Actuator Control Device

Abstract

To provide an actuator control device capable of improving responsiveness.SOLUTION: A control device 60 includes a drive control unit 78 and a position determination unit 75. The drive control unit 78 controls driving of a motor 40 so that a detent roller 26 moves to a target trough. The position determination unit 75 determines on the basis of a detection value of an output shaft sensor 55 that the detent roller 26 reaches the target trough. The drive control unit 78 executes return control for returning the motor 40 in a reverse direction within a range of a play between the motor 40 and an output shaft 15 after the detent roller 26 reaches the target trough. A backlash elimination time Xg for performing the return control is set in accordance with an arrival determination time Xj for determining that the detent roller 26 has reached the target trough.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an actuator control device. [Background technology]

[0002] Conventionally, there is known a shift range control device that switches the shift range by controlling the drive of a motor. For example, in Patent Document 1, after stopping the motor at a target position, return control is performed to return the rotational position of the motor within a play range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6862906 Summary of the Invention [Problem to be solved by the invention]

[0004] In the return control of Patent Document 1, the motor is driven in steps by the minimum driveable width according to the resolution. This type of control requires a highly accurate and noise-resistant sensor, and if the control is incorrect and the motor is driven beyond the play range, there is a risk that the detent roller will deviate from the valley position.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an actuator control device that can improve responsiveness. [Means for solving the problem]

[0006] The actuator control device of the present invention controls switching of the detent mechanism in a drive system (1) including an actuator (10) having a drive source (40) and a detent mechanism (20) having a detent member (21) and an engagement member (26) by driving the actuator to move the engagement member. The detent member is formed with a plurality of valleys (211, 212) and peaks (215) separating the valleys. The engagement member is movable between the valleys when the output shaft (15) is driven by the actuator.

[0007] The actuator control device includes a drive control unit (78) and a control amount calculation unit (76). The drive control unit controls the drive of the drive source so that the engaging member moves to the target valley portion. The control amount calculation unit calculates the energization time and energization amount of return control that returns the drive source in the reverse direction within the range of play between the drive source and the output shaft after the engaging member reaches the target valley portion. The control amount calculation unit calculates the energization time of the return control according to the arrival determination time that determines whether the engaging member has reached the target valley portion. This improves responsiveness. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram showing a parking lock system according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing a control device according to the first embodiment. [Figure 3] 10A is an explanatory diagram illustrating a switching process, and FIG. 10B is an explanatory diagram illustrating a return control. [Figure 4] 4 is a flowchart illustrating a switching process according to the first embodiment. [Figure 5] 4 is a flowchart illustrating a switching process according to the first embodiment. [Figure 6] 4 is a time chart illustrating a switching process according to the first embodiment. [Figure 7] 10 is a map showing a backlash elimination time calculation according to the second embodiment in accordance with the actuator temperature. [Figure 8]10 is a backlash-reducing duty calculation map according to the second embodiment, which is based on the actuator temperature. [Figure 9] 10 is a flowchart illustrating a switching process according to the third embodiment. [Figure 10] 10 is a time chart illustrating a switching process according to the third embodiment. [Figure 11] 10 is a flowchart illustrating a switching process according to the fourth embodiment. [Figure 12] 10 is a time chart illustrating a switching process according to the fourth embodiment. [Figure 13] 13 is a flowchart illustrating a switching process according to the fifth embodiment. [Figure 14] 13 is a flowchart illustrating a switching process according to the sixth embodiment. [Figure 15] 13 is a time chart illustrating a switching process according to the sixth embodiment. [Figure 16] 13 is a flowchart illustrating a switching process according to the seventh embodiment. [Figure 17] 13 is a flowchart illustrating a switching process according to the seventh embodiment. [Figure 18] 13 is a time chart illustrating a switching process according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) An actuator control device according to the present invention will now be described with reference to the drawings. In the following, substantially identical components in multiple embodiments will be denoted by the same reference numerals, and descriptions thereof will be omitted. A first embodiment is shown in FIGS. 1 to 6.

[0010] As shown in Fig. 1, an electric actuator 10 is applied to a parking lock system 1. The park lock system 1 includes the electric actuator 10, a detent mechanism 20, and a parking lock mechanism 30. The electric actuator 10 is a rotary type and includes a motor 40, such as a brushed DC motor, a reduction gear mechanism, and the like. The electric actuator 10 drives the detent mechanism 20 by rotating an output shaft 15.

[0011] The detent mechanism 20 has a detent plate 21, a detent spring 25, etc., and transmits the rotational driving force output from the electric actuator 10 to the parking lock mechanism 30.

[0012] The detent plate 21 is fixed to the output shaft 15 and driven by the electric actuator 10. On the side of the detent spring 25 of the detent plate 21, two valleys 211, 212 and a peak 215 separating the valleys 211, 212 are provided.

[0013] The detent spring 25, which is a biasing member, is an elastically deformable plate-like member, and has a detent roller 26 at its tip. The detent spring 25 biases the detent roller 26 toward the rotation center of the detent plate 21.

