JP2016118448A - Position detection device - Google Patents

Abstract

Provided is a position detection device capable of reducing the possibility of overlapping periods of driving of respective excitation coils when each detection unit is activated. In a position detection device, a processing unit (processing unit 33) is configured to detect a detection coil 22 (detection coil 32) in accordance with the position of an object 100 by driving an excitation coil 21 (excitation coil 31) during a measurement period. The acquisition process for acquiring the detection signal Y1 (detection signal Y2) induced by the The processing unit 33 monitors and executes whether or not the processing unit 23 is executing the acquisition process without driving the exciting coil 31 in the monitoring period set before the measurement period in the processing unit 33. If so, it is configured to execute a predetermined process. [Selection] Figure 1

Description

  The present invention generally relates to a position detection device, and more particularly to a position detection device including a plurality of detection units.

  Conventionally, an electromagnetic induction type displacement sensor (position detection device) that includes two detection circuits (detection units) and can detect the displacement of an object with the other detection unit even if one detection unit fails is provided. For example, it is disclosed in Patent Document 1. The position detection device includes two detection units each including a coil drive unit, two drive coils (excitation coils) connected to the coil drive units, and two detection coils connected to the detection units, respectively. It has. Further, this position detection device has an electromagnetic coupling member that can be displaced relative to the excitation coil and the detection coil. Each coil driving unit includes an oscillation circuit connected to a corresponding excitation coil and a timer that outputs an oscillation inhibition signal to the other oscillation circuit.

  In this position detection device, while one coil drive unit is driving the excitation coil, the drive of the other excitation coil is interrupted by the oscillation inhibition signal from the timer so that the two detection units are electromagnetically coupled in a time-sharing manner. The displacement of the member is detected.

JP 2005-265463 A

  However, in the above-described conventional example, it is not assumed that the periods in which the excitation coils are driven overlap each other when the detection units are activated. For this reason, in the above-described conventional example, when the periods for driving the respective excitation coils overlap at the time of activation of the respective detection units, for example, detection by the respective detection units may be performed at the same time and magnetic interference may occur.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a position detection device that can reduce the possibility that the periods during which the excitation coils are driven overlap each other when the detection units are activated.

  The position detection device of the present invention includes a first detection unit and a second detection unit, and the first detection unit includes a first excitation coil, a first detection coil, and a first processing unit. The two detection units include a second excitation coil, a second detection coil, and a second processing unit, and the first excitation coil is magnetically coupled to the first detection coil and the second detection coil, respectively. And the second excitation coil is magnetically coupled to the first detection coil and the second detection coil, respectively, and the first processing unit drives the first excitation coil during a measurement period, And it is comprised so that the 1st acquisition processing which acquires the 1st detection signal guided to the 1st detection coil according to the position of the object according to the drive of the 1st excitation coil may be performed intermittently, and the 2nd The processing unit includes the second excitation coil in the measurement period. And a second acquisition process for acquiring a second detection signal induced in the second detection coil according to the position of the object by driving the second excitation coil. In the monitoring period set before the measurement period in the second processing unit, the second processing unit does not drive the second excitation coil, and the first processing unit performs the first acquisition process. It is characterized in that it is configured to monitor whether or not it is executed and to execute a predetermined process when it is executed.

  In the position detection device, the second processing unit determines that the first processing unit is executing the first acquisition process when a signal is induced in the second detection coil during the monitoring period. It is preferable that it is comprised.

  In the position detection device, the first processing unit and the second processing unit are electrically connected to each other via a communication line, and the second processing unit receives a signal flowing through the communication line during the monitoring period. It is preferable that when there is a change, the first processing unit is configured to determine that the first acquisition process is being performed.

  In this position detection device, it is preferable that the process is a process of adjusting the start time of the measurement period in the second processing unit so as not to overlap the first acquisition process.

  In this position detection apparatus, it is preferable that the predetermined process is a process of stopping the operation of the second processing unit.

  In the position detection device, the second processing unit is guided to the second detection coil by driving the first excitation coil so that the period is divided between the first acquisition process and the second acquisition process. Preferably, the second acquisition process is executed at a timing based on the three detection signals.

  In this position detection device, it is preferable that the second processing unit is configured to determine the timing based on a lapse of a predetermined time after the induction of the third detection signal is completed.

  In this position detection apparatus, it is preferable that the second processing unit is configured to determine the timing based on a lapse of a certain time after starting the induction of the third detection signal.

  In this position detection device, the second processing unit has a function of counting the wave number of the third detection signal, and the second processing unit is based on the fact that the wave number has reached a predetermined number of times. It is preferable that the timing is determined.

  In this position detection device, the second processing unit has a function of measuring the amplitude of the third detection signal, and the second processing unit is configured based on the fact that the amplitude falls below a predetermined threshold. It is preferable that the timing is determined.

  In this position detection device, the first processing unit has a function of giving an end signal notifying the end of the first acquisition process to the first excitation coil, and the second processing unit is configured to perform the second detection. It is preferable that the timing is determined based on detecting the end signal induced in the coil.

  In the position detection device, it is preferable that the first processing unit is configured to stop the operation when the first detection signal is not detected in the first acquisition process.

  In the position detection device, the second processing unit has a function of measuring a second standby time when the second acquisition process is completed, and the second processing unit is within the second standby time. When the third detection signal is not detected, the second acquisition process is preferably executed.

  In this position detection device, when the second detection unit does not detect the third detection signal within the second standby time, the second acquisition unit is switched to a mode different from the normal time to execute the second acquisition process. It is preferable to be configured.

  In the position detection device, the first processing unit has a function of measuring a first waiting time when the first acquisition processing is completed, and the first processing unit drives the second excitation coil. When the fourth detection signal induced by the first detection coil is not detected within the first waiting time, the first acquisition process is performed, and the first waiting time and the second waiting time are configured. It is preferable that the times are different from each other.

  In this position detection apparatus, the second processing unit has a function of measuring a determination time when the second acquisition process is completed, and the second processing unit detects the third detection within the determination time. It is preferably configured to stop operation when a signal is detected.

  In this position detection apparatus, it is preferable that the period for executing the first acquisition process and the period for executing the second acquisition process have different lengths.

  In the position detection device, the first processing unit may be configured such that the second processing unit does not drive the first exciting coil in the monitoring period set before the measurement period in the first processing unit. Whether or not the second acquisition process is being executed is monitored, and when the second acquisition process is not being executed, the first acquisition process is preferably executed at the end of the monitoring period.

  In this position detection apparatus, it is preferable that two detection units are provided, and one of the two detection units is configured as the first detection unit and the other detection unit is configured as the second detection unit.

  In the present invention, the second processing unit monitors whether or not the first processing unit is executing the first acquisition process in the monitoring period before starting the measurement period, so that the predetermined value is determined according to the determination result. Can be executed. Therefore, the present invention can reduce the possibility that the first acquisition process and the second acquisition process are performed at the same time when each detection unit is activated, that is, the periods in which the excitation coils are driven overlap each other.

It is a schematic block diagram which shows an example of the position detection apparatus which concerns on Embodiment 1. FIG. FIG. 3 is a waveform diagram of each signal in the position detection device according to the first embodiment. FIG. 5 is a waveform diagram of each signal illustrating an example of timing determination in the position detection device according to the first embodiment. 5 is a time chart illustrating an example of an operation when a failure is detected in the position detection device according to the first embodiment. 3 is a time chart illustrating an example of an operation of the position detection apparatus according to the first embodiment. 5 is a flowchart illustrating an example of an operation in a measurement period of the position detection device according to the first embodiment. 3 is a time chart illustrating an example of an operation in a monitoring period of the position detection device according to the first embodiment. FIG. 8A and FIG. 8B are time charts showing an example of the operation when the activation timing of each detection unit is shifted in the position detection device according to the first embodiment. 5 is a time chart illustrating an example of an operation when each detection unit executes an acquisition process at almost the same timing in the position detection device according to the first embodiment. FIG. 10A is a time chart showing an example of the operation of the position detection device according to the first modification, and FIG. 10B is the position detection device according to the first modification, in which each detection unit executes acquisition processing at almost the same timing. It is a time chart which shows an example of the operation | movement at the time of doing. FIG. 11A is a time chart showing an example of the operation of the position detection device according to the second modified example, and FIG. 11B is the position detection device according to the second modified example, and each detection unit executes acquisition processing at almost the same timing. It is a time chart which shows an example of the operation | movement at the time of doing. It is a schematic block diagram which shows an example of the position detection apparatus which concerns on Embodiment 2. 10 is a time chart illustrating an example of an operation in a monitoring period of the position detection device according to the second embodiment. 9 is a time chart illustrating an example of an operation when the timings at which the detection units are activated are shifted in the position detection device according to the second embodiment.

