JP7165043B2 - electric brake device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric brake device mounted on a vehicle or the like, for example, and relates to a technique capable of suppressing vibration caused by inertia, rigidity, etc. of each component of the electric brake device.

The following techniques have been proposed as electric brake devices.
1. An electric brake actuator 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).

JP-A-6-327190 JP 2006-194356 A

For example, in an electric brake device using an electric linear motion actuator, such as Patent Documents 1 and 2, a vibration system including inertia of the electric brake actuator is formed, and the influence of the vibration system causes problems in the actuator control system. may occur.

For example, in the case of a disc brake device in which the piston is arranged on the inboard side, the friction material is pressed against the brake rotor by the protruding motion of the direct-acting actuator corresponding to the piston, and the disc slides to the inboard side due to the reaction force. , the friction material on the outboard side is pressed through the rigidity of the caliper.
At that time, if the thrust force of the linear motion actuator is constant, a uniform force is generated in the friction material on the inboard side and the friction material on the outboard side, and the caliper stops. It becomes a spring coupling system via the rigidity of the friction material and the mass of the caliper and the actuator, etc., and vibration may occur at a predetermined resonance frequency.

For example, in the case of an opposed-piston disc brake device in which the pistons are arranged on the inboard side and the outboard side, the inboard-side and outboard-side direct acting actuators corresponding to the pistons operate in a completely synchronized and symmetrical manner. If so, the above problem will be solved. However, in reality, due to uneven wear of the friction material, uneven temperature, etc., the pressing force of the friction material on the inboard side and the outboard side is not completely synchronized, and the same transient vibration as above is a problem. may be.

For example, in the case of a drum brake device in which the opposing linings on the inner side of the drum protrude from each other, the state of contact between the opposing linings and the brake drum can be transiently completely synchronized in the same manner as the opposed piston type disc brake device described above. In some cases, it becomes a spring coupling system through the rigidity of the actuator inertia, the actuator and the friction material, and vibration occurs at a predetermined resonance frequency.

Further, in the case of an electric brake device in particular, the stiffness may exhibit non-linear characteristics depending on the brake load, and the resonance frequency may fluctuate, which may cause a problem of unintended vibration. Furthermore, since the stiffness changes mainly due to the friction of the pad, lining, etc., the resonance frequency may change, resulting in a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric brake device that suppresses vibrations caused by the inertia and rigidity of each component of the electric brake device and enables highly accurate brake control.

The electric brake device 1 of the present invention includes a brake rotor 8, a friction member 9 that comes into contact with the brake rotor 8 to generate a braking force, an electric motor 4, and an output of the electric motor 4 that pushes the friction member 9. In an electric brake device comprising a friction material operating means 6 that converts into pressure and a control device 2 that controls the electric motor 4,
The control device 2 is
The peak frequency forming the peak gain in the vibration characteristics consisting of the gain and frequency of the spring vibration system expressed by the rigidity of the member including the friction material 9 and the friction material operating means 6 and the inertia of the friction material operating means 6 has a vibration attenuation processing unit 24 for attenuating the gain of the vibration characteristic to a predetermined gain or less.
The predetermined gain is a gain that is arbitrarily determined by design or the like, and is determined, for example, by obtaining an appropriate gain through either one or both of tests and simulations.

According to this configuration, the vibration characteristic consisting of the gain and frequency of the spring vibration system of the electric brake device is expressed (in other words, determined) by a mathematical formula including at least the rigidity and inertia of the friction material operating means 6 and the like. The vibration attenuation processing unit 24 attenuates the gain of the vibration characteristic below a predetermined gain at the peak frequency forming the peak gain of the vibration characteristic. By capturing the peak frequency that forms the peak gain and attenuating the gain of the vibration characteristic, the vibration can be converged and suppressed more efficiently. Therefore, the vibration caused by the inertia, the rigidity, etc. is suppressed, and high-precision brake control becomes possible.

The control device 2 has a vibration characteristic estimation unit 23 for estimating the vibration characteristic according to the input of the physical quantity related to the stiffness, and the vibration damping processing unit 24 estimates the vibration characteristic estimated by the vibration characteristic estimation unit 23. The gain of the vibration characteristic may be attenuated below a predetermined gain at a peak frequency forming a peak gain in the vibration characteristic. The physical quantity related to the rigidity is, for example, the brake load, the wear amount of the friction material, and the like.

If the vibration properties are already known and unchanged, there is no need to estimate the vibration properties. However, the rigidity of the electric brake device may change according to the brake load, the wear amount of the friction material, and the like. According to this configuration, the vibration characteristic estimator 23 estimates the vibration characteristic according to the input of the physical quantity related to stiffness. As a result, it is possible to accurately estimate the stiffness that changes from moment to moment depending on the brake load, the amount of wear of the friction material, and the like. Therefore, vibration caused by inertia and rigidity is suppressed, and more precise brake control is possible.

The control device 2 is
a braking force estimating means 19 for estimating a braking force corresponding to the contact force between the friction material 9 and the brake rotor 8 by the friction material operating means 6;
a brake stiffness estimation function unit 25 for estimating the stiffness of the electric brake device 1 at the estimated brake force based on the estimated brake force estimated by the brake force estimation means 19;
The vibration characteristic estimating section 23 may estimate the vibration characteristic using the estimated stiffness estimated by the brake stiffness estimating function section 25 .

