阅读说明：本技术 制动控制装置和制动控制方法 (Brake control device and brake control method ) 是由 伊多仓京士朗 伊藤贵广 松原谦一郎 后藤大辅 松浦谅 于 2019-10-17 设计创作，主要内容包括：本发明提供一种制动控制装置和制动控制方法,对于因温度变化或制动垫的不均磨损、制动盘的倾斜等而引起的刚性变化,能够低存储器负荷地、并且直到与计测范围相比推力更大的区间都高精度地进行推算。本发明的控制制动单元的制动控制装置中,所述制动单元包括能够被推压于被制动部件的摩擦部件、与所述摩擦部件抵接并能够在电动机的旋转驱动下在直线运动方向上移动的活塞、以及检测所述摩擦部件对所述被制动部件的推力的推力检测部,基于作为相对于所述活塞位置为第一斜率的推力变化的第一活塞范围、以及作为相对于所述活塞位置为与所述第一斜率不同的第二斜率的推力变化的第二活塞范围,来推算所述活塞位置与推力的关系作为所述制动单元的刚性。(The invention provides a brake control device and a brake control method, which can estimate rigidity change caused by temperature change, uneven abrasion of a brake pad, inclination of a brake disc and the like with low memory load and high precision until a section with larger thrust compared with a measurement range. In the brake control device for controlling a brake unit according to the present invention, the brake unit includes a friction member that can be pressed against a member to be braked, a piston that is in contact with the friction member and is movable in a linear motion direction by rotational driving of a motor, and a thrust detection unit that detects a thrust force of the friction member against the member to be braked, and the rigidity of the brake unit is estimated based on a first piston range in which the thrust force changes at a first inclination with respect to the piston position and a second piston range in which the thrust force changes at a second inclination different from the first inclination with respect to the piston position.)

1. A brake control device that controls a brake unit including a friction member that can be pressed against a member to be braked, a piston that is in contact with the friction member and is movable in a linear motion direction by rotational driving of a motor, and a thrust force detection unit that detects a thrust force of the friction member against the member to be braked, characterized in that:

the relationship between the piston position and the thrust force is estimated as the rigidity of the brake unit based on a first piston range that is a change in the thrust force having a first slope with respect to the piston position and a second piston range that is a change in the thrust force having a second slope different from the first slope with respect to the piston position.

2. The brake control apparatus according to claim 1, characterized in that:

estimating the stiffness based on a difference in positions of the first piston range and the second piston range.

3. The brake control apparatus according to claim 1, characterized in that:

the first piston range is a range of restoring force of deflection in which deflection occurs in the brake unit and the friction member makes one-side contact,

the second piston range is a range of pressing force after the friction member is in direct contact with the braked member.

4. The brake control apparatus according to claim 1, characterized in that:

estimating the rigidity based on a third piston range that is a variation in thrust force with respect to the piston position at a third slope different from the first slope and the second slope.

5. The brake control apparatus according to claim 1, characterized in that:

has a rigid estimation model learning unit for learning a rigid estimation model,

and performing sequential learning on an estimation model for estimating the rigidity.

6. A brake control method for controlling a motor of a brake unit that presses a friction member, characterized by:

the relationship between the piston position and the thrust force is estimated as the rigidity of the brake unit based on a first piston range that is a change in the thrust force having a first slope with respect to the piston position and a second piston range that is a change in the thrust force having a second slope different from the first slope with respect to the piston position.

7. The brake control method according to claim 6, characterized in that:

estimating the stiffness based on a difference in positions of the first piston range and the second piston range.

8. The brake control method according to claim 6, characterized in that:

the first piston range is a range of restoring force of deflection in which deflection occurs in the brake unit and the friction member makes one-side contact,

the second piston range is a range of pressing force after the friction member is in direct contact with the braked member.

9. The brake control method according to claim 6, characterized in that:

estimating the rigidity based on a third piston range that is a variation in thrust force with respect to the piston position at a third slope different from the first slope and the second slope.

10. The brake control method according to claim 6, characterized in that:

and performing sequential learning on an estimation model for estimating the rigidity.

Technical Field

The present invention relates to a structure of a brake system and control thereof, and particularly to a technique effective for application to electric braking of a motor vehicle requiring high control accuracy and responsiveness.

Background

Vehicles such as automobiles are equipped with a brake system that applies a braking force to wheels in accordance with the amount of depression of a brake pedal by a driver. The brake system has been a hydraulic system in many cases, and recently, an electric system is increasing.

