JP6765265B2 - Electric brake device - Google Patents

Description

The present invention relates to an electric brake device mounted on a vehicle, and relates to a technique capable of increasing the redundancy of the electric brake device.

The following techniques have been proposed as an electric brake device using an electric motor.
1. 1. An actuator for an electric brake using an electric motor, a linear motion mechanism, and a speed reducer (Patent Document 1).
2. An electric actuator using a planetary roller mechanism and an electric motor (Patent Document 2).
3. 3. An electric brake that detects pressing force with a strain gauge (Patent Document 3).

Japanese Patent Application Laid-Open No. 6-327190 Japanese Unexamined Patent Publication No. 2006-194356 Japanese Patent No. 4116084

For example, in an electric braking device using an electric actuator as in Patent Documents 1 to 3, a vehicle equipped with the electric braking device may not be able to obtain a desired braking force due to an abnormality in function. For this reason, extremely high redundancy is often required.
When a plurality of sensors are used to provide redundancy for an abnormality of a sensor used in a motor or the like, the cost of the sensor and the mounting space can become a problem. For example, when the operation is continued by another sensor even if an abnormality occurs in a predetermined sensor, multiplexing of at least three systems is required, and the above-mentioned problem may occur.

As the above countermeasure, a sensor alternative drive (sensorless drive) that estimates a value that can be detected by a sensor determined to be abnormal from information such as other sensors and input / output history may be applied. In that case, it is generally necessary to grasp the physical characteristics of the actuator in advance. For example, when the parameters change due to aged deterioration or the like, a decrease in estimation accuracy due to the parameter fluctuations may become a problem.

For example, in an electric braking device that detects the pressing force of a friction member with a pressing force sensor such as a strain gauge as in Patent Document 3, when an abnormality occurs in the pressing force sensor, there is a correlation with the rigidity of the electric braking device in advance. The actuator may be controlled based on the motor angle and the actuator stroke amount that generate a predetermined pressing force while grasping the relationship. In this case, for example, the rigidity changes greatly due to wear of the friction member, and the correlation may fluctuate, which may cause a problem of deterioration of control accuracy.

Alternatively, it may be controlled to exert the motor torque required to maintain a predetermined pressing force. In this case, the actually generated pressing force changes depending on the moment of inertia, the sliding resistance, and the hysteresis characteristic of the actuator efficiency. Therefore, for example, an increase in sliding resistance due to deterioration over time and a decrease in control accuracy due to a decrease in actuator efficiency can be a problem.

An object of the present invention is to provide an electric brake device capable of increasing redundancy and improving control accuracy when an abnormality occurs in a defined sensor.

The electric brake device DB of the present invention includes a brake rotor 8, a friction member 9 that contacts the brake rotor 8, a friction member operating means 6 that brings the friction member 9 into contact with the brake rotor 8, and the friction member operating means. A plurality of types that detect at least one of the pressing force generated on the contact surface between the electric motor 4 for driving the electric motor 4 and the friction member 9 and the brake rotor 8, the motor rotation angle of the electric motor 4, and the motor current. Sensors Sb, Sa, 23, and a control device 2 that controls the pressing force by controlling the electric motor 4 based on a given pressing force command and an output from the sensor Sb (Sa, 23). In an electric brake device including the brake operating means 24 for giving a command of the pressing force to the control device 2.
The control device 2
A sensor abnormality detecting means 20 for determining whether a defined sensor Sb (Sa, 23) among the plurality of types of sensors Sb, Sa, 23 is normal or abnormal, and
When the defined sensor Sb (Sa, 23) is determined to be abnormal by the sensor abnormality detecting means 20, other than the defined sensor Sb (Sa, 23) among the plurality of types of sensors Sb, Sa, 23. The sensor output of the defined sensor Sb (Sa, 23) is estimated using the output from another sensor Sa (Sb, 23), and the electric motor is based on the estimated estimated sensor output. Sensor alternative control means 21 for controlling 4 and
A vehicle stop determination means 28 for determining whether or not the vehicle on which the electric brake device is mounted is stopped is provided.
The sensor alternative control means 21
When the sensor Sb (Sa, 23) defined by the sensor abnormality detecting means 20 is determined to be normal and the vehicle is determined to be stopped by the vehicle stop determining means 28, the brake operating means 24 Sensor alternative control that estimates the sensor output of the predetermined sensor Sb (Sa, 23) and controls the electric motor 4 by using the output from the other sensor Sa (Sb, 23) regardless of the operation status of The estimated sensor output of the defined sensor Sb (Sa, 23) estimated from the execution result of the sensor substitution control and the actual sensor output from the defined sensor Sb (Sa, 23) are executed. Check the accuracy of sensor alternative control by comparing with the sensor output.
The defined sensor is a sensor arbitrarily defined by design or the like among a plurality of types of sensors, and is determined by seeking an appropriate sensor by, for example, either one or both of a test and a simulation.

