed as the transmission mechanism 22, and a ball screw mechanism is employed as the conversion mechanism 23, for example.

  The steering control device 6 is connected to a vehicle speed sensor 31 that detects a vehicle speed SPD of the vehicle and a torque sensor 32 that detects a steering torque T applied to the steering shaft 11 by the driver's steering. The steering control device 6 also detects the rotation angle of the motor 21 as a rotation angle sensor that detects the rotation angle of the motor 21 as a relative angle within a range of 360 °, and detects the rotation angle of the motor 21 as a relative angle. A second rotation angle sensor 34 is connected as a redundant rotation angle sensor. From the first and second rotation angle sensors 33 and 34, detection signals Sd1 and Sd2 comprising a sin signal and a cos signal are output, respectively. As described above, the motor 21 is mechanically coupled to the rack shaft 12 via the transmission mechanism 22 and the conversion mechanism 23, and the rotation angle of the rotation shaft 21 a of the motor 21 is the turning angle of the steered wheels 3. It is a value related to the steering angle of the steering shaft 11 which is the rotation axis that can be converted into The steering control device 6 is connected to a start switch 35 (for example, an operation position of an ignition key or a start switch) for starting a drive source of the vehicle, and a start signal Sig indicating the on / off state is input. Is done.

  The steering control device 6 controls the operation of the EPS actuator 5 by supplying driving power to the motor 21 based on various state quantities detected by these sensors. That is, the steering control device 6 executes assist control for applying an assist force to the steering mechanism 4 through the control of the EPS actuator 5.

  As shown in FIG. 2, the steering control device 6 supplies an interface group 41 as a calculation device, a microcomputer 42 as a steering angle calculation device that outputs a motor control signal, and drive power to the motor 21 based on the motor control signal. And a drive circuit 43 to be supplied.

  The interface group 41 is configured by integrating a plurality of electronic circuits on a single chip. The interface group 41 is always connected to the in-vehicle power source 52 mounted on the vehicle via the first connection line 51 and connected to the in-vehicle power source 52 via the second connection line 54 provided with a power relay 53 in the middle. Has been. The power relay 53 includes a mechanical relay, an FET (field effect transistor), and the like, and opens and closes according to the on / off state of the start signal Sig. Since the interface group 41 is always connected to the in-vehicle power supply 52 via the first connection line 51, power is supplied to the interface group 41 even when the start switch 35 is turned off, and the interface group 41 is operable. Further, the detection signals Sd1 and Sd2 are input to the interface group 41. Based on the detection signals Sd1 and Sd2, the interface group 41 outputs a count value Nn as rotation information indicating the rotation speed of the motor 21 (rotating shaft 21a) to the microcomputer 42, as will be described later.

  The drive circuit 43 is connected to the in-vehicle power supply 52 via a power supply line 55, and a drive relay 56 made of a mechanical relay, FET (field effect transistor) or the like is provided in the middle of the power supply line 55. . Therefore, the drive circuit 43 can supply drive power based on the power supply voltage of the in-vehicle power supply 52 when the drive relay 56 is turned on and the power supply line 55 becomes conductive.

  The microcomputer 42 is connected to the in-vehicle power supply 52 via the interface group 41, and when the start signal Sig is in an on state, the control voltage Vco within a predetermined voltage range set in advance is supplied from the interface group 41. It works by that. When the microcomputer 42 is supplied with the control voltage Vco from the interface group 41 and starts its operation, the microcomputer 42 outputs a relay signal Srl to the drive relay 56 and makes the power line 55 conductive. Therefore, when the driver operates the start switch 35 to be turned on, the control voltage Vco is supplied from the interface group 41, the microcomputer 42 is activated, and the drive relay 56 is turned on. In this state, drive power can be supplied.