[0014] When a rotational force greater than or equal to a predetermined value is applied to the detent plate 21, the detent spring 25 elastically deforms, and the detent roller 26 moves between the valleys 211 and 212. When the detent roller 26 fits into either of the valleys 211 or 212, the oscillation of the detent plate 21 is restricted, and the state of the parking lock mechanism 30 is fixed.

[0015] The parking lock mechanism 30 has a parking rod 31, a cone 32, a parking lever 33, a shaft 34, and a parking gear 35. The parking rod 31 is formed in a generally L-shape, and one end 311 is fixed to the detent plate 21. The other end 312 of the parking rod 31 is provided with a cone 32. The cone 32 is formed so that its diameter decreases toward the other end 312. When the detent plate 21 rotates in a direction in which the detent roller 26 fits into the valley 211 corresponding to the P range, the cone 32 moves in the direction of arrow P.

[0016] The parking lever 33 abuts against the conical surface of the cone 32 and is provided so as to be able to swing around a shaft 34. A protrusion 331 that can mesh with the parking gear 35 is provided on the parking lever 33 on the parking gear 35 side. When the cone 32 moves in the direction of arrow P due to rotation of the detent plate 21, the parking lever 33 is pushed up and the protrusion 331 meshes with the parking gear 35. On the other hand, when the cone 32 moves in the direction not indicated by arrow P, the meshing between the protrusion 331 and the parking gear 35 is released.

[0017] The parking gear 35 is connected to a drive shaft (not shown) and is provided so as to be able to mesh with a protrusion 331 of the parking lever 33. When the parking gear 35 meshes with the protrusion 331, rotation of the drive shaft is restricted. When the shift range is a range other than P, i.e., a not P range, the parking gear 35 is not locked by the parking lever 33, and rotation of the drive shaft is not prevented by the parking lock mechanism 30. Furthermore, when the shift range is P range, the parking gear 35 is locked by the parking lever 33, and rotation of the drive shaft is restricted.

[0018] Hereinafter, the valley portion 211 into which the detent roller 26 fits when in the P range will be referred to as the "P valley," the valley portion 212 into which the detent roller 26 fits when in the not P range will be referred to as the "not P valley," and the bottom of the valley portions 211 and 212 will be referred to as the "bottom."

[0019] As shown in Fig. 2, the control device 60 includes a drive circuit 61 and a control unit 70. The drive circuit 61 includes drive elements (not shown). The control unit 70 is mainly configured with a microcomputer or the like, and includes a CPU, ROM, RAM, I / O, and bus lines connecting these components (all not shown). Each process in the control unit 50 may be software processing in which the CPU executes a program stored in advance in a physical memory device (i.e., a readable non-transitory tangible recording medium) such as a ROM, or may be hardware processing using a dedicated electronic circuit.

[0020] The control unit 70 acquires the requested shift range, sets a target range, and controls the driving of the electric actuator 10 so that the detent roller 26 is positioned at the valleys 211, 212 corresponding to the target range. The control unit 70 has, as functional blocks, a signal acquisition unit 71, a rotation calculation unit 72, a temperature calculation unit 74, a position determination unit 75, a control amount calculation unit 76, and a drive control unit 78. The signal acquisition unit 71 acquires sensor signals including a position detection signal from the output shaft sensor 55, a current signal from the current sensor 56, and a temperature signal from the temperature sensor 57. The signal acquisition unit 71 also acquires a signal related to the requested shift range from a higher-level ECU (not shown) or the like.

[0021] The rotation calculation unit 72 calculates the output shaft angle θs and the output shaft angular velocity ω based on the detection values ​​of the output shaft sensor 55. The output shaft sensor 55 is not limited to a sensor that directly detects the rotation of the output shaft 15, but may instead detect the rotation of a shaft connected to the output shaft 15 or a gear or the like that constitutes a reduction mechanism provided between the motor shaft and the output shaft, and convert the rotation into an appropriate gear ratio or the like.

[0022] A current calculation unit 73 calculates a current value I of the motor current that is the current that is passed through the motor 40 based on the detection value of the current sensor 56. A temperature calculation unit 74 calculates an actuator temperature p based on the detection value of the temperature sensor 57. A position determination unit 75 determines the position of the detent roller 26 in the detent mechanism 20.

[0023] The control amount calculation unit 76 calculates a backlash eliminating time Xg and a backlash eliminating duty Dg as control amounts in the backlash eliminating control. Details of the backlash eliminating control will be described later. The drive control unit 78 controls the driving of the motor 40 by controlling the on / off operation of the drive elements of the drive circuit 61.

[0024] 3(a) and 3(b) schematically show the play between the motor 40 and the output shaft 15, with the left-right direction on the paper regarded as the direction of rotation, and show how the detent roller 26 moves between the valleys 211 and 212. In reality, the detent roller 26 moves between the valleys 211 and 212 as the detent plate 21, which rotates integrally with the output shaft 15, rotates. In FIGS. 3(a) and 3(b), the operation of the motor, etc. is indicated by dashed arrows.

[0025] In this embodiment, a speed reduction mechanism is provided between the motor 40 and the output shaft 15, and the total play between the motor shaft and the output shaft is defined as the backlash width Gw. As shown in FIG. 3(a), at time x10 before the motor 40 is driven, the motor shaft is positioned somewhere within the backlash width Gw. The motor 40 is driven in the direction not P, and when the backlash in the drive direction is eliminated at time x11, the output shaft 15 is driven, and the detent roller 26 is driven toward the apex of the ridge 215. Hereinafter, eliminating the backlash will be referred to as "backlash elimination" where appropriate.

