JP2016107939A - Electric parking brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly switch speed control and position control by relatively simple control, to reduce the number of part items for use, and to suppress the occurrence of positional displacement.SOLUTION: A control system 10 for releasing a parking brake comprises a speed control part (14) which outputs a target speed command value (Vcmd1) equivalent to a target speed in the case of driving an electric motor 21 at a constant rotational speed, and a position control part 13 which outputs a position control speed command value Vcmd2 which changes according to a position of an actuator. A target value decision part 15 compares magnitudes of the Vcmd1 and Vcmd2, and performs control so as to automatically select a smaller value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric parking brake device that can be mounted on a vehicle, and more particularly, to a control technique for releasing a parking brake.

  Patent Document 1 is known as a prior art of an electric parking brake device for a vehicle. In such an electric parking brake device, the parking brake mechanism can be moved using an actuator driven by an electric motor to switch between an operation state and a release state of the parking brake. Japanese Patent Application Laid-Open No. 2004-228561 shows that in an electric parking brake device for a manual vehicle, control is performed so as to change the release speed of the parking brake based on the speed at which the clutch pedal is operated and the inclination of the vehicle.

  Further, Patent Document 2 discloses a conventional technique related to a control device for a fluid actuator. In the configuration of FIG. 1 of Patent Document 2, a position compensation circuit 7 and a speed compensation circuit 9 are provided in a control system including a hydraulic cylinder 2 and a servo valve 4, and an output signal of the position compensation circuit 7 is provided. And the output signal of the speed compensation circuit 9 are selected by the control changeover switch 11, and the servo valve 4 is controlled by the selected signal. Further, the switching control of the control changeover switch 11 is automatically performed by comparing the speed detection signal Vs with the speed command signal Vr and comparing the position detection signal Ss with the position reference value S′r. The position reference value S′r is a value obtained by subtracting a certain value from the position command signal Sr. Further, the actual state of the hydraulic cylinder 2 detected by the position sensor 5 is set as a position detection signal Ss, and the position compensation circuit 7 performs compensation control based on the difference between the position command signal Sr and the position detection signal Ss. It is.

Japanese Patent No. 4415706 JP-A-4-181002

  By the way, in various apparatuses that move the movable part, it is possible to perform precise positioning control by detecting the actual situation using various sensors for detecting the position and feeding back to the control. However, the use of various sensors causes the following problems.

(1) The cost of the apparatus increases due to the cost of the sensor itself and the cost of the electric circuit associated with the sensor.
(2) When a position sensor or the like is installed, an adjustment operation such as alignment is required for each apparatus, so that the operation cost increases.
(3) When the number of parts such as sensors increases, the failure occurrence probability of the entire apparatus increases.
(4) As the number of parts such as sensors increases, the number of inspection items and adjustment items for maintaining the apparatus increases.

  Based on these problems, the electric parking brake device is required to change the sensor to be used to a low-cost sensor or to reduce the number of sensors. However, if the number of sensors to be used is to be suppressed to a minimum, there is a high possibility that a displacement will occur when the movable part is moved.

  For example, in the case of an electric parking brake device, there is a braking state position (P1) in which the actuator presses the movable portion against the brake pad, and a release state position (P2) that is a predetermined distance (L0) away from this position. It is necessary to position the movable part on either side. However, if the movement speed is high during the movement of the release operation (release) that moves from the position P1 to the position P2, it passes through the target position (P2) due to inertia and stops at the shifted position (P2 ′). There is a case. Thereafter, when the movable part is moved from the current position (P2 ′) to the target position (P1) in order to switch to the braking state, the distance becomes longer than the normal L0. become longer. Therefore, the driver of the vehicle may feel uncomfortable or feel that the operation is slow with respect to fluctuations in the time required for the operation of the electric parking brake device. Therefore, such a sense of incongruity and a delay in operation must be eliminated.

  Therefore, it is necessary to suppress positional deviation in the positioning control of the movable part in the electric parking brake device. For this purpose, it is conceivable to switch between speed control and position control as in Patent Document 2. However, in the technique of Patent Document 2, it is necessary to provide a position sensor. Further, in the technique of Patent Document 2, the condition for switching between speed control and position control is relatively complicated, and it is necessary to perform calculation for calculating the position reference value S′r every time comparison is performed. Further, it is not always possible to smoothly switch between speed control and position control.

