JP2011131859A - Electric actuator control device, and vehicle rear wheel toe angle control device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress degradation the traveling feel of a vehicle during the failure determining period when an operational quantity detection means is failed in a rear wheel toe angle control device. <P>SOLUTION: The rear wheel toe angle control device 10 controls an electric actuator 11 based on the preset control indicated value and the measured value by an operational quantity detection means. It determines an abnormal state in which any failure is suspected if the difference between the measured value by a stroke sensor 17 and the control indicated value is equal to or more than the predetermined threshold S, and the measured value by the stroke sensor 17 is unchanged; and determines that the stroke sensor 17 is failed if the abnormal state continues over the first determination time T1. If the abnormal state is determined, the operation of the electric actuator 11 is stopped before determining the failure of the stroke sensor 17. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric actuator control device and a vehicle rear wheel toe angle control device including the same, and relates to a control technique when an abnormal state in which a malfunction is suspected in an operation amount detection means of an electric actuator occurs.

  In recent years, in order to improve turning performance and steering stability of a vehicle, a four-wheel steering vehicle having a rear wheel toe angle varying device that variably controls a toe angle of a rear wheel has been developed. As the rear wheel toe angle varying device, an electric actuator is provided at a connecting portion of the suspension supporting the left and right rear wheels with the lateral link or the trailing link of the vehicle body, and both the left and right rear wheels are driven by driving these electric actuators. There is known a configuration in which the toe angle can be individually variably controlled (for example, Patent Document 1). When this type of electric actuator is used to control the toe angle of the rear wheel, the operation amount of the output shaft of the electric actuator is detected by the operation amount detection means, and the electric actuator is controlled based on the output of this operation amount detection means. It is common to do.

  When such a control is performed, if a failure occurs in the operation amount detection means, the normal travel of the vehicle is affected, so it is necessary to detect the failure accurately and quickly. In view of this, the applicant of the present invention, in the rear wheel toe angle control device that controls the actuator based on the control instruction value obtained according to the running state of the vehicle and the actual measurement value by the operation amount detection means, measured values by the operation amount detection means. When the abnormal state suspected of failure by comparing the control value with the control instruction value continues for a determination time set in accordance with the load state on the actuator due to the lateral force when the vehicle turns, it is determined that the operation amount detecting means is defective. An invention has been proposed (see Patent Document 2).

Japanese Patent Laid-Open No. 9-30438 JP 2009-241723 A

  However, in the invention of Patent Document 2, the actuator is stopped after the failure of the operation amount detecting means that requires a predetermined time is determined, so that the rear wheel toe angle is changed even during the determination period, and the traveling feel is reduced. May be exacerbated. In particular, since the rear wheels on the outside of the turn generate a large lateral force, if the operation amount detecting means on the outer wheel side breaks during turning, the toe angle change during the determination period has a great influence on the running feel.

  The present invention has been made in view of such a background, and provides an electric actuator control device capable of suppressing deterioration of the running feeling of a vehicle during a failure determination period when an operation amount detection unit fails. Objective.

  In order to solve the above problems, the first invention includes an electric actuator (11) and an operation amount detection means (stroke sensor 17) for detecting an operation amount (stroke amount) of the electric actuator (11). An electric actuator control device (ECU12) for controlling an electric actuator based on a set control instruction value and an actual measurement value by an operation amount detection means, wherein a difference between the actual measurement value by the operation amount detection means and the control instruction value is a predetermined threshold value (S) If the measured value by the operation amount detection means does not change and is determined to be an abnormal state in which a failure is suspected, and the abnormality continues for the first determination time (T1), the operation amount detection means has failed. If the abnormal state is determined, the operation of the electric actuator is stopped before the failure of the operation amount detecting means is determined. Characterized in that it was.

  According to the present invention, the operation of the electric actuator can be stopped earlier than before by stopping the operation of the electric actuator before the operation amount detection means is determined to be a failure. Therefore, when the operation amount detection unit fails, it is possible to suppress the influence due to the operation of the electric actuator during the failure determination period.

  Further, according to a second invention, in the electric actuator control device according to the first invention, the operation of the electric actuator is stopped when the abnormal state continues for a second determination time (T2) shorter than the first determination time. It is characterized by doing so.

