CN117824548A

CN117824548A - Method, device, control unit and medium for determining wear of a brake lining

Info

Publication number: CN117824548A
Application number: CN202311839405.XA
Authority: CN
Inventors: 刘龙
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2023-12-28
Filing date: 2023-12-28
Publication date: 2024-04-05

Abstract

The present disclosure relates to methods, devices, controllers, and media for determining wear of a brake pad. The method includes detecting a pressure of brake fluid used to drive a brake piston in response to a brake lining of the brake piston being moved from a first lining position. The method further includes determining a second liner position reached by the brake liner in response to detecting that the pressure meets a preset condition. The method further includes determining a first distance from the first pad position to the second pad position and determining wear information for the brake pad based on the first distance and a calibrated distance. In this way, a quantified degree of wear of the brake lining can be detected without requiring additional hardware, thereby providing more accurate brake lining wear information.

Description

Method, device, control unit and medium for determining wear of a brake lining

Technical Field

The present disclosure relates to the field of vehicle detection, and more particularly, to methods, devices, controllers, and media for determining wear of a brake lining.

Background

The braking system of the automobile comprises a service braking system and a parking braking system, wherein the service braking system is mainly used for reducing the speed of the automobile and braking during running, the parking braking system keeps the automobile from sliding in a stationary state, and the service braking system and the parking braking system can be matched to work together for braking during emergency braking. Service brake systems generally include brake pads, brake discs, and brake oil.

The safety of the brake system of a motor vehicle is very relevant. A large part of traffic accidents are caused by malfunctions of the brake system. Therefore, it is necessary to periodically inspect the brake system and replace parts of the brake system.

Disclosure of Invention

Embodiments of the present disclosure propose a solution for determining the degree of wear of a brake lining based on the brake fluid pressure and the position of the brake piston.

In a first aspect of the present disclosure, a method for determining wear of a brake lining is provided. The method includes detecting a pressure of brake fluid used to drive a brake piston in response to a brake lining of the brake piston being moved from a first lining position. The method further includes determining a second liner position reached by the brake liner in response to detecting that the pressure meets a preset condition. The method further includes determining a first distance from the first liner position to the second liner position. The method further includes determining wear information for the brake pads based on the first distance and a calibrated distance.

In a second aspect of the present disclosure, an apparatus for determining wear of a brake lining is provided. The apparatus includes a pressure detection module configured to detect a pressure of brake fluid used to drive a brake piston in response to a brake pad of the brake piston being moved from a first pad position. The apparatus further includes a position determination module configured to determine the second liner position reached by the brake liner in response to detecting that the pressure satisfies a preset condition. The apparatus also includes a distance determination module configured to determine a first distance from the first liner position to the second liner position. The apparatus also includes a wear determination module configured to determine wear information for the brake pads based on the first distance and a calibrated distance.

In a third aspect of the present disclosure, an electronic device is provided. The method comprises the following steps: at least one processor; and a memory coupled to the at least one processor and having instructions stored thereon that, when executed by the at least one processor, cause the electronic device to perform a method according to the first aspect of the present disclosure.

In a fourth aspect of the present disclosure, a computer-readable storage medium is provided. The computer-readable storage medium has stored thereon computer-executable instructions that are executed by a processor to implement the method provided according to the first aspect of the present disclosure.

It should be understood that what is described in this summary is not intended to limit the critical or essential features of the embodiments of the disclosure nor to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The above and other features, advantages and aspects of embodiments of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, wherein like or similar reference numerals designate like or similar elements, and wherein:

FIG. 1 illustrates a schematic diagram of an example wheel-side brake system in which various embodiments of the present disclosure may be implemented;

FIG. 2 illustrates a flowchart of an example method for determining wear of a brake lining according to some embodiments of the present disclosure;

FIG. 3 illustrates a flowchart of an example method for determining wear of a brake lining according to further embodiments of the present disclosure;

FIG. 4 illustrates a flowchart of an example method for determining wear of a brake lining according to further embodiments of the present disclosure;

5A-5C illustrate overall schematic views of a brake system in determining wear of a brake lining according to some embodiments of the present disclosure;

6A-6C illustrate schematic diagrams of wheel-side brake pistons in determining wear of a brake lining according to some embodiments of the present disclosure;

7A-7B illustrate schematic diagrams of pressure curves of brake fluid in determining wear of a brake lining according to some embodiments of the present disclosure;

FIG. 8 illustrates a block diagram of an example apparatus for determining wear of a brake lining according to some embodiments of the present disclosure; and

fig. 9 illustrates a block diagram of a device in which various embodiments of the present disclosure may be implemented.

Detailed Description

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure have been shown in the accompanying drawings, it is to be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure.

In describing embodiments of the present disclosure, the term "comprising" and its like should be taken to be open-ended, i.e., including, but not limited to. The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first," "second," and the like, may refer to different or the same object. Other explicit and implicit definitions are also possible below.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a similar fashion (e.g., "between …" and "directly between …", "adjacent" and "directly adjacent", etc.).

The brake linings of the brake system of a motor vehicle wear out due to friction with the brake disc. When the brake lining does not provide sufficient braking friction, the driver needs to replace the brake lining. Typically, the front brake pad replacement cycle of an automobile is about 3-5 kilometers, and the rear brake pad is relatively slightly longer, about 6-8 kilometers. In addition to estimating the replacement cycle based on mileage, the wear of the brake lining is related to numerous factors such as the condition of the vehicle, the driving habit of the vehicle owner, and what road is often left, so that the mileage is just a reference, and the specific wear of the brake lining needs to be monitored.