According to this configuration, when a push pressure command is given to the control device 2 from the brake operating means 24, the control device 2 controls the electric motor 4 based on the push pressure command. As a result, a pressing force is generated on the contact surface between the friction member 9 and the brake rotor 8. The plurality of types of sensors Sb, Sa, 23 detect at least one of the state quantities of the pressing force, the motor rotation angle, and the motor current. The control device 2 performs feedback control using the state quantity with respect to the command value.

The sensor abnormality detecting means 20 determines whether the sensor Sb (Sa, 23) is normal or abnormal. The sensor abnormality detecting means 20 can determine whether the sensor Sb (Sa, 23) is normal or abnormal, for example, by determining the range of the defined sensor Sb (Sa, 23) or comparing it with other sensing information.
When the defined sensor Sb (Sa, 23) is determined to be abnormal, the sensor alternative control means 21 uses the output from the sensor Sa (Sb, 23) that is not determined to be abnormal, and uses the output from the defined sensor Sa (Sb, 23). Based on the estimated sensor output of Sb (Sa, 23), sensor alternative control for controlling the electric motor 4 is performed.

The vehicle stop determination means 28 determines whether or not the vehicle is stopped. If the vehicle is stopped, the vehicle remains stopped by maintaining the minimum pressing force required to stop the vehicle. Therefore, since the sensor substitute control means 21 executes the confirmation operation of controlling the electric motor 4 as a sensor substitute, the feeling and safety are not impaired even if the pressing force is changed.
When the predetermined sensor Sb (Sa, 23) is determined to be normal and the vehicle is determined to be stopped, the sensor alternative control means 21 controls the electric motor 4 as a sensor alternative regardless of the operation status of the brake operating means 24. Perform a confirmation operation. Further, the sensor alternative control means 21 compares the estimated sensor output estimated from the execution result of the sensor alternative control with the actual sensor output from the defined sensor Sb (Sa, 23) to improve the accuracy of the sensor alternative control. Confirm. By confirming the accuracy of the sensor alternative control in this way, it is possible to improve the control accuracy when an abnormality occurs in the defined sensor Sb (Sa, 23). In addition, redundancy can be increased.

When the error between the estimated sensor output and the actual sensor output is larger than a predetermined value, the sensor alternative control means 21 has the estimated sensor output, the pressing force, and the motor rotation angle so that the error is reduced . And the sensor alternative control adjustment function unit 29 that corrects the relationship with any of the state quantities of the motor current may be provided.
The defined value is a value arbitrarily determined by design or the like, and is determined by obtaining an appropriate value by, for example, either one or both of a test and a simulation.
According to this configuration, the sensor alternative control adjustment function unit 29 determines the relationship between the sensor output and the state quantity so that the error is reduced while the defined sensor Sb (Sa, 23) is normal and the vehicle is stopped. By correcting it, the control accuracy of the sensor alternative control can be surely improved.

It said plurality of kinds of sensor includes a pressure sensor Sb for detecting the pressing force,
The sensor alternative control means 21 is based on the correlation between the pressure sensor output of the push pressure sensor Sb and the motor rotation angle of the electric motor 4, which depends on the rigidity of the electric brake device.
The electric motor 4 may be controlled to a motor rotation angle that is a predetermined pressure sensor output.
The defined pressure sensor output is a sensor output arbitrarily determined by design or the like, and is determined by obtaining an appropriate sensor output by, for example, one or both of a test and a simulation.
According to this configuration, the rigidity of the electric braking device can be changed to adjust the correlation parameter of the relationship between the motor rotation angle and the pressure sensor output.

It said plurality of kinds of sensor includes a pressure sensor Sb for detecting the pressing force,
The sensor alternative control means defines the relationship between the motor rotation angle of the electric motor for estimating the estimated sensor output and the pressing sensor output of the pressing pressure sensor based on the rigidity of the electric braking device. When confirming the accuracy of the sensor substitution control, the sensor substitution control adjustment function unit 29 corrects the rigidity for estimating the estimated sensor output to be low when the estimated sensor output exceeds the actual sensor output. When it falls below the value, the rigidity for estimating the estimated sensor output may be corrected to be high. By correcting the relationship between the motor rotation angle and the pressure sensor output in this way, the control accuracy can be further improved.

A condition in which the vehicle stop determination means 28 continues to detect zero speed for a predetermined time or longer by using at least one of the wheel speeds and at least one of the front-rear accelerations of the vehicle, the front-rear accelerations. When one of the conditions for continuing the detection of zero acceleration for a specified time or longer is satisfied, or when both conditions are satisfied, it is determined that the vehicle is stopped. Is also good. When the above conditions are satisfied, it is considered that the vehicle is stopped, and the sensor substitution control can be performed with high accuracy.