[0026] When the detent roller 26 overcomes the peak 215, the load torque reverses, and the output shaft 15 moves ahead due to the spring force of the detent spring 25, causing the detent roller 26 to move toward the valley 212. At time x13, the detent roller 26 reaches the bottom of the valley 212, and the motor shaft rotates within the backlash width Gw until time x15, when the motor 40 stops. Hereinafter, the amount of movement within the backlash after the detent roller 26 reaches the bottom of the target valley is referred to as the amount of movement within the backlash θg.

[0027] If the switching process is terminated while the state is as it is at time x15, the next time the range is switched from the not-P range to the P range, it will take longer to switch by the amount of backlash movement θg compared to when driving is started from a state where the play is eliminated in the P range direction. Therefore, in this embodiment, from time x15 when the stop control ends, backlash elimination control is performed in which the motor 40 is driven in the direction opposite to that at the time of switching according to the amount of backlash movement θg, thereby eliminating a certain amount of backlash within a range in which the detent roller 26 does not deviate from the valley (see FIG. 3(b)). Note that FIGS. 3(a) and 3(b) are shown corresponding to the times in FIG. 6.

[0028] The switching process of this embodiment will be described based on the flowcharts of Figures 4 and 5. The process of Figure 4 and the like is executed at a predetermined cycle by the control unit 70. Hereinafter, the "step" such as step S101 will be omitted and simply referred to as the symbol "S".

[0029] In S101, the control unit 70 determines whether the driving mode is the standby mode. If it is determined that the driving mode is not the standby mode (S101: NO), the process proceeds to S105. If it is determined that the driving mode is the standby mode (S101: YES), the process proceeds to S102.

[0030] In S102, the control unit 70 determines whether the target range has been switched. If it is determined that the target range has not been switched (S102: NO), the standby mode continues. If it is determined that the target range has been switched (S102: YES), the process proceeds to S103. In S103, the control unit 70 sets the drive mode to the switching mode. In S104, the drive control unit 78 turns on the power supply to the motor 40 to drive the motor 40. At this time, the duty is controlled to be the drive duty Dd.

[0031] In S105, the control unit 70 determines whether the drive mode is the switching mode. If it is determined that the drive mode is not the switching mode (S105: NO), the process proceeds to S109. If it is determined that the drive mode is the switching mode (S105: YES), the process proceeds to S106.

[0032] In S106, the position determination unit 75 determines whether the valley position determination flag Fvj is on. The valley position determination flag Fvj is turned on when the detent roller 26 reaches the bottom of the target valley based on the detection value of the output shaft sensor 55 and the arrival determination time Xj has elapsed. The time elapsed since the detection value of the output shaft sensor 55 reached the target value is measured by a valley position determination counter. If it is determined that the valley position determination flag Fvj is off (S106: NO), the motor 40 continues to be driven at the duty Dd. If it is determined that the valley position determination flag Fvj is on (S106: YES), the process proceeds to S107.

[0033] In S107, the control unit 70 sets the drive mode to the stop mode. In S108, the drive control unit 78 turns off the power supply to the motor 40. In the stop mode, a braking force is generated by circulating back electromotive force. Here, "power supply off" means stopping the power supply from the battery (not shown) to the motor 40.

[0034] 5, if it is determined that the drive mode is not the switching mode (S105: NO), the control unit 70 proceeds to S109, where it determines whether the drive mode is the stop mode. If it is determined that the drive mode is not the stop mode (S109: NO), the control unit 70 proceeds to S112. If it is determined that the drive mode is the stop mode (S109: YES), the control unit 70 proceeds to S110.

[0035] In S110, the control unit 70 determines whether the stop determination time Xoff has elapsed since the transition to the stop mode. If it is determined that the stop determination time Xoff has not elapsed (S110: NO), the control unit 70 increments a stop control counter that measures the elapsed time since the transition to the stop mode. If it is determined that the stop determination time Xoff has elapsed (S110: YES), the control unit 70 proceeds to S111, where the drive mode is set to the backlash reduction mode. The control unit 70 also resets the stop control counter.

[0036] If it is determined that the drive mode is not the stop mode (S109: NO), the control unit 70 proceeds to S112, where it determines whether the drive mode is the backlash reduction mode. If it is determined that the drive mode is not the backlash reduction mode (S112: NO), the control unit 70 skips the processing from S113 onwards. If it is determined that the drive mode is the backlash reduction mode (S112: YES), it proceeds to S113.

[0037] In S113, the control unit 70 determines whether or not the clearance elimination time Xg has elapsed since the start of the clearance elimination control. The clearance elimination time Xg is calculated as a function of the arrival determination time Xj related to the valley position determination. For example, in this embodiment, the arrival determination time Xj is multiplied by a predetermined coefficient k1 (see equation (1)). In the equation, f(Xj) indicates that it is a function of Xj. The same applies to functions related to other parameters. Moreover, map calculations may be used instead of function calculations. The same applies to each parameter described below. If it is determined that the clearance elimination time Xg has not elapsed (S113: NO), the process proceeds to S114. If it is determined that the clearance elimination time Xg has elapsed (S113: YES), the process proceeds to S115.