Conventionally, when a brake lining is extremely worn, friction between a clamp spring on the brake lining and a brake disc is caused, and a large noise is generated, so that a driver is reminded of replacing the brake lining. Furthermore, wires embedded therein are provided in the brake lining. When the brake pads are severely worn, the embedded lines in the brake pads will break, triggering a signal to the instrument panel to alert the driver to the replacement of the brake pads.

However, both of the above mechanisms only alert when the brake pads must be replaced, with some hysteresis. Furthermore, both of these mechanisms do not indicate the exact degree of wear of the brake pads, resulting in a failure to prompt the driver in time so that the driver can replace the brake pads at the desired moment.

In view of the above, embodiments of the present disclosure provide a scheme for determining a degree of wear of a brake lining based on a moving distance of a brake piston. In this solution, the brake lining can be actively driven in motion and two positions of the brake lining associated with wear are determined on the basis of the pressure change of the brake fluid used to drive the piston carrying the brake lining, and the degree of wear of the brake lining is identified on the basis of the difference between the distance between the two positions and the calibration distance. In this way, the self-mechanism of the brake system can be used to determine the degree of wear of the brake lining without additional sensing devices. Therefore, the wear degree of the brake lining can be actively detected without additional hardware cost, so that a driver can timely grasp the state of a brake system, and the driving safety is improved.

The scheme and principle of the embodiment of the present disclosure will be described in detail with reference to fig. 1 to 9. FIG. 1 illustrates a schematic diagram of an example wheel side brake system 100 in which various embodiments of the present disclosure may be implemented. As shown in fig. 1, the service brake system is provided with a disc brake 110 at one wheel. It should be appreciated that while FIG. 1 illustrates a floating caliper disc brake, the wear determination mechanism according to embodiments of the present disclosure is also applicable to fixed caliper disc brakes. The disc brake 110 includes a brake caliper outer body 111. Brake caliper outer body 111 spans the upper edge of brake disc 130 in a direction parallel to the axis of brake disc 130 coupled to the vehicle such that two brake pads 112-1 and 112-2 (individually or collectively brake pads 112) of brake caliper outer body 111 are located on either side of brake disc 130, respectively. The brake cylinder 113 is provided on one side of the brake caliper outer body 111. A brake piston 114 for carrying a brake lining 112-1 is arranged in the brake cylinder 113. The brake piston 114 is movable in the brake cylinder 113 towards the brake disc 130 and eventually reaches a position where the brake lining 112-1 is brought to bear against the brake disc 130 and from there towards the end of the brake cylinder 113 remote from the brake disc 130 and eventually reaches the inner wall 115 bearing against this end.

Wheel-side brake system 100 also includes a brake pump 101 coupled to disc brake 110. The brake pump 101 includes a motor 102 that provides power. The brake pump 101 further includes a plunger cylinder 103 and a brake plunger 104 located in the plunger cylinder 103. The motor 102 is configured to drive a brake plunger 104 to move within a plunger cylinder 103. The plunger cylinder 103 communicates with the brake cylinder 113 via the brake line 105 such that brake fluid can flow between the plunger cylinder 103 and the brake cylinder 113. In addition, the wheel side brake system 100 may further include a control valve for controlling the flow of brake fluid and a sensor for sensing a different kind of parameter. The wheel side brake system 100 also includes a controller 120. The controller 120 may, for example, receive sensed vehicle conditions from sensors and control the wheel side brake system 100 based on the sensed information.

The brake system can respond to the braking action of the driver by utilizing the internal sensor, converts the braking action of the driver into a signal and transmits the signal to a motor control unit in the brake pump, the control unit calculates the torque required by the motor, and then the torque is converted into the servo braking force of the valve body of the booster by a secondary gear unit device, and finally, the amplifying mechanism is driven to finally push the brake pump to start to work, so that the braking is realized.

In some embodiments, during driving, the driver depresses the brake pedal when the driver wants to stop the vehicle. At this point, the controller 120 may detect the braking command and control the motor 102 to push the brake plunger 104. The brake plunger 104 is driven by the motor 102 to deliver brake fluid from the plunger cylinder 103 to the brake cylinder 113. When brake fluid enters brake cylinder 113, the brake fluid pushes brake piston 114 in brake cylinder 113 to move brake lining 112-1 toward brake disc 130 until brake lining 112-1 abuts against an end face of brake disc 130. At the same time, the reaction force of the brake piston 114 to the brake caliper outer body 111 pushes a portion of the brake caliper outer body toward the brake disc 130, and thereby the brake pads 112-2 provided on the portion also abut against the brake disc 130, thereby achieving braking.

Further, after the vehicle is stopped, the controller 120 may also perform a method for determining grinding of the brake pads according to embodiments of the present disclosure. For example, the controller 120 may actively control the brake piston 113 to move from an initial position toward the brake disk 130. The controller 120 receives pressure sensing information from a sensor for detecting the pressure of the brake fluid and determines that the brake piston 113 reaches a final position where the brake pads 112 are in contact with the brake disc 130 based on a change in the pressure sensing information. Controller 120 may then determine the overall wear level of brake lining 112 based on the distance from the initial position to the final position and the calibrated distance corresponding to that distance. Schemes for determining wear of a brake lining according to embodiments of the present disclosure will be described in detail below in conjunction with fig. 2-7B.

Fig. 2 illustrates a flowchart of an example method 200 for determining wear of a brake lining according to some embodiments of the present disclosure. For discussion purposes, the method 200 will be described in connection with FIG. 1. The method 200 may be performed, for example, by the controller 120 shown in fig. 1. As shown in fig. 2, at 202, method 200 includes determining whether a brake pad of a brake piston is moved from a first pad position. For example, in the embodiment shown in fig. 1, the controller 120 may determine whether the brake pads 112 of the brake piston are moved from the first pad position. Upon determining that brake lining 112 is moved from the first lining position, method 200 proceeds to 204. In some embodiments, if it is determined that brake lining 112 is not being moved from the first lining position, method 200 may return to 202 such that the controller continues to determine whether brake lining 112 is being moved from the first lining position.