  The microcomputer 42 receives the detection signal Sd1 and the count value Nn. The microcomputer 42 calculates the rotation angle of the motor 21 as a relative angle from the detection signal Sd1 using an arctangent function. In the microcomputer 42, the relationship between the rotation angle of the motor 21 and the count value Nn and the steering angle is preliminarily determined based on a conversion coefficient determined by the gear ratio of the rack and pinion mechanism 17, the lead of the conversion mechanism 23, and the reduction ratio of the transmission mechanism 22. Based on the calculated rotation angle of the motor 21 and the count value Nn, the steering angle is calculated as an absolute angle including a range exceeding 360 °. Further, the vehicle speed SPD and the steering torque T are input to the microcomputer 42. The microcomputer 42 generates a motor control signal based on the steering angle, the vehicle speed SPD, and the steering torque T, and outputs the motor control signal to the drive circuit 43. As a result, drive power corresponding to the state quantity detected by each sensor is supplied to the motor 21 and its operation is controlled.

Next, the configuration of the interface group 41 will be described.
The interface group 41 includes a main circuit 60 that calculates a count value Nn as rotation information indicating the rotation state of the motor 21 based on the detection signals Sd1 and Sd2. The main circuit 60 includes a power supply circuit 61 that steps down the power supply voltage of the in-vehicle power supply 52 to a control voltage Vco within a predetermined voltage range. First and second connection lines 51 and 54 are connected to the input side of the power supply circuit 61. The output side of the power supply circuit 61 is connected to the microcomputer 42 via the microcomputer connection line 62 and to each circuit constituting the interface group 41. In FIG. 2, for convenience of explanation, connection lines that connect the power supply circuit 61 and the circuits constituting the interface group 41 are omitted. The power supply circuit 61 supplies the control voltage Vco to the microcomputer 42 only when the start switch 35 is turned on, while constantly supplying the control voltage Vco to each circuit constituting the interface group 41 regardless of whether the start switch 35 is turned on or off. Thereby, each circuit constituting the interface group 41 operates not only when the start switch 35 is turned on but also when it is turned off. Further, the main circuit 60 of the present embodiment obtains the detection signals Sd1 and Sd2 intermittently at a predetermined intermittent period when the start switch 35 is off, calculates the count value Nn, and detects when the start switch 35 is on. The signals Sd1 and Sd2 are always acquired and the count value Nn is calculated at a predetermined calculation period. Note that the predetermined intermittent period is a steering angle due to various factors when detecting whether the rotation angle of the motor 21 (rotating shaft 21a) is located in the first to fourth quadrants obtained by dividing the rotation range into four. Is set to a period in which the transition between quadrants of the same rotation angle does not jump over adjacent quadrants.

  The main circuit 60 includes an A / D converter 63 that performs A / D conversion on the detection signal Sd1 and an A / D converter 64 that performs A / D conversion on the detection signal Sd2. The main circuit 60 detects whether the rotation angle of the motor 21 (rotating shaft 21a) is located in the first to fourth quadrants based on the detection signal Sd1 ′ after A / D conversion, and performs the rotation. A rotation direction detection circuit 65 that detects the rotation direction of the motor 21 based on the transition of the quadrant of the corner is provided. The main circuit 60 includes a calculation redundancy circuit 66 that detects the rotation direction of the motor 21 based on the detection signal Sd1 ′, and a sensor redundancy circuit 67 that detects the rotation direction of the motor 21 based on the detection signal Sd2 ′. ing. The main circuit 60 outputs a counter 68 that counts a count value Nn indicating the number of rotations of the motor 21 based on the rotation direction of the motor 21, and a previous value Nn−1 of the count value Nn output from the counter 68. And a previous value output circuit 69.

  Specifically, the rotation direction detection circuit 65 binarizes the input detection signal Sd1 ′ (sin signal and cos signal) into a Hi level and a Lo level according to the signal level, and the signal level of the sin signal and the cos signal The rotation angle of the motor 21 is detected in any one of the first to fourth quadrants according to the combinations (4 sets in total) with the signal level. When the quadrant in which the rotation angle of the motor 21 is located in the latest computation cycle changes from the quadrant in which the rotation angle of the motor 21 is located in the previous computation cycle, the motor 21 rotates right or left according to the change. If the quadrant where the rotation angle of the motor 21 is located does not change, it is determined that the motor 21 is not rotating. That is, the rotation direction detection circuit 65 detects the rotation direction based on the transition of the quadrant of the rotation angle of the motor 21. The rotation direction signal Srd indicating the rotation direction of the motor 21 detected in this way is output to a calculation rotation direction comparison circuit 72, a sensor rotation direction comparison circuit 73, and a counter comparison circuit 74, which will be described later, in addition to the counter 68.