When the sensor alternative control means 21 executes the confirmation operation of the sensor alternative control, the electric motor so that the pressing force is higher than that in the case where the vehicle is stopped and the confirmation operation of the sensor alternative control is not executed. It may control the motor 4. In this case, it is possible to prevent the vehicle from undesirably starting to move when the sensor substitution control is performed while the vehicle is stopped.

The electric brake device of the present invention includes a brake rotor, a friction member that contacts the brake rotor, a friction member operating means that brings the friction member into contact with the brake rotor, and an electric motor that drives the friction member operating means. A plurality of types of sensors that detect at least one of the pressing force generated on the contact surface between the friction member and the brake rotor, the motor rotation angle of the electric motor, and the motor current, a command of the given pressing force, and The control in an electric brake device including a control device that controls the pressing force by controlling the electric motor based on an output from the sensor, and a brake operating means that gives a command of the pressing force to the control device. The apparatus includes a sensor abnormality detecting means for determining whether a specified sensor among the plurality of types of sensors is normal or abnormal, and the plurality of sensors when the specified sensor is determined to be abnormal by the sensor abnormality detecting means. The sensor output of the specified sensor is estimated using the output from another sensor that is a sensor other than the specified sensor, and the electric motor is controlled based on the estimated estimated sensor output. The sensor alternative control means is provided with a stop determination means for determining whether or not the vehicle on which the electric braking device is mounted is stopped, and the sensor alternative control means is defined by the sensor abnormality detecting means. When the sensor is determined to be normal and the vehicle is determined to be stopped by the stop determination means, the output from the other sensor is used regardless of the operation status of the brake operation means. The sensor output of the specified sensor is estimated, the confirmation operation of the sensor alternative control that controls the electric motor is executed, the estimated sensor output of the specified sensor estimated from the execution result of the sensor alternative control, and the above-mentioned determination. The accuracy of the sensor alternative control is confirmed by comparing with the actual sensor output from the sensor. Therefore, when an abnormality occurs in the defined sensor, the redundancy can be improved and the control accuracy can be improved.

It is a figure which shows the schematic structure of the electric brake device which concerns on embodiment of this invention. It is a block diagram which shows one configuration example of the electric brake device. It is a block diagram which shows the switch connection pattern at the time of executing the sensor substitution control which involves the parameter adjustment of the sensor substitution control means in the electric brake device. It is a block diagram which shows the switch connection pattern at the time of performing sensor substitution control at the time of abnormality of a push pressure sensor in the electric brake device. It is a flowchart which shows an example of the execution flow of a sensor alternative control means. It is a block diagram which shows the structural example of the electric brake device which concerns on other embodiment of this invention. It is a block diagram which shows the structural example of the electric brake device which concerns on still another Embodiment of this invention. It is a block diagram which shows the structural example of the electric brake device which concerns on still another Embodiment of this invention.

The electric brake device according to the embodiment of the present invention will be described with reference to FIGS. 1 to 5.
As shown in FIG. 1, the electric brake device DB includes an electric brake actuator 1, a control device 2, and a peripheral device 3 (FIG. 2). This electric brake device DB is mounted on the vehicle. First, the electric brake actuator 1 will be described.

The electric brake actuator 1 includes an electric motor 4, a reduction mechanism 5 for decelerating the rotation of the electric motor 4, a linear motion mechanism 6 as a friction member operating means, a parking brake mechanism 7 as a parking brake, and a brake rotor 8. , A friction member 9, an angle sensor Sa (FIG. 2), and a pressing force sensor Sb (FIG. 2). The electric motor 4, the reduction mechanism 5, and the linear motion mechanism 6 are incorporated in, for example, a housing (not shown). The brake rotor 8 may be a disc type or a drum type. The friction member 9 is composed of a brake pad, a brake shoe, or the like. The linear motion mechanism 6 includes a feed screw mechanism such as a ball screw mechanism and a planetary roller screw mechanism.

When the electric motor 4 is composed of a permanent magnet synchronous motor, it saves space and has high torque, which is suitable. However, for example, a DC motor using a brush, a reluctance motor not using a permanent magnet, an induction motor, or the like can also be applied. ..
The speed reduction mechanism 5 is a mechanism that reduces and transmits the rotation of the electric motor 4 to the tertiary gear 11 fixed to the rotating shaft 10, and includes a primary gear 12, an intermediate gear 13, and a tertiary gear 11. In this example, the reduction mechanism 5 decelerates the rotation of the primary gear 12 attached to the rotor shaft 4a of the electric motor 4 by the intermediate gear 13 and transmits the rotation to the tertiary gear 11 fixed to the end of the rotation shaft 10. It is possible.