In general, the stiffness of the brake device (mainly the stiffness of the friction material) becomes strongly nonlinear depending on the applied load, and accordingly the vibration characteristics also change. Therefore, in this configuration, the brake stiffness estimating function unit 25 estimates the stiffness based on the estimated braking force, and the vibration characteristic estimating unit 23 estimates the vibration characteristic using the estimated stiffness value at the current braking force. , which allows for more precise control.

The control device 2 is
a position estimation function unit 20 for estimating the position of the friction material operating means 6;
The correlation between the estimated position estimated by the position estimation function unit 20 and the estimated braking force is compared with a predetermined correlation between the estimated position and the estimated braking force when the friction material 9 is not worn. and a wear degree estimation function unit 26 for estimating the degree of wear of the friction material 9,
The brake stiffness estimation function unit 25 may have a function of adjusting a correlation parameter between the estimated brake force and the estimated stiffness based on the estimated wear degree estimated by the wear degree estimation function unit 26. good.
The degree of wear is, for example, the current amount of wear of the friction material 9 with reference to the time when the friction material 9 is not worn (amount of wear=0).

Abrasion occurs mainly in the friction material 9 due to the braking operation, and this friction greatly changes the rigidity. Therefore, the degree of wear of the friction material 9 is estimated, and the correlation parameter between the initial (non-wear) estimated braking force and estimated stiffness is adjusted. This enables accurate stiffness estimation.

The control device 2 is
an angular velocity estimation function unit 31 for estimating the angular velocity of the electric motor 4;
a torque ripple estimation function unit 32 for estimating values corresponding to the amplitude and angular period of the torque ripple of the electric motor 4;
The estimated angular velocity estimated by the angular velocity estimation function unit 31 and the torque ripple frequency estimated from the angular period of the torque ripple are within a predetermined range of the peak frequency in the vibration characteristics, and the estimated torque ripple estimated by the torque ripple estimation function unit 32. and a motor torque limiting function unit 30 that limits the torque of the electric motor 4 so as to decrease when the amplitude exceeds the threshold value.
The predetermined range and the threshold are arbitrarily determined by design or the like, and are determined by finding an appropriate range and threshold through one or both of tests and simulations, for example.

According to this configuration, even when a constant torque is desired to be output, torque ripple occurs in the electric motor 4. Therefore, when the torque ripple occurs at a frequency roughly matching the peak frequency of the vibration characteristics, the motor torque is limited. As a result, it is possible to prevent the vibration characteristic from being excited by the torque ripple, thereby improving the operation noise and the control accuracy.

The control device 2 has a function of following and controlling the electric motor 4 so that the estimated braking force follows a given braking force command value,
In this braking force follow-up control, the control device 2 controls and calculates at least one of motor torque, motor current, and motor voltage as a manipulated variable for causing the estimated braking force to reach the braking force command value. has the function of
The vibration attenuation processing unit 24 has a filter 24a that attenuates the gain of the peak frequency in the vibration characteristics to a predetermined gain or less for at least one of the motor torque, the motor current, and the motor voltage that have been controlled and calculated. may have
The predetermined gain is a gain that is arbitrarily determined by design or the like, and is determined, for example, by obtaining an appropriate gain through either one or both of tests and simulations.

The control device 2 has a function of following and controlling the electric motor so that the estimated braking force follows a given braking force command value,
In this braking force follow-up control, the control device 2 controls and calculates at least one of motor torque, motor current, and motor voltage as a manipulated variable for causing the estimated braking force to reach the braking force command value. has the function of
The vibration attenuation processing unit 24 has a brake control controller 22a that sets a parameter including a control gain used in the control calculation to a value that attenuates the gain of the peak frequency in the vibration characteristic to a predetermined gain or less. There may be.
The predetermined gain is a gain that is arbitrarily determined by design or the like, and is determined, for example, by obtaining an appropriate gain through either one or both of tests and simulations.

The electric brake device of the present invention comprises a brake rotor, a friction material that generates a braking force in contact with the brake rotor, an electric motor, and a friction material operation that converts the output of the electric motor into a pressing force of the friction material. means and a control device for controlling the electric motor, wherein the control device controls the rigidity of members including the friction material and the friction material operating means and the inertia of the friction material operating means. It has a vibration damping processing unit that attenuates the gain of the vibration characteristic below a predetermined gain at the peak frequency that forms the peak gain in the vibration characteristic consisting of the gain and frequency of the spring vibration system that is expressed. Therefore, it is possible to suppress vibration caused by the inertia and rigidity of each component of the electric brake device, thereby enabling highly accurate brake control.

