JP7700549B2 - Vehicle entrapment detection device - Google Patents

Description

The present invention relates to a vehicle entrapment detection device.

For example, the following Patent Document 1 describes a vehicle opening/closing body control device that drives an opening/closing body that opens and closes an opening in a vehicle. This control device performs pinch detection to detect if a foreign object is pinched between the opening and the opening/closing body as the opening/closing body is driven. The control device performs pinch detection based on the current of the motor that drives the opening/closing body.

JP 2020-147950 A

However, when a movable member of a vehicle, such as an opening/closing body, is displaced by the power of a motor, there may be a need to increase the motor's power midway. In such a case, the current flowing through the motor changes, which may reduce the accuracy of pinch detection.

Means for solving the above problems and their effects will be described below.
1. A vehicle entrapment detection device that is applied to a vehicle having a movable member and a motor for displacing the movable member, the movable member being one of an opening/closing body for opening and closing an opening of the vehicle and a movable part of a seat, and that executes an instruction acquisition process, a displacement process, and an entrapment detection process, the instruction acquisition process being a process for acquiring an instruction to displace the movable member, the displacement process being a process for driving the motor to displace the movable member when the instruction is acquired by the instruction acquisition process, and including an applied voltage increase process, the applied voltage increase process being a process for increasing an applied voltage to a terminal of the motor when the movable member is displaced by driving the motor, and the entrapment detection process being a process for detecting that entrapment has occurred due to the displacement of the movable member based on the magnitude of a detection value of a current flowing through the motor, and including a process for making an upper limit of the detection value for which entrapment is not determined to occur after the increase in the applied voltage higher than before the increase in the applied voltage.

The current flowing through the motor is positively correlated with the value obtained by subtracting the induced voltage caused by the rotation of the motor from the voltage applied to the motor's terminals. On the other hand, when pinching occurs, the force that tries to prevent the displacement of the movable part increases, and therefore the force that tries to prevent the rotation of the motor also increases. As a result, the induced voltage of the motor decreases as the motor decelerates, and the current flowing through the motor increases. Therefore, pinching can be detected based on the magnitude of the motor current.

In the above configuration, the voltage applied to the motor terminals increases during the displacement of the movable member. In that case, the motor current increases even though no pinching has occurred. Therefore, if the upper limit value of the current that does not determine pinching is the same before and after the increase in the applied voltage, the accuracy of pinching detection decreases. Therefore, in the above configuration, the upper limit value of the current that does not determine pinching is set to be higher after the applied voltage is increased than before. This makes it possible to suppress a decrease in the accuracy of pinching detection even when the applied voltage is increased midway.

2. The entrapment detection process includes a determination current value calculation process and a determination process, the determination current value calculation process is a process for calculating a determination current value, which is a current value used to determine entrapment, based on the detection value, the determination current value being a value smaller in proportion to the magnitude of the detection value when the applied voltage is large than when it is small, and the determination process is a process for determining whether entrapment has occurred based on a comparison of the magnitude of the determination current value and a determination value.

The above-mentioned judgment current value is set to a value smaller in proportion to the magnitude of the detected value when the applied voltage is large than when it is small. Therefore, even if the detected value increases due to an increase in the applied voltage, the judgment current value calculated based on the detected value can be prevented from increasing. Therefore, when determining whether the detected value exceeds the upper limit value by comparing the magnitude of the judgment current value with the judgment value, the upper limit value can be made larger after the applied voltage has increased than before it has increased.

3. The vehicle entrapment detection device described in 2 above, in which the determination current value calculation process includes a substitution process, in which the determination current value used for the entrapment detection determination each time is replaced with a value corresponding to the applied voltage before the increase during a predetermined period after the applied voltage is increased.

Although the motor current increases when the applied voltage is increased, there is a response delay in the increase in the current flowing through the motor due to the inductance of the motor coil, etc. Therefore, if the judgment current value is determined according to the value after the applied voltage has increased immediately after the applied voltage has increased, the judgment current value tends to drop significantly once. Therefore, for example, if the applied voltage increases at a timing when pinching has occurred but pinching has not yet been detected, there is a concern that the increase in the judgment current value due to pinching will be offset by the above-mentioned factors, which will delay the detection of pinching. Therefore, in the above configuration, for a predetermined period after the applied voltage is increased, the judgment current value is calculated according to the applied voltage before the increase. This makes it possible to suppress delays in pinching detection.

4. The vehicle entrapment detection device according to claim 3, wherein the predetermined period is a period during which the determination current value calculated based on the increased applied voltage is lower than the determination current value before the applied voltage is increased.

With the above configuration, it is possible to easily set the end point of the period during which the judgment current value based on the applied voltage after an increase drops significantly due to a delayed response of the motor current to the increase in the applied voltage.
5. The entrapment detection device for a vehicle according to any one of claims 2 to 4, wherein the determination process is a process for determining that the entrapment has occurred when a difference between a first current value and a second current value corresponding to each of a pair of the detection values sampled at different times exceeds a threshold value, the first current value and the second current value are the determination current values calculated based on the detection values at the different times, and a value obtained by adding the threshold value to the smaller of the first current value and the second current value is the determination value.

The force required to displace the movable member varies depending on the aging and temperature of the movable member. Therefore, even with the same applied voltage, the rotation speed of the motor when displacing the movable member varies depending on the aging and temperature of the movable member. In addition, the resistance value of the current flow path of the motor varies depending on the temperature of the flow path. Therefore, even with the same applied voltage, the rotation speed of the motor when displacing the movable member varies depending on the temperature of the flow path. In this way, the rotation speed of the motor when no pinching occurs varies depending on the various factors described above. Therefore, the current of the motor when no pinching occurs also varies depending on the various factors described above. Therefore, if the judgment value corresponding to the upper limit value is set to a fixed value for each applied voltage, it tends to be difficult to improve the accuracy of pinching detection.