In a brake system using an electric system, since the brake piston can be pulled back which is difficult to achieve in a hydraulic system, a clearance control for setting a required clearance between the brake pad and the brake disc can be performed, and improvement in fuel efficiency due to reduction in drag of the brake pad can be expected.

Further, when the pedal is depressed, the brake pad is brought into contact with the pedal by the gap control, and then the braking force is controlled by using the pressing force between the brake pad and the brake disc detected by the strain sensor or the like.

In this control, it is important to perform a control based on the stiffness characteristic of the caliper indicating the relationship between the position of the brake piston and the braking force, thereby controlling the braking force with high response and high accuracy, and improving safety and brake feeling.

As a technique for controlling the stiffness characteristics of the clip, for example, a technique described in patent document 1 is known. Patent document 1 discloses: "a brake control apparatus for a vehicle, comprising: a brake control unit that controls, independently for each wheel, a movement amount of a brake friction member in a brake unit that generates a braking force in the wheel; a storage unit for storing driving data required for controlling the movement amount; a vehicle running state detection unit that detects a physical quantity indicating a running state of the vehicle; and a vehicle control unit that controls a vehicle running state via the brake control unit of each wheel based on the physical quantity; the brake control device for a vehicle is characterized in that: the vehicle control means acquires control data obtained as a result of the brake means controlling the running state of the vehicle, and corrects and updates the drive data stored in the storage means using the acquired control data, thereby making it possible to generate the same pressing force "on the left and right wheels regardless of an error in the current sensor value and a change in the actuator rigidity caused by an aged change in the brake actuator.

Further, patent document 2 discloses: "an electric brake device includes a caliper including a motor, and in which a pressing member that presses a brake pad against a brake disc is pushed by the motor; and a control unit that calculates a pressing force command value of the pressing member against the brake pad in accordance with a brake instruction signal and controls the motor based on the pressing force command value, wherein the control unit estimates thrust of the pressing member from a rotational position of the motor, and wherein the control unit includes caliper rigidity estimation means that estimates rigidity of the caliper in accordance with a frequency at which the pressing member presses the brake pad and changes the pressing force command value of the brake pad calculated from the brake instruction signal in accordance with a result of the estimation of the rigidity, whereby a required braking force can be generated even if the rigidity of the caliper changes in an electric brake device that estimates thrust of the pressing member from the rotational position of the motor.

Further, patent document 3 discloses: "a brake device includes a thrust mechanism that presses a brake pad against a disc rotor, an actuator that drives the thrust mechanism, a pressing force detection unit that detects a pressing force generated by the thrust mechanism, a position detection unit that detects a displacement of the thrust mechanism, and a control unit that controls the actuator so as to generate a braking force in accordance with a pressing force signal of the pressing force detection unit and a brake instruction signal of a vehicle, wherein the control unit includes an abnormality detection unit that detects an abnormality of the pressing force detection unit based on a relative relationship between the pressing force signal of the pressing force detection unit and the displacement signal of the position detection unit, thereby being able to accurately detect an abnormality of a piston thrust sensor".

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2007-161154

Patent document 2: japanese patent laid-open No. 2008-184023

Patent document 3: japanese patent laid-open No. 2005-106153

Disclosure of Invention

Problems to be solved by the invention

In patent document 1, the control performance of the vehicle stabilization control is improved in response to a change in rigidity such as deterioration with age by updating the rigidity map data based on the data of the vehicle behavior in the vehicle stabilization control. However, according to this configuration, since the vehicle operation is updated after becoming unstable as a result of braking, there is a possibility that safety may be deteriorated if a rapid rigidity change occurs.

In addition, in patent document 2, by acquiring the rigidity characteristics from the measurement values of the position sensor and the thrust sensor and changing the rigidity characteristics according to the length of the data acquisition interval, the rigidity change corresponding to the temperature change can be appropriately estimated, and the controllability can be improved. However, since the stiffness table is generated based on the measured values, it is difficult to accurately estimate the stiffness characteristic of the high thrust section that has not been generated at the time of braking in the previous cycle, and since the stiffness characteristic is changed according to the time interval, it can be estimated only appropriately for the temperature change of the caliper, and it is difficult to estimate the time-independent change such as uneven wear of the brake pad and the inclination of the brake disc.