1 is a diagram schematically showing an electric brake device according to an embodiment of the invention; FIG. It is a block diagram of a control system of the electric brake device. It is a figure which shows the example of the damping characteristic which suppresses a vibration by the same electric brake device. It is a block diagram which shows the implementation example of the various arithmetic function parts of the same electric brake device. FIG. 5 is a block diagram showing an example of implementation of various arithmetic function units of an electric brake device according to another embodiment of the present invention; FIG. 4 is a block diagram of a control system of an electric brake device according to still another embodiment of the invention; It is a block diagram which shows the implementation example of the various arithmetic function parts of the same electric brake device. It is a block diagram which shows the modification of the implementation example of the various arithmetic function parts of the same electric brake device. It is a block diagram which shows the other modified example of the implementation example of the various arithmetic function parts of the same electric brake device. It is a block diagram which shows the other modified example of the implementation example of the various arithmetic function parts of the same electric brake device. It is a block diagram which shows the other modified example of the implementation example of the various arithmetic function parts of the same electric brake device. FIG. 4 is a block diagram of a control system of an electric brake device according to still another embodiment of the invention; It is a block diagram which shows the implementation example of the various arithmetic function parts of the same electric brake device. It is a figure which shows the example which restrict|limits a motor torque by a predetermined motor angular velocity by the electric brake device. It is a figure which shows the example of the damping characteristic which suppresses a vibration with one of electric brake devices. It is a figure which shows the other example of the damping characteristic which suppresses a vibration with one of electric brake devices.

An electric brake device according to an embodiment of the invention will be described with reference to FIGS. 1 to 4. FIG. This electric brake device is mounted on a vehicle, for example.
As shown in FIG. 1, this electric brake device 1 includes an electric linear motion actuator DA and a friction brake BR. First, the structures of the electric linear motion actuator DA and the friction brake BR will be described.

<Structures of Electric Linear Actuator DA and Friction Brake BR>
As shown in FIGS. 1 and 2, the electric linear motion actuator DA includes an actuator main body AH and a control device 2, which will be described later. The actuator main body AH has an electric motor 4, a deceleration mechanism 5, a linear motion mechanism 6 as friction material operating means, a parking brake mechanism 7, an angle sensor Sa, and a load sensor Sb.

The electric motor 4 is preferably composed of a permanent magnet type synchronous motor because it saves space and provides high torque. can also

As shown in FIG. 1, the friction brake BR has a brake rotor 8 that rotates in conjunction with the wheels of the vehicle, and a friction member 9 that comes into contact with the brake rotor 8 to generate a braking force. This friction material 9 is arranged in the vicinity of the brake rotor. A mechanism can be used in which the friction member 9 is pressed against the brake rotor 8 by operating the actuator main body AH to generate a braking force by the frictional force. The brake rotor 8 and friction material 9 may be, for example, a disc brake device using a brake disc and caliper, or a drum brake device using a drum and lining.

The deceleration mechanism 5 is a mechanism that decelerates rotation of the electric motor 4 and includes a primary gear 12 , an intermediate gear 13 and a tertiary gear 11 . In this example, the reduction mechanism 5 reduces 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 it to the tertiary gear 11 fixed to the end of the rotating shaft 10. It is possible.

The linear motion mechanism 6 is a mechanism that converts the rotary motion output by the reduction mechanism 5 into linear motion of the linear motion portion 14 by means of a feed screw mechanism, and causes the friction material 9 to contact and separate from the brake rotor 8 . The direct-acting portion 14 is detented and supported so as to be movable in the axial direction indicated by arrow A1. A friction material 9 is provided at the outboard side end of the direct acting portion 14 . By transmitting the rotation of the electric motor 4 to the linear motion mechanism 6 via the reduction mechanism 5, the rotary motion is converted into linear motion, which is converted into the pressing force of the friction material 9, thereby generating braking force. . When the electric brake device 1 is mounted on the vehicle, the outer side of the vehicle in the vehicle width direction is referred to as the outboard side. The center side of the vehicle in the vehicle width direction is called the inboard side.

A linear solenoid, for example, is applied as the actuator 16 of the parking brake mechanism 7 . The locking member 15 is advanced by the actuator 16 and engaged by being fitted into a locking hole (not shown) formed in the intermediate gear 13, and by prohibiting the rotation of the intermediate gear 13, the parking lock state is established. to By removing the locking member 15 from the locking hole, the rotation of the intermediate gear 13 is permitted, and the unlocked state is established.

As shown in FIG. 2 , the angle sensor Sa detects the rotation angle of the electric motor 4 . For the angle sensor Sa, for example, a resolver, a magnetic encoder, or the like is preferably used because of its high performance and reliability, but various sensors such as an optical encoder can also be used. Instead of using the angle sensor Sa, for example, angle sensorless estimation may be used in which the motor angle is estimated from the relationship between the voltage and the current of the electric motor 4 in the control device 2, which will be described later.

The load sensor Sb detects displacement or deformation of a predetermined portion on which the load of the linear motion mechanism 6 acts. As such a load sensor Sb, for example, a magnetic sensor, a strain sensor, a pressure sensor, or the like can be used. Without using the load sensor Sb, the control device 2 may perform load sensorless estimation from the motor angle, the rigidity of the electric brake device, the motor current, the efficiency of the electric linear motion actuator DA, and the like. Also, various sensors such as thermistors may be provided separately according to requirements.

<Regarding the control device 2>
Each control device 2 controls a corresponding electric motor 4 . Each control device 2 is connected to a power supply device 3 and a host ECU 17 which is a host control means of each control device 2 . The power supply device 3 supplies electric power to the electric motor 4 and the control device 2 . For the power supply device 3, for example, a low-voltage (for example, 12V) battery of a vehicle in which the electric brake device 1 (FIG. 1) is mounted can be applied.