Therefore, in the above configuration, the judgment value is the smaller of the first and second current values plus a threshold value. In this case, the smaller current value is the current that flows through the motor when no pinching occurs, and is a value that reflects the various factors described above. Therefore, the judgment value can be an appropriate value that takes into account the various factors described above.

6. The vehicle entrapment detection device according to claim 5, in which a voltage from a DC voltage source is applied to the motor via a switching element, the displacement process is to drive the motor by operating the switching element, and the applied voltage increase process is to increase the time ratio of the on-time to the on-off operation cycle of the switching element from a first time ratio to a second time ratio.

Even if the duty ratio is the same, if the magnitude of the voltage of the DC voltage source is different, the voltage applied to the motor will be different. Therefore, when the applied voltage increase process increases the duty ratio from the first duty ratio to the second duty ratio, the actual applied voltage at the first duty ratio and the actual applied voltage at the second duty ratio depend on the magnitude of the voltage of the DC voltage source. Therefore, the appropriate value for the current flowing through the motor when the duty ratio is set to each of the first duty ratio and the second duty ratio also depends on the magnitude of the voltage of the DC voltage source. Therefore, when pinching is detected by comparing the magnitude of the current flowing through the motor with a fixed value, the detection accuracy is likely to be low. Therefore, it is particularly effective to use the difference between the first current value and the second current value.

7. The entrapment detection device for a vehicle according to 5 or 6 above, in which the entrapment detection process includes a minimum value update process, which is a process for updating the first current value to a value corresponding to the current detection value when the value corresponding to the current detection value is smaller than the first current value, and the second current value is a value corresponding to the detection value sampled each time.

In the above configuration, the first current value is a value corresponding to the minimum detection value. Therefore, the difference between the first current value and the second current value when pinching occurs is a value that indicates with high precision the increase in motor current caused by pinching. Therefore, pinching can be detected with high precision based on the difference between the first current value and the second current value exceeding a threshold value.

8. The entrapment detection device for a vehicle according to 5 or 6 above, wherein the first current value and the second current value are values corresponding to a pair of the detection values sampled at a pair of timings separated by a specified period, and the specified period is a period during which the motor rotates by a predetermined angle.

When converting the torque of the motor into a force that displaces the movable member, the magnitude of the load torque applied to the motor may vary periodically due to the mechanical characteristics of the motor's power transmission path, etc. In that case, the current flowing through the motor varies with the variation in the load torque, regardless of whether pinching has occurred. In the above configuration, the first current value and the second current value are determined according to a pair of detection values sampled at a pair of timings separated by a specified period. This reduces the effect of the periodic variation in the load torque on the difference between the first current value and the second current value. Therefore, in the above configuration, pinching can be detected with high accuracy based on the difference between the first current value and the second current value exceeding a threshold value.

1 is a diagram showing a configuration of a vehicle seat and a control device according to an embodiment; FIG. 4 is a side view showing a target displacement state of the seat back in the embodiment. 4 is a flowchart showing a procedure of a process executed by a front ECU according to the embodiment; 5 is a side view illustrating interference between headrests in the embodiment. FIG. 4 is a flowchart showing a procedure of a process executed by a rear ECU according to the embodiment; 4 is a flowchart showing a procedure of a process executed by a rear ECU according to the embodiment; 4 is a flowchart showing a procedure of a process executed by a rear ECU according to the embodiment; 4 is a time chart illustrating a transition of a determination current value according to the embodiment; FIG. 11 is a side view illustrating a movable member according to a modified example of the embodiment.

Hereinafter, an embodiment will be described with reference to the drawings.
FIG. 1 shows the configuration of a seat and a control device in a vehicle.
The rear seat 10r shown in FIG. 1 is used in the rear seat of a vehicle. The rear seat 10r includes a seat cushion 12r, a seat back 14r, and a headrest 16r. The headrest 16r is provided at the upper end of the seat back 14r. Two lower rails 20r extending in the front-rear direction of the vehicle are provided in parallel on a floor portion 30 of the vehicle. Upper rails 22r are attached to the lower rails 20r, respectively, and are movable in the front-rear direction of the vehicle relative to the lower rails 20r. The seat cushion 12r is supported on each upper rail 22r. The seat cushion 12r is movable in the front-rear direction of the vehicle relative to the lower rails 20r together with the upper rails 22r.

The front seat 10f is used in the front seat of a vehicle. The front seat 10f includes a seat cushion 12f, a seat back 14f, and a headrest 16f. In this specification and drawings, the reference numbers of the members related to the front seat 10f are followed by an "f", while the reference numbers of the members related to the rear seat 10r are followed by an "r". Here, among the members related to the front seat 10f, those whose reference numbers match those of the members related to the rear seat 10r correspond to the members related to the rear seat 10r. In other words, the seat cushion 12f, the seat back 14f, and the headrest 16f correspond to the seat cushion 12r, the seat back 14r, and the headrest 16r, respectively.

The seat cushion 12f is movable integrally with the upper rail 22f relative to the lower rail 20f in the front-rear direction of the vehicle.
The rear seat 10r is provided with a slide actuator 40r and a reclining actuator 50r. The slide actuator 40r slides the seat cushion 12r in the front-rear direction of the vehicle by the power of a motor 42r. The reclining actuator 50r changes the inclination angle of the seat back 14r by the power of a motor 52r. More specifically, the reclining actuator 50r rotates and displaces the upper end side of the seat back 14r around an axis provided on the seat cushion 12r side of the seat back 14r.