[0038] Xg=f(Xj)=Xj×k1 (1)

[0039] In S114, the drive control unit 78 turns on the power supply to the motor 40 and drives the motor 40 in the direction opposite to that at the time of switching. At this time, the drive control unit 78 controls the duty to be a backlash-reducing duty Dg. The backlash-reducing duty Dg is calculated as a function of the drive duty Dd at the time of switching. For example, in this embodiment, the drive duty Dd is multiplied by a predetermined coefficient k2 (see equation (2)). In addition, the drive control unit 78 increments a backlash-reducing control counter that measures the elapsed time from the start of backlash-reducing control. The coefficients k1 and k2 can be set to any values.

[0040] Dg = f(Dd) = Dd × k2 (2)

[0041] In S115 which is to be entered when it is determined that the rattling packing time Xg has elapsed, the control unit 70 sets the drive mode to the standby mode and resets the rattling packing control counter. In S116, the drive control unit 78 turns off the power supply to the motor 40.

[0042] Here, by setting Xg < Xj and Dg < Dd, it is possible to prevent the output shaft 15 from rotating due to excessive rattling packing. Also, by setting Xg > Xj and Dg > Dd, it is possible to control the rattling packing amount in consideration of the delay related to the start of movement of the motor 40 from the start of rattling packing control.

[0043] The switching control of this embodiment will be described based on the time chart of FIG. 6. In FIG. 6, the common time axis is taken as the horizontal axis, and from the upper part, the required shift range, rotation angle, valley position determination flag Fvj, valley position determination counter, output shaft angular velocity, current value I of the motor current, duty, and drive mode are shown.

[0044] Regarding the rotation angle, the output shaft angle θs based on the detection value of the output shaft sensor 55 is shown by a solid line, and the motor angle θm corresponding to the behavior of the motor 40 is shown by a two-dot chain line, and the scales are aligned by gear ratio conversion. Also, the motor angle when the detent roller 26 is at the bottommost part of the valley portion 211 is "P valley", and the motor angle when it is at the bottommost part of the valley portion 212 is "not P valley". The same applies to FIG. 10 and the like. Also, the duty is the ratio of the voltage application time in PWM control, and positive and negative are defined according to the energization direction.

[0045] At time x10, when the target shift range switches from the P range to the not P range, the drive mode is changed from the standby mode to the switching mode, and the motor 40 is driven at the drive duty Dd. When the rattling is clogged in the traveling direction at time x11, the drive of the output shaft 15 is started. At time x12, when the detent roller 26 crosses the peak portion 215, the torque becomes reverse, and since the rattling is clogged at once on the opposite side, the output shaft angle θs changes steeply.

[0046] At time x13, the detent roller 26 reaches the bottom of the valley portion 212, and at time x14, when the arrival determination time Xj has elapsed since time x13, the valley position determination flag Fvj is turned on. Also, the power supply to the motor 40 is turned off, and stop control is performed.

[0047] At time x15, when the stop determination time Xoff has elapsed since the start of the stop control, the stop control is terminated, and backlash-eliminating control is performed, supplying current in the direction opposite to the range switching direction. The backlash-eliminating control has a duty of backlash-eliminating duty Dg and is performed for backlash-eliminating time Xg. At time x16, when the backlash-eliminating time Xg has elapsed from time x15, the backlash-eliminating control is terminated, the drive mode is changed to standby mode, and current supply to the motor 40 is terminated.

[0048] Since the amount of movement within the backlash θg can be regarded as the amount of rotation when the motor 40 is driven by energizing at the drive duty Dd for the arrival determination time Xj, backlash elimination control is performed in accordance with the amount of movement within the backlash θg, so the motor shaft is moved somewhat toward the direction of travel at the time of the next switch within the backlash width Gw. This makes it possible to appropriately eliminate backlash within the range of the backlash width Gw without using a high-precision sensor or the like, thereby improving responsiveness.

[0049] As described above, the control device 60 of this embodiment drives the electric actuator 10 having the motor 40, the detent mechanism 20, and the output shaft sensor 55 in the parking lock system 1, and controls the switching of the detent mechanism 20 by moving the detent roller 26.

[0050] The detent mechanism 20 has a detent plate 21 and a detent roller 26. The detent plate 21 is formed with a plurality of valleys 211, 212 and peaks 215 separating the valleys 211, 212. The detent roller 26 is movable between the valleys 211, 212 as the output shaft 15 is driven by the electric actuator 10. The output shaft sensor 55 is capable of detecting the position of the output shaft 15.

[0051] The control device 60 includes a drive control unit 78 and a control amount calculation unit 76. The drive control unit 78 controls the drive of the motor 40 so that the detent roller 26 moves to the target valley portion. The control amount calculation unit 76 calculates a backlash elimination time Xg and a backlash elimination duty Dg for backlash elimination control that returns the motor 40 in the reverse direction within the range of play between the motor 40 and the output shaft 15 after the detent roller 26 reaches the target valley portion.