  Even when a failure of the operation amount detection means is suspected, the electric actuator may be difficult to operate due to an external force, and it is not desirable to determine that the operation amount detection means has failed until such a case. Therefore, according to the present invention, the second determination time is provided, and while it is assumed that the state in which the electric actuator cannot be operated by an external force can be continued, the operation of the electric actuator is continued, so that the operation amount detection unit fails. Although it is not, it is possible to avoid stopping the operation of the electric actuator.

  The third aspect of the invention is that in the electric actuator control device according to the first or second aspect, when the abnormal state does not continue for the first determination time, the operation of the electric actuator (11) is resumed. Features.

  According to this invention, when the failure of the operation amount detecting means is not determined, the electric actuator that has been once stopped can be operated again, and the operation amount can be brought close to the control instruction value at an early stage.

  According to a fourth invention, in the electric actuator control device according to any one of the first to third inventions, the operation of the electric actuator is stopped by short-circuiting the power supply circuit.

  According to the present invention, the electric actuator can be brought into a regenerative braking state to generate a braking force, and the electric actuator whose operating state can be continued by an inertial force or an external force can be quickly brought into a stopped state.

  The fifth invention is a rear wheel toe angle control device (10), comprising the electric actuator control device according to any one of the first to fourth inventions, wherein the electric actuator is provided on the left and right sides of the vehicle (V). A pair of left and right is provided to individually change the toe angle of the rear wheel (5).

  According to this invention, when the malfunction of the operation amount detection means is suspected, the operation of the electric actuator is stopped early, so that the vehicle running feel can be prevented from being deteriorated by the change in the rear wheel toe angle. In addition, by providing the second determination time, when it is difficult for the electric actuator to operate during turning, the electric actuator can be stopped after taking this into consideration, and the operation amount detecting means It is possible to prevent the electric actuator from frequently stopping in spite of a failure. And when failure of the operation amount detection means is not determined, by operating the electric actuator again, it is possible to suppress a decrease in the driving feeling of the vehicle.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the driving | running | working feeling of a vehicle deteriorates during a failure determination period when the operation amount detection means fails.

1 is a schematic configuration diagram of a vehicle including a rear wheel toe angle control device according to the present invention. FIG. 2 is a perspective view of a left rear suspension shown in FIG. 1. FIG. 3 is a rear view of the left rear suspension shown in FIG. 2. FIG. 3 is a longitudinal sectional view of the left electric actuator shown in FIG. 2. FIG. 2 is a block diagram showing a schematic configuration of a main part related to rear wheel toe angle control in the ECU shown in FIG. 1. It is a graph explaining the point of the fault detection in the fault detection part shown in FIG. It is a graph explaining the point of the fault detection in the fault detection part shown in FIG. It is a schematic diagram explaining the state of the external force which acts on the lateral force of the rear wheel and the electric actuator shown in FIG. It is a flowchart which shows the procedure of the failure detection in the failure detection part shown in FIG. FIG. 6 is an operation explanatory diagram according to the failure detection procedure shown in FIG. 5. FIG. 6 is an operation explanatory diagram according to the failure detection procedure shown in FIG. 5.

  Hereinafter, an embodiment of a rear wheel toe angle control device 10 to which an electric actuator control device according to the present invention is applied will be described with reference to the drawings. In the description, for the wheels and members arranged for them, that is, tires, electric actuators, etc., subscripts L or R indicating left and right are attached to the numerals, respectively, for example, rear wheel 5L (left), For example, the rear wheel 5R (right) is referred to as the rear wheel 5.

  As shown in FIG. 1, a vehicle V including a rear wheel toe angle control device 10 according to the present invention includes front wheels 3L and 3R with tires 2L and 2R, and rear wheels 5L and 4R with tires 4L and 4R. The front wheels 3L and 3R and the rear wheels 5L and 5R are suspended from the vehicle body 1 by left and right front suspensions 6L and 6R and rear suspensions 7L and 7R, respectively.

  This vehicle V is provided for a front wheel steering device 9 that directly steers left and right front wheels 3L and 3R via a rack and pinion mechanism and a left and right rear suspension 7L and 7R by steering a steering wheel 8. A pair of left and right rear wheel toe angle control devices 10L and 10R that individually change the toe angles of the rear wheels 5L and 5R by driving the left and right electric actuators 11L and 11R are provided.