The reclining actuator 50r includes a motor 52r and a drive circuit 54r. The motor 52r is a DC motor. The drive circuit 54r includes two half-bridge circuits. That is, one of the two terminals of the motor 52r is connected to a connection point of the switching elements SW1 and SW2 that constitute a first half-bridge circuit. The other terminal is connected to a connection point of the switching elements SW3 and SW4 that constitute a second half-bridge circuit. The positive terminal of the battery B is connected to the switching elements SW1 and SW3 side of the drive circuit 54r, and the switching elements SW2 and SW4 side are grounded.

The slide actuator 40r includes, in addition to the motor 42r, a drive circuit 44r that drives the motor 42r.
The front seat 10f is provided with a slide actuator 40f and a reclining actuator 50f. The slide actuator 40f includes a motor 42f and a drive circuit 44f. The reclining actuator 50f includes a motor 52f and a drive circuit 54f.

The rear ECU 60r operates the slide actuator 40r and the reclining actuator 50r to control the control amount of the rear seat 10r as the control target. The control amount in this case is the position of the seat cushion 12r and the tilt angle of the seat back 14r. When controlling the control amount, the rear ECU 60r refers to the output signal Sm of the rotation angle sensor 56r. The output signal Sm is a pulse signal that is output each time the rotation angle of the motor 42r reaches a predetermined angle. The rear ECU 60r also refers to the detection value i of the current flowing through the motor 52r detected by the current sensor 58r.

In the rear ECU 60r, the CPU 62r, ROM 64r, storage device 66r, and peripheral circuit 68r are capable of communicating with each other via a communication line 69r. Here, the peripheral circuit 68r includes a circuit that generates a clock signal that regulates internal operations, a power supply circuit, a reset circuit, and the like. The rear ECU 60r controls the control amount by the CPU 62r executing a program stored in the ROM 64r.

The front ECU 60f operates the slide actuator 40f and the reclining actuator 50f to control the control amount of the front seat 10f as a control target. In the front ECU 60f, the CPU 62f, the ROM 64f, the storage device 66f, and the peripheral circuit 68f are capable of communicating with each other via a communication line 69f.

The front ECU 60f and the rear ECU 60r can communicate with each other via an in-vehicle network 70. The front ECU 60f and the rear ECU 60r also obtain an output signal from a user interface 72 via the in-vehicle network 70. The user interface 72 allows the user to input instructions to adjust the control amount of the front seat 10f and the control amount of the rear seat 10r. The instructions include an instruction to fold forward the seat back 14f of the front seat 10f and the seat back 14r of the rear seat 10r, as shown in FIG. 2. Hereinafter, this instruction will be referred to as a folding instruction. Below, the following will be described in detail in the order of "processing according to a folding instruction," "pre-processing of the entrapment detection process associated with the folding process," and "entrapment detection process."

(Processing according to convolution instructions)
Fig. 3 shows the procedure of the process executed by the front ECU 60f. The process shown in Fig. 3 is realized by the CPU 62f repeatedly executing a program stored in the ROM 64f, for example, at a predetermined interval. In the following description, the step number of each process is represented by a number preceded by "S".

In the series of processes shown in FIG. 3, the CPU 62f first determines whether the convolution flag F1 is "1" (S10). The convolution flag F1 indicates that processing according to the convolution instruction is being performed when it is "1", and indicates that processing is not being performed when it is "0". When the CPU 62f determines that the convolution flag F1 is "0" (S10: NO), it determines whether a convolution instruction is issued by operating the user interface 72 (S12). When the CPU 62f determines that a convolution instruction is issued (S12: YES), it assigns "1" to the convolution flag F1 (S14). Then, the CPU 62f drives the motor 52f by operating the drive circuit 54f (S16). Then, the CPU 62r determines whether a pulse signal, which is the output signal Sm of the rotation angle sensor 56f indicating that the rotation angle of the motor 52f has reached a predetermined angle, is detected (S18). When the CPU 62f determines that the detection has been performed (S18: YES), it updates the total number of rotations Ntot1 of the motor 52f (S20). Here, the total number of rotations Ntot1 has a one-to-one correspondence with the tilt angle of the seat back 14f. The total number of rotations Ntot1 is corrected by increasing or decreasing the amount depending on the rotation direction of the motor 52f. In this embodiment, it is assumed that the seat back 14f will lean forward more as the total number of rotations Ntot1 increases. Therefore, in the process of S20, the CPU 62f corrects the total number of rotations Ntot1 by increasing the amount.

Next, the CPU 62f determines whether the total number of rotations Ntot1 has reached a predetermined value Ntot1th (S22). The predetermined value Ntot1th corresponds to the inclination angle of the seat back 14f at which there is no possibility of interference between the head rest 16f of the front seat 10f and the head rest 16r of the rear seat 10r.

Figure 4 shows an example in which the headrest 16f of the front seat 10f and the headrest 16r of the rear seat 10r interfere with each other. That is, at the time when a folding command is issued, the tilt angles of the seat backs 14f and 14r can take various values because they are freely set by the user. In addition, the distance between the seat cushions 12f and 12r can also take various values. Therefore, when processing is performed in accordance with a folding command, there is a possibility that the headrest 16f of the front seat 10f and the headrest 16r of the rear seat 10r will interfere with each other.

Returning to FIG. 3, if the CPU 62f determines that the predetermined value Ntot1th has been reached (S22: YES), it notifies the rear ECU 60r of this via the in-vehicle network 70 (S24).