At 204, method 200 includes detecting a pressure of brake fluid for driving a brake piston. For example, in the embodiment shown in fig. 1, the controller 120 may detect the pressure of the brake fluid used to drive the brake piston 114. For example, a pressure sensor for sensing the brake fluid pressure may be provided at any position from the brake cylinder 113, the brake line 105, and up to the plunger cylinder 103. The controller 120 may receive a sensing signal from the pressure sensor.

At 206, the method 200 includes determining whether the detected pressure meets a preset condition. For example, in the embodiment shown in fig. 1, the controller 120 may determine whether the detected pressure satisfies a preset condition. In the event that the detected pressure is determined to meet the preset condition, the method 200 proceeds to 208. In some embodiments, in the event that the detected pressure is determined not to meet the preset condition, the method 200 may return to 204 and continue to detect the pressure of the brake fluid.

In some embodiments, the preset condition may be obtained by observing a pressure change of the brake fluid. In this embodiment, the pressure of the brake fluid may vary significantly when the brake piston reaches a certain position.

At 208, method 200 includes determining a second liner position at which the brake liner has reached. For example, in the embodiment shown in fig. 1, the controller 120 determines a second liner position to which the brake liner has reached. In some embodiments, the first pad position may be, for example, the position where brake pad 112-1 is against brake disk 130, and the second pad position may be the position where brake pad 112-1 is when brake piston 114 reaches inner wall 115 of brake cylinder 113. In some embodiments, the first pad position may be, for example, the position of brake pad 112-1 when brake piston 114 reaches inner wall 115 of brake cylinder 113, or any predetermined position prior to brake pad 112-1 contacting brake disk 130, and the second pad position may be the position of brake pad 112-1 when it abuts brake disk 130.

At 210, the method 200 includes determining a first distance from a first liner position to a second liner position. For example, in the embodiment shown in fig. 1, the controller 120 determines a first distance from a first liner position to a second liner position. At 212, the method 200 includes determining wear information for the brake lining based on the first distance and the calibrated distance. For example, in the embodiment shown in FIG. 1, the controller 120 determines the brake lining wear information based on the first distance and the calibrated distance. The wear information may be any suitable quantitative indication including a representation of the extent of wear, such as wear thickness, wear volume, and the like.

In the embodiment shown in fig. 2, it is possible to determine whether the brake lining completes a predetermined path associated with the brake lining, simply by detecting the pressure of the brake fluid used to move the brake lining during movement of the brake lining. The actual distance travelled is then compared with the nominal distance, and wear information for the brake lining can be calculated. In this way, a quantified degree of wear of the brake lining can be detected without additional hardware, giving the driver a more accurate wear indication.

FIG. 3 illustrates a flowchart of an example method 300 for determining wear of a brake lining according to further embodiments of the present disclosure. For discussion purposes, the method 300 will be described in connection with FIG. 1. The method 300 may be performed, for example, by the controller 120 shown in fig. 1.

At 302, the controller 120 determines whether the first pad position is where the brake pad contacts the brake disc or where the brake pad is where the brake piston is at an end within the brake cylinder. If the controller 120 determines that the first pad position is the position where the brake pad contacts the brake disc, then the method 300 proceeds to 304. At 304, the controller 120 draws brake fluid from within the brake cylinder to move the brake piston to an end within the brake cylinder. In some embodiments, the brake piston is driven with a brake fluid at a predetermined pressure to move the brake pads, the predetermined pressure being maintained within a predetermined pressure range. At 306, the controller 120 detects a pressure of brake fluid for driving the brake piston.

At 308, the controller 120 determines whether the pressure is less than a second pressure threshold. If the controller 120 determines that the pressure is less than the second pressure threshold, the method 300 proceeds to 310. Otherwise, the method 300 returns to 306 such that the controller 120 continues to detect the pressure of the brake fluid until the pressure is less than the second pressure threshold. At 310, the controller 120 determines that the brake piston reaches an end where the brake pad reaches a second pad position. At 312, the controller 120 determines a first distance from the first liner position to the second liner position. At 314, the controller 120 determines brake lining wear information based on the first distance and the calibrated distance. A scheme for determining the wear thickness will be described later with reference to fig. 4.

Returning to 302, if the controller 120 determines that the first pad position is the position where the brake pad is located when the brake piston is at the end within the brake cylinder, then the method 300 proceeds to 322. At 322, the controller 120 delivers brake fluid into the brake cylinder to bring the brake pads into contact with the brake disc via the brake piston. At 324, the controller 120 detects a pressure of brake fluid for driving the brake piston. At 326, the controller 120 determines whether the pressure is greater than a first pressure threshold. If the controller 120 determines that the pressure is greater than the first pressure threshold, the method 300 proceeds to 328. Otherwise, method 300 returns to 324 such that controller 120 continues to detect the pressure of the brake fluid until the pressure is less than the second pressure threshold.

At 328, the controller 120 determines that the brake pads reach a second pad position in contact with the brake disc. At 330, the controller 120 determines a first distance from the first liner position to the second liner position. At 332, the controller 120 determines brake lining wear information based on the first distance and the calibrated distance.

In the exemplary embodiment shown in fig. 3, different starting lining positions, i.e. a first lining position, and different end lining positions, i.e. a second lining position, are preset in the brake system. The operation of the brake system is different in different predetermined paths, so that wear detection errors in the event of failure of a single mode of operation can be avoided.