  The calculation redundancy circuit 66 detects the rotation direction of the motor 21 by executing the same calculation process as the rotation direction detection circuit 65 based on the input detection signal Sd1 '. The calculated redundant signal Scp indicating the rotation direction of the motor 21 thus detected is output to the calculated rotation direction comparison circuit 72.

  The sensor redundant circuit 67 detects the rotation direction of the motor 21 by executing the same arithmetic processing as the rotation direction detection circuit 65 based on the input detection signal Sd2 '. The sensor redundancy signal Ssp indicating the rotation direction of the motor 21 detected in this way is output to the sensor rotation direction comparison circuit 73.

  The counter 68 calculates a count value Nn indicating the number of rotations of the motor 21 based on the rotation direction signal Srd. The counter 68 of the present embodiment sets the number of rotations at the steering neutral position where the vehicle goes straight to zero, when the motor 21 rotates rightward from the same position, and when the motor 21 rotates leftward from the same position Is negative. The relationship between the rotation direction of the motor 21 and the sign of the count value Nn may be reversed. When the rotation direction of the motor 21 indicated by the input rotation direction signal Srd is the right direction, the counter 68 increments the count value Nn (Nn = Nn-1 + 1), and the rotation direction of the motor 21 is In the case of the left direction, the count value Nn is decremented (Nn = Nn−1−1). The counter 68 holds the count value Nn when the motor 21 is not rotating. The count value Nn calculated in this way is output to the previous value output circuit 69, the counter comparison circuit 74, and the microcomputer.

  The previous value output circuit 69 holds the input count value Nn for at least two calculation cycles. The previous value output circuit 69 outputs the previous value Nn−1 to the counter comparison circuit 74 every time the count value Nn is input.

  The interface group 41 includes an abnormality detection circuit 70 that detects an abnormality in the main circuit 60. The abnormality detection circuit 70 detects an abnormality of the voltage abnormality detection circuit 71 that detects an abnormality of the power supply circuit 61, an arithmetic rotation direction comparison circuit 72 that detects an abnormality of the rotation direction detection circuit 65, and the detection signals Sd1 ′ and Sd2 ′. And a counter comparison circuit 74 for detecting an abnormality of the counter 68.

  Specifically, the voltage abnormality detection circuit 71 detects an abnormality in the power supply circuit 61 based on whether or not the control voltage Vco output from the power supply circuit 61 is within a predetermined voltage range. Specifically, the voltage abnormality detection circuit 71 detects the control voltage Vco output from the power supply circuit 61, and the control voltage Vco is larger than the upper limit value Vup of the predetermined voltage range or the lower limit value Vlo of the predetermined voltage range. If not, a voltage abnormality flag (not shown) indicating that an abnormality has occurred in the power supply circuit 61 is set. On the other hand, the voltage abnormality detection circuit 71 does not set the voltage abnormality flag when the control voltage Vco is not more than the upper limit value Vup and not more than the lower limit value Vlo.

  The calculation rotation direction comparison circuit 72 detects an abnormality in the rotation direction detection circuit 65 based on the rotation direction signal Srd and the calculation redundancy signal Scp. Specifically, the calculation rotation direction comparison circuit 72 determines that the rotation direction detection circuit 65 is different when the rotation direction of the motor 21 indicated by the rotation direction signal Srd is different from the rotation direction of the motor 21 indicated by the calculation redundancy signal Scp. An operation abnormality flag (not shown) indicating that an abnormality has occurred is set. On the other hand, the calculation rotation direction comparison circuit 72 does not set the calculation abnormality flag when the rotation direction of the motor 21 indicated by the rotation direction signal Srd matches the rotation direction of the motor 21 indicated by the calculation redundancy signal Scp.