On the other hand, when the CPU 62f determines that the folding flag F1 is "1" (S10: YES), it determines whether the total number of rotations Ntot1 has reached the target number of rotations Ntot1* (S26). The target number of rotations Ntot1* is set to the total number of rotations Ntot1 when the seat back 14f is in the state shown in FIG. 2. When the CPU 62f determines that the target number of rotations Ntot1* has not been reached (S26: NO), it proceeds to the process of S16. On the other hand, when the CPU 62f determines that the target number of rotations Ntot1* has been reached (S26: YES), it assigns "0" to the folding flag F1 (S28). Then, the CPU 62f stops the motor 52f (S30).

When the CPU 62f completes the processing of S24 and S30, or when a negative judgment is made in the processing of S12, S18, and S22, the CPU 62f temporarily ends the series of processing steps shown in FIG. 3.

Figure 5 shows the procedure of the process executed by the rear ECU 60r. The process shown in Figure 5 is realized by the CPU 62r repeatedly executing a program stored in the ROM 64r, for example at a predetermined interval.

In the series of processes shown in FIG. 5, the CPU 62r first determines whether the convolution flag F2 is "1" (S31). When the convolution flag F2 is "1", it indicates that processing according to the convolution instruction is being performed, and when it is "0", it indicates that processing is not being performed. When the CPU 62r determines that the convolution flag F2 is "0" (S31: NO), it determines whether a convolution instruction has been issued by operating the user interface 72 (S32). When the CPU 62r determines that a convolution instruction has been issued (S32: YES), it assigns "1" to the convolution flag F2 (S34). Then, the CPU 62r determines whether a notification has been issued by the processing of S24 (S36). When the CPU 62r determines that a notification has not been issued (S36: NO), it determines whether the total number of rotations Ntot2 of the motor 52r is equal to or less than a predetermined value Ntot2th (S38). The total number of rotations Ntot2 has a one-to-one correspondence with the inclination angle of the seat back 14r. The predetermined value Ntot2th is set to the maximum value of the total number of rotations Ntot2 at which there is no possibility of interference between the headrest 16f of the front seat 10f and the headrest 16r of the rear seat 10r.

When the CPU 62r determines that the predetermined value Ntot2th is equal to or less than the predetermined value Ntot2th (S38: YES), it assigns the first duty ratio DL to the duty ratio D (S40). The duty ratio D indicates the ratio of the on time to the PWM period that turns on and off the switching element SW2 or the switching element SW4.

Then, the CPU 62r drives the drive circuit 54r according to the duty ratio D (S42). That is, the CPU 62r controls the rotation direction of the motor 52r by selecting whether to turn on the switching elements SW1 and SW4, or to turn on the switching elements SW3 and SW2. Furthermore, the CPU 62r turns on and off the switching element SW2 or the switching element SW4 at the duty ratio D.

The CPU 62r determines whether or not a pulse signal, which is the output signal Sm of the rotation angle sensor 56r indicating that the rotation angle of the motor 52r has reached a predetermined angle, has been detected (S46). When the CPU 62r determines that a pulse signal has been detected (S46: YES), the CPU 62r updates the total number of rotations Ntot2 of the motor 52r (S48). Here, the total number of rotations Ntot2 is corrected by increasing or decreasing the amount depending on the rotation direction of the motor 52r. In this embodiment, it is assumed that the seat back 14r will lean forward as the total number of rotations Ntot2 increases. Therefore, in the process of S48, the CPU 62r increases the total number of rotations Ntot2.

On the other hand, if the CPU 62r determines that a notification has been given by the processing of S24 (S36: YES), it assigns the second duty ratio DH to the duty ratio D (S50). The second duty ratio DH is set to a value greater than the first duty ratio DL. In this embodiment, the second duty ratio DH is set to "100". The CPU 62r then proceeds to the processing of S42. As a result, the drive circuit 54r is operated according to the second duty ratio DH.

In the process of S16 in FIG. 3, the duty ratio D is set to the second duty ratio DH and the drive circuit 54f is operated to drive the motor 52f.
Furthermore, when the CPU 62r determines that the folding flag F2 is "1" (S31: YES), it determines whether the total number of rotations Ntot2 has reached the target number of rotations Ntot2* (S52). The target number of rotations Ntot2* is set to the total number of rotations Ntot2 when the seat back 14r is in the state shown in FIG. 2. When the CPU 62r determines that the target number of rotations Ntot2* has not been reached (S52: NO), it proceeds to the process of S36. On the other hand, when the CPU 62r determines that the target number of rotations Ntot2* has been reached (S52: YES), it assigns "0" to the folding flag F2 (S54). When the CPU 62r completes the process of S54 or makes a negative determination in the process of S38, it stops the motor 52r (S56).

When the CPU 62r completes the processes of S48 and S56, or when a negative determination is made in the processes of S32 and S46, the CPU 62r temporarily ends the series of processes shown in FIG.
(Pre-processing of entrapment detection processing accompanying convolution processing)
The procedure of the pre-processing is shown in Fig. 6. The processing shown in Fig. 6 is realized by the CPU 62r repeatedly executing a program stored in the ROM 64r, for example, at a predetermined interval.