  The vehicle V also includes an ECU (Electronic Control Unit) 12 that controls the electric actuator 11 to control the toe angle of the rear wheel 5, a vehicle speed sensor 13, a steering angle sensor 14, a yaw rate sensor 15, and a lateral acceleration. A sensor 16 and other various sensors (not shown) are installed, and detection signals from the sensors are input to the ECU 12 for vehicle control.

  The ECU 12 includes a microcomputer, ROM, RAM, peripheral circuit, input / output interface, various drivers, and the like, and is connected to the sensors 13 to 16 and the electric actuators 11L and 11R via a communication line. The ECU 12 calculates the rear wheel toe angle based on the detection results of the sensors 13 to 16 and the like, determines the displacement amount of the electric actuators 11L and 11R, and performs the toe angle control of the rear wheels 5L and 5R.

  The electric actuators 11L and 11R are direct acting actuators in which the output rod linearly moves back and forth in the axial direction. The electric actuators 11L and 11R include stroke sensors 17L and 17R that detect the stroke position of the output rod. Each is installed. When the signals from the stroke sensors 17L and 17R are input to the ECU 12, feedback control of the electric actuators 11L and 11R is performed. As a result, the electric actuators 11L and 11R expand and contract by a predetermined amount determined by the ECU 12, and change the toe angles of the rear wheels 5L and 5R.

  According to the vehicle V configured in this way, the left and right electric actuators 11L and 11R are simultaneously symmetrically displaced to freely control toe-in / to-out of both rear wheels 5L and 5R under appropriate conditions. In addition, if one of the left and right electric actuators 11L and 11R is extended and the other is contracted, both rear wheels 5L and 5R can be steered left and right. For example, the vehicle V changes the rear wheels 5L and 5R to toe-out when accelerating and changes the rear wheels 5L and 5R to toe-in during braking and rear wheels 5L during high-speed turning. -Rear wheel toe angle control is performed to improve maneuverability by controlling toe angle (steering) with 5R in the same phase as the front wheel rudder and the rear wheels 5L and 5R in the opposite phase to the front wheel rudder angle during low-speed turning.

  As shown in FIGS. 2 and 3, the rear suspension 7L is of a double wishbone type, and includes a knuckle 21 that rotatably supports the rear wheel 5L, and an upper arm that connects the knuckle 21 to the vehicle body 1 so as to be movable up and down. 22 and the lower arm 23, an electric actuator 11L connected to the knuckle 21 and the vehicle body 1 to change the toe angle of the rear wheel 5L, a damper 24 with a suspension spring for buffering the vertical movement of the rear wheel 5L, and the like. Yes.

  The upper arm 22 and the lower arm 23 have base ends connected to the vehicle body 1 via rubber bush joints 25 and 26, respectively, and tip ends connected to the upper and lower portions of the knuckle 21 via ball joints 27 and 28, respectively. The electric actuator 11L has a base end connected to the vehicle body 1 via a rubber bush joint 29 and a tip end connected to the rear portion of the knuckle 21 via a rubber bush joint 30. The damper 24 with suspension spring has an upper end fixed to the vehicle body 1 and a lower end connected to the upper portion of the knuckle 21 via a rubber bush joint 31.

  By adopting such a configuration, when the electric actuator 11L is driven to extend, the rear portion of the knuckle 21 rotates outward in the vehicle width direction, so that the toe angle of the rear wheel 5L is inward with respect to the vehicle traveling direction. When the electric actuator 11L is driven to contract (toe-in side), the rear portion of the knuckle 21 rotates inward in the vehicle width direction, so that the toe angle of the rear wheel 5L faces outward with respect to the vehicle traveling direction ( Toe-out side).

  As shown in FIG. 4, the electric actuator 11L includes a first housing 32a in which a rubber bush joint 29 on the vehicle body 1 side is formed, and a second housing 32b fastened to the first housing 32a by a plurality of bolts 33. 32 and an output rod 35 supported by the second housing 32b so as to be stretchable and formed with a rubber bush joint 30 on the knuckle 21 side. An electric motor 41 serving as a drive source is accommodated in the first housing 32a, and is fastened to the first housing 32a with a bolt 36. A planetary gear type speed reducer 51, an elastic coupling 56, and a feed screw mechanism 61 using a trapezoidal screw are accommodated in the second housing 32b. When the electric motor 41 is driven, the rotation of the rotating shaft 42 is decelerated by the speed reducer 51, converted into a linear motion by the feed screw mechanism 61, and the output rod 35 is linearly driven.