Fig. 4 illustrates a flowchart of an example method 400 for determining wear of a brake lining according to further embodiments of the present disclosure. For discussion purposes, the method 400 will be described in connection with FIG. 1. The method 400 may be performed, for example, by the controller 120 shown in fig. 1. As shown in fig. 4, at 402, the controller 120 detects a position of a brake plunger in a brake pump that pumps brake fluid into a brake cylinder. In some embodiments, in the running brake system, a position sensor for detecting the position of the brake plunger is provided only in the brake pump. Therefore, it is necessary to calculate the volume change with the position of the brake plunger.

At 404, the controller 120 determines a first plunger position of the brake plunger when the brake pad is in the first pad position. At 406, the controller 120 determines a second plunger position of the brake plunger when the brake plunger is in the second liner position. At 408, the controller 120 determines a second distance from the first plunger position to the second plunger position. At 410, the controller 120 determines a change in volume of brake fluid based on the second distance and the second cross-sectional area of the brake pump.

Because of the inconvenience of the total volume of brake fluid, the volume change in the brake cylinder is considered to be equivalent to the volume change in the plunger cylinder without replenishing or recovering brake fluid from or to the brake fluid storage tank. At 412, the controller 120 obtains a first cross-sectional area of the brake cylinder. At 414, the controller 120 determines a first distance based on the volume change and the first cross-sectional area.

In the embodiment shown in fig. 4, the movement distance of the brake piston is converted into an acquirable movement distance of the brake piston. In this way, additional detection means can be omitted and the conversion process is simple with high reliability.

Fig. 5A illustrates a schematic diagram of a braking system 500 in one operational state in determining wear of a brake lining according to some embodiments of the present disclosure. As shown in fig. 5A, the brake system 500 includes a brake fluid storage tank 501 for storing and providing brake fluid to the system. The brake system 500 also includes a master cylinder 502. The master cylinder 502 is configured to convert a brake pedal force of a driver into a hydraulic braking force. For example, when the driver depresses the brake pedal, the brake fluid in the master cylinder 502 is input into the wheel-side brake system. In general, the master cylinder 502 is connected to the brake fluid storage tank 501 so as to balance the brake fluid in the master cylinder 502 when the volume of the brake fluid in the master cylinder 502 is changed due to temperature change, brake lining wear, and brake fluid leakage.

Downstream of the master cylinder 502, a circuit separation valve 503-1 and a circuit separation valve 503-2 are provided. Downstream of the circuit separating valve 503-1, two branches are provided. In one branch, a left front wheel brake system 510-1 and a feed valve 508-1 for the left front wheel brake system 510-1 are provided. In the other branch, in contrast, a right rear wheel brake system 510-2 and a liquid intake valve 508-2 for the right rear wheel brake system 510-2 are provided. Downstream of the circuit separating valve 503-2, two branches are likewise provided. In one branch, a left rear wheel brake system 510-3 and a feed valve 508-3 for the left rear wheel brake system 510-3 are provided. In the other branch, in contrast, a right front wheel brake system 510-4 and a feed valve 508-4 for the right front wheel brake system 510-4 are provided.

Further, a drain valve is provided between each wheel brake system 510 and the brake fluid storage tank 501. As shown in fig. 5A, a drain valve 509-1 is provided between the left front wheel brake system 510-1 and the brake fluid reservoir tank 501. A drain valve 509-2 is provided between the right rear wheel brake system 510-2 and the brake fluid reservoir tank 501. A drain valve 509-3 is provided between the left rear wheel brake system 510-3 and the brake fluid reservoir tank 501. A drain valve 509-4 is provided between the right front wheel brake system 510-4 and the brake fluid reservoir tank 501.

The brake system 500 further includes a brake pump 506 for delivering brake fluid. The brake pump 506 is connected to the brake fluid reservoir 501. A normally open electromagnetic valve 504 and a check valve 505 are provided in the line between the brake pump 506 and the brake fluid reservoir 501. The brake pump 506 on the other hand is split into two branches. One of the branches is connected to the line before the branch downstream of the circuit separating valve 503-2. A brake pump separation valve 507-1 is provided in the branch. Wherein the other branch is connected to the line before the branch downstream of the circuit breaker valve 503-1. A brake pump release valve 507-2 is provided in the branch.

The vehicle is instructed to perform a method of determining a wear condition of a brake lining according to the present disclosure. In executing a method, first, conditions for executing the method are created. In order to enable the vehicle to stay stably in place, 4 wheel-side brake systems are activated to perform a braking operation. In the embodiment shown in FIG. 5A, the controller closes circuit breaker valve 503-1 and circuit breaker valve 503-2 and opens brake pump breaker valve 507-1 and brake pump breaker valve 507-2. In addition, the controller opens all of the inlet valves 508 and closes all of the outlet valves 509 to allow brake fluid to enter the wheel side brake system.

After the valve control operation is completed, the controller controls the brake pump 506 to perform the pressure build operation. Under control of the controller, the brake plungers of the brake pumps 506 are driven to pump brake fluid in plunger cylinders of the brake pumps 506 into the 4 wheel side brake systems. At this time, the brake fluid enters into two branches from the brake pump 506 and is divided into a first portion and a second portion. A first portion of the brake fluid enters the line downstream of the circuit breaker valve 503-2 via the open brake pump breaker valve 507-1. Thereafter, the first portion of brake fluid is again divided into a first sub-portion and a second sub-portion along with the branching of the line. The first sub-portion of brake fluid enters the left rear wheel brake system 510-3 via the open inlet valve 508-3. The second sub-portion of brake fluid enters the right front wheel brake system 510-4 via the open inlet valve 508-4. On the other hand, the second portion of brake fluid is again divided into a third sub-portion and a fourth sub-portion along with the branching of the line. The third sub-portion of brake fluid enters left front wheel brake system 510-1 via open inlet valve 508-1. The fourth sub-portion of brake fluid enters the right rear wheel brake system 510-2 via the open inlet valve 508-2. Thereby, the 4 wheel side brake systems perform a braking operation. The state at the time of braking operation of one wheel side braking system will be described below with reference to fig. 6A.