In the series of processes shown in FIG. 6, the CPU 62r first obtains the detection value i of the current flowing through the motor 52r (S60). Next, the CPU 62r calculates the filtered current ifil0 by low-pass filtering the detection value i (S62). Then, the CPU 62r assigns the value obtained by multiplying the filtered current ifil0 by "100/D" to the judgment current value ifil1 (S64). "100/D" is a coefficient for reducing the difference in the magnitude of the detection value i and the filtered current ifil0 due to the difference in the duty ratio D. That is, the voltage applied to the motor 52r is larger when the duty ratio D is the second duty ratio DH compared to when the duty ratio D is the first duty ratio DL. In other words, the effective value of the voltage applied to the motor 52r is larger. Therefore, the detection value i and the magnitude of the filtered current ifil0 are larger when the duty ratio D is the second duty ratio DH than when the duty ratio D is the first duty ratio DL. On the other hand, the coefficient "100/D" is smaller when the duty ratio D is the second duty ratio DH than when the duty ratio D is the first duty ratio DL. Therefore, the determination current value ifil1 does not change significantly when the duty ratio D is the first duty ratio DL and when the duty ratio D is the second duty ratio DH.

Next, the CPU 62r determines whether or not this is the timing when the duty ratio D has switched from the first duty ratio DL to the second duty ratio DH (S66). If the CPU 62r determines that this is the timing when the duty ratio D has switched (S66: YES), it assigns the determination current value ifil1 calculated in the process of S64 immediately before this timing to the reference value ifillast (S68).

On the other hand, if the CPU 62r determines that it is not the timing of switching (S66: NO), it determines whether the determination current value ifil1 is smaller than the reference value ifillast (S70). If the CPU 62r determines that it is smaller (S70: YES), it assigns the value obtained by multiplying the filtered current ifil0 by "100/DL" to the determination current value ifil1 (S72).

It should be noted that the CPU 62r temporarily ends the series of processes shown in FIG. 6 when completing the processes of S68 and S72, or when a negative determination is made in the process of S70.
(Pinch detection process)
The procedure of the entrapment detection process is shown in Fig. 7. The process shown in Fig. 7 is realized by the CPU 62r repeatedly executing a program stored in the ROM 64r, for example, at a predetermined interval.

In the series of processes shown in FIG. 7, the CPU 62r first assigns the smaller of the minimum value ifilmin and the current value for determination ifil1 to the minimum value ifilmin (S80). Then, the CPU 62r determines whether the value obtained by subtracting the minimum value ifilmin from the current value for determination ifil1 is greater than the threshold value Δth1 (S82). This process is a process for determining whether or not pinching has occurred due to the displacement of the seat back 14r. In other words, when pinching occurs, the force required to displace the seat back 14r increases, and the rotation speed of the motor 52r decreases. This reduces the induced voltage of the motor 52r, and the magnitude of the current flowing through the motor 52r increases.

If the CPU 62r determines that the difference is greater than the threshold value Δth1 (S82: YES), it determines that pinching has been detected (S90). Then, the CPU 62r forcibly stops the motor 52r (S92).

On the other hand, when the CPU 62r determines that the difference is equal to or less than the threshold value Δth1 (S82: NO), it determines whether the motor 52r has rotated by the pulsation period ΔNtot2 or more after the start of the folding process (S84). The pulsation period ΔNtot2 is the period of the fluctuation due to mechanical factors in the magnitude of the force required to displace the seat back 14r. The pulsation period ΔNtot2 is a value that is previously adapted as a value specific to the mechanism for displacing the seat back 14r, such as the number of gear teeth.

When the CPU 62r determines that the seat back 14r has rotated by at least the pulsation period ΔNtot2 (S84: YES), the CPU 62r assigns the judgment current value ifil1 sampled the pulsation period ΔNtot2 before to the pre-cycle current value ifilr (S86). The CPU 62r then determines whether the absolute value of the value obtained by subtracting the pre-cycle current value ifilr from the judgment current value ifil1 is greater than the threshold value Δth2 (S88). This process is also a process for determining whether entrapment has occurred due to the displacement of the seat back 14r.

When the CPU 62r determines that the difference is greater than the threshold value Δth2 (S88: YES), the CPU 62r proceeds to the process of S90.
When the CPU 62r completes the process of S92 or makes a negative determination in the processes of S84 and S88, the CPU 62r temporarily ends the series of processes shown in FIG.

Here, the operation and effects of this embodiment will be described.
8 illustrates an example of the transition of the determination current value ifil1. As shown in Fig. 8, when the duty ratio D switches from the first duty ratio DL to the second duty ratio DH at time t1, the CPU 62r substitutes the determination current value ifil1 immediately before that for the reference value ifillast.

Here, when the time ratio is switched from the first time ratio DL to the second time ratio DH, the filtered current ifil0 increases. However, even if the effective value of the voltage increases, a response delay occurs before the current flowing through the motor 52r reaches a steady value due to the inductance of the coil of the motor 52r. Therefore, when the determination current value ifil1 is calculated using the coefficient "100/DH", the determination current value ifil1 becomes smaller than the reference value ifillast due to the decrease in the coefficient "100/D" at time t1. Therefore, while the determination current value ifil1 calculated using the coefficient "100/DH" is smaller than the reference value ifillast, the CPU 62r assigns the value obtained by multiplying the filtered current ifil0 by the coefficient "100/DL" to the determination current value ifil1. Then, after time t2 when the determination current value ifil1 calculated using the coefficient "100/DH" becomes equal to or greater than the reference value ifillast, the CPU 62r adopts the determination current value ifil1 calculated using the coefficient "100/DH".

Figure 8 shows that the current flowing through motor 52r reaches a steady-state value at time t3. Incidentally, before time t1, the current flowing through motor 52r reaches a steady-state value when duty ratio D is the first duty ratio DL. As shown in Figure 8, in this embodiment, the difference between the steady-state value of determination current value ifil1 at the first duty ratio DL and the steady-state value of determination current value ifil1 at the second duty ratio DH is sufficiently small.