  The present invention has been made in view of the above-described circumstances, and its purpose is to enable smooth switching between speed control and position control with relatively simple control, and to reduce the number of parts to be used. Another object of the present invention is to provide an electric parking brake device that can suppress the occurrence of displacement.

In order to achieve the above-described object, an electric parking brake device according to the present invention is characterized by the following (1) to (6).
(1) An electric parking brake device having an actuator driven based on the rotational driving force of an electric motor,
The control system for releasing the parking brake
A speed control unit that outputs a target speed command value corresponding to a target speed when the electric motor is driven at a constant rotational speed;
A position control unit that outputs a position control speed command value that changes according to the position of the movable unit of the actuator;
A target value determining unit that outputs one of the target speed command value and the position control speed command value as a control target value of the electric motor based on a result of comparing the target speed command value and the position control speed command value; ,
A motor operation amount calculator that determines an operation amount of the electric motor based on the control target value;
An electric parking brake device comprising:
(2) The electric parking brake device according to (1) above,
The target value determination unit outputs the smaller one of the target speed command value and the position control speed command value as the control target value of the electric motor.
An electric parking brake device characterized by that.
(3) The electric parking brake device according to (2) above,
The target value determining unit outputs the target speed command value as the control target value of the electric motor, and then outputs the position control speed command value as the control target value of the electric motor.
An electric parking brake device characterized by that.
(4) The electric parking brake device according to any one of (1) to (3) above,
The position controller is
A stroke counter that counts a pulse signal generated with the rotation of the electric motor or the movement of the movable part of the actuator;
A reference value of the moving amount of the movable part of the actuator, or a reference moving amount holding unit that holds a reference value of the position;
A speed command value calculation unit that calculates the position control speed command value based on a difference value between the reference value held by the reference movement amount holding unit and a count value of the stroke counter;
An electric parking brake device comprising:
(5) The electric parking brake device according to (4) above,
A permanent magnet fixed to a drive shaft of the electric motor or a rotary shaft connected to the drive shaft;
A magnetic sensor disposed at a position adjacent to the movement path of the permanent magnet;
Further comprising
Applying a signal output from the magnetic sensor to an input of the stroke counter;
An electric parking brake device characterized by that.
(6) The electric parking brake device according to (5) above,
A motor speed calculation unit that generates a signal representing the motor rotation speed based on the pulse signal output from the magnetic sensor;
Further comprising
The motor operation amount calculation unit determines an operation amount of the electric motor based on a difference between the control target value and the motor rotation speed output by the motor speed calculation unit.
An electric parking brake device characterized by that.

According to the electric parking brake device configured as described in (1) above, the target value determination unit simply performs a simple control for comparing the target speed command value and the position control speed command value. And position control can be switched automatically. In addition, when these are switched, the target speed command value and the position control speed command value are almost the same value, so that the control target value does not change suddenly and can be switched smoothly. . Further, since the driving speed can be lowered by switching to position control when approaching the target position, it is possible to suppress stop position deviation.
According to the electric parking brake device having the configuration (2), the position control speed command value can be output as the control target value of the electric motor when the movable part approaches the target stop position up to a predetermined distance.
According to the electric parking brake device having the configuration of (3) above, in a situation where the position control speed command value changes in a direction of decreasing as the movable part approaches the target stop position, the movable part is brought to the target stop position. When approaching a predetermined distance, the position control speed command value can be output as the control target value of the electric motor by switching from speed control to position control.
According to the electric parking brake device having the configuration (4), the position control speed command value can be controlled to change with a change in the position of the movable portion of the actuator. Further, for example, when the stroke counter counts in the direction of increasing the count value, the position control speed command value can be changed to decrease as the movable part approaches the target stop position. Further, it is possible to switch between speed control and position control without using a position sensor.
According to the electric parking brake device having the configuration (5), the pulse signal can be generated using a relatively inexpensive magnetic sensor and permanent magnet. Further, since the movement amount of the movable part can be grasped using the stroke counter, it is not necessary to use a position sensor.
According to the electric parking brake device having the configuration of (6), it is possible to adjust the operation amount of the electric motor so that an error between the control target value and the actual motor rotation speed becomes small. The speed of the electric motor can be feedback controlled so as to approach the target value.