[0052] The control amount calculation unit 76 calculates the backlash elimination time Xg according to the arrival determination time Xj that determines whether the detent roller 26 has reached the target valley. By eliminating the backlash in the direction opposite to the current driving direction, i.e., in the next traveling direction, according to the arrival determination time Xj during which the detent roller 26 is running freely within the backlash, it is possible to perform appropriate return control without using a high-precision position sensor, and it is possible to improve responsiveness.

[0053] The control amount calculation unit 76 calculates the backlash-eliminating duty Dg in accordance with the drive duty Dd during the switching drive of the detent mechanism 20. This makes it possible to set an appropriate amount of current depending on the actual output, for example, when there is a difference in output torque depending on the drive direction of the electric actuator 10.

[0054] The backlash elimination control is performed after the detent roller 26 reaches the target valley and the motor 40 is stopped by the stop control. Furthermore, when the stop determination time Xoff has elapsed since the start of the stop control, it is determined that the motor 40 has stopped. This allows the current value to be kept small compared to when backlash elimination control is continuously performed after it is determined that the detent roller 26 has reached the target valley. Furthermore, wear on the sliding parts of the electric actuator 10 can be suppressed.

[0055] (Second embodiment) The second embodiment is shown in Fig. 7 and Fig. 8. The control unit 70 calculates the clearance elimination time Xg based on the arrival determination time Xj and the actuator temperature p (see formula (3)). Alternatively, as shown in Fig. 7, the clearance elimination time Xg may be calculated using a map according to the actuator temperature. The actuator temperatures p1 to p3 are calculated based on the actuator temperature p1. <p2<p3である。

[0056] Xg = Xj × f(p) (3)

[0057] The control unit 70 calculates the backlash-reducing duty Dg based on the drive duty Dd and the actuator temperature p (see equation (4)). Alternatively, as shown in Fig. 8, the backlash-reducing duty Dg may be calculated using a map according to the actuator temperature p.

[0058] Dg = Dd × f(p) (4)

[0059] When the actuator temperature p is high, the torque required to start the motor 40 is small, and when the actuator temperature p is low, the torque required to start the motor 40 is large. Therefore, by making the backlash eliminating time Xg and the backlash eliminating duty Dg variable according to the actuator temperature p and making the backlash eliminating time Xg and the backlash eliminating duty Dg larger when the actuator temperature p is low than when the temperature is high, it is possible to reduce variations in backlash eliminating performance due to temperature. Note that one of the backlash eliminating time Xg or the backlash eliminating duty Dg may be variable according to temperature, and the other may be a fixed value.

[0060] At least one of the backlash eliminating time Xg and the backlash eliminating duty Dg is variable in accordance with the actuator temperature p. This allows appropriate backlash eliminating control to be performed in accordance with the actuator temperature p. In addition, the same effects as those of the above embodiment are achieved.

[0061] (Third embodiment) The third embodiment is shown in Figures 9 and 10. The switching process of this embodiment will be described based on the flowchart in Figure 9. Note that the latter half of the process, which is started after a negative determination in S205, is the same as in Figure 5, and therefore will not be described here. The same applies to Figure 11, etc., which will be described later.

[0062] The processes of S201 to S206 are the same as those of S101 to S106 in Fig. 4. If a negative determination is made in S205, the process proceeds to S109 in Fig. 5. If it is determined that the valley position determination flag Fvj is on (S206: YES), the process proceeds to S209, and if it is determined that the valley position determination flag Fvj is off (S206: NO), the process proceeds to S207.

[0063] In S207, the control unit 70 determines whether the output shaft angular velocity ω is stable. Here, if the state in which the amount of change in the output shaft angular velocity ω is equal to or less than a predetermined value continues for a predetermined time, the control unit 70 determines that the output shaft angular velocity ω is stable. If it is determined that the output shaft angular velocity ω is not stable (S207: NO), the process of S208 is skipped. If it is determined that the output shaft angular velocity ω is stable (S207: YES), the process proceeds to S208.

[0064] In S208, the control unit 70 stores the output shaft angular velocity ω in a stable region where the output shaft angular velocity ω is stable as the in-drive angular velocity ωd. The in-drive angular velocity ωd may be a value at any timing other than a region where the output shaft angle θs changes suddenly, such as when the detent roller 26 goes over a peak. However, it is preferable to store the value immediately before the motor stops. For example, the in-drive angular velocity ωd may be the value immediately before the inflection point of the output shaft angle θs before the detent roller 26 goes over a peak, or the value immediately before the output shaft angle θs stagnates as the detent roller 26 reaches the bottom. Alternatively, the in-drive angular velocity ωd may be a calculated value, such as an average value, using multiple detected values.

[0065] S209 and S210, which are executed when it is determined that the valley position determination flag Fvj is on (S206: YES), are similar to S107 and S108 in Fig. 4. In S211, the control unit 70 calculates the free running amount θj at the arrival determination time Xj using the driving angular velocity ωd (Equation (5)). In other words, in this embodiment, it can also be understood that the free running amount θj is calculated without using the detection value of the rotation angle sensor that detects the rotation angle of the motor 40.