In contrast, as shown in FIG. 8, for the filtered current ifil0, the steady-state value IH at the second time ratio DH is much larger than the steady-state value IL at the first time ratio DL. Therefore, for example, if two values sampled at different times in the process of S82 are used as the filtered current ifil0 instead of the judgment current value ifil1, a positive judgment is more likely to be made after the second time ratio DH is used. Therefore, for example, if the threshold value Δth1 is set to a value appropriate for the first time ratio DL, there is a risk of erroneously determining that pinching has occurred at the second time ratio DH even though pinching has not actually occurred. Also, if the threshold value Δth1 is set to a value appropriate for the second time ratio DH, there is a risk of erroneously determining that pinching has not occurred at the first time ratio DL even though pinching has actually occurred.

This is because, although the upper limit of the current magnitude at which it should not be determined that pinching has occurred varies depending on the duty ratio D, when using the filtered current ifil0, this upper limit is fixed. In other words, if it is appropriate to set the upper limit to the steady-state value plus the threshold value Δth1, then the upper limit at the first duty ratio DL should be a predetermined value greater than the steady-state value IL, while the upper limit at the second duty ratio DH should be a predetermined value greater than the steady-state value IH.

In contrast, according to this embodiment, by using the current value ifil1 for judgment, the upper limit of the filtered current ifil0 at which it is not judged that pinching has occurred in the process of S82 is as follows. That is, at the first time ratio DL, if the minimum value ifilmin is considered to be approximately the steady value IL, it is approximately "IL + (DL / 100) Δth1". On the other hand, at the second time ratio DH, if the minimum value ifilmin is considered to be approximately the steady value IL, it is approximately "(100 / DL) · IL + Δth1". In this embodiment, "IL > Δth1". Therefore, by switching the time ratio D to the second time ratio DH, the upper limit value is raised. Incidentally, this argument is also valid for the detection value i in the same way. That is, in this embodiment, the upper limit of the detection value i at which it is not judged that pinching has occurred is larger at the second time ratio DH than at the first time ratio DL.

Therefore, according to this embodiment, even if the duty ratio D is changed during the displacement of the seat back 14r, entrapment can be detected with high accuracy.
According to the present embodiment described above, the following actions and effects can be obtained.

(1) The presence or absence of entrapment is determined based on the degree to which the determination current value ifil1 exceeds the minimum value ifilmin and the absolute value of the difference between the determination current value ifil1 and the pre-cycle current value ifilr. This allows the detection value i that is not determined to be entrapment and the upper limit value of the filtered current ifil0 to be adjusted to appropriate values according to various factors that change the magnitude of the current other than the duty ratio D. That is, for example, they can be adjusted to appropriate values according to the aging of the rear seat 10r, the temperature of the rear seat 10r, the temperature of the current flow path of the motor 52r, and the terminal voltage of the battery B. Therefore, entrapment detection can be calculated with higher accuracy compared to the case where the upper limit value is fixed for each duty ratio D.

That is, the force required to displace the seat back 14r varies depending on the aging and temperature of the rear seat 10r. Therefore, even if the voltage applied to the motor 52r is the same, the rotation speed of the motor 52r when displacing the seat back 14r varies depending on the aging and temperature of the rear seat 10r. In addition, the resistance value of the current flow path of the motor 52r varies depending on the temperature of the flow path. Therefore, even if the voltage applied to the motor 52r is the same, the rotation speed of the motor 52r when displacing the seat back 14r varies depending on the temperature of the flow path. In addition, if the terminal voltage of the battery B varies, the rotation speed of the motor 52r varies even if the duty ratio D is the same. In this way, the rotation speed of the motor 52r when no pinching occurs varies depending on the various factors described above. Therefore, the current of the motor 52r when no pinching occurs varies depending on the various factors described above. Therefore, if the upper limit at which pinching is not detected is set to a fixed value for each duty ratio D, it tends to be difficult to improve the accuracy of pinching detection.

(2) In the process of S88, the CPU 62r determines whether or not there is entrapment depending on whether the absolute value of the value obtained by subtracting the pre-cycle current value ifilr from the determination current value ifil1 is greater than the threshold value Δth2. This makes it possible to determine whether or not there is entrapment while suppressing the effects of periodic fluctuations in the load torque applied to the motor 52r when displacing the seat back 14r.

(3) The determination current value is defined so that the steady-state value of the determination current value ifil1 at the second duty ratio DH is slightly smaller than the steady-state value of the determination current value ifil1 at the first duty ratio DL. This makes it possible to prevent the criteria for pinching detection from being relaxed after the duty ratio D is changed.

(4) After the duty ratio D is changed, if the determination current value ifil1 calculated using the coefficient "100/DH" is less than the reference value ifillast, the determination current value ifil1 is determined by multiplying the coefficient "100/DL" by the filtered current ifil0. This prevents the minimum value ifilmin from being updated to an inappropriate value. In addition, pinching can be detected more quickly compared to a case in which pinching detection is masked for a predetermined period of time after the duty ratio D is changed.