The linear motion mechanism 6 converts the rotary motion output by the deceleration mechanism 5 into a linear motion of the linear motion unit 14 by various screw mechanisms such as a planetary roller screw and a ball screw, and is a friction member with respect to the brake rotor 8. This is a mechanism for bringing the 9 into contact with each other. The linear motion portion 14 is stopped from rotating and is movably supported in the axial direction A1. A friction member 9 is provided at the outboard side end of the linear motion portion 14. By transmitting the rotation of the electric motor 4 to the linear motion mechanism 6 via the reduction mechanism 5, the rotational motion is converted into a linear motion, which is converted into the pressing force of the friction member 9 to generate a braking force. .. The outboard side is a state in which the electric brake device DB is mounted on the vehicle, the outside of the vehicle in the vehicle width direction is referred to as the outboard side, and the center side of the vehicle in the vehicle width direction is referred to as the inboard side.

The parking brake mechanism 7 has a lock member 15 and an actuator 16. A plurality of locking holes (not shown) are formed on the outboard side end surface of the intermediate gear 13 at regular intervals in the circumferential direction. The lock member 15 is configured to be lockable in any one of these locking holes. For example, a solenoid is applied as the actuator 16. A parking lock state is achieved by advancing the lock member (solenoid pin) 15 by the actuator 16 and fitting it into the locking hole formed in the intermediate gear 13 to lock the intermediate gear 13 and prohibiting the rotation of the intermediate gear 13. To. By retracting the lock member 15 to the actuator 16 and disengaging it from the locking hole, the intermediate gear 13 is allowed to rotate and is brought into an unlocked state.

The control device 2 and the like will be described.
FIG. 2 is a block diagram showing a configuration example of this electric brake device. Note that this configuration example shows the configuration required for the present proposal, and for example, the configuration required for the actual system configuration such as the power supply device and other sensors such as the thermistor is appropriately provided regardless of this figure. It shall be. This configuration example shows an example using the pressing force feedback control. The peripheral device 3 is connected to the upper stage of the control device 2, and the electric brake actuator 1 is connected to the lower stage of the control device 2. The control device 2 includes a push pressure converter 17, a brake push pressure controller 18, a motor current controller 19, a sensor abnormality detecting means 20, a sensor alternative control means 21, a motor driver 22, and a current sensor 23.

The peripheral device 3 includes a brake operating means 24, a wheel speed sensor 25, and an acceleration sensor 26. The pressing force command corresponding to the operation amount of the brake operating means 24 is output as a detection signal by a brake sensor (not shown) and input to the control device 2. As the brake operating means 24, for example, a brake pedal or the like can be used, but other operating means such as a joystick may be used, or a higher-level ECU such as a vehicle VCU may be used.

The pressing force converter 17 converts the detection signal into a pressing force command value. The conversion by the pressing force converter 17 may be referred to by a predetermined look-up table (abbreviation: LUT) or the like, or may be appropriately calculated by a mathematical formula or the like.

The brake pressing force controller 18 performs servo control so that the feedback pressing force follows the pressing force command value. In the design of the brake pressing force controller 18, PID (Proportional-Integral-Differential Controller) or state feedback, other non-linear control, adaptive control and the like can be appropriately used. Further, FIG. 2 shows an example in which the motor current command value is output from the brake press pressure controller 18 as the operation amount. In the brake pressing pressure controller 18, high-performance motor control can be executed by using a current map according to torque or rotation speed, a current derivation formula, or the like in generating the motor current command value, which is preferable. ..

The motor current controller 19 performs servo control so as to make the feedback current follow the motor current command value given from the brake pressing force controller 18. In the motor current controller 19, the motor current flowing through the electric motor 4 is obtained from the current sensor 23, and current feedback control is performed. The current sensor 23 may use a non-contact type that detects the magnetic field of the transmission line between the motor driver 22 and the electric motor 4, and a method of providing a shunt resistor or the like on the transmission line and detecting by the voltage at both ends is used. You may use it. Further, it may be a method of detecting by the voltage or the like at a predetermined position of the motor driver circuit.

PID or state feedback, other non-linear control, adaptive control and the like can be appropriately used in the design of the motor current controller 19, and feedforward control typified by non-interference control may be used in combination. The motor current controller 19 can be configured as an equation of motion including the brake pressing force controller 18 described above, and can be made into one control calculation loop.

In this example, the sensor abnormality detecting means 20 determines whether the pressing pressure sensor Sb is normal or abnormal. The pressing force sensor Sb detects the pressing force generated on the contact surface between the friction member 9 (FIG. 1) and the brake rotor 8 (FIG. 1). As the pressing force sensor Sb, for example, a magnetic sensor can be applied. When the friction member 9 (FIG. 1) presses the brake rotor 8 (FIG. 1), this magnetic sensor magnetically detects the reaction force on the inboard side acting on the linear motion mechanism 6 as the amount of displacement in the axial direction. To do. As the pressing force sensor Sb, a strain sensor or a pressure sensor other than the magnetic sensor can be used.
As the angle sensor Sa, for example, a resolver or a magnetic encoder is suitable for high accuracy and high reliability, but various sensors such as an optical encoder can also be applied.