[0066] θj=ωd×Xj (5)

[0067] In S212, the control amount calculation unit 76 calculates the backlash-eliminating time Xg. In S213, the control amount calculation unit 76 calculates the backlash-eliminating duty Dg. The backlash-eliminating time Xg and the backlash-eliminating duty Dg are calculated as functions of the idle running amount θj (see equations (6) and (7)). a1, a2, b1, and b2 in the equations simply mean the slope and intercept of a linear function, and can be set to any value. Although equations (6) and (7) treat the backlash-eliminating time Xg and the backlash-eliminating duty Dg as linear functions of the idle running amount θj, they may also be functions of quadratic or higher order. The same applies to equations (10) and (11) described below.

[0068] Xg=f1(θj)=a1×θj+b1 ···(6) Dg=f2(θj)=a2×θj+b2 (7)

[0069] The switching process of this embodiment will be described based on the time chart of Fig. 10. The process from time x20 to x24 is substantially the same as the process from x10 to x14 in Fig. 6. In this embodiment, the driving angular velocity ωd is stored in the region where the output shaft angular velocity ω is stable between time x21 and time x22.

[0070] At time x24, when the valley position determination flag Fvj is turned on, power to the motor 40 is turned off. In addition, the idle amount θj during the arrival determination time Xj (i.e., from time x23 to time x24) is calculated using the driving angular velocity ωd, and the backlash elimination time Xg and the backlash elimination duty Dg are calculated based on the estimated idle amount θj.

[0071] At time x25, the drive mode switches from stop control to backlash elimination control, and backlash elimination control is performed with backlash elimination time Xg and backlash elimination duty Dg calculated based on the idle running amount θj. At time x26, when the backlash elimination time Xg has elapsed since time x25, the backlash elimination control ends, the drive mode switches to standby mode, and power to the motor 40 is stopped.

[0072] The control amount calculation unit 76 estimates the amount of free running using the driving angular velocity ωd, which is the driving speed of the output shaft 15 when the detent mechanism 20 is switched, and the arrival determination time Xj, and calculates the backlash elimination time Xg and the backlash elimination duty Dg based on the estimated amount of free running. This allows for appropriate backlash elimination control. The same effects as those of the above embodiment are also achieved.

[0073] (Fourth embodiment) A fourth embodiment is shown in Figures 11 and 12. The switching process of this embodiment will be described based on the flowchart in Figure 11. The processes of S301 to S308 are the same as the processes of S101 to S108 in Figure 4. In S309, which is performed after the power supply is turned off, the control unit 70 stores the peak current when the power supply is turned off as the power supply off current Istop.

[0074] In S310, the control amount calculation unit 76 calculates the output shaft angular velocity ω using the power-off current Istop (Equation (8)), and calculates the idle amount θj at the arrival determination time Xj using the calculated output shaft angular velocity ω (Equation (9)). In the equations, R is the circuit resistance, Ke is the torque constant, and C is a correction coefficient. In Equation (8), correction is performed using the correction coefficient C in consideration of the possibility that the peak current may be missed by the current sensor 56, which detects the current discretely, but correction does not have to be performed. The processing of S311 and S312 is the same as the processing of S212 and S213 in FIG. 9.

[0075] From V=Ke×ω and V=I×R, ω=Istop×R / Ke (8) θj=ω×Xj×C =Istop×R / Ke×Xj×C (9)

[0076] The switching process of this embodiment will be described based on the time chart of FIG. 12. The process from time x30 to time x33 is the same as the process from time x10 to time x13 in FIG. 6. At time x34, the valley position determination flag Fvj is turned on and the motor 40 is de-energized. The power-off current Istop, which is the peak value of the back electromotive force, is stored. The power-off current Istop is used to calculate the free running amount θj, and the backlash elimination time Xg and the backlash elimination duty Dg are calculated based on the estimated free running amount θj. In this embodiment, the output shaft angular velocity ω is calculated from the power-off current Istop, so the free running amount θj can be calculated without using the detection value of the output shaft sensor 55.

[0077] At time x35, when the drive mode switches from stop control to backlash elimination control, backlash elimination control is performed with backlash elimination time Xg and backlash elimination duty Dg calculated based on the idle running amount θj. At time x26, when the backlash elimination time Xg has elapsed since time x35, the backlash elimination control ends, the drive mode changes to standby mode, and power to the motor 40 is stopped.

[0078] In this embodiment, the output shaft angular velocity ω used to calculate the idling amount θj is calculated based on the peak current after power supply to the motor 40 is stopped. This makes it possible to calculate the output shaft angular velocity ω without using the detection value of the output shaft sensor 55. In addition, the same effects as those of the above embodiment are achieved.

[0079] (Fifth embodiment) The fifth embodiment is shown in Fig. 13. The flowchart in Fig. 13 is the same as Fig. 11 except that S359 to S362 replace S309 to S312. In S359, the control unit 70 stores the power-off current Istop as well as the actuator temperature p at the time of power-off.