<Correspondence>
The correspondence between the matters in the above embodiment and the matters described in the above "Means for solving the problem" column is as follows. Below, the correspondence is shown for each number of the means for solving the problem described in the "Means for solving the problem" column. [1] The vehicle entrapment detection device corresponds to the rear ECU 60r. The movable portion of the seat corresponds to the seat back 14r. The instruction acquisition process corresponds to the process of S32. The displacement process corresponds to the processes of S40, S42, and S50. The entrapment detection process corresponds to the processes of S60 to S72, and S80 to S90. The applied voltage increase process corresponds to the process of S50. [2] The determination current value calculation process corresponds to the processes of S60 to S72. The determination process corresponds to the processes of S82 and S88. The judgment value corresponds to a value obtained by adding a threshold value Δth1 to the minimum value ifilmin and a value obtained by adding a threshold value Δth2 to the smaller of the judgment current value ifil1 and the pre-cycle current value ifilr in the process of S88. [3,4] The replacement process corresponds to the processes of S66 to S72. The predetermined period corresponds to the period from time t1 to t2 in FIG. 8. [5] The first current value corresponds to the minimum value ifilmin in the process of S82 and either the judgment current value ifil1 or the pre-cycle current value ifilr in the process of S88. The second current value corresponds to the judgment current value ifil1 in the process of S82 and either the judgment current value ifil1 or the pre-cycle current value ifilr in the process of S88. The threshold corresponds to the threshold value Δth1 in the process of S82 and the threshold value Δth2 in the process of S88. [6] The switching elements correspond to the switching elements SW1 to SW4. [7] The minimum value update process corresponds to the process of S80. [8] The first current value and the second current value correspond to the determination current value ifil1 and the previous-period current value ifilr in the process of S88. The specified period corresponds to the pulsation period ΔNtot2.

<Other embodiments>
This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

"About the current value for judgment"
In the above embodiment, the determination current value ifil1 is calculated by multiplying the filtered current ifil0 by 100/D, but this is not limited to the above. For example, the determination current value ifil1 may be calculated by multiplying the detection value i by 100/D.

The coefficient for making the judgment current value ifil1 a smaller value relative to the magnitude of the detection value i when the applied voltage is large than when it is small is not limited to "100/D". For example, a constant K other than "100" may be used to make it "K/D". Here, the first time ratio DL may be used as the constant K.

It is not essential that the steady-state value of the determination current value ifil1 at the second duty ratio DH be set to be greater than the steady-state value of the determination current value ifil1 at the first duty ratio DL.
The determination current value ifil1 is not limited to a value obtained by multiplying the detection value i or the filtered current ifil0 by a coefficient. For example, the determination current value ifil1 may be calculated by the CPU 62r using map data. Here, the map data may be data in which the detection value i or the filtered current ifil0 and a variable indicating the applied voltage are used as input variables, and the determination current value ifil1 is used as an output variable.

- The value of the variable indicating the applied voltage used in calculating the judgment current value ifil1 is not limited to the duty ratio D. For example, as described in the "Regarding the motor" section below, if a brushless motor is used as the motor and the applied voltage has a sinusoidal shape, the amplitude value of the applied voltage may be used.

"Minimum value update process"
The minimum value ifilmin is not limited to the minimum value of the determination current value ifil1 from the start of driving the motor 52r. For example, when the load when displacing the seat back 14r changes depending on the position of the seat back 14r, the minimum value ifilmin may be updated for each section where the load is approximately constant.

"About pinch detection processing"
In the processes of S82 and S88, it is not essential that the threshold values Δth1 and Δth2 are fixed values. For example, when one of a pair of determination current values ifil1 that are compared with the threshold values Δth1 and Δth2 is a value at the first duty ratio DL and the other is a value at the second duty ratio DH, the threshold values Δth1 and Δth2 may be made smaller. This can be simply achieved by correcting the threshold values Δth1 and Δth2 to a value obtained by multiplying them by "DL/100".

・For example, in the process of S82, the filtered current ifil0 and its minimum value may be used instead of the judgment current value ifil1 and its minimum value. In that case, the threshold value Δth1 may be increased by using the increase in the duty ratio D as a trigger. Here, the upper limit value of the filtered current ifil0 that does not detect pinching is the minimum value of the filtered current ifil0 plus the threshold value Δth1. Therefore, the upper limit value is changed to a larger value by the increase in the duty ratio D. Incidentally, as described in the "Minimum value update process" section, when the minimum value ifilmin is determined for each section, the process of increasing the threshold value Δth1 is changed as follows. That is, the threshold value Δth1 is changed to be increased only when the applied voltage increases after the sampling of the minimum value ifilmin. Note that it is not essential to use the filtered current ifil0 and its minimum value for the process of increasing the threshold value Δth1. For example, the detection value i and its minimum value may be used.

Also, for example, in the process of S88, the threshold value Δth2 may be increased only when the applied voltage increases within one pulsation cycle from the execution timing of the process.
About the replacement process
The timing for switching the coefficient for calculating the determination current value ifil1 from "100/DL" to "100/DH" is not limited to the timing exemplified in Fig. 6. In other words, the timing when a predetermined period has elapsed since the applied voltage was increased is not limited to the timing exemplified in Fig. 6. For example, it may be the timing when the current value of the filtered current ifil0 falls below the previous value.

For example, a masking period may be provided in which the pinch detection process is not performed for a predetermined period after the applied voltage is increased.
"About measures against pinching"
The process for dealing with the situation in which pinching is detected is not limited to the process of S92. For example, the process may be a process of reversing the rotation of the motor 52r. Note that in order to reverse the rotation of the motor 52r, the rotation speed of the motor 52r must be set to zero once, and therefore this can be considered to include a process of stopping the motor 52r.

- The process for dealing with the situation in which pinching is detected does not necessarily have to include a process for stopping the motor 52r. For example, the process may be a process for operating the speaker to sound an alarm while controlling the torque of the motor 52r to zero.

"Applied voltage increase process"
The purpose of the process of increasing the applied voltage to the motor 52r is not limited to the purpose of avoiding interference between the headrest 16f of the front seat 10f and the headrest 16r of the rear seat 10r. For example, the applied voltage may be reduced during the period required for the user to sense that the seat backs 14f, 14r have begun to move, and then the applied voltage may be increased.