The sensor abnormality detecting means 20 detects an abnormality of the pressing pressure sensor Sb by determining the range of the pressing pressure sensor Sb or comparing it with other sensing information. The sensor abnormality detecting means 20 is, for example, a reaction force torque that depends on the correlation between a predetermined pressing force and the motor angle depending on the rigidity of the electric braking device, or the equivalent lead and load conversion efficiency in the linear motion mechanism 6. Compare the equations of motion such as motor current, actuator inertia, etc. with the pressing force. The sensor abnormality detecting means 20 may determine that the pressing pressure sensor Sb is abnormal when the pressing pressure sensor output deviates significantly from the comparison result. Alternatively, a sensor having an abnormality diagnosis function may be applied to the pressing pressure sensor Sb, and the self-diagnosis result may be used as an abnormality determination result.

When the range determination is performed by the sensor abnormality detecting means 20, when the pressing force deviates from the range of the pressing force to be output by the pressing force sensor Sb, the pressing force sensor Sb has an abnormality. You may judge that. The determined value is appropriately determined based on the result of, for example, an experiment or a simulation.

The sensor alternative control means 21 has a function of controlling the brake pressing force without using the pressing force sensor Sb. Normally, as shown in FIG. 2, the brake pressing force controller 18 causes the feedback pressing force from the pressing force sensor Sb to follow the pressing force command value from the pressing force converter 17. When the pressing force sensor Sb is detected as abnormal by the sensor abnormality detecting means 20, as shown in FIGS. 3 and 4, the sensor alternative control means 21 is a sensor that is not determined to be abnormal (in this example, the angle sensor Sa). Alternatively, the output from the current sensor 23) is used to control the electric motor 4 based on the estimated sensor output that estimates the sensor output of the pressing pressure sensor Sb when there is no abnormality.

Here, FIG. 3 shows a switch connection pattern when executing sensor substitution control for adjusting parameters of the sensor substitution control means 21, and FIG. 4 shows a switch when executing sensor substitution control when the pressing force sensor Sb is abnormal. Shows the connection pattern.
As shown in FIGS. 3 and 4, the sensor alternative control means 21 includes a push pressure command generation unit 27, a vehicle stop determination means 28, a parameter adjustment unit 29, a control switching unit 30, and a push pressure estimation unit 31.

The pressing force command generation unit 27 has a function of generating a pressing force command for performing parameter adjustment described later. The pressing force command for parameter adjustment can be appropriately given in advance as a signal pattern suitable for parameter adjustment, such as a monotonous pressure boosting signal that does not generate a hysteresis loop.

Further, the pressing force command for parameter adjustment is at least a value larger than the pressing force command value based on the operation of the brake operating means 24 so that safety is not impaired even if the braking force (pressing pressure) decreases. It may be set as. At this time, for example, in a system provided with a plurality of electric brake devices, the pressing force command for performing parameter adjustment set to be at least larger than the pressing force command value based on the operation of the brake operating means 24 is all electric. It may be achieved by the sum of the braking forces in the braking device. In this case, a load is generated for integrated control of a plurality of electric brake devices, but the degree of freedom of the pressing force that can be determined as the pressing force command value for parameter adjustment increases, which is suitable for more accurate parameter adjustment. ..

The vehicle stop determination means 28 determines whether or not the vehicle on which the electric braking device is mounted is stopped. If the vehicle is stopped, the vehicle remains stopped by maintaining the minimum pressing force required to stop the vehicle. Therefore, since the sensor substitute control means 21 executes the confirmation operation of controlling the electric motor 4 as a sensor substitute, the feeling and safety are not impaired even if the pressing force is changed. In this case, if the vehicle is extremely low speed, the safety is not impaired, so that the extremely low speed state of the vehicle may be regarded as a stop. However, even if the vehicle is extremely low speed, it may affect the feeling of the driver of the vehicle.

Therefore, for example, it is desirable to determine that the vehicle has stopped reliably, for example, when the determination that the vehicle speed is zero has elapsed for a predetermined time. Specifically, the vehicle stop determination means 28 uses at least one of at least one wheel speed and the front-rear acceleration of the vehicle to continue detecting the zero speed for a predetermined time or longer. It is determined that the vehicle is stopped when any one of the conditions for continuing the detection of zero acceleration for a predetermined time or longer, or when both conditions are satisfied. The wheel speed is given by the wheel speed sensor 25. The wheel speed sensor 25 is provided for each wheel. The wheel speed sensor 25 may be, for example, an ABS sensor. The front-rear acceleration of the vehicle is given by the acceleration sensor 26. The acceleration sensor 26 may be, for example, a G sensor.