  According to the electric parking brake device of the present invention, it is possible to smoothly switch between speed control and position control with relatively simple control, reduce the number of parts to be used, and suppress the occurrence of positional deviation. Is possible. Further, by suppressing the positional deviation, it is possible to prevent the required time until the parking brake shifts from the released state to the operating state (braking state) from becoming longer or changing.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

FIG. 1 is a block diagram illustrating a configuration example of a control system of an electric parking brake device according to an embodiment of the present invention. FIG. 2 is a flowchart showing a control procedure of main parts in the control system shown in FIG. FIG. 3 is a time chart showing changes in signals at various parts during the brake releasing operation of the control system shown in FIG. FIG. 4 is a longitudinal sectional view showing a configuration of an actuator used for driving the electric parking brake device.

  Specific embodiments relating to the electric parking brake device of the present invention will be described below with reference to the drawings.

<Outline of electric parking brake device>
An electric parking brake device mounted on a vehicle controls the on / off of the brake by positioning the parking brake mechanism at two types of positions, a brake state position (P1) and a brake release position (P2). An actuator including an electric motor is employed to drive the parking brake mechanism.

  By the way, when moving from the brake released position (P2) to the braked position (P1), the movable portion can be stopped at the same position without using a special position sensor. In other words, when the movable part collides with the brake pad, the electric motor is forcibly locked and a different lock current flows, so if the drive of the electric motor is stopped when this lock current is detected, the braking state is It can be stopped at the position (P1).

  On the other hand, when moving from the braked position (P1) to the brake released position (P2), the electric motor does not collide with anything and stop forcibly. It is necessary to stop at the position (P2). However, when driving at a relatively high speed, even if the driving of the electric motor is stopped when the movable portion reaches the target position (P2), the target position (due to the influence of the inertia of the drive mechanism) It will stop at the position (P2 ′) that has shifted past P2).

  Then, when moving from the shifted position (P2 ') to the position (P1) in the braking state, the moving distance becomes longer than usual, so the time required for the movement becomes longer. In other words, due to the occurrence of the position shift, the length of time until the on / off of the electric parking brake device is changed fluctuates, that is, becomes longer, which gives the driver a sense of incongruity. Even if it is necessary to prevent displacement, it is desirable not to use a sensor such as a position sensor as much as possible in order to reduce costs, and it is desirable that the operation of the control system is not complicated.

  Therefore, the electric parking brake device of the present invention, which will be described later, includes a special control system that can suppress the positional deviation by simple control without using the position sensor.

<Example of actuator configuration>
FIG. 4 shows a configuration example of the actuator 20 that can be used for driving the electric parking brake device according to the embodiment of the present invention.

  The actuator 20 shown in FIG. 4 includes an electric motor 21. The electric motor 21 is a DC motor whose driving speed changes according to the applied voltage. A reduction mechanism 22 is connected to the drive shaft of the electric motor 21, and a screw mechanism 23 is connected to the output side of the reduction mechanism 22.

  The speed reduction mechanism 22 includes a plurality of gears, and transmits the rotational driving force of the drive shaft of the electric motor 21 to the screw mechanism 23 at a reduced speed. The screw mechanism 23 converts the movement in the rotational direction of the speed reduction mechanism 22 into a linear movement. The linear motion on the output side of the screw mechanism 23 is transmitted to the movable rod 25 via the compression coil spring 24.

  The tip of the movable rod 25 is connected to a drive cable for a parking brake mechanism (not shown). That is, when the movable rod 25 linearly moves in the left-right direction in FIG. 4, the pulling force of the drive cable changes, and the movable part of the parking brake mechanism moves to the position (P1) in the braking state and the position (in the brake released state) Move to P2).

  A permanent magnet 26 is fixed to the drive shaft of the electric motor 21 shown in FIG. Further, a Hall IC 27 is fixed at a position facing the permanent magnet 26. The permanent magnet 26 is arranged so that the position of each magnetic pole rotates as the drive shaft of the electric motor 21 rotates. Therefore, when the drive shaft of the electric motor 21 rotates, the facing state and distance between the permanent magnet 26 and the Hall IC 27 change. The Hall IC 27 is an integrated circuit incorporating a Hall element, and can detect a change in magnetism from the permanent magnet 26 accompanying the rotation of the drive shaft of the electric motor 21 and output this change as a pulse signal.