  The sensor rotation direction comparison circuit 73 detects an abnormality in the detection signals Sd1 'and Sd2' based on the rotation direction signal Srd and the sensor redundancy signal Ssp. Specifically, the sensor rotation direction comparison circuit 73 detects the detection signal Sd1 ′, when the rotation direction of the motor 21 indicated by the rotation direction signal Srd is different from the rotation direction of the motor 21 indicated by the sensor redundancy signal Ssp. A sensor abnormality flag (not shown) indicating that an abnormality has occurred in Sd2 ′ is set. On the other hand, the sensor rotation direction comparison circuit 73 does not set the sensor abnormality flag when the rotation direction of the motor 21 indicated by the rotation direction signal Srd matches the rotation direction of the motor 21 indicated by the sensor redundancy signal Ssp.

  The counter comparison circuit 74 detects an abnormality of the counter 68 based on the rotation direction signal Srd, the count value Nn, and the previous value Nn-1. Specifically, when the difference between the count value Nn and the previous value Nn-1 does not match the rotation direction of the motor 21 indicated by the rotation direction signal Srd, the counter comparison circuit 74 rotates, for example, the motor 21. If there is a difference between the count value Nn and the previous value Nn-1 in spite of the absence, a counter abnormality flag (not shown) indicating that an abnormality has occurred in the counter 68 is set. On the other hand, the counter comparison circuit 74 does not set the counter abnormality flag when the difference between the count value Nn and the previous value Nn-1 corresponds to the rotation direction of the motor 21 indicated by the rotation direction signal Srd.

When at least one of the above-described abnormality flags is set, the microcomputer 42 notifies the fact through a warning light (not shown) and stops the calculation of the steering angle.
Here, when an abnormality occurs in the abnormality detection circuit, there is a possibility that it cannot be detected even if the count value Nn calculated by the main circuit 60 is abnormal. In consideration of this point, the interface group 41 of this embodiment includes a BIST (Built-in Self-test) circuit 80 that diagnoses the abnormality detection circuit 70. The BIST circuit 80 includes a power supply BIST circuit 81 for diagnosing the voltage abnormality detection circuit 71, a calculation BIST circuit 82 for diagnosing the calculation rotation direction comparison circuit 72, a sensor BIST circuit 83 for diagnosing the sensor rotation direction comparison circuit 73, and a counter And a counter BIST circuit 84 for diagnosing the comparison circuit 74.

  Specifically, the power supply BIST circuit 81 determines whether or not the voltage abnormality detection circuit 71 sets a voltage abnormality flag when at least one of the upper limit value Vup and the lower limit value Vlo is changed during diagnosis of the voltage abnormality detection circuit 71. The voltage abnormality detection circuit 71 is diagnosed based on the above. Specifically, the power supply BIST circuit 81, for example, when the voltage abnormality detection circuit 71 does not set the voltage abnormality flag even though the control voltage Vco is set to a value outside the predetermined voltage range, the voltage abnormality detection circuit A power supply BIST abnormality flag (not shown) indicating that an abnormality has occurred in 71 is set. On the other hand, the power supply BIST circuit 81 does not set the power supply BIST abnormality flag when the voltage abnormality detection circuit 71 sets the voltage abnormality flag, for example, by setting the control voltage Vco to a value outside the predetermined voltage range. .

  The calculation BIST circuit 82 determines whether or not the calculation rotation direction comparison circuit 72 sets a calculation abnormality flag when the test signal Scb indicating the rotation direction of the motor 21 is transmitted during diagnosis of the calculation rotation direction comparison circuit 72. Based on this, the calculation rotation direction comparison circuit 72 is diagnosed. Specifically, the arithmetic BIST circuit 82, for example, transmits a test signal Scb having a different rotational direction, but the arithmetic rotational direction comparison circuit 72 is abnormal when the arithmetic rotational direction comparison circuit 72 does not set the abnormal operation flag. A calculation BIST abnormality flag (not shown) indicating that the error has occurred is set. On the other hand, the arithmetic BIST circuit 82 does not set the arithmetic BIST abnormality flag when the arithmetic rotation direction comparison circuit 72 sets the arithmetic abnormality flag when, for example, the test signal Scb having a different rotation direction is transmitted.