(Embodiment 1)
As shown in FIG. 1, the position detection device 1 according to Embodiment 1 of the present invention includes a detection unit 2 (here, a first detection unit) and a detection unit 3 (here, a second detection unit). . The detection unit 2 includes a (first) excitation coil 21, a (first) detection coil 22, and a (first) processing unit 23. The detection unit 3 includes a (second) excitation coil 31, a (second) detection coil 32, and a (second) processing unit 33. The excitation coil 21 is magnetically coupled to the detection coil 22 and the detection coil 32, respectively. In addition, the excitation coil 31 is magnetically coupled to the detection coil 22 and the detection coil 32, respectively.

  The processing unit 23 is configured to intermittently execute the (first) acquisition process during the measurement period. In the (first) acquisition process, the excitation coil 21 is driven, and the excitation coil 21 is driven to the detection coil 22 in accordance with the position of the object 100 (first) the detection signal Y1 (see FIG. 2). It is a process to acquire. The processing unit 33 is configured to intermittently execute the (second) acquisition process in the measurement period. In the (second) acquisition process, the excitation coil 31 is driven, and the excitation coil 31 is driven to guide the detection coil 32 according to the position of the object 100 (second) detection signal Y2 (see FIG. 2). It is a process to acquire.

  Then, the processing unit 33 monitors whether or not the processing unit 23 is executing the acquisition process without driving the excitation coil 31 in the monitoring period set before the measurement period in the processing unit 33, and executes it. If so, it is configured to execute predetermined processing.

  Hereinafter, the position detection device 1 according to Embodiment 1 of the present invention will be described in detail. However, the configuration described below is only an example of the present invention, and the present invention is not limited to the following embodiment, and the technical idea according to the present invention is not deviated from this embodiment. Various changes can be made in accordance with the design or the like as long as they are not.

<Basic configuration>
First, the basic configuration of the position detection device 1 of the present embodiment will be described. As shown in FIG. 1, the position detection device 1 according to the present embodiment includes a detection unit 2 and a detection unit 3 that detect the position of the object 100. In the position detection device 1 of the present embodiment, the object 100 is a metal piece interlocked with a vehicle brake pedal. Therefore, the position detection device 1 of the present embodiment can be used to detect the amount of depression of the brake by detecting the position of the metal piece. Of course, it is not intended to limit the application of the position detection device 1, and may be other applications as long as it is an application for detecting the position of the object 100.

  The detection unit 2 includes an excitation coil 21, a detection coil 22, a processing unit 23, and an amplifier 24. The detection unit 3 includes an excitation coil 31, a detection coil 32, a processing unit 33, and an amplifier 34. The detection units 2 and 3 are configured to be mounted on a single substrate, for example. Further, the excitation coil 21, the detection coil 22, the excitation coil 31, and the detection coil 32 are arranged in the same region on the substrate. Therefore, the excitation coil 21 is magnetically coupled to the detection coils 22 and 32, respectively. The excitation coil 31 is magnetically coupled to the detection coils 22 and 32, respectively. Of course, the arrangement of the excitation coils 21 and 31 and the detection coils 22 and 32 is not limited, and any arrangement may be used as long as they are magnetically coupled to each other.

  In FIG. 1, the excitation coil 21, the detection coil 22, the excitation coil 31, and the detection coil 32 are each configured by a single coil, but may be configured by combining a plurality of coils.

  The processing unit 23 is connected to an ECU (Electronic Control Unit) 4 via electric wires 41 to 43. Further, the processing unit 33 is connected to the ECU 4 via the electric wires 44 to 46. The electric wire 41 (electric wire 44) is a power supply line for supplying an operating voltage to the processing unit 23 (processing unit 33). The electric wire 42 (electric wire 45) is a signal line used for communication between the processing unit 23 (processing unit 33) and the ECU 4. Here, the communication method between the processing unit 23 (processing unit 33) and the ECU 4 may be either an analog communication method or a digital communication method. When the communication method is digital, bidirectional communication is possible between the processing unit 23 (processing unit 33) and the ECU 4 via the electric wire 42 (electric wire 45). The electric wire 43 (electric wire 46) is a ground wire used for connecting the ground of the processing unit 23 (processing unit 33) and the ground of the ECU 4 to each other.

  The processing unit 23 (processing unit 33) is configured by, for example, a microcomputer. Of course, the processing unit 23 (processing unit 33) may be configured by hardware other than the microcomputer such as an FPGA (Field-Programmable Gate Array) or a dedicated IC (Integrated Circuit) instead of the microcomputer. The processing unit 23 (processing unit 33) may be configured by integrating a later-described amplifier 24 (amplifier 34) with a microcomputer or hardware other than the microcomputer. Furthermore, the processing unit 23 (processing unit 33) may be configured by combining a microcomputer and other hardware.

<Measurement period>
In the position detection device 1 of the present embodiment, the processing unit 23 (33) performs different operations in the measurement period in which the position of the object 100 is actually detected and the monitoring period set before the measurement period. It is configured. First, the operation of the processing unit 23 (processing unit 33) during the measurement period will be described.

  The processing unit 23 (processing unit 33) is configured to intermittently execute a position detection process for detecting the position of the object 100. In the position detection device 1 of the present embodiment, the position detection process includes an acquisition process and a calculation process. In the acquisition process, the processing unit 23 (processing unit 33) gives the excitation coil 21 (excitation coil 31) a drive signal X1 (drive signal X2) that is a rectangular wave having a predetermined frequency and a predetermined wave number, thereby exciting the excitation coil. 21 (excitation coil 31) is driven (see FIG. 2). In the position detection device 1 of the present embodiment, the processing unit 23 (processing unit 33) drives the excitation coil 21 (excitation coil 31) by giving the drive signal X1 (drive signal X2). It may be a configuration. For example, a resonance capacitor (not shown) is connected in parallel with the excitation coil 21 (excitation coil 31) to form a resonance circuit, and the processing unit 23 (processing unit 33) applies positive feedback to the resonance circuit. It may be configured to oscillate and drive the excitation coil 21 (excitation coil 31). That is, the processing unit 23 (processing unit 33) only needs to be configured to drive the excitation coil 21 (excitation coil 31).

  In the acquisition process, the processing unit 23 (processing unit 33) acquires the detection signal Y1 (detection signal Y2) that is induced in the detection coil 22 (detection coil 32) by driving the excitation coil 21 (excitation coil 31). (See FIG. 2). In order to acquire the detection signal Y1 (detection signal Y2), for example, a built-in timer or ADC (Analog to Digital Converter) is used. In the position detection device 1 of the present embodiment, the detection signal Y1 (detection signal Y2) induced in the detection coil 22 (detection coil 32) is amplified by the amplifier 24 (amplifier 34) and then processed by the processing unit 23 (processing unit 33). ).

  Here, the object 100 is magnetically coupled to the excitation coil 21 (excitation coil 31), and an induced current flows by driving the excitation coil 21 (excitation coil 31). Since the induced current changes according to the position of the object 100, the detection signal Y1 (detection signal Y2) also changes according to the position of the object 100. Therefore, the processing unit 23 (processing unit 33) executes arithmetic processing for calculating the position of the object 100 based on the acquired detection signal Y1 (detection signal Y2). Note that the time required for the acquisition process and the calculation process is, for example, 1 ms.