On the other hand, patent document 3 describes an example in which the stiffness characteristic is used for determining a failure of the thrust sensor, and describes that the stiffness characteristic is generated by polynomial approximation of a plurality of measurement points. According to the rigidity estimation method of patent document 3, there is a risk that the rigidity estimation accuracy is reduced by the approximation error, and further, since analysis of a large number of measurement points is required to improve the accuracy, there is a possibility that the memory load is increased.

Accordingly, an object of the present invention is to provide a brake control device and a brake control method that can estimate a change in rigidity due to a temperature change, uneven wear of a brake pad, inclination of a brake disc, or the like with high accuracy, with a low memory load, and up to a section where a thrust is larger than a measurement range.

Means for solving the problems

In order to solve the above-described problems, the present invention provides a brake control device for controlling a brake unit including a friction member that can be pressed against a member to be braked, a piston that is in contact with the friction member and is movable in a linear motion direction by rotational driving of a motor, and a thrust detection unit that detects a thrust force of the friction member against the member to be braked, wherein a relationship between the piston position and the thrust force is estimated as a stiffness of the brake unit based on a first piston range that is a change in the thrust force with respect to the piston position with a first gradient and a second piston range that is a change in the thrust force with respect to the piston position with a second gradient different from the first gradient.

Further, the present invention is a brake control method for a motor that controls a brake unit that presses a friction member, characterized in that: the relationship between the piston position and the thrust force is estimated as the rigidity of the brake unit based on a first piston range that is a change in the thrust force having a first inclination with respect to the piston position and a second piston range that is a change in the thrust force having a second inclination different from the first inclination with respect to the piston position.

Effects of the invention

According to the present invention, it is possible to provide a brake control device and a brake control method that can estimate a change in rigidity due to a temperature change, uneven wear of a brake pad, inclination of a brake disk, or the like with high accuracy at a low memory load and up to a section where a thrust is larger than a measurement range.

This makes it possible to perform stable braking control regardless of a change in rigidity, and to improve safety and feeling during braking.

Problems, structures, and effects other than those described above will be described with reference to the following embodiments.

Drawings

Fig. 1 is a schematic view of a brake system of embodiment 1.

Fig. 2 is a functional block diagram of the rigidity estimating unit according to embodiment 1.

Fig. 3 is a flowchart showing a rigidity estimation operation method according to embodiment 1.

Fig. 4 is a conceptual diagram illustrating the principle of generating the rigidity characteristic in embodiment 1.

Fig. 5 is a conceptual diagram of the calculation of the rigidity calculation unit in example 1.

Fig. 6 is a conceptual diagram of the effect of the invention of embodiment 1.

Fig. 7 is a functional block diagram of the rigidity estimating unit according to embodiment 2.

Fig. 8 is a functional block diagram of the rigidity estimating unit according to embodiment 3.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted for overlapping portions. The present invention is not limited to the following examples, and various modifications and application examples of the technical concept of the present invention are included in the scope thereof.

Example 1

A brake system of embodiment 1 of the present invention is explained with reference to fig. 1 to 6. Fig. 1 is a schematic diagram of a brake system according to the present embodiment, and shows a configuration corresponding to electric braking of one of a plurality of wheels of a vehicle.

As shown in fig. 1, a brake system 1 of the present embodiment includes a drive mechanism 2, a brake control device 10, a brake mechanism 11, and a rotation/linear motion conversion mechanism 12 as main components. Among them, the drive mechanism 2 is composed of a motor 2a and a reduction gear 2 b. The brake control device 10 incorporates a thrust control unit (motor controller) 3 and a rigidity estimation unit 4. The brake mechanism 11 is disposed so that a brake pad (friction member) 11a and a brake disk (braked member) 11b can be brought into contact with and separated from each other. The rotation/linear motion converting mechanism 12 is composed of a piston 12a and a feed screw 12b, and is substantially rod-shaped in the present embodiment.

In fig. 1, a unit (brake unit) including the drive mechanism 2, the brake pad 11a, and the rotation/linear motion conversion mechanism 12 is referred to as a caliper 5. The caliper 5 functions to press the brake pad 11a against the brake disc 11b, and can achieve braking by friction.

In this brake system 1, a rotational driving force generated by a motor 2a is decelerated by a speed reducer 2b, the decelerated rotational driving force is converted into a linear driving force via a feed screw 12b, and a brake pad 11a is pressed against a brake disc 11b by linear driving of a piston 12a, thereby applying a braking force to the rotating brake disc 11 b. Hereinafter, the direction in which the piston 12a approaches the brake disk 11b is defined as a positive direction (+), and the opposite direction is defined as a negative direction (-).