  The stroke sensor 17L provided on the outer peripheral surface of the second housing 32b includes a magnet 71 fixed to the output rod 35 by a bolt 66 attached to the outer peripheral surface of the output rod 35, and a differential housed in the sensor housing 72. And a transformer 73. The differential transformer 73 is disposed close to the magnet 71 so as to extend in parallel with the linear drive direction of the output rod 35, and both ends thereof are fixed to the second housing 32b. The differential transformer 73 is wound with a primary coil (not shown) and two secondary coils having the same number of turns close to both ends in the axial direction of the primary coil, and the magnet 71 is the length of the primary coil. The expansion / contraction stroke of the output rod 35 is obtained by detecting the differential voltage generated when moving in the direction.

  Next, the ECU 12 will be described with reference to FIG. The ECU 12 includes a microcomputer 82 and left and right motor drive units 86L and 86R. The microcomputer 82 includes a control target value calculation unit 83, a drive signal generation unit 84, and a failure detection unit 85.

  The control target value calculation unit 83 calculates a rear wheel toe angle control target value based on input signals from the vehicle speed sensor 13, the steering angle sensor 14, the yaw rate sensor 15, and the lateral acceleration sensor 16. The drive signal generation unit 84 converts the rear wheel toe angle control target value input from the control target value calculation unit 83 into the stroke amount of the electric actuators 11L and 11R, the control target stroke amount (control instruction value), and the stroke Compared with the actual stroke amount (actually measured value) indicated by the input signals from the sensors 17L and 17R, a drive signal for driving the electric actuators 11L and 11R is generated so that the two approach each other. The failure detection unit 85 detects a sticking failure of the stroke sensors 17L and 17R according to a failure detection procedure described later.

  The left and right motor drive units 86L and 86R each have a bridge circuit including a gate drive circuit and a plurality of transistors. Based on the drive signal generated by the drive signal generation unit 84, the left and right motor drive units 86L and 86R are connected to the electric actuators 11L and 11R. While controlling the drive current and detecting an abnormal state or failure suspected of failure by the failure detection unit 85 and receiving a motor brake instruction signal to be described later, the terminals of the electric actuator 11 are short-circuited. The motor 41 is brought into a regenerative braking state, and its operation is stopped while applying a braking force. Note that the short circuit between the terminals is performed by ON / OFF control of the gate terminal of the transistor by the gate driving circuit.

  Below, the processing content of the failure detection part 85 is demonstrated. FIGS. 6 and 7 are graphs for explaining the procedure of failure detection in the failure detection unit 85 shown in FIG. The failure detection unit 85 determines whether or not the stroke sensors 17L and 17R are in an abnormal state suspected of failure, and when this abnormal state occurs, the elapsed time starts counting, and the abnormal state is determined to be a predetermined first determination. When it continues until time T1 passes, it determines with the sticking failure of the stroke sensors 17L and 17R.

  In addition, when the stroke sensor 17 in an abnormal state suspected of malfunctioning is on the turning outer wheel side (FIG. 6), when this abnormal state continues until a second determination time T2 shorter than the first determination time T1 elapses. Sends a motor brake instruction signal to stop the operation while applying a braking force to the electric motor 41 by short-circuiting the terminals of the electric actuator 11. On the other hand, when the stroke sensor 17 in an abnormal state suspected of failure is on the turning inner wheel side (FIG. 7), the motor brake instruction signal is transmitted simultaneously with the determination that the stroke sensors 17L and 17R are stuck.

  Here, the determination of whether or not there is an abnormal state in which a failure is suspected is made by comparing the actual measurement values by the stroke sensors 17L and 17R and the control instruction values. Specifically, when the actual measurement value by the stroke sensors 17L and 17R does not change and a deviation of a predetermined threshold value S or more occurs between the actual measurement value and the control instruction value, an abnormal state in which a failure is suspected is obtained. It is judged that there is.