  That is, assuming that the detection unit 2 is the first detection unit, the processing unit 23 (first processing unit) is configured to intermittently execute the (first) acquisition process in the measurement period. In the (first) acquisition process, the processing unit 23 drives the excitation coil 21 by giving a drive signal X1 to the excitation coil 21 (first excitation coil). And the process part 23 acquires the detection signal Y1 (1st detection signal) induced | guided | derived to the detection coil 22 (1st detection coil) according to the position of the target object 100 by the drive of the excitation coil 21. FIG. Assuming that the detection unit 3 is the second detection unit, the processing unit 33 (second processing unit) is configured to intermittently execute the (second) acquisition process in the measurement period. In the (second) acquisition process, the processing unit 33 drives the excitation coil 31 by giving the drive signal X2 to the excitation coil 31 (second excitation coil). Then, the processing unit 33 acquires a detection signal Y2 (second detection signal) that is induced in the detection coil 32 (second detection coil) according to the position of the object 100 by driving the excitation coil 31.

  The processing unit 23 (processing unit 33) determines the timing for executing the acquisition process in a state where the acquisition process is not being executed (hereinafter referred to as “standby state”), and executes the acquisition process at the determined timing. Is configured to do. For example, it is assumed that the processing unit 23 of the detection unit 2 is executing acquisition processing and the processing unit 33 of the detection unit 3 is in a standby state. In this case, a detection signal Y3 is induced in the detection coil 32 by driving the excitation coil 21 (see FIG. 2). The processing unit 33 determines the timing for executing the acquisition process based on the detection signal Y3. And the process part 33 performs an acquisition process at the determined timing.

  Similarly, it is assumed that the processing unit 33 of the detection unit 3 is executing an acquisition process and the processing unit 23 of the detection unit 2 is in a standby state. In this case, a detection signal Y4 is induced in the detection coil 22 by driving the excitation coil 31 (see FIG. 2). The processing unit 23 determines the timing for executing the acquisition process based on the detection signal Y4. And the process part 23 performs an acquisition process at the determined timing.

  That is, assuming that the detection unit 2 is a first detection unit and the detection unit 3 is a second detection unit, the above processing can be expressed as follows. That is, the processing unit 23 (first processing unit) executes the (first) acquisition process so that the period is divided between the (first) acquisition process and the (second) acquisition process. More specifically, the processing unit 23 (first processing unit) detects the detection signal Y4 (fourth detection signal) induced in the detection coil 22 (first detection coil) by driving the excitation coil 31 (second excitation coil). ) Based on the (first) acquisition process. Further, the processing unit 33 (second processing unit) executes the (second) acquisition process so that the periods are divided between the (first) acquisition process and the (second) acquisition process. More specifically, the processing unit 33 (second processing unit) detects the detection signal Y3 (third detection signal) that is induced in the detection coil 32 (second detection coil) by driving the excitation coil 21 (first excitation coil). ) Is performed at a timing based on (2).

  In the position detection device 1 according to the present embodiment, as illustrated in FIG. 3, the processing unit 33 determines the timing based on the elapse of a certain time T12 after the induction of the detection signal Y3 is completed. That is, the period during which the detection unit 2 executes the acquisition process is a period in which the drive signal X1 is given to the excitation coil 21, and the detection signal Y3 is induced in the detection coil 32 during this period. Therefore, the processing unit 33 determines that the acquisition process by the detection unit 2 has ended with the end of the induction of the detection signal Y3, and executes the acquisition process after a predetermined time T12 has elapsed. Similarly, the processing unit 23 determines the timing based on the elapse of a predetermined time T12 after the induction of the detection signal Y4 is completed.

  That is, assuming that the detection unit 2 is a first detection unit and the detection unit 3 is a second detection unit, the above processing can be expressed as follows. That is, the processing unit 33 (second processing unit) is configured to determine the timing based on the elapse of a predetermined time T12 after the induction of the detection signal Y3 (third detection signal) is completed. Similarly, the processing unit 23 (first processing unit) is configured to determine the timing based on the elapse of a predetermined time T12 after the induction of the detection signal Y4 (fourth detection signal) is completed. . The fixed time T12 in the processing unit 23 and the fixed time T12 in the processing unit 33 may be the same length or may be different from each other.

  In order to realize the above processing, for example, a configuration in which the detection signal Y3 (detection signal Y4) is periodically read by the ADC is conceivable. In this configuration, it is possible to determine that the induction of the detection signal Y3 (detection signal Y4) has ended when the level of the read signal continuously falls below a predetermined threshold. Moreover, in order to implement | achieve said process, the structure which resets the said counter using a free running counter as a trigger that detection signal Y3 (detection signal Y4) switches from a low level to a high level, for example can be considered. In this configuration, when the counter overflows or reaches a predetermined count value, it can be determined that the induction of the detection signal Y3 (detection signal Y4) has ended.

  Here, the period during which the processing unit 23 (processing unit 33) executes the acquisition process is a period in which the drive signal X1 (drive signal X2) is given to the excitation coil 21 (excitation coil 31) (see FIG. 3). The time required for the acquisition process is set in advance. The detection signal Y3 (detection signal Y4) is guided to the detection coil 32 (detection coil 22) when the excitation coil 21 (excitation coil 31) is driven. That is, if the timing at which the detection signal Y3 (detection signal Y4) is guided to the detection coil 22 (detection coil 32) is detected, the timing at which the acquisition process ends can be detected.

  Therefore, as illustrated in FIG. 3, the processing unit 33 (second processing unit) determines the timing based on the elapse of a certain time T11 from the start of the induction of the detection signal Y3 (third detection signal). You may comprise as follows. Similarly, the processing unit 23 (first processing unit) may be configured to determine the timing based on the elapse of a certain time T11 from the start of the induction of the detection signal Y4 (fourth detection signal). Good. The fixed time T11 in the processing unit 23 and the fixed time T11 in the processing unit 33 may be the same length or may be different from each other.

  Further, since the time required for the acquisition process is preset, the wave number of the drive signal X1 (drive signal X2) is also preset. That is, if the wave number of the detection signal Y3 (detection signal Y4) is counted, the timing at which the acquisition process ends can be detected based on the fact that the wave number has reached a predetermined number.

  Therefore, the processing unit 33 (second processing unit) may have a function of counting the wave number of the detection signal Y3 (third detection signal). Then, the processing unit 33 may be configured to determine the timing based on the fact that the wave number has reached a predetermined number. Similarly, the processing unit 23 (first processing unit) may have a function of counting the wave number of the detection signal Y4 (fourth detection signal). Then, the processing unit 23 may be configured to determine the timing based on the fact that the wave number has reached a predetermined number. The function of counting the wave number of the detection signal Y3 (detection signal Y4) can be realized by conventionally known simple hardware or software.

  The timing at which the acquisition process ends can also be detected by detecting that the amplitude of the detection signal Y3 (detection signal Y4) has fallen below a predetermined threshold. Therefore, the processing unit 33 (second processing unit) may have a function of measuring the amplitude of the detection signal Y3 (third detection signal). Then, the processing unit 33 may be configured to determine the timing based on the fact that the amplitude has fallen below a predetermined threshold. Similarly, the processing unit 23 (first processing unit) may have a function of measuring the amplitude of the detection signal Y4 (fourth detection signal). Then, the processing unit 23 may be configured to determine the timing based on the fact that the amplitude has fallen below a predetermined threshold. The function of measuring the amplitude of the detection signal Y3 (detection signal Y4) can be realized by conventional well-known simple hardware or software such as a rectifier circuit or ADC.

  Although not shown in the position detection device 1 of the present embodiment, a resonance capacitor is connected in parallel with the detection coil 22 (detection coil 32), and is configured not to detect high-frequency noise. Yes. In this configuration, free vibration (reverberation) may remain in the detection signals Y1 to Y4 due to the resonance effect of the detection coil 22 (detection coil 32) and the resonance capacitor. Therefore, it is desirable that the processing unit 23 (processing unit 33) determines that the acquisition process is completed when the reverberation of the detection signal becomes sufficiently small. Whether or not a resonance capacitor is used is arbitrary.