"About moving parts"
The movable member that is the target of pinching detection and is also a member that constitutes the seat is not limited to the seat back 14f, 14r. For example, the movable member may be the seat cushion 12f, 12r. In other words, pinching may be detected when the upper rail 22f, 22r is displaced relative to the lower rail 20f, 20r.

- The movable member that is the subject of entrapment detection is not limited to the member that constitutes the seat. For example, it may be an opening/closing body that opens and closes an opening in the vehicle, such as a sliding door 84 shown in FIG. 9. The sliding door 84 shown in FIG. 9 opens and closes an opening 82 in the vehicle 80.

"About the pinch detection device"
The pinch detection device is not limited to a device equipped with a CPU and a ROM and executing software processing. For example, a dedicated hardware circuit such as an ASIC may be provided to perform hardware processing of at least a part of the software processing in the above embodiment. That is, the pinch detection device may have any of the following configurations (a) to (c). (a) A processing device that executes all of the above processing according to a program, and a program storage device such as a ROM that stores the program. (b) A processing device and a program storage device that execute a part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing. (c) A dedicated hardware circuit that executes all of the above processing. Here, there may be a plurality of software execution devices equipped with a processing device and a program storage device, and a plurality of dedicated hardware circuits.

"About the motor drive circuit"
The motor drive circuit is not limited to an H-bridge circuit. For example, the motor may be a brushless motor and the drive circuit may be an inverter. In that case, if the motor is a three-phase brushless motor, the inverter may be energized in a 120° energization method. The duty ratio D may be 100% when the switching element is turned on for a period of 120°. In that case, the duty ratio D can be set to a value less than "100%" by determining a PWM period during the same period and turning on and off the switching element. The voltage applied to the motor is not limited to a rectangular wave voltage. For example, the duty ratio of the inverter may be changed to a sinusoidal waveform to change the applied voltage to the terminals of the motor to a sinusoidal waveform. In that case, increasing the applied voltage means increasing the amplitude of the sinusoidal voltage.

"others"
In FIG. 1, the front ECU 60f and the rear ECU 60r may be integrated together.
In the example shown in Fig. 1, three rows of seats may be arranged in the vehicle. In this case, the rear seat 10r in Fig. 1 may be the rearmost seat or the center seat.

10f...Front seat 10r...Rear seat 12f, 12r...Seat cushion 14f, 14r...Seat back 16f, 16r...Head rest 50f, 50r...Reclining actuator 52f, 52r...Motor 54f, 54r...Drive circuit 60f...Front ECU
60r…Rear ECU

Claims (7)

The present invention is applied to a vehicle including a movable member and a motor for displacing the movable member,
The movable member is one of a movable portion of a seat and an opening/closing body that opens and closes an opening of the vehicle,
Executes an instruction acquisition process, a displacement process, and an entrapment detection process;
the instruction acquisition process is a process of acquiring an instruction to displace the movable member,
the displacement process is a process of driving the motor to displace the movable member when the instruction is acquired by the instruction acquisition process, and includes an applied voltage increase process;
the applied voltage increasing process is a process of increasing an applied voltage to a terminal of the motor when the movable member is displaced by driving the motor,
the pinch detection process includes a process of detecting the occurrence of pinch due to displacement of the movable member based on the magnitude of a detection value of a current flowing through the motor, and a process of setting an upper limit of the detection value at which pinch is not determined to occur after the applied voltage has increased to a value higher than that before the applied voltage has increased ,
The pinch detection process includes a determination current value calculation process and a determination process,
The determination current value calculation process is a process of calculating a determination current value, which is a current value used for determining whether or not the vehicle is pinched, based on the detection value,
the judgment current value is set to a value smaller relative to the magnitude of the detection value when the applied voltage is large than when the applied voltage is small,
The determination process is a process for determining whether or not the entrapment has occurred based on a magnitude comparison between the determination current value and a determination value . The judgment current value calculation process includes a substitution process,
2. The vehicle entrapment detection device according to claim 1, wherein the replacement process is a process of replacing the determination current value used for determining the entrapment detection each time, for a predetermined period after the applied voltage is increased, with a value corresponding to the applied voltage before being increased. The vehicle entrapment detection device according to claim 2, wherein the predetermined period is a period during which the determination current value calculated based on the increased applied voltage is lower than the determination current value before the applied voltage is increased. the determination process is a process of determining that the pinching has occurred when a difference between a first current value and a second current value corresponding to each of the pair of detection values sampled at different timings exceeds a threshold value;
the first current value and the second current value are the determination current values calculated based on the detection values at different timings,
4. The entrapment detection device for a vehicle according to claim 1, wherein the determination value is a value obtained by adding the smaller of the first current value and the second current value to the threshold value. A voltage of a DC voltage source is applied to the motor via a switching element,
the displacement process drives the motor by operating the switching element;
5. The entrapment detection device for a vehicle according to claim 4, wherein the applied voltage increasing process is a process for increasing a ratio of an on-time to a cycle of an on-off operation of the switching element from a first ratio to a second ratio. The pinch detection process includes a minimum value update process,
the minimum value update process is a process of updating the first current value to a value corresponding to the current detection value when a value corresponding to the current detection value is smaller than the first current value;
6. The entrapment detection device for a vehicle according to claim 4, wherein the second current value is a value corresponding to the detection value sampled each time. the first current value and the second current value are values corresponding to a pair of the detection values sampled at a pair of timings that are spaced apart by a specified period,
6. The entrapment detection device for a vehicle according to claim 4, wherein the specified period is a period during which the motor rotates by a predetermined angle.