Fig. 6A illustrates a schematic diagram of a wheel-side brake system 600 in one operating state in determining wear of a brake lining according to some embodiments of the present disclosure. Here, the wheel side brake system 600 may be any one of 4 wheel side brake systems. As shown in fig. 6A, wheel-side brake system 600 includes a disc brake 610. The disc brake 610 includes a brake caliper outer body 611. The brake caliper outer body 611 spans the upper edge of the brake disc 630 in a direction parallel to the axis of the brake disc 630 such that the two brake pads 612-1 and 612-2 (individually or collectively brake pads 612) of the brake caliper outer body 611 are located on either side of the brake disc 630, respectively. A brake cylinder 613 is provided at one side of the brake caliper outer body 611. A brake piston 614 for carrying a brake lining 612-1 is arranged in the brake cylinder 613.

Wheel-side brake system 600 also includes a brake pump 601 coupled to a disc brake 610. The brake pump 601 includes a motor 602 that provides power. The brake pump 601 further includes a plunger cylinder 603 and a brake plunger 604 located in the plunger cylinder 603. The motor 602 is configured to drive a brake plunger 604 to move within a plunger cylinder 603. The plunger cylinder 603 communicates with the brake cylinder 613 via a brake line 605 so that brake fluid can flow between the plunger cylinder 603 and the brake cylinder 613. In addition, the wheel side brake system 600 may further include a control valve for controlling the flow of brake fluid and a sensor for sensing a different kind of parameter. Wheel side brake system 600 also includes a controller 620. The controller 620 may be, for example, an Electronic Control Unit (ECU) of the brake system that receives sensed vehicle conditions from sensors and controls the wheel side brake system 600 based on the sensed information.

The wheel side brake system as described in the embodiment shown in fig. 5A has performed a braking operation. During this operation, the controller 620 controls the motor 602 to push the brake plunger 604, for example, if a brake command is detected. The brake plunger 604 is driven by the motor 602 to transfer brake fluid in the plunger cylinder 603 to the brake cylinder 613. When brake fluid enters the brake cylinder 613, the brake fluid pushes the brake piston 614 in the brake cylinder 613 to move the brake pads 612-1 toward the brake disk 630 until the brake pads 612-1 abut against the end face of the brake disk 630. At the same time, the reaction force of brake piston 614 against brake caliper outer body 611 pushes a portion of the brake caliper outer body also toward brake disc 630, whereby brake pads 612-2 provided on the portion also abut against brake disc 630, thereby effecting braking. At this time, brake pad 612-1 is located at position PB1 (which may be referred to as a first pad position). Correspondingly, the brake plunger 604 is located at position PP1 (which may be referred to as a first plunger position).

After all of the wheels are braked, the method of determining the wear condition of the brake pads according to the present disclosure may continue to be performed. At this time, one wheel side brake system among the 4 wheel side brake systems is selected to detect the degree of wear of the brake linings of the wheel side brake system. The selected brake pad will then be moved. Fig. 5B illustrates a schematic diagram of a brake system 500 in another operational state in determining wear of a brake lining according to some embodiments of the present disclosure. As shown in FIG. 5B, the selected wheel side brake system is the right front wheel side brake system 510-4. To unseat the brake pads of the right front wheel side brake system 510-4 from a position against the brake disc, the controller closes the inlet valve 508-1, the inlet valve 508-2, the inlet valve 508-3 so that only brake fluid in the brake cylinders of the right front wheel side brake system 510-4 can be drawn into the brake pump 506.

After the valve control operation is completed, the controller controls the brake pump 506 to perform a decompression operation. Under the control of the controller, the brake plungers of the brake pump 506 are driven to expand the volumes in the plunger cylinders, thereby pumping brake fluid in the brake cylinders of the right front wheel side brake system 510-4 into the plunger cylinders of the brake pump 506. At this time, the brake fluid is introduced from the brake cylinder of the right front wheel side brake system 510-4 into the plunger cylinder of the brake pump 506 via the fluid inlet valve 508-4 and the brake pump release valve 507-1 until a preset stop condition is satisfied. The state of the right rear wheel side brake system 510-4 at the time of the extraction operation will be described below with reference to fig. 6B.

During operation as shown in fig. 6B, the controller 620 controls the motor 602 to push the brake plunger 604 to expand the volume in the plunger cylinder 603, for example, in the event that a brake command is detected. Thereby, the pressure in the plunger cylinder 603 becomes small, so that the brake fluid flows from the brake cylinder 613 into the plunger cylinder 603 by the pressure. At the same time, the pressure in the brake cylinder 613 becomes small and reaches below atmospheric pressure. The brake piston 614 is subjected to an external atmospheric pressure greater than the pressure in the brake cylinder 613 and the resulting pressure differential urges the brake piston 614 to move in a direction away from the brake disc 630 towards the end within the brake cylinder 613. When the brake piston 614 reaches the end, the brake piston 614 abuts against the inner wall 615 of the brake cylinder 613 and is no longer moved. At this time, the controller 620 may determine that the brake pad 612 reaches the preset position by, for example, a pressure change of the brake fluid, and end the extraction operation. At this time, the brake pad 612 is located at position PB2 (may be referred to as a second pad position), and the brake plunger 604 is located at position PP2 (may be referred to as a second plunger position). The trend of the pressure of the brake fluid during the pumping operation will be described below with reference to fig. 7A.