  Further, the processing unit 23 (processing unit 33) executing the acquisition process may supply an end signal notifying the end of the acquisition process to the excitation coil 21 (excitation coil 31). The processing unit 23 (processing unit 33) in the standby state can detect the timing when the acquisition process ends when the end signal is guided to the detection coil 22 (detection coil 32). As the end signal, for example, a specific bit string or a signal having a frequency different from that of the drive signal X1 (drive signal X2) can be considered.

  That is, the processing unit 23 (first processing unit) may have a function of giving an end signal notifying the end of the (first) acquisition process to the exciting coil 21 (first exciting coil). Then, the processing unit 33 (second processing unit) may be configured to determine the timing based on detecting an end signal induced in the detection coil 32 (second detection coil). Similarly, the processing unit 33 (second processing unit) may have a function of giving an end signal notifying the end of the (second) acquisition processing to the excitation coil 31 (second excitation coil). And you may comprise the process part 23 (1st process part) so that a timing may be determined based on having detected the completion | finish signal induced | guided | derived to the detection coil 22 (1st detection coil).

  That is, the position detection device 1 of the present embodiment is configured to alternately execute the acquisition process by the processing unit 23 of the detection unit 2 and the acquisition process by the processing unit 33 of the detection unit 3 as shown in FIG. Has been. That is, when the acquisition process ends, the detection unit 2 shifts to a standby state, waits until the detection process of the detection unit 3 ends, and then executes the acquisition process again. Similarly, when the acquisition process ends, the detection unit 3 shifts to a standby state, waits until the detection process of the detection unit 2 ends, and then executes the acquisition process again. Therefore, since the detection unit 2 and the detection unit 3 execute the acquisition process alternately, the position detection device 1 of the present embodiment can prevent magnetic interference with each other.

  Further, in the position detection device 1 of the present embodiment, the processing unit 23 (processing unit 33) executes a process of determining whether or not the detection unit 2 (detecting unit 3) is normal when executing the acquisition process. To do. That is, in the processing unit 23 (processing unit 33), when the detection signal Y1 (detection signal Y2) is not induced in the detection coil 22 (detection coil 32), at least one of the excitation coil 21 or the detection coil 22 is out of order. Judge. And if the process part 23 (process part 33) judges that it has failed, it will output a failure signal to ECU4 and will stop operation | movement.

  That is, assuming that the detection unit 2 is a first detection unit and the detection unit 3 is a second detection unit, the above processing can be expressed as follows. That is, the processing unit 23 (first processing unit) is configured to stop the operation when the detection signal Y1 (first detection signal) is not detected in the (first) acquisition process. Similarly, the processing unit 33 (second processing unit) is configured to stop the operation when the detection signal Y2 (second detection signal) is not detected in the (second) acquisition process.

  In this configuration, since the acquisition process is not executed by the detection unit 2 (detection unit 3) in which some failure has occurred, the acquisition process can be executed by the normal detection unit 2 (detection unit 3). Therefore, with this configuration, it is possible to reduce the possibility of unnecessary mutual interference by the detection unit 2 (detection unit 3) in which some failure has occurred. Note that whether or not to adopt the configuration is arbitrary.

  Furthermore, in the position detection device 1 of the present embodiment, the processing unit 23 (processing unit 33) determines whether or not the detection unit 2 (detection unit 3) that should be executing the acquisition process is normal in the standby state. Execute the process to determine. That is, when the processing unit 23 (processing unit 33) finishes the acquisition process, the processing unit 23 (processing unit 33) counts the waiting time T2 with a built-in timer (see FIG. 4). Then, the processing unit 23 (processing unit 33) should be performing the acquisition process when the detection signal Y4 (detection signal Y3) is not induced in the detection coil 22 (detection coil 32) within the standby time T2. It is determined that the detection unit 3 (detection unit 2) is out of order. When it is determined that there is a failure, the processing unit 23 (processing unit 33) executes acquisition processing when the standby time T2 has elapsed. Thereafter, the processing unit 23 (processing unit 33) repeats the acquisition process every time the standby time T2 elapses.

  That is, assuming that the detection unit 2 is a first detection unit and the detection unit 3 is a second detection unit, the above processing can be expressed as follows. That is, the processing unit 33 (second processing unit) has a function of measuring the (second) standby time T2 when the (second) acquisition processing is completed. The processing unit 33 is configured to execute the (second) acquisition process when the detection signal Y3 (third detection signal) is not detected within the standby time T2. Similarly, the processing unit 23 (first processing unit) has a function of measuring the (first) waiting time T2 when the (first) acquisition processing is completed. Then, the processing unit 23 is configured to execute the (first) acquisition process when the detection signal Y4 (fourth detection signal) is not detected within the standby time T2.

  In this configuration, even if any failure occurs in the detection unit 2 (detection unit 3) that is executing the acquisition process, the detection unit 2 (detection unit 3) in a standby state continuously executes the acquisition process. Can do. Therefore, in this configuration, it is possible to avoid the detection unit 2 (detection unit 3) in the standby state from continuing to wait. Note that whether or not to adopt the configuration is arbitrary.

  In the above configuration, when the processing unit 23 (processing unit 33) determines that there is a failure, the processing unit 23 (processing unit 33) may switch to a mode different from the normal mode and repeat the acquisition process. For example, when it is determined that there is a failure, switching to a mode in which the standby time T2 is shortened can be considered. In this case, the interval at which the normal processing unit 23 (processing unit 33) executes the acquisition process can be reduced.

  That is, the processing unit 23 (first processing unit) switches to a mode different from the normal mode when the detection signal Y4 (fourth detection signal) is not detected within the (first) standby time T2 (first). You may be comprised so that an acquisition process may be performed. Similarly, the processing unit 33 (second processing unit) switches to a mode different from the normal mode when the detection signal Y3 (third detection signal) is not detected within the (second) standby time T2 (second processing). ) The acquisition process may be executed.

  The processing unit 23 (processing unit 33) performs an output process of outputting a position signal corresponding to the calculation result to the ECU 4 using, for example, a built-in DAC (Digital to Analog Converter) via the electric wire 42 (electric wire 45). To do. The processing unit 23 (processing unit 33) may be configured to output a position signal to the ECU 4 by a PWM (Pulse Width Modulation) method. In addition, the processing unit 23 (processing unit 33) may be configured to output a position signal to the ECU 4 by a radio signal using radio waves as a medium. In this configuration, the processing unit 23 (processing unit 33) and the ECU 4 each require a wireless module. Further, the processing unit 23 (processing unit 33) may execute the above-described arithmetic processing and output processing in parallel with the acquisition processing or may be executed in a standby state.

  The ECU 4 supplies the operating voltage to the detection unit 2 (detection unit 3) via the electric wire 41 (electric wire 44) using, for example, an operation such as starting the engine of the vehicle as a trigger, thereby causing the detection unit 2 and the detection unit 3 to operate. It has a function to start. In the position detection device 1 of the present embodiment, the ECU 4 starts the detection unit 2 and the detection unit 3 at the same timing. Note that “same” is an expression including “simultaneous” or “almost simultaneous”. Moreover, ECU4 reads the position signal output via the electric wire 42 (electric wire 45) from the detection part 2 (detection part 3) regularly (for example, every 3 ms). Thereby, the ECU 4 can know the position of the object 100. Then, the ECU 4 executes various processes according to the position of the object 100. The position signal is output to the ECU 4 as a DC voltage of 0.5 V to 4.5 V that varies depending on the position of the object 100, for example. Of course, the range of the position signal voltage is not limited to this range. The ECU 4 only needs to acquire a position signal from at least one of the detection unit 2 and the detection unit 3.