The pressing force estimation unit 31 has a function of estimating the pressing force based on information other than the pressing sensor output of the pressing force sensor Sb. The pressing force estimation unit 31 may estimate the pressing force based on the correlation between the predetermined pressing force and the motor angle, which depends on the rigidity of the electric braking device, for example, and may estimate the pressing force, such as the motor current, the actuator inertia, or sliding. The pressing force may be estimated by deriving the reaction force torque from the equation of motion such as resistance. Alternatively, these methods may be used in combination as appropriate.

The parameter adjusting unit 29 as the sensor alternative control adjustment function unit appropriately adjusts the correlation parameter used for the pressing pressure estimation by comparing the pressing pressure estimation result by the pressing pressure estimating unit 31 with the normal pressing sensor output. Specifically, when the error between the pressing pressure estimation result (estimated sensor output) and the actual pressing sensor output is larger than a predetermined value, the parameter adjusting unit 29 corrects the correlation parameter so that the error is reduced. ..

For example, when based on the correlation between a predetermined pressing force and the motor angle, which depends on the rigidity of the electric braking device, the rigidity can be changed to adjust the correlation parameter. Further, when the reaction force torque is derived from the equations of motion such as the motor current, the actuator inertia, and the sliding resistance, the correlation parameter can be adjusted by changing the actuator inertia or the sliding resistance. These methods may be used in combination as appropriate.

The control switching unit 30 switches the signal flow for realizing switching between the pressing pressure feedback control and the sensor alternative control. As shown in FIG. 2, if the feedback signal to the brake pressing force controller 18 is the pressing sensor output of the pressing force sensor Sb, the pressing force feedback control system is obtained. As shown in FIGS. 3 and 4, if the feedback signal to the brake pressing force controller 18 is used as the pressing force estimation value of the pressing force estimation unit 31, the sensor alternative control system is obtained. For example, when the parameter adjusting unit 29 acquires a signal for parameter adjustment, or when an abnormality is detected in the pressing pressure sensor Sb by the sensor abnormality detecting means 20, the control system is appropriately switched according to a predetermined situation. be able to.

When the above functions are implemented by, for example, a computer such as a microcomputer, FPGA, or DSP, they are inexpensive and highly functional, which is preferable. Further, the switch units 32 and 33 in FIGS. 2 to 4 are described for convenience, and can be mounted on the arithmetic unit as a data flow branch instead of a physical switch. Further, these functions may be an arithmetic unit dedicated to the electric brake device, and may be implemented as a part of the functions of other arithmetic units such as VCU.

The motor driver 22 is preferable because it is inexpensive and has high performance if, for example, a half-bridge circuit using a switch element such as an FET is configured and PWM control is performed to determine the motor applied voltage according to a predetermined duty ratio. Alternatively, the motor driver 22 may be provided with a transformer circuit or the like to perform PAM control.

FIG. 5 is a flowchart showing an example of the execution flow of the sensor alternative control means.
2 to 4 will be described with reference to them as appropriate. For example, the treatment under conditions of power on the vehicle is started, the control unit 2 obtains the target pressing force F _r in accordance with the operation amount of the brake operating means 24 (step S1). Next, the sensor abnormality detecting means 20 determines whether the pressing pressure sensor Sb is normal or abnormal (step S2). When it is determined that the pressing pressure sensor Sb is normal (step S2: yes), the sensor output (pressing pressure F _b ) from the pressing pressure sensor Sb is acquired (step S3).

Next, the vehicle stop determination means 28 determines whether or not the vehicle is stopped (step S4). While the vehicle is stopped, for example, the sensor outputs of the plurality of wheel speed sensors 25 are all zero, the sensor outputs of the acceleration sensor 26 are substantially zero, and the vehicle is stopped in a state where the above-mentioned state continues for a predetermined time. If it is determined, the stopped state can be reliably determined, which is preferable. However, it can be appropriately set according to the requirements, such as omitting a part of the above conditions according to the required estimation accuracy.

When it is determined that the vehicle is not stopped (step S4: no), the feedback signal to the brake pressing force controller 18 is calculated as the pressing sensor output of the pressing force sensor Sb (step S13). After that, this process ends. When it is determined that the vehicle is stopped (step S4: yes), the target pressing force _Fr ′ for parameter adjustment is acquired from the pressing force command generation unit 27 (step S5). Next, the pressing force command value to be input to the brake pressing force controller 18 is set to F _r ′. In other words, F _r is updated to F _r ′ (step S6).

Next, the pressing force estimation unit 31 sets a target angle θ _r ′ that is F _r ′ from the actuator rigidity F = f (θ) (step S7). Next, the sensor substitute control unit 21 executes a control operation to the target angle theta _{r 'set} for the electric motor 4 (step S8). In other words, the confirmation operation of controlling the electric motor 4 as a sensor substitute is executed regardless of the operation status of the brake operating means 24. Next, the sensor alternative control means 21 determines whether or not the acquisition of data for confirming the accuracy of the sensor alternative control is completed (step S9).