  The sensor BIST circuit 83 determines whether or not the sensor rotation direction comparison circuit 73 sets a sensor abnormality flag when the test signal Ssb indicating the rotation direction of the motor 21 is transmitted at the time of diagnosis of the sensor rotation direction comparison circuit 73. Based on this, the sensor rotation direction comparison circuit 73 is diagnosed. Specifically, when the sensor rotation direction comparison circuit 73 does not set the sensor abnormality flag even though the sensor BIST circuit 83 transmits the test signal Ssb having a different rotation direction, for example, the sensor rotation direction comparison circuit 73 has an abnormality. A sensor BIST abnormality flag (not shown) indicating that the error has occurred is set. On the other hand, the sensor BIST circuit 83 does not set the sensor BIST abnormality flag when the sensor rotation direction comparison circuit 73 sets the sensor abnormality flag when, for example, the test signal Ssb having a different rotation direction is transmitted.

  The counter BIST circuit 84 determines whether or not the counter comparison circuit 74 sets a counter abnormality flag when the counter comparison circuit 74 transmits a test signal Snb indicating the rotation direction of the motor 21 and the count value Nn when the counter comparison circuit 74 is diagnosed. Based on this, the counter comparison circuit 74 is diagnosed. Specifically, the counter BIST circuit 84 transmits a signal whose difference between the count value Nn indicated by the test signal Snb and the previous value Nn−1 does not correspond to the rotation direction of the motor 21. When the comparison circuit 74 does not set the counter abnormality flag, a counter BIST abnormality flag (not shown) indicating that an abnormality has occurred in the counter comparison circuit 74 is set. On the other hand, when the counter BIST circuit 84 transmits a signal in which the difference between the count value Nn indicated by the test signal Snb and the previous value Nn-1 does not correspond to the rotation direction of the motor 21, the counter comparison circuit 74 counts the counter. When the abnormality flag is set, the counter BIST abnormality flag is not set.

When at least one of the above BIST abnormality flags is set, the microcomputer 42 notifies that effect through a warning lamp (not shown) and stops the calculation of the steering angle.
Next, the operation of the steering control device 6 will be described.

  As shown in FIG. 3, when the start switch 35 is off, the microcomputer 42 is stopped because the control voltage Vco is not supplied from the interface group 41 (power supply circuit 61) to the microcomputer 42. At this time, the main circuit 60 intermittently acquires the detection signals Sd1 and Sd2 at a predetermined intermittent period to detect the rotation direction of the motor 21 and the count value Nn, and the abnormality detection circuit 70 detects abnormality of the main circuit 60. Do. Thereby, even when the start switch 35 is off, for example, when the steering wheel 2 is steered, the count value Nn is increased or decreased by the arithmetic processing of the interface group 41.

  Here, when the start switch 35 is turned on at time t1, the control voltage Vco supplied to the microcomputer 42 rises, becomes stable within a predetermined voltage range at time t2, and arithmetic processing in the microcomputer 42 is started. . At this time, the microcomputer 42 detects the steering angle based on the count value Nn continuously increased or decreased even when the start switch 35 is turned off by the interface group 41. Thereby, the steering angle calculated by the microcomputer 42 includes an angle change that occurs when the start switch 35 is turned off.

  The main circuit 60 and the abnormality detection circuit 70 are intermittent in the initial period until the control voltage Vco supplied to the microcomputer 42 is stabilized, that is, from the time t1 to the time t2, in the same manner as when the start switch 35 is turned off. Operates on. Further, after time t2, the main circuit 60 continuously acquires the detection signals Sd1 and Sd2 to detect the rotation direction and the count value Nn, and the abnormality detection circuit 70 detects abnormality of the main circuit 60. In the interface group 41, the power supply BIST circuit 81, the arithmetic BIST circuit 82, and the sensor BIST circuit are in the initial period, immediately before or after the main circuit 60 and the abnormality detection circuit 70 perform the intermittent operation. 83 and a diagnosis by the counter BIST circuit 84 is performed.