As the host ECU 17, for example, an electric control unit (VCU) that controls the vehicle in general is applied. Alternatively, a dedicated ECU for integrated control of the electric brake device may be used, or a predetermined electric brake control device among a plurality of electric brake devices may also have the functions of a higher-level ECU. The high-level ECU 17 has an integrated control function for each control device 2 . The higher-level ECU 17 includes command means 17a, and the command means 17a outputs a target brake force command value to each control device 2 in accordance with the output of a sensor that changes according to the amount of operation of brake operation means (not shown). Output. Note that the command means 17a can also output brake force command values to each control device 2, for example, by judging braking in an automatically driven vehicle without relying on the operation of the brake operation means.

Each control device 2 includes various control calculation function units that perform control calculations, and a motor driver 18 . The various control arithmetic function units are configured by, for example, a processor such as a microcomputer, or an arithmetic unit such as FPGA or ASIC, and peripheral circuits. The various control calculation function units have a load estimation function unit 19, a position estimation function unit 20, and a brake control function unit 21, which are brake force estimation means.

The load estimation function unit 19 estimates the axial load (estimated load) of the linear motion mechanism 6 from the output of the load sensor Sb or the like as a value that can be equivalent to the braking force. Alternatively, when load sensorless estimation is performed, the load estimation function unit 19 may be configured to estimate the axial load of the linear motion mechanism 6 using information such as the motor angle and current. If the coefficient of friction of the friction brake is fixed in the load estimation function unit 19, the estimated load can be converted into an estimated braking force.

The position estimation function unit 20 has a function of estimating the axial position of the linear motion unit 14 (FIG. 1) of the linear motion mechanism 6 from the output of the angle sensor Sa or the like. Alternatively, the position estimating function unit 20 may estimate an amount that can correspond to the position, such as the motor angle, from the output of the angle sensor Sa or the like. When the angle sensorless estimation is performed, the position estimation function unit 20 estimates the position of the linear motion mechanism 6 (the axial position of the linear motion unit 14 (FIG. 1)) from the relationship between the voltage and the current of the electric motor 4. You may

The brake control function unit 21 has a control calculation unit 22 and a vibration damping processing unit 24 . The control calculation unit 22 performs follow-up control of the electric motor 4 so that the estimated brake force estimated by the load estimation function unit 19 from the output of the load sensor Sb or the like follows the brake force command value requested by the command means 17a. do.

The control calculation unit 22 may, for example, use feedback control that directly uses the braking force command value and the estimated braking force, or may convert the braking force into another physical quantity such as an angle to perform control calculations. The feedback control calculation may be, for example, a calculation structure in which a plurality of minor feedback loops are provided such that a motor current control loop is provided in a braking force control loop, and a structure in which the motor operation amount is calculated in a single feedback loop. may be Alternatively, feedforward control or the like may be used, or may be used in combination as appropriate.

The vibration attenuation processing unit 24 attenuates the gain of the vibration characteristic below a predetermined gain at the peak frequency forming the peak gain in the vibration characteristic.
The vibration characteristic consists of the gain and frequency of the spring vibration system represented by the stiffness and inertia of the constituent members, which will be described later. The gain of the spring vibration system represents the amplification factor of the transmission characteristic of the braking force τ _B (s) with respect to the torque (motor torque) τ _M (s) of the electric motor 4 that fluctuates at a predetermined frequency. The frequency of the spring vibration system is synonymous with the fluctuation frequency of the manipulated variables such as torque, voltage, and current.

The constituent members include the friction material 9 ( FIG. 1 ) and the linear motion mechanism 6 . Said inertia consists of the mass of said component. In the case of a disc brake, the constituent members include a pad (friction material), a caliper, a direct acting actuator, and the like. In the case of a drum brake, the structural members include a direct acting actuator and the like.

When the rigidity of the component members, which is the spring rate κ, and the inertia, which is the mass m of the component members, are known in advance by tests, simulations, or the like, the electric brake device is, for example, It is not necessary to store the unique vibration characteristics in a storage unit or the like (not shown) and estimate the vibration characteristics each time.

The vibration attenuation processing unit 24 attenuates the gain of the vibration characteristic below a predetermined gain at the peak frequency forming the peak gain in the vibration characteristic (vibration component). In the gain curve of the Bode diagram of the closed loop system, the maximum value is called "peak gain", and the frequency at that time is called "peak frequency". The vibration damping processing section 24 has a function of adjusting the brake control calculation parameter with the vibration component having the frequency characteristic as the vibration damping target.

The vibration damping processor 24 is, for example, a filter such as a low-pass filter or a band-pass filter, which will be described later, and the function of adjusting the brake control calculation parameter may be a function of adjusting the cutoff frequency of the filter. In this case, a filter corresponding to vibration characteristics is provided as the vibration damping processor 24 . When the manipulated variable input to this filter is the torque command value, the torque command value is attenuated according to the filter function, thereby attenuating the gain of the vibration characteristic to a predetermined gain or less. When the manipulated variable input to the filter is voltage or current, the voltage or current is attenuated according to the filter function, thereby attenuating the gain of the vibration characteristic to a predetermined gain or less. Alternatively, the vibration attenuation processing unit 24, for example, has a function of setting the control calculation parameter in the control calculation unit 22 so that the control characteristic suppresses the peak gain in the frequency characteristic estimated by the vibration characteristic estimation unit 23. good.