In step S9, for example, the sensor alternative control means 21 sets in advance an operation pattern of the electric brake device capable of sufficiently determining the control accuracy of the sensor alternative control means 21, and has a situation in which the operation pattern is completed. It may be determined that the data acquisition is completed. When it is determined that the data acquisition is not completed (step S9: no), this process is terminated. Upon determining that the data acquisition has been completed (step S9: yes), the parameter adjusting unit 29 compares F _r ′ and F _b (step S10).

Next, the parameter adjusting unit 29 determines whether or not the error between F _r ′ and F _b is larger than the predetermined value (step S11). When it is determined that the error is equal to or less than the predetermined value (step S11: no), this process is terminated. Upon determining that the error is larger than the predetermined value (step S11: yes), the parameter adjusting unit 29 corrects the actuator rigidity function f (θ) so that the error is reduced (step S12). In the parameter correction in step S12, for example, the coefficient of the function f (θ) may be directly calculated back from the relationship between θ and F under a predetermined condition, and a parameter optimization method such as a response surface methodology may be applied to the acquired data group. It may be applied and obtained. The former is suitable for reducing the calculation load, and the latter is suitable for improving the accuracy of parameter adjustment. After that, this process ends.

In step S2, it is determined that the pressing force sensor Sb is abnormal (step S2: no), and the sensor alternative control means 21 sets a target angle θ _r that is F _r ′ from the actuator rigidity F = f (θ). (Step S14). Thereafter, the sensor substitute control unit 21 executes a control operation to the target angle theta _r set for the electric motor 4 (step S15). After that, this process ends.

The action and effect will be described.
When the pressing force sensor Sb is determined to be normal and the vehicle is stopped, the sensor alternative control means 21 executes a confirmation operation of controlling the electric motor 4 as a sensor alternative regardless of the operation status of the brake operation means 24. Further, the sensor alternative control means 21 compares the estimated sensor output estimated from the execution result of the sensor alternative control with the actual sensor output from the pressing force sensor Sb to confirm the accuracy of the sensor alternative control. When the error between the estimated sensor output and the actual sensor output is larger than a predetermined value, the parameter adjusting unit 29 corrects the relationship between the sensor output and the state quantity so that the error is reduced. Therefore, by operating the electric brake actuator 1 while the vehicle is stopped, which does not affect the behavior of the vehicle, the accuracy of the pad wear and actuator deterioration of the sensor alternative control system of the electric brake device is not impaired without impairing the safety and feeling. Guarantee is possible.

Other embodiments will be described.
In the following description, the same reference numerals will be given to the parts corresponding to the matters previously described in each embodiment, and duplicate description will be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described above unless otherwise specified. It has the same effect from the same configuration. In addition to the combination of the parts specifically described in each embodiment, it is also possible to partially combine the embodiments as long as the combination does not cause any trouble.

Instead of the brake pressing force controller 18 of FIG. 2, as shown in FIG. 6, a pressing force feedback system including a pressing force / angle converter 34, a target motor angle corrector 35, and a motor angle controller 36 is configured. You may. In this example, an angle control system that converts the pressing force into an angle is configured in advance by the pressing force / angle converter 34, and the error with respect to the pressing force command is converted into the corrected value of the command angle by the target motor angle corrector 35. A pressing pressure feedback system is configured by a motor angle controller 36 and the like. In this example, as compared with the above-described embodiment (see FIG. 2), the parameter adjusting unit 29 adjusts the correlation for converting the target pressing force into the target angle, and the pressing force error when executing the sensor alternative control. The signal for correcting the command angle is blocked from.

FIG. 7 shows an example in which the sensor alternative control means 21 that does not use the angle sensor Sa is configured as a redundant system in response to an abnormality in the angle sensor Sa. In this example, information other than the sensor output of the angle command generation unit 37 for generating the angle command for adjusting the parameters and the sensor output of the angle sensor Sa instead of the pressing pressure command generating unit 27 and the pressing pressure estimating unit 31 in FIG. 2, respectively. The sensor alternative control means 21 including the angle estimation unit 38 and the like for estimating the motor angle based on the above is configured. Further, the sensor abnormality detecting means 20 of this example detects an abnormality of the angle sensor Sa. The angle estimator 38 may apply an estimator that estimates interlinkage flux, saturated salient poles, inductance salient poles, and the like. The parameter adjusting unit 29 may adjust the motor parameters and the observer gain used in the estimator.

FIG. 8 shows an example in which the sensor alternative control means 21 that does not use the current sensor 23 is configured as a redundant system in response to an abnormality in the current sensor 23. In this example, information other than the sensor output of the current command generation unit 39 and the current sensor 23 that generate a current command for parameter adjustment instead of the pressing pressure command generation unit 27 and the pressing pressure estimation unit 31 in FIG. 2, respectively. The sensor alternative control means 21 including the current estimation unit 40 and the like for estimating the motor current based on the above is configured. Further, the sensor abnormality detecting means 20 of this example detects an abnormality of the current sensor 23. The examples of FIGS. 2, 6 to 8 may be used in combination as appropriate.