Fig. 7A illustrates a schematic diagram of a pressure map 700A of brake fluid in a process of determining wear of a brake lining according to some embodiments of the present disclosure. As shown in fig. 7A, the pressure map 700A includes a horizontal axis 701 indicating the volume of brake fluid and a vertical axis 702 indicating the brake fluid pressure. Pressure map 700A also includes a pressure curve 703 of brake fluid pressure as a function of volume. Pressure map 700A corresponds to, for example, a pressure change during a brake fluid extraction operation shown in fig. 6B. When the brake pump pumps brake fluid, the pressure of the brake fluid is slightly less than atmospheric pressure so that the brake piston moves under a pressure differential to an end within the brake cylinder. During this process, the brake fluid pressure is stably maintained within a predetermined range. This may be achieved, for example, by slowly moving the brake plungers by a motor. When the brake piston reaches the end in the brake cylinder, the brake piston cannot move any further, at which point the pressure of the brake fluid will drop sharply, i.e. the pressure curve 703 reaches the inflection point 704. By detecting the inflection point of the pressure drop, it is thereby possible to determine whether the brake piston reaches the end portion in the brake cylinder.

Returning to fig. 6A, wheel-side brake system 600 also includes a position sensor for detecting the position of brake plunger 604. By means of the position sensor, the controller 620 can obtain the initial position PP1 and the end position PP2 of the brake plunger 604 and can accordingly obtain the distance DP1 between the two positions. Based on the distance DP1 and the cross-sectional area of the plunger cylinder 603, the controller 620 calculates a change in the volume of the brake fluid in the plunger cylinder 603 during the process of drawing the brake fluid, that is, the volume of the brake fluid drawn into the plunger cylinder 603 from the brake cylinder 613. This volume change is equivalent to the volume change of the brake fluid in the plunger cylinder 603. The controller 620 calculates a distance DB1 of brake lining movement based on the determined volume change and the cross-sectional area of the brake cylinder 613. Finally, the controller 620 calculates the difference between the distance DB1 and the calibrated distance to obtain the overall wear of the brake pads, i.e., the thickness of the brake pads 612-1 and 6212-2 as a whole relative to the unworn brake pads. The calibration distance may be, for example, the movement distance of an unworn brake lining detected when the operating process shown in fig. 5A and 5B is performed for an unworn brake lining.

After the operation of fig. 5B, the brake piston may be moved in reverse and the distance of movement of the brake lining during the process determined, thereby again calculating the wear thickness of the brake lining. Fig. 5C illustrates a schematic diagram of a brake system 500 in yet another operational state in determining wear of a brake lining according to some embodiments of the present disclosure. As shown in fig. 5C, to move the brake pads of the right front wheel side brake system 510-4 from the end within the brake cylinders toward the brake disc, the controller controls the normally open solenoid valve 504 to close so that only brake fluid in the brake pump 506 can be delivered to the brake cylinders of the right front wheel side brake system 510-4.

After the valve control operation is completed, the controller controls the brake pump 506 to perform the pressure build operation. Under control of the controller, the brake plungers of the brake pump 506 are driven to reduce the volume in the plunger cylinders, thereby delivering the brake fluid in the plunger cylinders of the brake pump 506 to the brake cylinders of the right front wheel side brake system 510-4. At this time, brake fluid is introduced from the plunger cylinder of the brake pump 506 into the brake cylinder of the right front wheel side brake system 510-4 via the brake pump separation valve 507-1 and the fluid intake valve 508-4 until a preset stop condition is satisfied. The state of the right rear wheel side brake system 510-4 after this operation will be described below with reference to fig. 6C.

During operation as shown in fig. 5C, the controller 620 controls the motor 602 to push the brake plunger 604 to reduce the volume in the plunger cylinder 603, for example, in the event a brake command is detected. Thereby, the pressure in the plunger cylinder 603 becomes large, so that the brake fluid flows from the plunger cylinder 603 into the brake cylinder 613 by the pressure. At the same time, the pressure in the brake cylinder 613 becomes large and reaches above atmospheric pressure. The brake piston 614 is subjected to a pressure in the brake cylinder 613 that is greater than the ambient atmospheric pressure, and the resulting pressure differential urges the brake piston 614 to move from the end within the brake cylinder 613 in a direction toward the brake disc 630. When the brake piston 614 reaches the brake disc, i.e. the brake lining 612 is resting against the brake disc 630, the brake piston 614 is no longer moved. At this time, the controller 620 may determine that the brake pad 612 reaches the preset position by, for example, a pressure change of the brake fluid, and end the pressure building operation. At this time, the brake pad 612 is located at a position PB3 (may be referred to as a second pad position, and accordingly the initial position PB2 is referred to as a first pad position), and the brake plunger 604 is located at a position PP3 (may be referred to as a second pad position, and accordingly the initial position PP2 is referred to as a first pad position). The trend of the pressure of the brake fluid during the pumping operation will be described below with reference to fig. 7B.

Fig. 7B illustrates a schematic diagram of a pressure map 700B of brake fluid in a process of determining wear of a brake lining in accordance with some embodiments of the present disclosure. As shown in fig. 7B, pressure map 700B includes a pressure curve 705 of brake fluid pressure as a function of volume. Pressure map 700B corresponds to, for example, a pressure change during a brake fluid pressure build operation shown in fig. 5C. When the brake pump pumps brake fluid, the pressure of the brake fluid is slightly greater than atmospheric pressure so that the brake piston moves toward the brake disc under a pressure differential. During this process, the brake fluid pressure is stably maintained within a predetermined range. This may be achieved, for example, by slowly moving the brake plungers by a motor. When the brake lining is resting on the brake disc, the brake piston cannot move any further, at which point the pressure of the brake fluid will increase sharply, i.e. the pressure curve 705 reaches the inflection point 706. By detecting the inflection point of the pressure rise, it is thereby possible to determine whether the brake piston reaches the brake disc and whether the brake lining is in abutment against the brake disc.