  Furthermore, the ECU 4 can know the presence or absence of a failure of the detection unit 2 (detection unit 3) from a failure signal output from the detection unit 2 (detection unit 3) via the electric wire 42 (electric wire 45). The failure signal is output to the ECU 4 as a DC voltage of 0.2V or less, or 4.8V or more, for example. Of course, the voltage of the failure signal is not limited to these voltages.

  In the position detection device 1 according to the present embodiment, the processing unit 23 (processing unit 33) performs arithmetic processing based on the acquired detection signal Y1 (detection signal Y2). Also good. For example, the processing unit 23 (processing unit 33) may be configured to output the acquired detection signal Y1 (detection signal Y2) to the ECU 4 without executing the arithmetic processing. In this configuration, the ECU 4 may calculate the position of the object 100 based on the detection signal Y1 (detection signal Y2).

  Hereinafter, an example of the operation in the measurement period of the position detection device 1 of the present embodiment will be specifically described with reference to the drawings. In the following description, it is assumed that the detection unit 2 is a first detection unit and the detection unit 3 is a second detection unit at startup. Of course, at the time of activation, the detection unit 3 may be the first detection unit and the detection unit 2 may be the second detection unit. As shown in FIG. 6, first, when the ECU 4 activates the detection units 2 and 3, the detection units 2 and 3 initialize the processing unit 23 (processing unit 33), and then start a monitoring period. Then, the detection units 2 and 3 start the measurement period after the monitoring period ends (S1). And since the detection part 2 is a 1st detection part (S2), the process part 23 performs an acquisition process before the process part 33 (S3).

  That is, the processing unit 23 (first processing unit) is configured to execute the (first) acquisition process before the processing unit 33 (second processing unit) executes the (second) acquisition process at startup. Has been. With this configuration, it is possible to prevent the detection unit 2 and the detection unit 3 from simultaneously executing the acquisition process at the time of activation. In order to realize this configuration, each of the detection unit 2 and the detection unit 3 stores in advance information on which of the first detection unit and the second detection unit is activated. The information may be stored in, for example, a memory (not shown) built in the processing unit 23 (processing unit 33), or may be included in a program executed at the time of activation.

  At this time, the processing unit 23 executes processing for determining whether or not the detection unit 2 is normal (S4). And if the process part 23 judges that the detection part 2 has failed, it will output a failure signal to ECU4 (S5), and will stop operation | movement (S6). If the processing unit 23 determines that the detection unit 2 is normal, the processing unit 23 shifts to a standby state (S7). When shifting to the standby state, the processing unit 23 executes the same processing as the processing unit 33 described below.

  On the other hand, since the detection unit 3 is a second detection unit (S2), the processing unit 33 shifts to a standby state when activated (S8). In the standby state, the processing unit 33 determines the timing for executing the acquisition process based on the detection signal Y3 that is guided to the detection coil 32 by driving the excitation coil 21.

  At this time, the processing unit 33 executes a process of determining whether or not the detection unit 2 that should be executing the acquisition process is normal (S8). If the processing unit 33 determines that the detection unit 2 is normal, the processing unit 33 performs an acquisition process in the same manner as the processing unit 23 (S3). If the processing unit 33 determines that the detection unit 2 is out of order, the processing unit 33 repeats the acquisition process thereafter (S9). At this time, the processing unit 33 may switch to a mode different from the normal mode and repeat the acquisition process.

  As described above, in the position detection device 1 of the present embodiment, the processing unit 33 (second processing unit) is divided into the (first) acquisition process and the (second) acquisition process in the measurement period. (2) The acquisition process is executed intermittently. The (second) acquisition process is determined at a timing based on the detection signal Y3 (third detection signal) induced in the (second) detection coil 32 by driving the (first) excitation coil 21. That is, in the position detection device 1 of the present embodiment, the processing unit 33 magnetically detects the timing when the (first) acquisition process ends. For this reason, the position detection apparatus 1 of this embodiment does not electrically detect the timing when the acquisition process ends. Therefore, in the position detection device 1 according to the present embodiment, even if any one of the detection units breaks down and electrically affects the other detection units, the detection units 2 and 3 magnetically interfere with each other. Can be prevented.

  In the position detection device 1 of the present embodiment, the detection unit 2 includes a power supply line (electric wire 41) and a grounding wire (electrical wire 43), and the detection unit 3 includes a power supply line (electrical wire 44) and a grounding wire (electrical wire 46). Although it is the structure to connect, the structure which shared one power supply line and one ground line may be sufficient, respectively. In this configuration, the detection unit 2 and the detection unit 3 are not electrically independent from each other. However, even in this configuration, as described above, even if one of the detection units breaks down and electrically affects the other detection units, the detection units 2 and 3 magnetically interfere with each other. Can be prevented.

<Possibility of mutual interference at startup>
By the way, in the position detection apparatus 1 of this embodiment, the detection part 2 and the detection part 3 are started at the same timing by ECU4 in principle. For this reason, in the position detection apparatus 1 of the present embodiment, one detection unit 2 (detection unit 3) executes acquisition processing at the time of activation, and the other detection unit 3 (detection unit 2) shifts to a standby state at the time of activation. . However, in the position detection device 1 of the present embodiment, the detection unit 2 and the detection unit 3 may be activated at different timings due to an abnormality of the ECU 4 or the like, although it is extremely rare. In this case, in the position detection device 1 according to the present embodiment, when there is no monitoring period to be described later, when the detection units 2 and 3 are activated, the detection unit 2 and the detection unit 3 execute acquisition processing (that is, each excitation coil 21 and 31 drive periods may overlap). As described above, when the driving periods of the excitation coils 21 and 31 overlap, the position detection processing by the detection unit 2 and the detection unit 3 is performed at the same time, and there is a possibility that they may interfere with each other magnetically.

<Monitoring period>
In order to solve the above problem, in the position detection device 1 of the present embodiment, assuming that the detection unit 2 is a first detection unit and the detection unit 3 is a second detection unit, the processing unit 23 (first processing unit) is The monitoring period is started before the measurement period. Similarly, the processing unit 33 (second processing unit) is configured such that the monitoring period is started before the measurement period. In particular, in the position detection apparatus 1 of the present embodiment, as shown in FIG. 7, when the detection unit 2 (detection unit 3) is activated, the processing unit 23 (processing unit 33) monitors after initialization. The period is configured to start. The time required for initialization is, for example, 10 ms. The length of the monitoring period is a predetermined length, for example, 3 ms. Note that the length of the monitoring period may be variable.

  In the monitoring period, the (first) processing unit 23 monitors whether the (second) processing unit 33 is executing the (second) acquisition process without driving the (first) exciting coil 21. . The (first) processing unit 23 is configured to execute a predetermined process if the (second) processing unit 33 determines that the (second) acquisition process is being executed. As will be described in detail later, the predetermined processing here is processing for avoiding magnetic interference caused by acquisition processing by the detection units 2 and 3 being performed simultaneously.

  Here, the (first) processing unit 23 monitors whether or not a signal (detection signal Y4) is induced in the (first) detection coil 22. When the signal (detection signal Y4) is induced in the (first) detection coil 22, the (first) processing unit 23 executes the (second) acquisition process. It is comprised so that it may determine. Further, the (first) processing unit 23 is configured to shift to the measurement period when the monitoring period ends when the signal (detection signal Y4) is not induced in the (first) detection coil 22 in the monitoring period.

  Similarly, the (second) processing unit 33 determines whether the (first) processing unit 23 is executing the (first) acquisition process without driving the (second) exciting coil 31 during the monitoring period. To monitor. The (second) processing unit 33 is configured to execute a predetermined process if the (first) processing unit 23 determines that the (first) acquisition process is being executed.

  Here, the (second) processing unit 33 monitors whether or not a signal (detection signal Y3) is induced in the (second) detection coil 32. When the signal (detection signal Y3) is induced in the (second) detection coil 32, the (second) processing unit 33 performs the (first) acquisition process. It is comprised so that it may determine. In addition, the (second) processing unit 33 is configured to shift to the measurement period when the monitoring period ends when the signal (detection signal Y3) is not induced in the (second) detection coil 32 in the monitoring period.