The sensor alternative control means 21 controls the electric motor so that the pressing force is higher when the confirmation operation for sensor alternative control is executed than when the confirmation operation for sensor alternative control is not executed when the vehicle is stopped. There may be. In this case, it is possible to prevent the vehicle from undesirably starting to move when the sensor substitution control is performed while the vehicle is stopped.

Although the embodiments for carrying out the present invention have been described above based on the embodiments, the embodiments disclosed this time are exemplary in all respects and are not limiting. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

2 ... Control device 4 ... Electric motor 6 ... Linear mechanism (friction member operating means)
8 ... Brake rotor 9 ... Friction member Sa ... Angle sensor Sb ... Push pressure sensor 20 ... Sensor abnormality detecting means 21 ... Sensor alternative control means 23 ... Current sensor 24 ... Brake operating means 28 ... Stop determination means 29 ... Parameter adjusting unit (sensor) Alternative control adjustment function part)

Claims (6)

A brake rotor, a friction member that contacts the brake rotor, a friction member operating means that brings the friction member into contact with the brake rotor, an electric motor that drives the friction member operating means, and the friction member and the brake rotor. Based on a plurality of types of sensors that detect at least one of the pressing force generated on the contact surface, the motor rotation angle of the electric motor, and the motor current, a given pressing force command, and an output from the sensor. In an electric brake device including a control device that controls the pressing force by controlling the electric motor, and a brake operating means that gives a command of the pressing force to the control device.
The control device
A sensor abnormality detecting means for determining whether a defined sensor among the plurality of types of sensors is normal or abnormal, and
When the specified sensor is determined to be abnormal by the sensor abnormality detecting means, the output from a sensor other than the specified sensor among the plurality of types of sensors is used to determine the above. A sensor alternative control means that estimates the sensor output of the sensor and controls the electric motor based on the estimated estimated sensor output, and
A vehicle stop determination means for determining whether or not the vehicle on which the electric brake device is mounted is stopped is provided.
The sensor alternative control means
When the sensor abnormality detecting means determines that the specified sensor is normal and the vehicle stop determination means determines that the vehicle is stopped, the other is not limited to the operating status of the brake operating means. Using the output from the sensor of, the sensor output of the specified sensor is estimated, and the confirmation operation of the sensor alternative control that controls the electric motor is executed.
An electric brake device for confirming the accuracy of sensor substitution control by comparing the estimated sensor output of the defined sensor estimated from the execution result of the sensor substitution control with the actual sensor output from the defined sensor. In the electric braking device according to claim 1, when the error between the estimated sensor output and the actual sensor output is larger than a predetermined value, the sensor alternative control means reduces the estimated sensor output so that the error is reduced. An electric braking device having a sensor alternative control adjustment function unit that corrects the relationship between the pressing force and any of the state quantities of the pressing force, the motor rotation angle, and the motor current . The electric brake apparatus according to claim 2, wherein the plurality of kinds of sensor includes a pressure sensor for detecting the pressing force, said sensor alternate control means is based on the rigidity of the electric brake system, the estimated sensor output When the relationship between the motor rotation angle of the electric motor for estimation and the press sensor output of the press pressure sensor is defined, and the sensor alternative control adjustment function unit confirms the accuracy of the sensor alternative control, the estimated sensor output is changed low stiffness for estimating the estimated sensor output when exceeding the actual sensor output, the electric brake system to change higher the rigidity for estimating the estimated sensor output when below. The electric brake apparatus according to any one of claims 1 to 3, wherein the plurality of kinds of sensor includes a pressure sensor for detecting the pressing force,
The sensor alternative control means is a motor rotation that provides a predetermined pressing sensor output based on the correlation between the pressing sensor output of the pressing pressure sensor and the motor rotation angle of the electric motor, which depends on the rigidity of the electric braking device. An electric brake device that controls the electric motor at the corner. In the electric braking device according to any one of claims 1 to 4, the stop determination means uses at least one of at least one wheel speed and the front-rear acceleration of the vehicle to use the wheels. When either one of the conditions where the speed is continuously detected for the specified time or longer, the condition where the front-rear acceleration is continued for the specified time or longer, or both conditions are satisfied. An electric braking device that determines that the vehicle is stopped when the above is satisfied. In the electric brake device according to any one of claims 1 to 5, when the sensor alternative control means executes the confirmation operation of the sensor alternative control, the vehicle is stopped and the sensor alternative control is performed. An electric brake device that controls the electric motor so that the pressing force exceeds the pressing force as compared with the case where the confirmation operation of the above is not executed.

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