It should be understood that the volume changes shown after the pressure curves in fig. 7A and 7B reach the inflection point are exaggerated for illustrative purposes. That is, the volume change of the brake fluid after the pressure curve reaches the inflection point is much smaller than the moving distance of the brake lining and is therefore negligible.

Returning to fig. 6B, by means of the position sensor, the controller 620 can obtain the initial position PP2 and the end position PP3 of the brake plunger 604, and can accordingly obtain the distance DP2 between the two positions. Based on the distance DP2 and the cross-sectional area of the plunger cylinder 603, the controller 620 calculates a change in the volume of brake fluid in the plunger cylinder 603 during pumping of brake fluid, i.e., the volume of brake fluid pumped from the plunger cylinder 603 into the brake cylinder 613. This volume change is equivalent to the volume change of the brake fluid in the plunger cylinder 603. The controller 620 calculates a distance DB2 of brake lining movement based on the determined volume change and the cross-sectional area of the brake cylinder 611. Finally, the controller 620 calculates the difference between the distance DB2 and the calibrated distance, resulting in the overall wear of the brake pads. The calibration distance may be, for example, the movement distance of an unworn brake lining detected when the operating process shown in fig. 5C is performed for an unworn brake lining.

It should be appreciated that the wear detection shown in fig. 5A-7B, while comprising two wear thickness detection processes, may be performed independently. Furthermore, in an embodiment combining two detection processes, by two different ways for moving the brake lining, the method can be made to cover different operations of the actuation pump for pumping brake fluid and pumping brake fluid in order to exclude errors that may occur in one of the ways.

In some embodiments, after two calculated wear thicknesses are obtained, brake 620 may calculate the difference between the two. If the calculated difference is greater than the predetermined threshold, the brake 620 may determine that the resulting wear thickness is unreliable and needs to be re-detected. If the calculated difference is less than the predetermined threshold, the brake 620 may determine that the resulting wear thickness is reliable and calculate an average of the two as the final wear thickness. In some embodiments, the wear thickness detection may be performed multiple times and the average of the multiple results calculated as the final wear thickness.

In some embodiments, in performing the determination of the degree of wear of the brake pads according to embodiments of the present disclosure, the ongoing process is terminated whenever an ignition or power-up action of the user is detected, to avoid affecting normal use.

Fig. 8 illustrates a block diagram of an example apparatus 800 for determining wear of a brake lining according to some embodiments of the present disclosure. As shown in fig. 8, the apparatus 800 includes a pressure detection module 802. The pressure detection module 802 is configured to detect a pressure of brake fluid for driving the brake piston in response to a brake lining of the brake piston being moved from a first lining position. The apparatus 800 also includes a location determination module 804. The position determination module 804 is configured to determine a second liner position at which the brake liner reaches in response to detecting that the pressure meets a preset condition. The apparatus 800 also includes a distance determination module 806. The distance determination module 806 is configured to determine a first distance from the first liner position to the second liner position. The apparatus 800 further includes a wear determination module 808. The wear determination module 808 is configured to determine wear information for the brake pads based on the first distance and the calibrated distance.

In some embodiments, the distance determination module 806 includes: a first volume determining unit configured to determine a volume change of brake fluid in a brake cylinder in which the brake piston is located; a first area acquisition unit configured to acquire a first cross-sectional area of the brake cylinder; and a first distance determining unit configured to determine a first distance based on the volume change and the first cross-sectional area.

In some embodiments, the first volume determination unit comprises: a position detection unit configured to detect a position of a brake plunger in a brake pump that pumps brake fluid into a brake cylinder; a first position determining unit configured to determine a first plunger position of the brake plunger when the brake lining is located at the first lining position; a second position determining unit configured to determine a second plunger position of the brake plunger when the brake plunger is located at the second lining position; a second distance determining unit configured to determine a second distance from the first plunger position to the second plunger position; and a second volume determining unit configured to determine a volume change of the brake fluid based on the second distance and a second cross-sectional area of the brake pump.

In some embodiments, the wear determination module 808 includes: a calibration distance acquisition unit configured to acquire a calibration distance associated with an unworn brake lining; and a wear determination unit configured to determine a difference between the calibration distance and the first distance as wear information.

In some embodiments, the apparatus 800 further comprises: and a piston driving module configured to drive the brake piston with a brake fluid of a predetermined pressure to move the brake pads, and the predetermined pressure is maintained within a predetermined pressure range.

In some embodiments, the piston drive module comprises: a first lining position determining unit configured to determine a first lining position as a position where the brake lining contacts the brake disc; and an extraction unit configured to extract brake fluid from within the brake cylinder to move the brake piston to an end within the brake cylinder.

In some embodiments, the location determination module 804 includes: an end position determining unit configured to determine that the brake piston reaches the end in response to determining that the pressure is less than a second pressure threshold, wherein the brake lining reaches a second lining position.

In some embodiments, the extraction unit further comprises: and a line shut-off unit configured to shut off the lines of the brake fluid storage tank and the brake pump so that only the brake fluid in the brake cylinder is pumped into the brake pump.

In some embodiments, the piston drive module comprises: a second lining position determining unit configured to determine a first lining position as a position where the brake lining is located when the brake piston is located at an end portion within the brake cylinder; and a delivery unit configured to deliver brake fluid into the brake cylinder to bring the brake pads into contact with the brake disc via the brake piston.