When the above braking operation is performed, the thrust control unit (motor controller 3) in the brake control device 10 controls the rotation speed and position of the motor 2a to adjust the pressing force of the brake pad 11 a. The brake control device 10 estimates the braking force of the brake pad 11a based on the thrust detected by the thrust sensor 31 provided in the rotational/linear motion conversion mechanism 12. Further, the brake control device 10 estimates the position of the brake pad 11a based on the rotational position detected by the position sensor 32 provided in the motor 2 a. In addition, the position sensor 32 may be attached to the piston 12a so that the position of the piston 12a can be directly detected.

Here, the brake control device 10 is connected with a control signal line 21, communication lines 22 and 23, and a main power line 26. The thrust control unit 3 and the rigidity estimating unit 4 inside are connected to each other by communication lines 24 and 25. Among them, the Control signal line 21 inputs a Control command from a higher-level Control device such as a vehicle Control ECU (Electronic Control Unit) to the brake Control device 10, and the communication lines 22 and 23 communicate information other than the Control command with the higher-level Control device. Here, the host control device and the brake control device 10 are independent from each other, but may be a control device in which both devices are integrated.

Next, the rigidity estimating unit 4 will be described in detail with reference to fig. 2. As shown in fig. 2, the rigidity estimating unit 4 includes a rigidity characteristic detecting unit 40, a first slope calculating unit 41, a second slope calculating unit 42, a position deviation calculating unit 43, and a rigidity calculating unit 44, and receives a signal from the thrust control unit 3 via a communication line 24 and outputs the signal to the thrust control unit 3 via a communication line 25.

The actual rigidity estimating Unit 4 includes a CPU (Central Processing Unit), an arithmetic device such as a microcomputer, a main storage device such as a semiconductor memory, an auxiliary storage device such as a hard disk, and hardware such as a communication device, and executes a program stored in the main storage device by the arithmetic device with reference to a database or the like recorded in the auxiliary storage device to realize each function shown in fig. 2.

Rigidity characteristics detection section 40

The stiffness characteristic detection unit 40 calculates a first inclination (L1), a second inclination (L2), and a position deviation (Δ X) required for estimating stiffness, using the thrust value signal from the thrust sensor 31 and the position signal of the piston 12a estimated by the position sensor 32, and outputs the calculation results.

First slope calculating section 41

The first slope calculation unit 41 compares a thrust force value signal from the thrust sensor 31 generated after the piston 12a is moved toward the brake disk 11b and the brake pad 11a is brought into contact with the brake disk 11b with the detection thresholds SF1L and SF1H stored as internal values of the first slope calculation unit, and detects the position signals X1L and X1H of the piston 12a at the time when the thresholds are exceeded, thereby calculating the slope (inclination) of thrust force increase with respect to the amount of advance of the piston 12a, and outputting the first slope L1 and the position X1 of the piston 12a at the time when the first slope is calculated.

Second slope calculating section 42

The second slope calculating unit 42 compares a thrust force value signal from the thrust sensor 31 generated after the piston 12a is moved toward the brake disk 11b and the brake pad 11a is brought into contact with the brake disk 11b with the detection thresholds SF2L and SF2H stored as internal values of the second slope calculating unit, and detects the position signals X2L and X2H of the piston 12a at the time when the thresholds are exceeded, thereby calculating the slope of thrust force increase with respect to the amount of advance of the piston 12a, and outputting the second slope L2 and the position X2 of the piston 12a at the time when the second slope is calculated.

Position error calculation section 43

The positional deviation calculation unit 43 calculates the positional deviation Δ X from the difference between the first inclination position X1 and the second inclination position X2 obtained from the first inclination calculation unit 41 and the second inclination calculation unit 42.

Rigidity calculation section 44

The rigidity calculation unit 44 calculates rigidity based on the first slope L1, the second slope L2, and the positional deviation Δ X.

Here, the principle of generating the rigidity characteristic will be described with reference to fig. 4. The rigidity characteristic represents a relation of the thrust force with respect to the advance of the piston 12 a. The piston 12a is stationary with a clearance provided to prevent drag when not braking. On the other hand, during braking, the piston 12a moves forward, and at the time of the amount of forward clearance, the brake pad 11a is pushed into contact with the brake disc 11b, and thrust starts to be generated (a in fig. 4).