  The electric actuators 11L and 11R operate in the extending direction or the contracting direction by a drive signal based on the control instruction value in the ECU 12, that is, the control target stroke amount corresponding to the target toe angle. At this time, the stroke of the electric actuators 11L and 11R The time required for the amount of change when the position changes toward the control instruction value to appear as an actual measurement value by the stroke sensors 17L and 17R changes according to the load state due to the external force acting on the electric actuators 11L and 11R.

  That is, if the direction of the external force is a direction that suppresses the operation of the electric actuators 11L and 11R, the electric actuators 11L and 11R are difficult to operate, and thus a deviation immediately appears between the actually measured value and the control instruction value. On the other hand, if the direction of the external force is a direction that promotes the operation of the electric actuators 11L and 11R, the electric actuators 11L and 11R are easy to operate. Therefore, a deviation hardly appears between the actually measured value and the control instruction value.

  On the other hand, when the vehicle V is turning, the vehicle body 1 rolls so that the rear wheel 5 outside the turn generates a greater lateral force than the rear wheel 5 on the turn inner wheel side. FIG. 8 is a schematic diagram for explaining the lateral force of the rear wheel 5 and the external force acting on the electric actuators 11L and 11R. FIG. 8A is a view of the vehicle V viewed from directly above, and FIG. The figure which looked at V from right behind is shown in figure (C) which looked at rear-wheel 5L * 5R from right above, respectively. Here, an example of a right turn is shown, but a left turn appears symmetrically with this.

  That is, as shown in FIG. 8A, when the vehicle V turns, as shown in FIG. 8B, a roll is generated in which the vehicle body 1 is tilted outward by the centrifugal force. At this time, the load Wo acting on the rear wheel 5L on the outer side of the turn is larger than the load Wi on the rear wheel 5R on the inner side of the turn, and a lateral force Fo acting on the rear wheel 5L on the outer side due to friction between the road surface and the tire is turned. It becomes larger than the lateral force Fi of the rear wheel 5R on the inner ring side.

  As shown in FIG. 8C, the lateral force Fo · Fi generates an axial force FA in the electric actuators 11L and 11R. This axial force FA is large on the outside of the turn, acts on the contraction direction in the electric actuator 11L outside the turn, and acts on the extension direction on the electric actuator 11R inside the turn. For this reason, the phenomenon that it is difficult to extend on the extension side on the outside of the turn and easily contracts on the contraction side appears remarkably, and the electric actuator 11L is greatly affected by the operation by the axial force FA. On the other hand, since the axial force FA is small inside the turn, the influence of the electric actuator 11R on the operation by the axial force FA is small.

  Here, with respect to the kingpin axis K (see FIG. 3) connecting the ball joints 27 and 28 of the rear suspensions 7L and 7R, the grounding portions of the tires 4L and 4R on which the lateral force Fo and Fi act and the electric actuators 11L and 11R Are on the same side, the lateral forces Fo and Fi acting on the tires 4L and 4R cause the electric actuators 11L and 11R to generate an axial force FA in the contraction direction.

  As described above, in the electric actuator 11L on the turning outer wheel side, the expansion operation or the contraction operation is suppressed by the large axial force FA according to the specifications of the rear suspension 7, and thus the actual measurement value by the stroke sensor 17L is not easily changed. Deviation may easily occur between the value and the control instruction value. Because of such a state, it is determined that there is a sticking failure until a deviation is likely to occur between the actually measured value by the stroke sensor 17L and the control instruction value even though the stroke sensor 17L is normal. If a motor brake instruction signal is sent after the vehicle is turned, the running feeling of the vehicle V is deteriorated by the rear wheel 5L outside the turn that generates a large lateral force Fo.

  Therefore, when the stroke sensor 17 in an abnormal state suspected of malfunctioning is on the turning outer wheel side, when the abnormal state continues for the second determination time T2, a motor brake instruction signal is sent to the terminal of the electric actuator 11 Short-circuit between them. Thereby, when the failure determination is performed on the side of the turning outer wheel where deterioration of the traveling feeling is expected, the deterioration of the traveling feeling due to the operation of the electric actuator 11 during the failure determination period is avoided. Further, by short-circuiting the terminals to stop the operation of the electric actuator 11, the lateral force Fo generates an axial force in the operation direction, so that the operation state is easily maintained by the inertial force even after the energization is stopped. The actuator 11 can be brought into a stop state at an early stage.