  Hereinafter, an example of the operation including the monitoring period of the position detection device 1 of the present embodiment will be described. In the following description, “activation” refers to activation by supplying an operating voltage from the ECU 4 to the processing unit 23 (processing unit 33), or reset of the processing unit 23 (processing unit 33) due to occurrence of some abnormality. Includes a reboot by. In addition, “startup” includes restarting of the processing unit 23 (processing unit 33) accompanying recovery from an instantaneous power failure or instantaneous voltage drop. Moreover, the operation | movement in the measurement period of the process part 23 (process part 33) should just be an operation | movement which performs an acquisition process intermittently, and is not limited to the operation | movement demonstrated to the above-mentioned <measurement period>.

  First, the case where the detection part 2 and the detection part 3 start at the same timing is demonstrated using FIG. In this case, the monitoring period in the processing unit 23 and the monitoring period in the processing unit 33 are almost the same. Therefore, since the detection signal Y4 is not induced in the detection coil 22 during the monitoring period, the processing unit 23 executes the acquisition process at the end of the monitoring period and shifts to the measurement period. In addition, since the detection signal Y3 is not induced in the detection coil 32 during the monitoring period, the processing unit 33 enters a standby state at the end of the monitoring period and shifts to the measurement period. Thereafter, the processing unit 23 and the processing unit 33 intermittently execute the acquisition process so that the periods during which the acquisition process is executed do not overlap each other.

  Next, the case where the detection unit 3 is activated later than the detection unit 2 will be described with reference to FIG. 8A. In this case, since the detection signal Y4 is not induced in the detection coil 22 during the monitoring period, the processing unit 23 executes an acquisition process at the end of the monitoring period and shifts to the measurement period. On the other hand, the monitoring period in the processing unit 33 overlaps the period in which the processing unit 23 executes the acquisition process. For this reason, the detection signal Y <b> 3 is induced in the detection coil 32 during the monitoring period of the processing unit 33. Accordingly, the processing unit 33 executes a predetermined process at the end of the monitoring period.

  Next, the case where the detection unit 2 is activated later than the detection unit 3 will be described with reference to FIG. 8B. In this case, since the detection signal Y3 is not induced in the detection coil 32 during the monitoring period, the processing unit 33 enters a standby state at the end of the monitoring period and shifts to the measurement period. On the other hand, the monitoring period in the processing unit 23 overlaps the period in which the processing unit 33 executes the acquisition process. For this reason, the detection signal Y <b> 4 is induced in the detection coil 22 during the monitoring period of the processing unit 23. Therefore, the processing unit 23 executes a predetermined process at the end of the monitoring period.

  As described above, in the position detection device 1 of the present embodiment, assuming that the detection unit 2 is the first detection unit and the detection unit 3 is the second detection unit, the processing unit 33 (second processing unit) is as follows. It is configured. That is, the (second) processing unit 33 monitors and executes whether or not the (first) processing unit 23 is executing the (first) acquisition process in the monitoring period set before the measurement period. If so, it is configured to execute a predetermined process.

  For this reason, the (second) detection unit 3 executes a predetermined process according to the result of the determination as to whether or not the (first) detection unit 2 is executing the (first) acquisition process during the monitoring period. be able to. Therefore, in the position detection device 1 of the present embodiment, the first acquisition process and the second acquisition process are executed simultaneously when the detection units 2 and 3 are activated, that is, the periods in which the excitation coils 21 and 31 are driven overlap. The possibility can be reduced.

  Here, the predetermined process may be a process of shifting to the measurement period based on the signal induced in the monitoring period. In other words, when the processing unit 33 (second processing unit) executes the predetermined process, the start time of the measurement period in the (second) processing unit 33 is adjusted so as not to overlap with the (first) acquisition processing. It may be a process to do. Similarly, when the processing unit 23 (first processing unit) executes the predetermined processing, the start time of the measurement period in the (first) processing unit 33 is adjusted so as not to overlap with the (second) acquisition processing. It may be a process to do. For example, the detection signal Y4 (detection signal Y3) is guided to the detection coil 22 (detection coil 32) from the start of the monitoring period, and the induction of the detection signal Y4 (detection signal Y3) is completed by the end of the monitoring period. There are cases. In this case, the processing unit 23 (processing unit 33) starts the acquisition process at a timing based on the end point of the detection signal Y4 (detection signal Y3).

  Further, for example, the detection signal Y4 (detection signal Y3) is guided to the detection coil 22 (detection coil 32) from the middle of the monitoring period, and the induction of the detection signal Y4 (detection signal Y3) is completed before the monitoring period ends. The case where it does not think is possible. In this case, the processing unit 23 (processing unit 33) starts the acquisition process at a timing based on the starting point of the detection signal Y4 (detection signal Y3).

  Further, for example, the detection signal Y4 (detection signal Y3) is guided to the detection coil 22 (detection coil 32) from the middle of the monitoring period, and the induction of the detection signal Y4 (detection signal Y3) is completed before the monitoring period ends. If you want to. In this case, the processing unit 23 (processing unit 33) starts the acquisition process at a timing based on one of the starting time point and the ending time point of the detection signal Y4 (detection signal Y3).

  In any of the above cases, each of the detection units 2 and 3 can shift to the measurement period while avoiding magnetic mutual interference.

  Further, the predetermined process may be a process of stopping the operation of the processing unit 33 when the processing unit 33 (second processing unit) executes. Similarly, the predetermined process may be a process of stopping the operation of the processing unit 23 when the processing unit 23 (first processing unit) executes. In this case, since the acquisition process is not executed by the detection unit 2 (detection unit 3) that is estimated to have some sort of failure, the acquisition process can be executed by the normal detection unit 2 (detection unit 3). Accordingly, in this case, it is possible to reduce the possibility of unnecessary mutual interference by the detection unit 2 (detection unit 3) that is estimated to have some sort of failure.

  Further, in the position detection device 1 of the present embodiment, as shown in FIGS. 7, 8A, and 8B, for example, the processing unit 23 (first processing unit) is configured as follows. That is, the (first) processing unit 23 does not drive the (first) exciting coil 21 and the (second) processing unit 33 performs (second) acquisition processing in the monitoring period of the (first) processing unit 23. Monitor whether or not The (first) processing unit 23 is configured to execute the (first) acquisition process at the end of the monitoring period when the (second) processing unit 33 is not executing the (second) acquisition process. Has been. That is, the processing unit 23 (first processing unit) executes the (first) acquisition process before the processing unit 33 (second processing unit) executes the (second) acquisition process at the end of the monitoring period. Is configured to do.

  With this configuration, it is possible to prevent the detection unit 2 and the detection unit 3 from simultaneously executing acquisition processing at the end of the monitoring period. Note that whether or not to adopt the configuration is arbitrary.

<Possibility of mutual interference during the measurement period>
By the way, in the position detection device 1 of the present embodiment, although extremely rare, the detection unit 2 and the detection unit 3 may execute the acquisition process at almost the same timing in the measurement period. Hereinafter, an example of the operation in this case will be described with reference to FIG. The processing unit 23 of the detection unit 2 shifts to a standby state after completing the acquisition process. Here, since the detection unit 2 and the detection unit 3 execute the acquisition process at almost the same timing, the detection signal Y4 is not guided to the detection coil 22 until the standby time T2 elapses after the acquisition process ends. . Therefore, the processing unit 23 executes the acquisition process again when the standby time T2 has elapsed. On the other hand, the processing unit 33 of the detection unit 3 also shifts to a standby state when the acquisition process ends. Here, since the detection signal Y3 is not guided to the detection coil 32 from the end of the acquisition process until the standby time T2 elapses, the processing unit 33 again executes the acquisition process when the standby time T2 elapses.

  Therefore, the detection unit 2 and the detection unit 3 repeatedly execute the acquisition process at almost the same timing. Here, even if the timings at which the detection unit 2 and the detection unit 3 execute the acquisition process coincide with each other, the period and phase of the signals transmitted by both driving the excitation coil 21 and the excitation coil 31 are completely complete. They do not match and magnetically interfere with each other. For this reason, both the detection unit 2 and the detection unit 3 may continue to output position signals including errors.