When the piston 12a is further advanced, first, a restoring force generated by the deflection of the caliper or the like is detected by the thrust sensor 31. Since the brake pad 11a is in the one-side contact state in the range where the deflection of the caliper occurs after the brake pad 11a comes into contact with the brake disc 11B, the apparent rigidity (B in fig. 4) is low (the increase in force with respect to the amount of piston advance is small).

The restoring force is gradually reduced by further gradually advancing the piston 12a to recover from the deflected state (C in fig. 4). When the piston 12a is gradually advanced, the brake pad 11a and the brake disk 11b come into contact with each other, that is, the brake pad 11a is gradually brought close to and brought into contact with the brake disk 11b in the positive direction, and an increase in force due to the rigidity of the brake pad 11a is obtained (D in fig. 4).

In order to appropriately capture these changes in rigidity, the rigidity calculation unit 44 calculates rigidity based on the first slope L1, the second slope L2, and the positional deviation Δ X.

Here, parameters used for the rigidity calculation will be described with reference to fig. 5. The first slope calculation unit 41 holds the values F1L and F1H of the thrust sensor 31 and the values of the piston positions X1L and X1H at the time when the thresholds SF1L and SF1H are exceeded, and calculates the slope L1 as (F1H-F1L)/(X1H-X1L). The same operation (operation of the second slope L2) is also performed in the second slope operation unit 42, and Δ X, which is the difference between the positions of the first slope L1 and the second slope L2, is further calculated.

The rigidity is calculated using these 3 parameters (L1, L2, Δ X), and a method of calculating rigidity includes extracting various kinds of rigidity data obtained by experiments at a design stage, and constructing an estimation model corresponding to a rigidity change by regression analysis. The estimation model at this time is, for example, as shown in the following expression (1).

f(Z1，Z2，Z3)＝c+α*Z1+β*Z2+γ*Z3…(1)

Here:

f (Z1, Z2, Z3): piston estimated position (rigidity characteristic) to achieve arbitrary thrust

Z1: first slope (L1)

Z2: second slope (L2)

Z3: position error (Delta X)

c. α, β, γ: regression coefficient

In the regression analysis, the regression coefficient of expression (1) can be set so that the estimation error becomes minimum, and therefore, the rigidity estimation can be performed with high accuracy with respect to the rigidity change.

However, the regression model may be designed in advance, or may be learned during traveling. Mainly, the rigidity may be estimated using information of the first slope (L1), the second slope (L2), and the positional deviation (Δ X).

The functional blocks of the rigidity estimating unit 4 shown in fig. 2 are actually executed by software stored in the memory of the microcomputer. The operation flow is described below with reference to fig. 3.

Step S10

In step S10, it is determined whether the vehicle is currently in a braking state. This determination can be made based on whether or not the driver has depressed the brake pedal by a predetermined amount or more and the thrust command value is 0 or more. When the vehicle is in the non-braking state (no), the vehicle jumps to the end and waits for the next starting timing. On the other hand, when the vehicle is in the braking state (yes), the process proceeds to the next step S11.

Step S11

Step S11 corresponds mainly to the processing in the first slope calculating unit 41, and compares the output F of the thrust sensor 31 provided in the rotation/linear motion conversion mechanism 12 with the threshold SF1L, and if F is equal to or less than the threshold (no), it waits, and if F is equal to or more than the threshold (yes), it proceeds to step S12.

Step S12

Step S12 corresponds mainly to the processing in the first slope calculating unit 41, and the value F1L of the thrust sensor 31 and the value X1L of the position sensor 32 at the time when the threshold value is exceeded are held and stored in the memory, and the process proceeds to step S13.

Here, these pieces of information are stored in a temporary storage area of a RAM (Random Access Memory) provided in the microcomputer, and are used for the calculation to be executed in the following control procedure. In addition, other information may be detected together with the brake system 1.

Step S13

Step S13 corresponds mainly to the processing in the first slope calculating unit 41, and compares the output F of the thrust sensor 31 provided in the rotation/linear motion conversion mechanism 12 with the threshold SF1H, and if F is equal to or less than the threshold (no), it waits, and if F is equal to or more than the threshold (yes), it proceeds to step S14.

Step S14

Step S14 corresponds mainly to the processing in the first slope calculating unit 41, and the value F1H of the thrust sensor 31 and the value X1H of the position sensor 32 at the time when the threshold value is exceeded are held and stored in the memory, and the process proceeds to step S15.