<Example of control system configuration>
A configuration example of a control system of the electric parking brake device according to the embodiment of the present invention is shown in FIG. The electric parking brake device shown in FIG. 1 includes the actuator 20 and the controller 10 described above.

  It is assumed that the controller 10 is actually composed of an electric circuit mainly composed of a microcomputer. Of course, a logic circuit that realizes an equivalent function can be used instead of the microcomputer.

  The controller 10 shown in FIG. 1 includes an initial counter position holding unit 11, a stroke position counter 12, a position control speed command value calculation unit 13, a target speed command value holding unit 14, a speed target value selection unit 15, and a rotation speed detection value calculation. The unit 16, the motor operation amount calculation unit 17, the driver 18, the difference calculation units 19 a and 19 b are provided as functional units.

  The initial counter position holding unit 11 is a storage area allocated on, for example, the internal memory of the microcomputer or an external nonvolatile memory (not shown), and holds an initial counter position value Vcn0.

  The stroke position counter 12 is a counter function realized by software processing of the microcomputer, for example, and is a rising edge, a falling edge, or both rising and falling edges of the motor rotation pulse signal 27a output from the Hall IC 27. Count the number of By counting by the stroke position counter 12, the actual rotation amount of the electric motor 21 and the moving stroke or position of the movable part can be grasped.

  The difference calculation unit 19a is a calculation function realized by software processing of the microcomputer, for example, and calculates the stroke counter count value Vcnst output by the stroke position counter 12 from the initial counter position value Vcn0 output by the initial counter position holding unit 11. The subtraction result is output as the remaining moving distance value Vpr. That is, a value corresponding to the remaining moving distance from the current position of the movable part to the target stop position is output as Vpr.

  The position control speed command value calculation unit 13 is a calculation function realized by software processing of the microcomputer, for example, and is necessary for position control based on the remaining movement distance value Vpr appearing in the output of the difference calculation unit 19a. A position control speed command value Vcmd2 is calculated. Actually, as in the case of general control, the position control speed command value calculation unit 13 uses the calculation formula that combines proportional control (P), integral control (I), and differential control (D). From this, an appropriate position control speed command value Vcmd2 is calculated. Further, since Vpr changes as the position of the movable part changes, the position control speed command value Vcmd2 also changes sequentially according to the position.

  The target speed command value holding unit 14 holds a target speed command value Vcmd1 necessary for speed control. This target speed command value Vcmd1 is a value irrelevant to the position of the movable part. For example, a predetermined constant is used as the target speed command value Vcmd1. That is, the target speed command value Vcmd1 corresponds to a target speed (a constant value) when the electric motor 21 is driven at a constant rotational speed.

  The speed target value selection unit 15 is a comparison function realized by, for example, software processing of the microcomputer. The target speed command value Vcmd1 output from the target speed command value holding unit 14 and the position control speed command value calculation unit 13 output. The position control speed command value Vcmd2 to be compared is compared in magnitude and the value is selected and output. In the present embodiment, the position control speed command value Vcmd2 changes in a direction of decreasing as the position of the movable part approaches the target stop position. Therefore, the speed target value selection unit 15 selects the smaller one of Vcmd1 and Vcmd2. This is selected and output as the rotation speed target value Vv1.

  The rotation speed detection value calculation unit 16 is a calculation function realized by software processing of the microcomputer, for example, and calculates the rotation speed detection value Vv2 based on the motor rotation pulse signal 27a output from the Hall IC 27. Specifically, the pulse period of the motor rotation pulse signal 27a is measured, and the rotation speed detection value Vv2 is calculated by converting the measured pulse period.

  The difference calculation unit 19b is a calculation function realized by software processing of the microcomputer, for example. The difference calculation unit 19b subtracts the rotation speed detection value Vv2 from the rotation speed target value Vv1 output from the speed target value selection unit 15, and calculates the calculation result. Output as speed deviation ΔVv.