  Therefore, hereinafter, a first modified example and a second modified example that solve the above-described problem in the measurement period will be described.

(First modification)
In the position detection device 1 of the first modification, as shown in FIG. 10A, the standby time T22 of the detection unit 3 is set longer than the standby time T21 of the detection unit 2. That is, assuming that the detection unit 2 is the first detection unit and the detection unit 3 is the second detection unit, the (first) standby time T21 set by the processing unit 23 (first processing unit) and the processing unit 33 ( The (second) standby time T22 set by the second processing unit is different from each other.

  Hereinafter, an example of an operation when the detection unit 2 and the detection unit 3 execute the acquisition process at almost the same timing in the position detection device 1 of the first modification will be described with reference to FIG. 10B. The processing unit 23 of the detection unit 2 shifts to a standby state after completing the acquisition process. Here, since the detection unit 2 and the detection unit 3 execute the acquisition process at almost the same timing, the detection signal Y4 is not guided to the detection coil 22 until the standby time T21 elapses after the acquisition process ends. . Therefore, the processing unit 23 executes the acquisition process again when the standby time T21 has elapsed.

  On the other hand, the processing unit 33 of the detection unit 3 also shifts to a standby state when the acquisition process ends. Here, the processing unit 23 executes the acquisition process from the end of the acquisition process until the standby time T22 elapses. Therefore, since the detection signal Y3 is guided to the detection coil 32 within the standby time T22, the processing unit 33 determines the timing for executing the acquisition process based on the detection signal Y3. And the process part 33 performs an acquisition process at the determined timing. Thereafter, the detection unit 2 and the detection unit 3 execute acquisition processing alternately.

  As described above, the position detection device 1 of the first modification can return to the normal acquisition process even if the detection unit 2 and the detection unit 3 execute the acquisition process at almost the same timing.

(Second modification)
In the position detection device 1 of the second modified example, as shown in FIG. 11A, the processing unit 23 (processing unit 33) of the detection unit 2 (detecting unit 3) functions to count the determination time T3 when the acquisition process is completed. have. When the detection signal Y4 (detection signal Y3) is induced in the detection coil 22 (detection coil 32) within the determination time T3, the processing unit 23 (processing unit 33) detects the detection unit 2 (detection unit 3). Judge that it is broken. And if the process part 23 (process part 33) judges that it has failed, it will output a failure signal to ECU4 and will stop operation | movement. Further, in the position detection device 1 of the second modified example, as illustrated in FIG. 11A, the period during which the processing unit 33 executes the acquisition process is longer than the period during which the processing unit 23 executes the acquisition process.

  That is, assuming that the detection unit 2 is the first detection unit and the detection unit 3 is the second detection unit, the processing unit 33 (second processing unit) counts the determination time T3 when the (second) acquisition process is completed. It has a function. The processing unit 33 is configured to stop the operation when detecting the detection signal Y3 (third detection signal) within the determination time T3. Similarly, the processing unit 23 (first processing unit) has a function of measuring the determination time T3 when the (first) acquisition processing ends. The processing unit 23 is configured to stop the operation when detecting the detection signal Y4 (fourth detection signal) within the determination time T3. Further, the period for executing the (first) acquisition process and the period for executing the (second) acquisition process have different lengths.

  Hereinafter, an example of the operation when the detection unit 2 and the detection unit 3 execute the acquisition process at almost the same timing in the position detection device 1 of the second modification will be described with reference to FIG. 11B. The processing unit 23 of the detection unit 2 measures the determination time T3 when the acquisition process is finished. Here, since the period during which the processing unit 33 of the detection unit 3 executes the acquisition process is longer than the period during which the processing unit 23 executes the acquisition process, the detection signal Y4 is guided to the detection coil 22 within the determination time T3. . Therefore, the processing unit 23 determines that a failure has occurred and stops the operation.

  On the other hand, the processing unit 33 of the detection unit 3 also counts the determination time T3 when the acquisition process ends. Here, since the processing unit 23 has already stopped operating, the detection signal Y3 is not guided to the detection coil 32 within the determination time T3. Therefore, the processing unit 33 executes the acquisition process again when the standby time T2 has elapsed. Thereafter, the processing unit 33 executes an acquisition process for each standby time T2.

  As described above, when the detection unit 2 and the detection unit 3 execute the acquisition process at almost the same timing, the position detection device 1 according to the second modification determines that there is mutual interference and detects one of the detection units 2. The processing unit 23 (processing unit 33) of the (detecting unit 3) stops operating. Therefore, the position detection device 1 according to the second modification can avoid the state of mutual magnetic interference and can continue the acquisition process by the remaining detection units 2 (detection units 3).

(Embodiment 2)
In the position detection device 1 according to the first embodiment, the processing unit 23 (processing unit 33) monitors whether or not the detection signal Y4 (detection signal Y3) is induced in the detection coil 22 (detection coil 32) during the monitoring period. However, other configurations may be used. Hereinafter, a position detection apparatus 1 according to Embodiment 2 of the present invention will be described with reference to the drawings. Note that in the position detection device 1 of the present embodiment, the description of the components common to the position detection device 1 of the first embodiment is omitted as appropriate.

  In the position detection apparatus 1 of the present embodiment, as shown in FIG. 12, the (first) processing unit 23 and the (second) processing unit 33 are electrically connected to each other by a single communication line 5. The (first) processing unit 23 and the (second) processing unit 33 can perform bidirectional communication via the single communication line 5.

  Specifically, the processing unit 23 (processing unit 33) includes a signal generation unit that generates a signal flowing through the communication line 5. The signal generation unit includes a series circuit of a pull-up resistor and a switch, and is electrically connected between the power supply of the processing unit 23 (processing unit 33) and the circuit ground. The first connection point of the pull-up resistor and the switch in the processing unit 23 and the second connection point of the pull-up resistor and the switch in the processing unit 33 are electrically connected to each other by the communication line 5. Hereinafter, when the communication line 5 is not connected, the voltage between the first connection point and the circuit ground is “first output voltage V1”, and the voltage between the second connection point and the circuit ground is “second output”. This will be referred to as “voltage V2”.

  The processing unit 23 (processing unit 33) is configured to turn on the switch while the acquisition process is being executed, and to turn off the switch when the acquisition process is not being executed. Accordingly, the first output voltage V1 is at the L (Low) level while the processing unit 23 is executing the acquisition process, and is at the H (High) level when the acquisition process is not being performed. Similarly, the second output voltage V2 is at the L level while the processing unit 33 is executing the acquisition process, and is at the H level while the processing unit 33 is executing the acquisition process.

  Here, in practice, the first connection point and the second connection point are electrically connected to each other by the communication line 5. Therefore, the potential of the communication line 5 is a logical product of the first output voltage V1 and the second output voltage V2. That is, one processing unit 23 (processing unit 33) determines whether or not the other processing unit 33 (processing unit 23) is executing an acquisition process by monitoring the potential of the communication line 5. Can do.

  Hereinafter, an example of the operation including the monitoring period of the position detection device 1 of the present embodiment will be described. First, the case where the detection unit 2 and the detection unit 3 are activated at the same timing will be described with reference to FIG. In this case, the monitoring period in the processing unit 23 and the monitoring period in the processing unit 33 are almost the same. For this reason, in the monitoring period of the processing unit 23 (processing unit 33), both the first output voltage V1 and the second output voltage V2 remain at the H level and do not vary. That is, the potential of the communication line 5 does not change during the monitoring period of the processing unit 23 (processing unit 33).

  Accordingly, since the potential of the communication line 5 does not change during the monitoring period (the signal flowing through the communication line 5 does not change), the processing unit 23 executes an acquisition process at the end of the monitoring period and shifts to the measurement period. Further, since the potential of the communication line 5 does not change during the monitoring period (the signal flowing through the communication line 5 does not change), the processing unit 33 enters a standby state at the end of the monitoring period and shifts to the measurement period. Thereafter, the processing unit 23 and the processing unit 33 intermittently execute the acquisition process so that the periods during which the acquisition process is executed do not overlap each other.