Step S15

Step S15 corresponds mainly to the processing in the first slope calculation unit 41, and calculates the first slope L1 ═ F1H-F1L)/(X1H-X1L from the information obtained in steps S11 to S14.

Step S21

Step S21 corresponds mainly to the processing in the second slope calculating unit 42, and compares the output F of the thrust sensor 31 provided in the rotation/linear motion conversion mechanism 12 with the threshold SF2L, and if F is below the threshold (no), it waits, and if F is above the threshold (yes), it proceeds to step S22.

Step S22

Step S22 corresponds mainly to the processing in the second slope calculator 42, and the value F2L of the thrust sensor 31 and the value X2L of the position sensor 32 at the time when the threshold value is exceeded are held and stored in the memory, and the process proceeds to step S23.

Step S23

Step S23 corresponds mainly to the processing in the second slope calculating unit 42, and compares the output F of the thrust sensor 31 provided in the rotation/linear motion conversion mechanism 12 with the threshold SF2H, and if F is below the threshold (no), it waits, and if F is above the threshold (yes), it proceeds to step S24.

Step S24

Step S24 corresponds mainly to the processing in the second slope calculator 42, and the value F2H of the thrust sensor 31 and the value X2H of the position sensor 32 at the time when the threshold value is exceeded are held and stored in the memory, and the process proceeds to step S25.

Step S25

Step S25 corresponds mainly to the processing in the second slope calculation unit 42, and calculates the second slope L2 ═ F2H-F2L)/(X2H-X2L from the information obtained in steps S21 to S24.

Step S31

Step S31 corresponds mainly to the processing of the positional deviation calculation unit 43, and calculates the difference Δ X between the piston positions at which the first slope L1 and the second slope L2 are calculated, as X2L-X1H.

Step S41

Step S41 corresponds mainly to the processing of the rigidity calculation unit 44, and calculates the rigidity characteristics by substituting the first slope L1, the second slope L2, and the positional deviation Δ X into the estimation model f (Z1, Z2, Z3) generated by regression analysis at the time of design.

The effect of the present invention is shown in fig. 6. In the present embodiment, the stiffness change can be appropriately estimated by the above calculation. For example, if the apparent rigidity changes to high rigidity due to excessive wear of the brake pad 11a, if the rigidity is not estimated, the piston 12a is excessively advanced as indicated by the left broken line (not estimated) in the drawing, and the thrust overshoots. On the other hand, if the stiffness is properly estimated, the thrust can be controlled without overshoot as indicated by the dotted line (the present invention).

For example, if the apparent rigidity of the brake disk 11b changes to low rigidity due to inclination of the disk due to lateral acceleration during traveling, the response decreases due to insufficient advance of the piston 12a as indicated by the broken line on the right side in the figure (not estimated), if the rigidity is not estimated. On the other hand, if the rigidity is appropriately estimated, the responsiveness is improved as indicated by a dotted line (the present invention).

In the present invention, since the rigidity can be estimated with high accuracy, the contact position (a in fig. 4) between the brake pad 11a and the brake disk 11b, which is the point at which the thrust starts to increase, can be detected with high accuracy, and therefore the piston positioning control during non-braking, in which the clearance is kept constant, can also be performed with high accuracy.

Further, according to patent document 2, although measurement needs to be performed by increasing the force to a high thrust when the rigidity characteristic is to be obtained up to the high thrust, in the present invention, if the thrust is increased to a threshold value necessary for estimation, estimation is possible up to a high thrust section, and therefore estimation can be performed only by the operation in the normal braking range.

Further, according to patent document 3, although there is a possibility that the memory load increases for higher accuracy, in the present invention, the memory consumption amount may be small because the estimation can be performed only with the first slope L1, the second slope L2, and the positional deviation Δ X.

As described above, the brake control device 10 of the present embodiment controls a brake including a brake caliper, a brake pad 11a, a brake disc 11b, a piston 12a coupled to the brake pad 11a and moving in a linear motion direction by rotation of the motor 2a, and a thrust detection unit (thrust sensor 31) that detects thrust of the brake pad 11a against the brake disc 11b, and estimates the relationship between the position of the piston 12a, which is the stiffness of the brake caliper, and the thrust of the brake pad 11a against the brake disc 11b based on the first piston range (X1H-X1L) in which the position of the thrust change against the piston 12a becomes the first slope L1 and the second piston range (X2H-X2L) in which the position of the thrust change against the piston 12a becomes the second slope L2 different from the first slope L1.