As shown in FIG. 2 , the motor driver 18 converts the DC power of the power supply device 3 into AC power used to drive the electric motor 4 based on the control signal given from the brake control function unit 21 . If the motor driver 18 constitutes a half-bridge circuit including switch elements such as FETs, for example, and is configured to perform PWM control that determines the voltage applied to the motor according to a predetermined duty ratio, it is inexpensive and has high performance. Alternatively, a transformer circuit or the like (not shown) may be provided to perform PAM control.

<Example of damping characteristics that suppress vibration>
FIG. 3 is a diagram showing an example of damping characteristics for suppressing vibration by the vibration damping processor 24 (FIG. 2) of this electric brake device. Henceforth, it demonstrates, also referring FIG. 2 suitably. FIG. 3 shows an example in which the attenuation characteristic is a low-pass filter characteristic. The upper diagram in FIG. 3 shows the vibration characteristics found by testing, simulation, or the like. The vibration damping processing unit 24 sets the damping characteristic shown in the lower diagram of FIG. 3 so that the damping rate is greater than a predetermined value at least at the peak frequency that forms the peak gain with respect to the vibration characteristic shown in the upper diagram of FIG. The attenuation characteristic may be, for example, the characteristic of a filter shown in FIG. 4 or the like, which will be described later, or the characteristic of a control system controlled by a controller shown in FIG. 8 or the like, which will be described later.

<Example of implementation of various calculation function parts>
FIG. 4 is a block diagram showing an implementation example of various arithmetic function units of this electric brake device. In FIG. 4, the "vibration suppression filter 24a" provided for the torque command value applied from the brake controller 22a to the current controller 22b corresponds to the vibration damping processor 24 in FIG. The brake control controller 22a and the current control controller 22b in FIG. 4 correspond to the control calculation section 22 in FIG. The characteristics of the vibration suppression filter 24a are determined by the vibration characteristics of the spring coupling system consisting of the inertia and rigidity of the electric brake device.

If the vibration suppression filter 24a is a low-pass filter, for example, it attenuates the input torque command value as the frequency becomes higher. The damped torque command value is output from the vibration suppression filter 24a and input to the current controller 22b. For example, when the vibration suppression filter 24a is a bandpass filter, it attenuates a predetermined frequency band of the torque command value to be input. This torque command value is output and input to the current controller 22b. Also, the torque command value may be another physical quantity having a strong rank correlation with torque, such as a current norm command value.

<Effect>
According to the electric brake device 1 described above, the vibration attenuation processing unit 24 attenuates the gain of the vibration characteristic to a predetermined gain or less at the peak frequency forming the peak gain in the vibration characteristic. If the peak frequency forming the peak gain is captured and the gain of the vibration characteristic is attenuated, the vibration can be converged and suppressed more efficiently. Therefore, the vibration caused by the inertia, the rigidity, etc. is suppressed, and high-precision brake control becomes possible.

<About other embodiments>
In the following description, the same reference numerals are given to the parts corresponding to the items previously described in each embodiment, and duplicate descriptions are omitted. When only a portion of the configuration is described, the other portions of the configuration are the same as those previously described unless otherwise specified. The same configuration has the same effect. It is possible not only to combine the parts specifically described in each embodiment, but also to partially combine the embodiments if there is no particular problem with the combination.

As shown in FIG. 5, in contrast to FIG. 4, a vibration suppression filter 24a may be provided for the electric motor voltage, which is the manipulated variable of the current controller 22b. For example, if the vibration suppression filter 24a is a low-pass filter, the higher the frequency of the input voltage, the more attenuated it becomes. The damped voltage is output from the vibration suppressing filter 24 a and input to the electric motor 4 . The vibration suppression filter 24a, for example, when it is a bandpass filter, attenuates a predetermined frequency band of the input voltage.
4 and 5 show an example in which the vibration suppression filter 24a having a filtering function is provided. The control gain or the like of the brake control controller 22a may be set so as to have characteristics equivalent to . Alternatively, the control gain or the like of the current controller 22b may be set so that the characteristics of the current control system configured in the current controller 22b are equivalent to the characteristics of the vibration suppressing filter 24a. These control gains are also set according to the vibration characteristics.

As shown in FIG. 2, the brake control function unit 21 in the control device 2 may include a vibration characteristic estimation unit 23 that estimates the vibration characteristic in accordance with a physical input related to the rigidity of the component. . In this case, the vibration attenuation processing unit 24 attenuates the gain of the vibration characteristic to a predetermined gain or less at the peak frequency forming the peak gain in the vibration characteristic estimated by the vibration characteristic estimation unit 23 . If the vibration properties are already known and unchanged, there is no need to estimate the vibration properties. However, when the rigidity of the electric brake device changes greatly according to the brake load, the vibration characteristics may also change.