[0080] In S360, the control amount calculation unit 76 calculates the idling amount θj using the power-off current Istop and the actuator temperature p (equation (10)). In S361 and S362, the backlash-eliminating time Xg and the backlash-eliminating duty Dg are calculated (equations (11) and (12)). Note that the subscript (p) indicates a function of the actuator temperature p. Also, a1(p) and a2(p) in equations (11) and (12) indicate that the slope of the linear function is a function of the actuator temperature p, and b1(p) and b2(p) indicate that the intercept of the linear function is a function of the actuator temperature p.

[0081] θj=Istop×R(p) / Ke(p)×Xj×C (10) Xg=a1(p)×θj+b1(p) (11) Dg=a2(p)×θj+b2(p) ···(12)

[0082] Here, the idle amount θj, backlash-reducing time Xg, and backlash-reducing duty Dg are made variable according to the actuator temperature p, but for example, the idle amount θj may be calculated according to equation (10) according to the actuator temperature p, and the backlash-reducing time Xg and backlash-reducing duty Dg may be calculated according to equations (6) and (7) regardless of temperature. Also, either the backlash-reducing time Xg or the backlash-reducing duty Dg may be adjusted according to temperature.

[0083] In this embodiment, by temperature-compensating the circuit resistance R and the torque constant Ke, it is possible to calculate the output shaft angular velocity ω with high accuracy, and therefore the idling amount θj can be calculated appropriately. Also, by making the backlash eliminating time Xg and backlash eliminating duty Dg longer when the temperature is low than when the temperature is high, depending on the actuator temperature p, it is possible to reduce variations in backlash eliminating performance due to the actuator temperature p.

[0084] The control amount calculation unit 76 calculates the free running amount θj using the actuator temperature p. Specifically, the circuit resistance R and torque constant Ke used to calculate the output shaft angular velocity ω are temperature-corrected, and the free running amount θj is calculated using the corrected output shaft angular velocity ω. This makes it possible to estimate the free running amount θj with higher accuracy. In addition, the same effects as those of the above embodiment are achieved.

[0085] (Sixth embodiment) The sixth embodiment is shown in Figures 14 and 15. The switching process of this embodiment will be described based on the flowchart in Figure 14. The first half of the process is the same as that in Figure 9, so its description will be omitted. As in the fourth and fifth embodiments, the idling amount θj may be calculated based on the power-off current Istop, or the parameter may be made variable depending on the actuator temperature p.

[0086] FIG. 14 is the same as FIG. 5 except that S120 replaces S110. In S120, the control unit 70 determines whether the absolute value of the current value I of the motor current is equal to or less than the current determination threshold Ith. The current determination threshold Ith is set to a value at which the back electromotive force can be considered to have converged. If it is determined that the absolute value of the current value I is greater than the current determination threshold Ith (S120: NO), S111 is skipped and the stop mode continues. If it is determined that the absolute value of the current value I is equal to or less than the current determination threshold Ith (S120: YES), the process proceeds to S111, and the drive mode is set to the backlash reduction mode.

[0087] Furthermore, the time elapsed since the start of the stop control may be measured by a stop control counter, and when the stop determination time Xoff from the start of the stop mode has elapsed, the system may transition to backlash-reducing control. This allows transition to backlash-reducing control even when determination based on the current value I cannot be made due to, for example, an abnormality in the current sensor 56.

[0088] The switching control of this embodiment will be described based on the time chart of Fig. 15. In Fig. 15, the horizontal axis represents a common time axis, and the requested shift range, rotation angle, valley position determination flag Fvj, valley position determination counter, output shaft angular velocity, motor current value I, stop determination, duty, and drive mode are shown. In this embodiment, the current determination threshold Ith is approximately 0, and so its illustration has been omitted to avoid complication.

[0089] The processing from time x40 to time x44 is the same as the processing from time x10 to time x14 in Figure 6. Furthermore, before time x44, the stop determination is OFF. At time x44, the process shifts to stop control, and when the absolute value of the current value I becomes equal to or less than the current determination threshold Ith at time x45, the stop determination is turned ON and the process shifts to backlash-eliminating control. When backlash-eliminating control is started and the absolute value of the current value I becomes greater than the current determination threshold Ith, the stop determination is turned OFF.

[0090] In this embodiment, stopping of the motor 40 is determined based on the current value I of the motor 40 during the stop control. This allows the control to be quickly shifted to backlash elimination control after the motor is stopped. In addition, the same effects as those of the above embodiment are achieved.

[0091] Seventh embodiment The seventh embodiment is shown in Figures 16 to 18. The switching process of this embodiment is shown in Figures 16 and 17. The processes of S401 to S408 in Figure 16 are the same as the processes of S201 to S208 in Figure 9. If it is determined that the valley position determination flag Fvj is on (S406: YES), the process proceeds to S409, and the drive mode is set to the backlash reduction mode. The processes of S410 to S412 are the same as S211 to S213 in Figure 9, but the backlash reduction time Xg and backlash reduction duty Dg may be set based on the arrival determination time Xj and drive duty Dd, as in the first embodiment. Furthermore, each parameter may be made variable depending on the actuator temperature p.

[0092] If it is determined in S405 that the drive mode is not the switching mode (S405: NO), the process proceeds to S413 to S417 in Fig. 17, which are the same as S112 to S116 in Fig. 5. That is, in this embodiment, when the valley position determination flag Fvj is turned on, the process proceeds to backlash elimination mode and backlash elimination control is performed without performing stop control.