  Next, the case where the detection unit 3 is activated later than the detection unit 2 will be described with reference to FIG. In this case, since the potential of the communication line 5 does not change during the monitoring period (the signal flowing through the communication line 5 does not change), the processing unit 23 executes an acquisition process at the end of the monitoring period and shifts to the measurement period. On the other hand, the monitoring period in the processing unit 33 overlaps the period in which the processing unit 23 executes the acquisition process. For this reason, the first output voltage V1 changes from the H level to the L level during the monitoring period in the processing unit 33. That is, during the monitoring period in the processing unit 33, the potential of the communication line 5 changes (the signal flowing through the communication line 5 changes). Therefore, the processing unit 33 determines that the processing unit 23 is executing the acquisition process during the monitoring period, and executes a predetermined process at the end of the monitoring period.

  As described above, in the position detection device 1 of the present embodiment, the (first) processing unit 23 and the (second) processing unit 33 are electrically connected to each other by the communication line 5. The (second) processing unit 33 determines that the (first) processing unit 23 is executing the (first) acquisition process when there is a change in the signal flowing through the communication line 5 during the monitoring period. It is configured. Even in this configuration, the (second) detection unit 3 executes a predetermined process according to the determination result of whether or not the (first) detection unit 2 is executing the (first) acquisition process in the monitoring period. can do.

  In the position detection device 1 according to the present embodiment, the (first) processing unit 23 and the (second) processing unit 33 only need to be able to communicate with each other. For example, the (first) processing unit 23 and the (second) processing unit 33 may be electrically connected to each other via the two communication lines 5. In this configuration, one-way communication from the (first) processing unit 23 to the (second) processing unit 33 and one-way communication from the (second) processing unit 33 to the (first) processing unit 23 are performed. It is possible to carry out using two communication lines 5. In the processing unit 23 (processing unit 33), the communication line 5 may be electrically connected to circuit ground via a pull-down resistor. In this configuration, the switch only needs to be electrically connected between the power supply and the communication line 5.

  In the above description, the detection unit 2 is assumed to be a first detection unit and the detection unit 3 is assumed to be a second detection unit. However, the detection unit 2 is assumed to be a second detection unit, and the detection unit 3 is assumed to be a first detection unit. Even so it is the same. That is, the position detection device 1 of each embodiment includes two detection units 2 and 3, one of the two detection units 2 and 3 is a first detection unit, and the other detection unit is a second detection unit. What is necessary is just to be comprised as. That is, the detection units 2 and 3 have the same configuration, and function as both the first detection unit and the second detection unit. Therefore, in the position detection device 1 of each embodiment, even if any one of the detection units fails, the other detection unit can execute the acquisition process.

  Moreover, although the position detection apparatus 1 of each embodiment is provided with the two detection parts 2 and 3, it is not the meaning which limits the number of detection parts. That is, the position detection device 1 of each embodiment may include three or more detection units. In this case, the position detection device 1 may be configured so that the processing units of the detection units sequentially execute the acquisition process and the periods in which the detection units execute the acquisition process do not overlap.

DESCRIPTION OF SYMBOLS 1 Position detection apparatus 2,3 Detection part 21,31 Excitation coil 22,32 Detection coil 23,33 Processing part 100 Target object

Claims (19)

A first detector and a second detector;
The first detection unit includes a first excitation coil, a first detection coil, and a first processing unit,
The second detection unit includes a second excitation coil, a second detection coil, and a second processing unit,
The first excitation coil is magnetically coupled to the first detection coil and the second detection coil, respectively.
The second excitation coil is magnetically coupled to the first detection coil and the second detection coil, respectively.
In the measurement period, the first processing unit drives the first excitation coil and outputs a first detection signal that is guided to the first detection coil according to the position of an object by driving the first excitation coil. The first acquisition process to be acquired is configured to be executed intermittently,
The second processing unit drives the second excitation coil during the measurement period, and the second detection signal is guided to the second detection coil according to the position of the object by driving the second excitation coil. Is configured to intermittently execute the second acquisition process of acquiring
In the monitoring period set before the measurement period in the second processing unit, the second processing unit performs the first acquisition process without driving the second excitation coil. A position detection apparatus configured to execute a predetermined process when monitoring whether or not it is running.   The second processing unit is configured to determine that the first processing unit is executing the first acquisition process when a signal is induced in the second detection coil during the monitoring period. The position detection device according to claim 1. The first processing unit and the second processing unit are electrically connected to each other by a communication line,
The second processing unit is configured to determine that the first processing unit is executing the first acquisition process when there is a change in a signal flowing through the communication line in the monitoring period. The position detection apparatus according to claim 1, wherein   4. The process according to claim 1, wherein the predetermined process is a process of adjusting a start time of the measurement period in the second processing unit so as not to overlap with the first acquisition process. The position detection device according to item.   The position detection apparatus according to claim 1, wherein the predetermined process is a process of stopping the operation of the second processing unit.   The second processing unit has a timing based on a third detection signal that is induced in the second detection coil by driving the first excitation coil so that the period is divided between the first acquisition process and the second acquisition process. The position detection device according to claim 1, wherein the second acquisition process is executed.   The position according to claim 6, wherein the second processing unit is configured to determine the timing based on a lapse of a predetermined time after the induction of the third detection signal is completed. Detection device.   7. The position according to claim 6, wherein the second processing unit is configured to determine the timing based on a lapse of a predetermined time from the start of induction of the third detection signal. Detection device. The second processing unit has a function of counting the wave number of the third detection signal,
The position detection device according to claim 6, wherein the second processing unit is configured to determine the timing based on the wave number reaching a predetermined number of times. The second processing unit has a function of measuring the amplitude of the third detection signal,
The position detection device according to claim 6, wherein the second processing unit is configured to determine the timing based on the fact that the amplitude falls below a predetermined threshold. The first processing unit has a function of giving an end signal notifying the end of the first acquisition process to the first excitation coil,
The position detection device according to claim 6, wherein the second processing unit is configured to determine the timing based on detecting the end signal induced in the second detection coil. .   The said 1st process part is comprised so that an operation | movement may be stopped when not detecting the said 1st detection signal in a said 1st acquisition process. The position detection apparatus described in 1. The second processing unit has a function of measuring a second waiting time when the second acquisition process is completed,
The said 2nd process part is comprised so that the said 2nd acquisition process may be performed when not detecting the said 3rd detection signal within the said 2nd standby | waiting time. The position detection device according to any one of the above.   The second processing unit is configured to execute the second acquisition process by switching to a mode different from a normal time when the third detection signal is not detected within the second standby time. The position detection device according to claim 13, characterized in that: The first processing unit has a function of measuring a first waiting time when the first acquisition process is completed,
The first processing unit performs the first acquisition process when the fourth detection signal induced in the first detection coil by driving the second excitation coil is not detected within the first standby time. Composed of
The position detection device according to claim 13 or 14, wherein the first waiting time and the second waiting time have different lengths from each other. The second processing unit has a function of measuring a determination time when the second acquisition process ends.
The position according to any one of claims 6 to 15, wherein the second processing unit is configured to stop the operation when detecting the third detection signal within the determination time. Detection device.   The position detection device according to claim 16, wherein a period for executing the first acquisition process and a period for executing the second acquisition process are different from each other.   In the monitoring period set before the measurement period in the first processing unit, the second processing unit executes the second acquisition process without driving the first excitation coil in the first processing unit. 18. The apparatus according to any one of claims 1 to 17, wherein the first acquisition process is executed at the end of the monitoring period when it is monitored and not executed. The position detection device according to item. With two detectors,
The detection unit according to claim 1, wherein one of the two detection units is configured as the first detection unit, and the other detection unit is configured as the second detection unit. Position detection device.

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