Therefore, the vibration characteristic estimator 23 estimates the vibration characteristic according to the input of the physical quantity related to stiffness. A physical quantity related to stiffness is, for example, a brake load (estimated load). The estimated load is estimated by the load estimation function unit 19 . For the estimation of the stiffness, for example, analysis or actual measurement may be performed in advance, and an LUT or the like may be provided to obtain the stiffness according to the estimated load, or a predetermined stiffness calculation function may be used. As a result, it is possible to accurately estimate the stiffness that changes from moment to moment due to the brake load or the like. Therefore, vibration caused by inertia and rigidity is suppressed, and more precise brake control is possible.

FIG. 6 shows an example in which a brake stiffness estimating function unit 25 and a wear degree estimating function unit 26 are provided in addition to the example of FIG. The brake stiffness estimation function unit 25 estimates the stiffness of the electric brake device at the estimated brake force based on the estimated brake force estimated by the load estimation function unit 19 and the like. The brake stiffness estimation function unit 25 has a friction material stiffness estimation unit 27 and a device stiffness estimation unit 28 .

The friction material stiffness estimator 27 mainly estimates the stiffness of the friction material 9 . The device stiffness estimator 28 estimates, for example, the stiffness of the brake disc (brake rotor 8), caliper and actuator in a disc brake device, or the drum and actuator in a drum brake device. In addition, in the example of FIG. 6, the load estimating function unit 19 is limited to functions other than the load estimating function using the rigidity of the electric brake device.

The brake stiffness estimating function unit 25 has a function of estimating the stiffness of the electric brake device from the position estimated by the position estimating function unit 20 and the load estimated by the load estimating function unit 19 . Since the stiffness of the electric brake device greatly changes according to the brake load, it is preferable to estimate the stiffness of the electric brake device according to the estimated load. For the estimation of the stiffness, for example, analysis or actual measurement may be performed in advance, and an LUT or the like may be provided to obtain the stiffness according to the estimated load, or a predetermined stiffness calculation function may be used.

The wear degree estimation function unit 26 calculates the correlation between the estimated position estimated by the position estimation function unit 20 and the estimated load (estimated braking force) estimated by the load estimation function unit 19 when the friction material 9 is not worn. A current wear degree of the friction material 9 is estimated by comparing with a predetermined correlation between the estimated position and the estimated load.

The rigidity of the friction material 9 (FIG. 1) changes greatly as the wear progresses. For this reason, the wear degree estimating function unit 26 assumes, for example, that the stiffness is a combination of the stiffness of the friction material 9 including the degree of wear as a variable and the stiffness of other than the friction material, and the estimated position and the estimated load. Find the degree of wear that matches the actual result. The brake stiffness estimation function unit 25 adjusts the correlation parameter between the estimated brake force and the estimated stiffness based on the degree of wear estimated by the wear degree estimation function unit 26 .

For example, it is possible to provide a function of updating and correcting the LUT for obtaining the stiffness or the stiffness calculation function according to the degree of wear. The degree of wear is calculated by the wear degree estimation function unit 26, for example, using the least squares method or the like, using a predetermined stiffness calculation function that includes the degree of wear as a variable, and the correlation between the actually measured estimated position and the estimated load. It may have a function of identifying a degree of wear that is highly consistent with respect to.
By estimating the current stiffness of the electric brake device by the brake stiffness estimating function unit 25 and reflecting it in the calculation of the vibration characteristics in the vibration characteristic estimating unit 23, more accurate electric brake control becomes possible.

FIG. 7 is a block diagram showing an implementation example of various arithmetic function units of this electric brake device. FIG. 7 shows, in the embodiment shown in FIG. 6, the stiffness of each part of the electric brake device that exhibits non-linear characteristics depending on the brake force with respect to FIG. An example of providing a stiffness estimator 25a (corresponding to the brake stiffness estimation function unit 25 in FIG. 6) for estimating the stiffness of the device is shown. The relationship between the estimated braking force and the stiffness may be determined in advance by analysis or actual measurement, and determined in a LUT or the like that obtains the stiffness according to the estimated load, or the estimated stiffness may be calculated from the estimated braking force using a predetermined stiffness calculation function. may be calculated. The vibration characteristic estimator 23 estimates the vibration characteristic from the estimated stiffness and inertia. The characteristics of the vibration suppression filter 24a are determined by the vibration characteristics of the spring coupling system, which are estimated by the vibration characteristics estimator 23 and are composed of the inertia and stiffness of the electric brake device. It should be noted that, in the example of FIG. 5 described above as well, a configuration in which the stiffness estimator 25a is provided can be configured as in the example of FIG.

FIGS. 8 and 9 show the stiffness estimator for the case where the brake control controller 22a or current control controller 22b adjusts the control gain and the like so as to have similar control characteristics without providing a filter in the implementation example of FIG. 25a is applied. 8 and 9, the vibration characteristic estimator 23 estimates the vibration characteristic from the stiffness and inertia estimated by the stiffness estimator 25a. Each controller 22a, 22b adjusts the control gain of each controller 22a, 22b according to the vibration characteristics that change depending on the rigidity.