The rigidity of the brake caliper is estimated based on the difference (positional deviation Δ X) between the positions of the first piston range (X1H-X1L) and the second piston range (X2H-X2L).

The first piston range (X1H-X1L) is a range of restoring force of the deflection in which the brake caliper deflects and the brake pad 11a contacts one side, and the second piston range (X2H-X2L) is a range of pressing force after the brake pad 11a contacts the brake disc 11 b.

According to the present embodiment, the rigidity and the pad contact position can be estimated with high accuracy with a low microcomputer load, and the brake control performance can be improved.

Example 2

A brake system according to embodiment 2 of the present invention will be described with reference to fig. 7. Fig. 7 is a functional block diagram of the rigidity estimating unit in the present embodiment, and corresponds to a modification of embodiment 1 (fig. 2). In addition, the same points as those in embodiment 1 will not be described repeatedly.

As shown in fig. 7, the rigidity estimating unit of the present embodiment is configured by adding a third slope calculating unit 51 and a fourth slope calculating unit 52 to the configuration of embodiment 1 (fig. 2).

For example, in addition to the first slope L1 and the second slope L2, the rigidity is also estimated based on a third piston range in which the position of the thrust force change with respect to the piston 12a is a third slope L3 that is different from the first slope L1 and the second slope L2. Further, the rigidity is estimated based on the fourth piston range of the fourth slope L4 different from the first slope L1, the second slope L2, and the third slope L3, in addition to the first slope L1, the second slope L2, and the third slope L3, with respect to the position of the piston 12a, the thrust force change.

When the change in rigidity is complicated and sufficient rigidity estimation accuracy cannot be obtained by using the first slope L1 and the second slope L2, the accuracy can be improved by adding the third slope L3 and the fourth slope L4.

Example 3

A brake system according to embodiment 3 of the present invention will be described with reference to fig. 8. Fig. 8 is a functional block diagram of the rigidity estimating unit in the present embodiment, and corresponds to a modification of embodiment 1 (fig. 2). In addition, the same points as those in embodiment 1 will not be described repeatedly.

As shown in fig. 8, the rigidity estimation unit of the present embodiment is configured by adding a rigidity estimation model learning unit 61 to the configuration of embodiment 1 (fig. 2). As described above, although the rigidity estimation model constructed in advance at the time of design is used in example 1, the rigidity may be measured in real time during traveling or stopping as in this example, and the estimation model may be sequentially learned. This makes it possible to construct an estimation model that can cope with a special rigidity change that cannot be considered in designing.

In the above embodiments, the electric brake of the automobile has been described as an application target of the brake control device and the control method thereof of the present invention, but the present invention is not limited to this, and can be applied to an electric brake mounted on a railroad, an elevator, or the like, for example, in addition to an automobile, and similar effects can be obtained.

In the above embodiments, the brake caliper 5 is described as an example of the brake unit according to the present invention, but the present invention can also be applied to a brake control device having a drum brake type electric cylinder unit that presses a brake shoe against a drum that rotates together with a wheel, and a brake control method of the electric cylinder unit, and similar effects can be obtained.

The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention, and are not limited to having all the configurations described. Further, a part of the structure of one embodiment may be replaced with the structure of another embodiment, and the structure of another embodiment may be added to the structure of one embodiment. In addition, other configurations can be added, deleted, and replaced for a part of the configurations of the embodiments.

Description of the reference numerals

1 … brake system, 2 … drive mechanism, 2a … motor, 2b … speed reducer, 3 … thrust control unit (motor controller), 4 … rigidity estimation unit, 5 … brake caliper (brake unit), 10 … brake control device, 11 … brake mechanism, 11a … brake pad (friction member), 11b … brake disk (braked member), 12 … rotation/linear motion conversion mechanism, 12a … piston, 12b … feed screw, 21 … control signal line, 22-25 … communication line, 26 … main power line, 31 … thrust sensor, 32 … position sensor, 40 … rigidity characteristic detection unit, 41 … first inclination calculation unit, 42 … second inclination calculation unit, 43 … position deviation calculation unit, 44 … rigidity calculation unit, 51 … third inclination calculation unit, 52 … fourth inclination calculation unit, 61 … rigidity estimation model learning unit.