The operation and effect of this embodiment will be described.
(1) Since the interface group 41 includes the BIST circuit 80 that diagnoses the abnormality detection circuit 70, the BIST circuit 80 can detect that an abnormality has occurred in the abnormality detection circuit 70. Therefore, when the count value Nn calculated by the main circuit 60 is abnormal, it can be prevented that the count value Nn is output without being detected by the abnormality detection circuit 70. Thereby, the reliability of the count value Nn output from the interface group 41 (main circuit 60) can be improved.

  (2) The BIST circuit 80 is operated by the BIST circuit 80 after the start switch 35 is turned on until the control voltage Vco is stabilized, that is, before the microcomputer 42 starts a calculation process such as a steering angle. Since the diagnosis 70 is performed, it is possible to suppress the diagnosis by the BIST circuit 80 from affecting the arithmetic processing of the microcomputer 42.

  (3) In the BIST circuit 80, the main circuit 60 and the abnormality detection circuit 70 perform processing for calculating the count value Nn based on the detection signals Sd1 and Sd2 detected by the first and second rotation angle sensors 33 and 34. Since the diagnosis of the abnormality detection circuit 70 is performed when there is not, it is possible to suppress the diagnosis by the BIST circuit 80 from affecting the calculation of the count value Nn and the abnormality detection.

  (4) Since the voltage abnormality detection circuit 71 for detecting an abnormality in the power supply circuit 61 is diagnosed by the power supply BIST circuit 81, the count value Nn calculated in a state where a normal control voltage is not supplied is output. Can be suppressed.

  (5) Since the calculation rotation direction comparison circuit 72 that detects an abnormality of the rotation direction detection circuit 65 based on the rotation direction signal Srd and the calculation redundancy signal Scp is diagnosed by the calculation BIST circuit 82, the rotation detected by the abnormal calculation Output of the direction to the counter 68 can be suppressed.

  (6) Since the sensor BIST circuit 83 diagnoses the sensor rotation direction comparison circuit 73 that detects the abnormality of the detection signals Sd1 ′ and Sd2 ′ based on the rotation direction signal Srd and the sensor redundancy signal Ssp, the abnormal detection signal Sd1 The rotation direction detected based on 'can be prevented from being output to the counter 68.

  (7) Since the counter BIST circuit 84 diagnoses the counter comparison circuit 74 that detects the abnormality of the counter 68 based on the comparison between the count value Nn and the previous value Nn-1 while considering the rotation direction, Output of the count value Nn to the microcomputer 42 can be suppressed.

This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
In the above embodiment, the interface group 41 may be stopped after the calculation process by the microcomputer 42 is started. In this case, the microcomputer 42 continuously steers by increasing or decreasing the steering angle based on the count value Nn acquired at the start of the arithmetic processing according to the rotation angle of the motor 21 obtained based on the detection signal Sd1. The corner can be calculated.

  In the above embodiment, the detection signal Sd1 is input to the microcomputer 42. However, the present invention is not limited to this. For example, the detection signal Sd1 'after A / D conversion may be input. That is, the interface group 41 may output the count value Nn and the detection signal Sd1 'as rotation information to the microcomputer 42.

  In the above embodiment, the rotation direction detection circuit 65 detects whether the rotation angle of the motor 21 is located in the first to fourth quadrants based on the binarized detection signal Sd1 ′. Alternatively, for example, the rotation angle of the motor 21 may be calculated from the detection signal Sd1 ′ using an arctangent function, and it may be detected which of the first to fourth quadrants is based on the calculated rotation angle. In this case, the rotation direction of the motor 21 may be detected based on the calculated change amount (differential value) of the rotation angle. Note that the operation redundancy circuit 66 and the sensor redundancy circuit 67 may similarly detect the rotation direction of the motor 21 by other methods.

  In the above embodiment, as long as the main circuit 60 includes at least the power supply circuit 61, the A / D converter 63, the rotation direction detection circuit 65, and the counter 68, for example, a configuration that does not include the operation redundancy circuit 66 may be used. The configuration of the main circuit 60 can be changed as appropriate.