  The motor operation amount calculation unit 17 is a calculation function realized by software processing of the microcomputer, for example, and calculates the motor operation amount Vout based on the speed deviation ΔVv output from the difference calculation unit 19b. That is, the motor operation amount Vout is generated such that the speed deviation ΔVv that is an error between the rotational speed target value Vv1 and the rotational speed detection value Vv2 representing the actual rotational speed of the electric motor 21 is small. Actually, in the same way as in the case of general control, actually, the motor operation amount calculation unit 17 is calculated using a calculation formula that combines proportional control (P), integral control (I), and differential control (D). However, an appropriate motor operation amount Vout is calculated from the speed deviation ΔVv.

  The driver 18 generates a voltage proportional to Vout according to the motor operation amount Vout output from the motor operation amount calculation unit 17. The voltage output from the driver 18 is applied to the exciting coil of the electric motor 21 and the electric motor 21 is driven by this voltage.

  When the drive shaft of the electric motor 21 rotates, a motor rotation pulse signal 27a is output from the Hall IC 27 every time it rotates by a certain amount, and the motor rotation pulse signal 27a is applied to the controller 10 as a feedback signal.

<Description of main control procedures>
FIG. 2 shows the control procedure of the main part during the brake release operation (release) by the control system shown in FIG. The control procedure of FIG. 2 will be described below.

  In step S11, the difference calculation unit 19a described above subtracts the stroke counter count value Vcnst from the initial counter position value Vcn0, and outputs the result as the remaining movement distance value Vpr.

  In step S12, the above-described position control speed command value calculation unit 13 calculates the position control speed command value Vcmd2 based on the remaining movement distance value Vpr. When the movable part moves, the remaining moving distance value Vpr changes with the change in position, and the position control speed command value Vcmd2 output by the position control speed command value calculation part 13 also changes.

  In step S13, the speed target value selection unit 15 compares the magnitude relationship between the target speed command value Vcmd1 and the position control speed command value Vcmd2. If “Vcmd2 ≧ Vcmd1”, the process proceeds to S14, and if “Vcmd2 <Vcmd1”, the process proceeds to S15.

  In step S14, the speed target value selection unit 15 selects the target speed command value Vcmd1 and outputs it as the rotation speed target value Vv1. In step S15, the speed target value selection unit 15 selects the position control speed command value Vcmd2 and outputs it as the rotation speed target value Vv1.

  In step S16, the above-described difference calculation unit 19b subtracts the rotation speed detection value Vv2 from the rotation speed target value Vv1, and outputs the calculation result as a speed deviation ΔVv.

  In step S17, the motor operation amount calculator 17 described above calculates an appropriate motor operation amount Vout based on the speed deviation ΔVv.

<Specific examples of signal changes>
FIG. 3 shows changes in signals and control amounts at various parts during brake release (release) operation of the control system shown in FIG. In FIG. 3, it is assumed that release is started at time t1 from the state where the movable part is in the braked position P1, and the control procedure as shown in FIG. 2 is executed.

  At time t1, since “Vcmd1 <Vcmd2”, the speed target value selection unit 15 selects the target speed command value Vcmd1. In this case, the motor operation amount calculation unit 17 outputs an appropriate motor operation amount Vout to control the rotational drive of the electric motor 21 so as to accelerate until reaching a constant speed Vr corresponding to the target speed command value Vcmd1.

  For example, when the actual rotational speed of the electric motor 21 reaches Vr, which is the target speed, at time t2, the rotational speed detection value Vv2 output from the rotational speed detection value calculation unit 16 approaches the rotational speed target value Vv1, The speed deviation ΔVv is reduced and the motor operation amount Vout is also reduced. Thereby, the electric motor 21 is rotationally driven at a constant speed Vr for a while after the time t2.

  On the other hand, the value Vcn0 of the initial counter position corresponds to the number of pulses of the motor rotation pulse signal 27a generated while the movable part moves a distance from the braked position P1 to the released reference position P2, and is a constant value (for example, Numerical value “100”).

  The stroke position counter 12 counts the pulses in the direction in which the count value is cleared to 0 when the release is started and the count value increases from 0. Therefore, the stroke counter count value Vcnst output from the stroke position counter 12 gradually increases from time t1, as shown in FIG. Further, since the remaining moving distance value Vpr is “Vcn0−Vcnst”, it gradually decreases from time t1, as shown in FIG.