  Next, with reference to FIG. 9, the procedure of the failure detection in the failure detection part 85 shown in FIG. 5 is demonstrated.

  The failure detection unit 85 first determines whether or not the actual measurement value by the monitored stroke sensor 17R is constant and whether or not the deviation (absolute value) between the actual measurement value and the control instruction value is equal to or greater than the threshold value S. It is determined whether or not the right stroke sensor 17R is in an abnormal state in which a failure is suspected (step ST1). If it is determined in step ST1 that the right stroke sensor 17R is in an abnormal state suspected of malfunctioning (Yes), it is determined whether or not the vehicle V is turning left based on the vehicle speed, steering angle, lateral acceleration, and the like. Determination is made (step ST2).

  If it is determined in step ST2 that the vehicle V is turning left (Yes), whether or not the abnormal state continues for the second determination time T2 because the right stroke sensor 17R in the abnormal state is on the turning outer wheel side. Is determined (step ST3). When it is determined in step ST3 that the abnormal state does not continue over the second determination time T2 (No), this process is terminated as it is. On the other hand, if it is determined in step ST3 that the abnormal state has continued for the second determination time T2 (Yes), a motor brake instruction signal is sent to the right motor drive unit 86R to stop the right electric actuator 11R ( Step ST4).

  Thereafter, it is determined whether or not the abnormal state continues for the first determination time T1 (step ST5). If it is determined in step ST2 that the vehicle V is not traveling left turn (No), the effect of the operation of the right electric actuator 11R on the vehicle feel during the failure determination period is not so large. The process proceeds to step ST5 without performing the process in ST4.

  If it is determined in step ST5 that the abnormal state has continued for the first determination time T1 (Yes), the right stroke sensor 17R is determined to be a fixing failure (step ST6), and this process is terminated. On the other hand, if it is determined in step ST5 that the abnormal state does not continue for the first determination time T1 (No), a motor brake release signal is sent to the right motor drive unit 86R to resume the operation of the right electric actuator 11R. (Step ST7), and this process is terminated.

  Returning to step ST1, when it is determined that the right stroke sensor 17R is not in an abnormal state suspected of failure (No), whether or not the measured value by the monitored stroke sensor 17L is constant, and the measured value and Based on whether or not the deviation (absolute value) from the control instruction value is greater than or equal to the threshold value S, it is determined whether or not the left stroke sensor 17L is in an abnormal state suspected of failure (step ST8). If it is determined in step ST8 that the left-side stroke sensor 17L is not in an abnormal state suspected of malfunctioning (No), this process is terminated as it is. On the other hand, when it is determined in step ST8 that the left stroke sensor 17L is in an abnormal state suspected of failure (Yes), the processing performed for the right stroke sensor 17R (step ST2 to step ST7) is also performed for the left stroke sensor 17L. Similar processing is performed.

  That is, based on the vehicle speed, steering angle, lateral acceleration, and the like, it is first determined whether or not the vehicle V is turning right (step ST9). If it is determined in step ST9 that the vehicle V is traveling right turn (Yes), the abnormal state continues for the second determination time T2 because the left stroke sensor 17L in the abnormal state is on the turning outer wheel side. It is determined whether or not (step ST10). When it is determined in step ST10 that the abnormal state does not continue over the second determination time T2 (No), this process is terminated as it is. On the other hand, when it is determined in step ST10 that the abnormal state has continued for the second determination time T2 (Yes), a motor brake instruction signal is sent to the left motor drive portion 86L to stop the left electric actuator 11L ( Step ST11).

  Thereafter, it is determined whether or not the abnormal state continues for the first determination time T1 (step ST12). If it is determined in step ST9 that the vehicle V is not turning right (No), the effect of the operation of the left electric actuator 11L on the vehicle feel during the failure determination period is not so great, so that step ST10 , ST11 is not performed, and the process proceeds to step ST12.

  When it is determined in step ST12 that the abnormal state has continued for the first determination time T1 (Yes), the left stroke sensor 17L is determined to be a fixing failure (step ST13), and this process is terminated. On the other hand, when it is determined in step ST11 that the abnormal state does not continue for the first determination time T1 (No), a motor brake release signal is sent to the left motor drive unit 86L to resume the operation of the left electric actuator 11L. Then, this process is terminated as it is.