  In the above embodiment, the abnormality detection circuit 70 includes the voltage abnormality detection circuit 71, the calculation rotation direction comparison circuit 72, the sensor rotation direction comparison circuit 73, and the counter comparison circuit 74. However, the present invention is not limited to this, and at least one of these is provided. If it is provided, other circuits may be eliminated, and the configuration of the abnormality detection circuit 70 can be changed as appropriate.

  In the above embodiment, the power supply BIST circuit 81 detects the voltage abnormality based on whether or not the voltage abnormality detection circuit 71 sets the voltage abnormality flag when at least one of the upper limit value Vup and the lower limit value Vlo is changed. The circuit 71 was diagnosed. However, the present invention is not limited to this. For example, when a test signal indicating a voltage is transmitted to the voltage abnormality detection circuit 71, the diagnosis may be performed based on whether or not the voltage abnormality detection circuit 71 sets a voltage abnormality flag. . Further, the diagnostic method using the arithmetic BIST circuit 82, the sensor BIST circuit 83, and the counter BIST circuit 84 can be changed as appropriate.

  In the above embodiment, the BIST circuit 80 includes the power supply BIST circuit 81, the arithmetic BIST circuit 82, the sensor BIST circuit 83, and the counter BIST circuit 84. However, the present invention is not limited to this, and as long as at least one of these is included. Other circuits may be eliminated, and the configuration of the BIST circuit 80 can be changed as appropriate.

  In the above-described embodiment, the arithmetic unit is configured by the interface group 41. However, the arithmetic unit is not limited to this. It may be configured.

  In the above embodiment, EPS1 is adopted as the steering device to be controlled by the steering control device 6, and the microcomputer 42 calculates the steering angle of the steering wheel 2 (steering shaft 11). However, the present invention is not limited to this, for example, a steer-by-wire (SBW) type steering device is employed, and the microcomputer 42 calculates the rotation angle of a pinion shaft or the like as a rotation axis that can be converted into the turning angle of the steered wheels 3 as an absolute angle. May be.

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus (EPS), 6 ... Steering control apparatus (rotation angle detection apparatus), 21 ... Motor, 21a ... Rotating shaft, 33 ... 1st rotation angle sensor (rotation angle sensor), 34 ... 2nd rotation angle Sensor (redundant rotation angle sensor), 35 ... start switch, 41 ... interface group (arithmetic unit), 42 ... microcomputer (steering angle arithmetic unit), 60 ... main circuit, 61 ... power supply circuit, 63, 64 ... A / D conversion 65 ... rotational direction detection circuit, 66 ... arithmetic redundancy circuit, 67 ... sensor redundancy circuit, 68 ... counter, 69 ... previous value output circuit, 70 ... abnormality detection circuit, 71 ... voltage abnormality detection circuit, 72 ... arithmetic rotation direction Comparison circuit 73 ... Sensor rotation direction comparison circuit, 74 ... Counter comparison circuit, 80 ... BIST circuit, 81 ... Power supply BIST circuit, 82 ... Operation BIST circuit, 83 ... Sensor BIST circuit, 84 Counter BIST circuit, Nn: count value, Nn-1: previous value, Scp: operation redundancy signal, Scb, Snb, Ssb ... test signal, Sd1, Sd2 ... detection signal, Sig ... start signal, Srd ... rotation direction signal, Ssp ... sensor redundancy signal, Vco ... control voltage, Vlo ... lower limit value, Vup ... upper limit value.

Claims (7)