  The target speed command value Vcmd1 output from the target speed command value holding unit 14 is a constant value (for example, a numerical value “20”). Further, since the position control speed command value Vcmd2 output by the position control speed command value calculation unit 13 changes according to the remaining movement distance value Vpr, it gradually decreases from time t1 as shown in FIG.

  Further, when the position of the movable part approaches the reference position P2 in the released state, which is the target stop position, the position control speed command value Vcmd2 decreases to a value close to the target speed command value Vcmd1. For example, when the condition “Vcmd2 <Vcmd1” is satisfied at time t3, the speed target value selection unit 15 selects the smaller position control speed command value Vcmd2, and outputs this as the rotational speed target value Vv1. That is, the target value of the rotational speed is automatically switched from the target speed command value Vcmd1 that is the output of the speed control system to the position control speed command value Vcmd2 that is the output of the position control system at time t3. At this time, since the values of Vcmd1 and Vcmd2 are the same, a rapid change does not occur with the switching, and a smooth switching is realized.

  In the section after time t3, the position control speed command value Vcmd2 continues to decrease as the movable part moves, so the rotational speed target value Vv1 decreases and the motor operation amount Vout also gradually changes in the deceleration direction. Therefore, as shown in FIG. 3 and the like, the motor rotation speed is slowly reduced from time t3.

  Then, when the position of the movable part reaches the reference position P2 in the released state, which is the target stop position (time t4), the motor rotation speed is very low, so the drive is immediately stopped without causing overshoot. can do.

  If only speed control is performed without switching control, the drive is suddenly stopped at a high rotational speed (Vr) when the target stop position (P2) is reached. Due to the influence of inertia, as indicated by a virtual line (two-dot chain line) in FIG. 3, the vehicle stops after passing through the target stop position (P2), resulting in a positional shift.

  By using the control system shown in FIG. 1, the speed control and the position control can be appropriately switched by a simple process, and the occurrence of the positional deviation can be suppressed. By preventing the displacement, it is possible to prevent the required time required for switching from the brake release state to the braking state in the electric parking brake device from becoming long or fluctuating. Moreover, since it is not necessary to mount a position sensor, an increase in apparatus cost can be suppressed and no special adjustment work is required.

  In the actuator 20 shown in FIG. 4, the rotation of the drive shaft of the electric motor 21 is detected by the Hall IC 27, but the movement of other movable parts is detected to detect the stroke position counter 12 and the rotation speed detection value. A pulse signal that can be used by the arithmetic unit 16 may be generated.

Here, the features of the embodiment of the electric parking brake device according to the present invention described above are briefly summarized and listed in the following [1] to [6], respectively.
[1] An electric parking brake device having an actuator (20) driven based on a rotational driving force of an electric motor (21),
A control system (controller 10) for releasing the parking brake
A speed control unit (target speed command value holding unit 14) that outputs a target speed command value (Vcmd1) corresponding to a target speed when the electric motor is driven at a constant rotational speed;
A position control unit (position control speed command value calculation unit 13) that outputs a position control speed command value (Vcmd2) that changes according to the position of the movable part of the actuator;
Based on the comparison result between the target speed command value and the position control speed command value, one of the target speed command value and the position control speed command value is set as the control target value (rotation speed target value Vv1) of the electric motor. A target value determination unit (speed target value selection unit 15) to output;
A motor operation amount calculator (17) for determining an operation amount of the electric motor based on the control target value;
An electric parking brake device comprising:
[2] The electric parking brake device according to [1] above,
The target value determination unit outputs a smaller one of the target speed command value (Vcmd1) and the position control speed command value (Vcmd2) as the control target value of the electric motor.
An electric parking brake device characterized by that.
[3] The electric parking brake device according to [2] above,
The target value determining unit outputs the target speed command value as the control target value of the electric motor, and then outputs the position control speed command value as the control target value of the electric motor.
An electric parking brake device characterized by that.
[4] The electric parking brake device according to any one of [1] to [3],
The position controller is
A stroke counter (stroke position counter 12) that counts a pulse signal generated with the rotation of the electric motor or the movement of the movable part of the actuator;
A reference movement amount holding unit (switch 11) for holding a reference value of the moving amount of the movable part of the actuator or a reference value of the position;
A speed command value calculation unit (difference calculation unit 19a) that calculates the position control speed command value based on a difference value between the reference value held by the reference movement amount holding unit and the count value of the stroke counter. When,
An electric parking brake device comprising:
[5] The electric parking brake device according to [4] above,
A permanent magnet (26) fixed to a drive shaft of the electric motor or a rotary shaft connected to the drive shaft;
A magnetic sensor (Hall IC 27) disposed at a position adjacent to the movement path of the permanent magnet;
Further comprising
Applying a signal output from the magnetic sensor to an input of the stroke counter;
An electric parking brake device characterized by that.
[6] The electric parking brake device according to [5] above,
A motor speed calculation unit (rotation speed detection value calculation unit 16) that generates a signal representing the motor rotation speed based on the pulse signal output from the magnetic sensor;
Further comprising
The motor operation amount calculation unit determines an operation amount of the electric motor based on a difference (speed deviation ΔVv) between the control target value and the motor rotation speed output by the motor speed calculation unit.
An electric parking brake device characterized by that.