[0093] The switching process of this embodiment will be described based on the time chart in Figure 18. The process from time x50 to time x53 is the same as the process from time x20 to time x23 in Figure 10. At time x54, when the valley position determination flag Fvj is turned on, backlash elimination control is performed with the backlash elimination duty Dg. At time x55, when the backlash elimination control starts at time x54 and the backlash elimination time Xg has elapsed, the drive mode is switched to the standby mode and power supply to the motor 40 is stopped.

[0094] In this embodiment, the backlash elimination control is continuously performed from the timing when it is determined that the detent roller 26 has reached the target valley portion. This allows the backlash elimination control to be started earlier, and also provides the same effects as the above embodiment.

[0095] In the embodiment, the parking lock system 1 corresponds to the "drive system," the electric actuator 10 corresponds to the "actuator," the motor 40 corresponds to the "drive source," the detent plate 21 corresponds to the "detent member," the detent roller 26 corresponds to the "engagement member," and the control device 60 corresponds to the "actuator control device."

[0096] Furthermore, the backlash eliminating control corresponds to the "return control," the backlash eliminating time Xg corresponds to the "energization time of the return control," the backlash eliminating duty Dg corresponds to the "energization amount of the return control," the output shaft angular velocity ω corresponds to the "drive speed of the output shaft," and the current Istop when power is turned off corresponds to the "peak current after power is turned off to the drive source." Furthermore, the target valley when switching from the P range to the notP range is valley 212, and the target valley when switching from the notP range to the P range is valley 211.

[0097] (Other embodiments) In the above embodiment, the drive source is a brushed DC motor. In other embodiments, the drive source may be a motor other than a brushed DC motor, or may be a solenoid or the like. In the above embodiment, the electric actuator is a rotary type, but in other embodiments, it may be a linear type.

[0098] In the above embodiment, the electric actuator is applied to a parking lock system. In other embodiments, the electric actuator may be applied to an in-vehicle system other than a parking lock system or a drive system other than an in-vehicle system.

[0099] The present invention may be characterized as follows, for example: "The actuator control device according to claim 4 or 5, wherein the control amount calculation unit estimates the free running amount using the temperature of the actuator.", "The actuator control device according to any one of claims 1 to 6, wherein the return control is performed after the engaging member reaches the target valley portion and the drive source is stopped by stop control.", and "The actuator control device according to any one of claims 1 to 6, wherein the return control is performed continuously from the timing when it is determined that the engaging member has reached the target valley portion."

[0100] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer. As described above, the present invention is not limited to the above embodiments and can be embodied in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0101] 1. Parking lock system (drive system) 10. Electric actuator (actuator) 15 Output shaft 20: Detent mechanism 21: Detent plate (detent member) 221, 222... Valley 215... Peak 26 Detent roller (engagement member) 40 Motor (drive source) 55 Output shaft sensor 60...Control device (actuator control device) 76: Control amount calculation unit 78: Drive control unit

Claims

1. an actuator (10) having a drive source (40); a detent mechanism (20) including a detent member (21) having a plurality of valleys (211, 212) and peaks (215) separating the valleys, and an engaging member (26) that is movable between the valleys when the output shaft (15) is driven by the actuator; In a drive system (1) comprising: an actuator control device that controls switching of the detent mechanism by driving the actuator and moving the engagement member, a drive control unit (78) that controls the drive of the drive source so that the engagement member moves to the target valley portion; a control amount calculation unit (76) that calculates a current application time and a current application amount of a return control for returning the drive source in a reverse direction within a range of play between the drive source and the output shaft after the engagement member reaches the target valley portion; Equipped with The control amount calculation unit calculates the energization time of the return control in accordance with an arrival determination time for determining whether the engagement member has reached the target valley portion.

2. The actuator control device according to claim 1 , wherein the control amount calculation unit calculates the amount of current supplied to the return control in accordance with the amount of current supplied to the detent mechanism during switching drive.

3. 3. The actuator control device according to claim 2, wherein at least one of a return time during which the return control is performed and an amount of current supplied during the return control is variable depending on the temperature of the actuator.

4. 4. The actuator control device according to claim 1, wherein the control amount calculation unit estimates a free running amount using the drive speed of the output shaft and the arrival determination time when the detent mechanism is switched and calculates a current application time and current application amount in the return control based on the estimated free running amount.

5. 5. The actuator control device according to claim 4, wherein the drive speed of the output shaft is calculated based on a peak current after power supply to the drive source is stopped.

6. The actuator control device according to claim 4 , wherein the control amount calculation unit estimates the free running amount using a temperature of the actuator.

7. 3. The actuator control device according to claim 1, wherein the return control is performed after the engaging member reaches the target valley portion and the drive source is stopped by stop control.

8. The actuator control device according to claim 7 , wherein the stop of the drive source is determined based on a current value of the drive source during the stop control.

9. The actuator control device according to claim 7 , wherein it is determined that the drive source has stopped when a stop determination time has elapsed since the start of the stop control.

10. 3. The actuator control device according to claim 1, wherein the return control is continuously performed from the timing when it is determined that the engaging member has reached the target valley portion.

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