10 and 11 show, for each of the embodiments of FIGS. 7 and 8, the stiffness based on the degree of wear estimated by the degree-of-wear estimator 26a (corresponding to the degree-of-wear estimating function unit 26 in FIG. 6). An example of adjusting the parameters (LUT, arithmetic function, etc.) of the estimator 25a is shown. The degree of wear is mainly the degree of wear of the friction material 9 (FIG. 1). For example, the thickness of a disc brake pad (friction material) when it is not worn (new) is about several tens of millimeters, but the thickness that is regarded as the wear limit is several millimeters or less, and the pad rigidity is several times at maximum. A ten-fold change occurs.

Therefore, the degree of wear that occurs mainly in the friction material 9 (FIG. 1) is estimated by the degree of wear estimator 26a, and the stiffness is estimated by adjusting the predetermined parameter of the stiffness estimator 25a according to the degree of wear. The vibration characteristic estimator 23 estimates the vibration characteristic from the stiffness and inertia estimated by the stiffness estimator 25a. This makes it possible to achieve highly accurate brake control. Even when the wear degree estimator 26a is added to other embodiments, it can be applied only by changing the positions of some functional blocks.

FIG. 12 shows an example in which a motor excitation suppressing function unit 29 and a motor torque limiting function unit 30 are provided in addition to the example of FIG. The motor excitation suppression function unit 29 includes an angular velocity estimation function unit 31 that estimates the angular velocity of the electric motor 4 and a torque ripple estimation function unit 32 that estimates values corresponding to the amplitude and angular period of the torque ripple of the electric motor 4 .

The angular velocity estimating function unit 31 may, for example, have a function of estimating a differential equivalent value of the angle detected by the angle sensor Sa as an angular velocity, and estimates the angular velocity by an observer or the like using an equation of motion including motor inertia and the like. It can be a function.
The torque ripple estimating function unit 32 may have a function of estimating the torque ripple of the electric motor 4 based on the result obtained in advance by analysis or experiment, etc. from the electric motor drive conditions such as the motor current.

The motor torque limiting function unit 30 determines that the torque ripple frequency estimated from the estimated angular velocity estimated by the angular velocity estimation function unit 31 and the angular period of the torque ripple is within a predetermined range of the peak frequency in the vibration characteristics, and the torque ripple estimation function unit 32 When the estimated torque ripple amplitude estimated by the above exceeds the threshold value, the torque of the electric motor 4 is restricted to be small. The motor torque limiting function unit 30 can have a function of limiting the motor torque based on constraints such as the maximum motor current. This function may be provided in FIG. 2 or FIG.

As shown in FIG. 12 , based on the angular velocity estimation function unit 31 and the torque ripple estimation function unit 32, the motor excitation suppression function unit 29 controls the motor torque limit function unit 30 when a torque ripple exceeding a predetermined value occurs in a predetermined band. It can be a function to adjust the limit value and limit the electric motor torque. As a result, it is possible to prevent the torque ripple of the electric motor 4 from exciting the resonance gain based on the inertia and rigidity of the electric brake device.

Any one of the configurations shown in FIGS. 2, 6, and 12 may be employed, and for example, some or all of the components shown in FIGS. 6 and 12 may be used together.
In addition, configurations such as a current sensor (not shown) can be appropriately provided as necessary. Also, each function is provided as a block for convenience, and may be integrated or divided as necessary.

FIG. 13 is an implementation example of various arithmetic function units for the embodiment of FIG. A torque ripple estimator 32a in FIG. 13 corresponds to the torque ripple estimation function unit 32 in FIG. A torque limiter 30a in FIG. 13 corresponds to the motor torque limiting function unit 30 in FIG.
Even when a constant torque is desired to be output, torque ripple occurs in the electric motor 4. Therefore, when torque ripple occurs at a frequency substantially matching the peak frequency of vibration characteristics, the torque limiter 30a limits the motor torque. As a result, it is possible to prevent the vibration characteristic from being excited by the torque ripple, thereby improving the operation noise and the control accuracy.

FIG. 14 is a diagram showing an example of limiting the motor torque at a predetermined motor angular velocity by the electric brake device of FIG. 12. In FIG. Regarding motor torque, it is generally known that torque fluctuations (torque ripple) synchronizing with the rotation of the electric motor occur even if the specification outputs a constant torque. The torque ripple is generated at an integral multiple of the angular velocity (least common multiple of the number of poles and the number of slots). Therefore, the torque ripple estimator 32a (Fig. 13) estimates the torque ripple frequency from the motor angular velocity, and the torque limiter 30a (Fig. 13) detects the motor torque when the torque ripple frequency is near the peak frequency of the vibration system. limit. This can prevent the vibration system from being excited.

FIG. 15 shows an example in which the vibration attenuation processing unit 24 (FIG. 2, etc.) is a bandpass filter and the attenuation characteristic is a bandpass filter characteristic.
FIG. 16 shows an example in which the brake stiffness estimating function unit 25 (see FIG. 7, etc.) adjusts the damping characteristic in accordance with the change in the vibration characteristic that accompanies the change in stiffness. Vibration characteristics before the stiffness change are represented by solid lines in the upper diagram of FIG. 16, and vibration characteristics after the stiffness changes are represented by dotted lines in the upper diagram of FIG. The damping characteristics before the stiffness change are represented by solid lines in the lower diagram of FIG. 16, and the damping characteristics after the stiffness changes are represented by dotted lines in the lower diagram of FIG.