Based on a detection signal from a rotation angle sensor that detects a rotation angle of a motor connected to a rotation shaft that can be converted into a turning angle of a steered wheel, a rotation information indicating a rotation state of the rotation shaft is calculated. The main circuit;
An abnormality detection circuit for detecting an abnormality of the main circuit;
An arithmetic unit comprising a BIST circuit for diagnosing the abnormality detection circuit. The arithmetic unit according to claim 1,
The BIST circuit is a control supplied to a rudder angle calculation device that calculates a rotation angle of the rotation shaft indicated by an absolute angle based on the rotation information output from the main circuit after turning on a vehicle start switch. An arithmetic unit for diagnosing the abnormality detection circuit during an initial period until the voltage becomes stable. In the arithmetic unit according to claim 1 or 2,
The main circuit calculates the rotation information by intermittently obtaining the detection signal from the rotation angle sensor when the start switch of the vehicle is off.
The abnormality detection circuit detects an abnormality of the main circuit at the time of calculation of the main circuit when the start switch is off,
The BIST circuit is an arithmetic unit for diagnosing the abnormality detection circuit when the start switch is off and the main circuit is not calculating the rotation information. In the arithmetic unit as described in any one of Claims 1-3,
The main circuit includes a power supply circuit that generates a control voltage to be supplied to another circuit based on the power supply voltage,
The abnormality detection circuit includes a voltage abnormality detection circuit that detects an abnormality based on whether or not the control voltage is within a predetermined voltage range set in advance,
The BIST circuit includes a power supply BIST circuit for diagnosing the voltage abnormality detection circuit based on whether or not an abnormality is detected by the voltage abnormality detection circuit when the upper and lower limit values defining the predetermined voltage range are changed. Including arithmetic unit. In the arithmetic unit as described in any one of Claims 1-4,
The main circuit is:
Based on the detection signal from the rotation angle sensor, it is detected which of the quadrants obtained by dividing the rotation range of the motor into a plurality of divided quadrants, and the rotation of the motor based on the transition of the quadrant of the rotation angle A rotation direction detection circuit for detecting a direction;
A calculation redundant circuit for detecting in which quadrant the rotation angle is located based on a detection signal from the rotation angle sensor, and detecting a rotation direction of the motor based on transition of the quadrant of the rotation angle; Including
The abnormality detection circuit includes a calculation rotation direction comparison circuit that detects an abnormality based on a comparison between the rotation direction detected by the rotation direction detection circuit and the rotation direction detected by the calculation redundancy circuit;
The BIST circuit compares the calculated rotation direction based on whether or not an abnormality is detected by the calculated rotation direction comparison circuit when a test signal indicating the rotation direction is transmitted to the calculated rotation direction comparison circuit. An arithmetic unit including an arithmetic BIST circuit for diagnosing a circuit. In the arithmetic unit according to any one of claims 1 to 5,
The main circuit is:
Based on the detection signal from the rotation angle sensor, it is detected which of the quadrants obtained by dividing the rotation range of the motor into a plurality of divided quadrants, and the rotation of the motor based on the transition of the quadrant of the rotation angle A rotation direction detection circuit for detecting a direction;
The rotation angle of the motor provided separately from the rotation angle sensor is detected based on a detection signal from a redundant rotation angle sensor that detects the rotation angle as a relative angle, and the rotation angle is detected in which of the quadrants. A sensor redundant circuit that detects a rotation direction of the motor based on a transition of the quadrant of a corner;
The abnormality detection circuit includes a sensor rotation direction comparison circuit that detects an abnormality based on a comparison between the rotation direction detected by the rotation direction detection circuit and the rotation direction detected by the sensor redundant circuit;
The BIST circuit compares the sensor rotation direction based on whether or not an abnormality is detected by the sensor rotation direction comparison circuit when a test signal indicating the rotation direction is transmitted to the sensor rotation direction comparison circuit. An arithmetic unit including a sensor BIST circuit for diagnosing a circuit. In the arithmetic unit according to any one of claims 1 to 6,
The main circuit is:
Based on a detection signal from the rotation angle sensor, it is detected which of the quadrants obtained by dividing the rotation range of the motor into a plurality of quadrants. A rotation direction detection circuit for detecting a direction;
A counter that counts a count value as the rotation information indicating the number of rotations of the motor based on the rotation direction of the motor;
A previous value output circuit that outputs the previous value of the count value output from the counter,
The abnormality detection circuit includes a counter comparison circuit that detects an abnormality based on a comparison between the count value and the previous value in consideration of the rotation direction;
When the BIST circuit transmits a test signal indicating the rotation direction and the count value to the counter comparison circuit, based on whether or not an abnormality is detected by the counter comparison circuit, the counter comparison circuit Arithmetic unit including a counter BIST circuit for diagnosing