DESCRIPTION OF SYMBOLS 10 Controller 11 Initial counter position holding part 12 Stroke position counter 13 Position control speed command value calculating part 14 Target speed command value holding part 15 Speed target value selecting part 16 Rotation speed detection value calculating part 17 Motor operation amount calculating part 18 Driver 19a, 19b Difference calculation unit 20 Actuator 21 Electric motor 22 Deceleration mechanism 23 Screw mechanism 24 Compression coil spring 25 Movable rod 26 Permanent magnet 27 Hall IC
27a Motor rotation pulse signal P1 Braking state position P2 Release state reference position Vcn0 Initial counter position value Vcnst Stroke counter count value Vpr Remaining travel distance value Vcmd1 Target speed command value Vcmd2 Position control speed command value Vv1 Rotation speed target value Vv2 Rotation speed detection value ΔVv Speed deviation Vout Motor operation amount

Claims (6)

An electric parking brake device having an actuator driven based on a rotational driving force of an electric motor,
The control system for releasing the parking brake
A speed control unit that outputs a target speed command value corresponding to a target speed when the electric motor is driven at a constant rotational speed;
A position control unit that outputs a position control speed command value that changes according to the position of the movable unit of the actuator;
A target value determining unit that outputs one of the target speed command value and the position control speed command value as a control target value of the electric motor based on a result of comparing the target speed command value and the position control speed command value; ,
A motor operation amount calculator that determines an operation amount of the electric motor based on the control target value;
An electric parking brake device comprising: The electric parking brake device according to claim 1,
The target value determination unit outputs the smaller one of the target speed command value and the position control speed command value as the control target value of the electric motor.
An electric parking brake device characterized by that. The electric parking brake device according to claim 2,
The target value determining unit outputs the target speed command value as the control target value of the electric motor, and then outputs the position control speed command value as the control target value of the electric motor.
An electric parking brake device characterized by that. The electric parking brake device according to any one of claims 1 to 3,
The position controller is
A stroke counter that counts a pulse signal generated with the rotation of the electric motor or the movement of the movable part of the actuator;
A reference value of the moving amount of the movable part of the actuator, or a reference moving amount holding unit that holds a reference value of the position;
A speed command value calculation unit that calculates the position control speed command value based on a difference value between the reference value held by the reference movement amount holding unit and a count value of the stroke counter;
An electric parking brake device comprising: The electric parking brake device according to claim 4,
A permanent magnet fixed to a drive shaft of the electric motor or a rotary shaft connected to the drive shaft;
A magnetic sensor disposed at a position adjacent to the movement path of the permanent magnet;
Further comprising
Applying a signal output from the magnetic sensor to an input of the stroke counter;
An electric parking brake device characterized by that. The electric parking brake device according to claim 5,
A motor speed calculation unit that generates a signal representing the motor rotation speed based on the pulse signal output from the magnetic sensor;
Further comprising
The motor operation amount calculation unit determines an operation amount of the electric motor based on a difference between the control target value and the motor rotation speed output by the motor speed calculation unit.
An electric parking brake device characterized by that.

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