  As described above, in the vehicle V in which the failure determination is performed by the ECU 12, the following operational effects can be obtained. 10 and 11 show the electric actuator 11 when the outer wheel side stroke sensor 17 falls into an abnormal state when the electric actuator 11 is driven during turning and the toe angle of the rear wheel 5 is changed. It is a graph which shows the change of stroke amount. In the figure, the solid line indicates the stroke amount according to the present invention, and the broken line indicates the stroke amount according to the prior art.

  First, the stroke change of the electric actuator 11 when the failure determination according to the prior art is performed will be described. When the stroke sensor 17 is fixed, the deviation between the actually measured values by the stroke sensors 17L and 17R and the control instruction value increases and exceeds the threshold value S. At this point, it is determined that there is an abnormal state in which a failure is suspected, and counting for failure determination is started. On the other hand, the electric actuator 11 is continuously driven based on the deviation between the actually measured value and the control instruction value. When the elapsed time of the abnormal state reaches the first determination time T1, it is determined that the stroke sensor 17 has failed, and at the same time, a motor brake instruction signal is sent out by the ECU 12. Thereafter, when the motor brake is applied, the stroke amount of the electric actuator 11 gradually decreases due to the overrun of the electric motor 41 due to the inertial force, and becomes constant over time.

  On the other hand, when the failure determination according to the present invention is performed, until the stroke sensor 17 is fixed and counting for failure determination is started, the elapsed time of the abnormal state is set to the second determination time T2. At this point, the ECU 12 sends a motor brake instruction signal. After that, when the motor brake is applied, the stroke amount of the electric actuator 11 gradually decreases and becomes constant without waiting for the first determination time to elapse.

  Since the stroke change remains in the electric actuator 11 even when the motor brake is applied, if the stroke sensor 17 has not failed, the failure determination period (from the start of counting until the first determination time is reached). ) Can be determined by whether or not the abnormal state continues. Therefore, even if the motor brake is applied once, if the abnormal state does not continue for the first determination time, it is not determined as a failure, and the count for failure determination is reset as shown in FIG. The motor brake is released and energization is resumed. On the other hand, when the stroke sensor 17 is out of order, as shown in FIG. 10, it is determined as a failure when the elapsed time of the abnormal state reaches the first determination time.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above-described embodiment, the electric actuator control device is applied to the rear wheel toe angle control device 10, but as long as the electric actuator is used, the control device is also applied to other control devices such as an electric power steering control device. can do. In the above embodiment, the operation of the electric actuator 11 is stopped by short-circuiting the power supply circuit. However, the operation may be stopped simply by setting the current to the electric actuator 11 to zero. In addition to these changes, the specific configuration and arrangement of each device can be changed as appropriate without departing from the spirit of the present invention.

V Vehicle 5L / 5R Rear wheel 10L / 10R Rear wheel toe angle controller 11L / 11R Electric actuator 12 ECU (Electric actuator controller)
17L / 17R Stroke sensor (operation amount detection means)
85 Failure detection unit 86L / 86R Motor drive unit

Claims (5)

An electric actuator control device that includes an electric actuator and an operation amount detection unit that detects an operation amount of the electric actuator, and controls the electric actuator based on a set control instruction value and an actual measurement value by the operation amount detection unit. There,
When the difference between the actual measurement value by the operation amount detection means and the control instruction value is equal to or greater than a predetermined threshold value and the actual measurement value by the operation amount detection means does not change, it is determined as an abnormal state in which a failure is suspected. When continuing for the first determination time, it is determined that the operation amount detection means is out of order,
When the abnormal state is determined, the electric actuator control device is configured to stop the operation of the electric actuator before the failure of the operation amount detecting means is determined.   2. The electric actuator control device according to claim 1, wherein the operation of the electric actuator is stopped when the abnormal state continues for a second determination time shorter than the first determination time.   The electric actuator control device according to claim 1, wherein when the abnormal state does not continue for the first determination time, the operation of the electric actuator is resumed.   The electric actuator control device according to any one of claims 1 to 3, wherein the operation of the electric actuator is stopped by short-circuiting a power supply circuit. The electric actuator control device according to any one of claims 1 to 4,
A rear wheel toe angle control device, wherein the electric actuators are provided in a pair of left and right to individually change the toe angles of the left and right rear wheels of the vehicle.

Images