As the conversion mechanism of the linear motion mechanism 6, various screw mechanisms such as planetary rollers and ball screws, mechanisms utilizing inclination such as ball ramps, and the like can be used.
The load sensor Sb may be an external sensor such as a sensor that detects the wheel torque of a wheel on which a brake is mounted, or the longitudinal force of a vehicle equipped with an electric brake device, instead of the sensor described above.

As mentioned above, although the form for implementing this invention was demonstrated based on embodiment, embodiment disclosed this time is an illustration and is not restrictive at all points. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

DESCRIPTION OF SYMBOLS 1... Electric brake device 2... Control device 4... Electric motor 6... Linear motion mechanism (friction material operating means)
8... Brake rotor 9... Friction material 19... Load estimating function unit (brake force estimating means)
20 Position estimating function unit 22a Brake control controller 23 Vibration characteristic estimating unit 24 Vibration damping processing unit 25 Brake stiffness estimating function unit 26 Wear degree estimating function unit 30 Motor torque limiting function unit 31 Angular velocity estimating function unit 32 Torque ripple estimation function unit

Claims (5)

A brake rotor, a friction material that generates a braking force in contact with the brake rotor, an electric motor, a friction material operating means that converts the output of the electric motor into a pressing force of the friction material, and controls the electric motor. In an electric brake device comprising a control device that
The control device is
At the peak frequency that forms the peak gain in the vibration characteristics consisting of the gain and frequency of the spring vibration system expressed by the rigidity of the member including the friction material and the friction material operating means and the inertia of the friction material operating means, a vibration damping processing unit that damps the gain of the vibration characteristic to a predetermined gain or less ;
The control device has a vibration characteristic estimator that estimates the vibration characteristic according to the input of the physical quantity related to the stiffness, and the vibration damping processor performs , at a peak frequency forming a peak gain, attenuating the gain of the vibration characteristic below a defined gain;
The control device is
braking force estimating means for estimating a braking force corresponding to a contact force between the friction material and the brake rotor by the friction material manipulating means;
a brake stiffness estimation function unit for estimating the stiffness of the electric brake device at the estimated brake force based on the estimated brake force estimated by the brake force estimation means;
The vibration characteristic estimating section estimates the vibration characteristic using the estimated stiffness estimated by the brake stiffness estimating function section . 2. The electric brake device according to claim 1 , wherein the control device comprises:
a position estimation function unit that estimates the position of the friction material operating means;
The correlation between the estimated position estimated by the position estimation function unit and the estimated braking force is compared with a predetermined correlation between the estimated position and the estimated braking force when the friction material is not worn, and the current a wear degree estimating function unit for estimating the degree of wear of the friction material;
The brake stiffness estimation function unit has a function of adjusting a correlation parameter between the estimated brake force and the estimated stiffness based on the estimated wear degree estimated by the wear degree estimation function unit. A brake rotor, a friction material that generates a braking force in contact with the brake rotor, an electric motor, a friction material operating means that converts the output of the electric motor into a pressing force of the friction material, and controls the electric motor. In an electric brake device comprising a control device that
The control device is
At the peak frequency that forms the peak gain in the vibration characteristics consisting of the gain and frequency of the spring vibration system expressed by the rigidity of the member including the friction material and the friction material operating means and the inertia of the friction material operating means, a vibration damping processing unit that damps the gain of the vibration characteristic to a predetermined gain or less;
The control device is
an angular velocity estimating function unit that estimates the angular velocity of the electric motor;
a torque ripple estimation function unit that estimates a value corresponding to the amplitude and angular period of the torque ripple of the electric motor;
The estimated angular velocity estimated by the angular velocity estimation function unit and the torque ripple frequency estimated from the angular period of the torque ripple are within a predetermined range of the peak frequency in the vibration characteristics, and the estimated torque ripple amplitude estimated by the torque ripple estimation function unit is and a motor torque limiting function unit that limits the torque of the electric motor so as to decrease when the threshold value is exceeded. 3. The electric brake device according to claim 1 , wherein the control device has a function of following and controlling the electric motor so that the estimated braking force follows a given braking force command value,
In the brake force follow-up control, the control device controls and calculates at least one of motor torque, motor current, and motor voltage as a manipulated variable for causing the estimated brake force to reach the brake force command value. have the function
The vibration attenuation processing unit has a filter that attenuates the gain of the peak frequency in the vibration characteristics to a predetermined gain or less for at least one of the motor torque, the motor current, and the motor voltage that are controlled and calculated. electric brake device. 3. The electric brake device according to claim 1 , wherein the control device has a function of following and controlling the electric motor so that the estimated braking force follows a given braking force command value,
In the brake force follow-up control, the control device controls and calculates at least one of motor torque, motor current, and motor voltage as a manipulated variable for causing the estimated brake force to reach the brake force command value. have the function
The vibration attenuation processing unit has a brake control controller that sets a parameter including a control gain used in the control calculation to a value that attenuates a gain of a peak frequency in the vibration characteristic to a predetermined gain or less.

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