In some embodiments, the location determination module 804 includes: an end position determining unit configured to determine that the brake lining reaches a second lining position in contact with the brake disc in response to determining that the pressure is greater than a first pressure threshold.

In some embodiments, the apparatus 800 further comprises: a multiple piston moving unit configured to move a plurality of brake pistons of a vehicle such that a plurality of brake pads attached to the plurality of brake pistons respectively abut against corresponding brake discs.

In some embodiments, the piston drive module comprises: a single piston driving unit configured to drive one of the plurality of brake pistons; and a piston holding unit configured to hold other brake pistons of the plurality of brake pistons in place.

It is to be appreciated that with the apparatus 800 of the present disclosure, at least one of the advantages that can be achieved with the methods or processes described above can be achieved.

Fig. 9 shows a schematic block diagram of an example device 900 that may be used to implement embodiments of the present disclosure. The example device 900 may be, for example, the controller 120 of fig. 1, the controller 620 of fig. 6A-6C. As shown, the device 900 includes a computing unit 901 that can perform various suitable actions and processes in accordance with computer program instructions stored in a Read Only Memory (ROM) 902 or loaded from a storage unit 908 into a Random Access Memory (RAM) 903. In the RAM 903, various programs and data required for the operation of the device 900 can also be stored. The computing unit 901, the ROM 902, and the RAM 903 are connected to each other by a bus 904. An input/output (I/O) interface 905 is also connected to the bus 904.

Fig. 9 shows a schematic block diagram of an example device 900 that may be used to implement embodiments of the present disclosure. As shown, device 900 includes a processor 901 that can perform various suitable actions and processes in accordance with computer program instructions stored in a Read Only Memory (ROM) 902 loaded into a Random Access Memory (RAM) 903. In the RAM 903, various programs and data required for the operation of the device 900 can also be stored. The processor 901, the ROM 902, and the RAM 903 are connected to each other by a bus 904. An input/output (I/O) interface 905 is also connected to the bus 904.

The various processes and treatments described above, such as method 200, method 300, and method 400, may be performed by processor 901. For example, in some embodiments, the methods 200, 300, and 400 may be implemented as computer software programs, tangibly embodied on a machine-readable medium. In some embodiments, some or all of the computer program may be loaded and/or installed onto device 900 via ROM 902. When the computer program is loaded into RAM 903 and executed by processor 901, one or more actions of method 200, method 300, and method 400 described above may be performed.

The present disclosure may be methods, apparatus, systems, and/or computer program products. The computer program product may include a computer readable storage medium having computer readable program instructions embodied thereon for performing aspects of the present disclosure.

The computer readable storage medium may be a tangible device that can hold and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: random Access Memory (RAM), read Only Memory (ROM), erasable programmable read only memory (EPROM or flash memory), static Random Access Memory (SRAM), and any suitable combination of the foregoing. Computer-readable storage media, as used herein, are not to be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., optical pulses through fiber optic cables), or electrical signals transmitted through wires.

The computer readable program instructions described herein may be downloaded from a computer readable storage medium to a respective computing/processing device or to an external computer or external storage device over a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmissions, wireless transmissions, routers, firewalls, switches, gateway computers and/or edge servers. The network interface card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium in the respective computing/processing device.

Computer program instructions for performing the operations of the present disclosure can be assembly instructions, instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, c++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program instructions may be executed entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, aspects of the present disclosure are implemented by personalizing electronic circuitry, such as programmable logic circuitry, field Programmable Gate Arrays (FPGAs), or Programmable Logic Arrays (PLAs), with state information of computer readable program instructions, which can execute the computer readable program instructions.

Various aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions.

These computer readable program instructions may be provided to a processing unit of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processing unit of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable medium having the instructions stored therein includes an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer, other programmable apparatus or other devices implement the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

The foregoing description of the embodiments of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvement of the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for determining wear of a brake lining, comprising:

detecting a pressure of brake fluid for driving a brake piston in response to a brake lining of the brake piston being moved from a first lining position;

determining a second liner position reached by the brake liner in response to detecting that the pressure meets a preset condition;

determining a first distance from the first liner position to the second liner position; and

wear information for the brake lining is determined based on the first distance and the calibrated distance.

2. The method of claim 1, wherein determining the first distance from the first liner position to the second liner position comprises:

Determining the volume change of brake fluid in a brake cylinder where the brake piston is located;

acquiring a first cross-sectional area of the brake cylinder; and

the first distance is determined based on the volume change and the first cross-sectional area.

3. The method of claim 2, wherein determining the change in volume of the brake fluid comprises:

detecting a position of a brake plunger in a brake pump that pumps the brake fluid into the brake cylinder;

determining a first plunger position of the brake plunger when the brake pad is in the first pad position;

determining a second piston position of the brake piston when the brake piston is in the second liner position;

determining a second distance from the first plunger position to the second plunger position; and

the change in volume of the brake fluid is determined based on the second distance and a second cross-sectional area of the brake pump.

4. The method of claim 1, wherein determining the wear information for the brake pad comprises:

acquiring the calibrated distance associated with an unworn brake pad; and

and determining the difference between the calibration distance and the first distance as the abrasion information.

5. The method of claim 1, further comprising:

the brake piston is driven with the brake fluid at a predetermined pressure to move the brake pads, the predetermined pressure being maintained within a predetermined pressure range.

6. The method of claim 5, wherein driving the brake piston comprises:

determining the first lining position as the position where the brake lining contacts the brake disc; and

the brake fluid is extracted from the brake cylinder to move the brake piston to an end within the brake cylinder.

7. The method of claim 6, wherein determining that the brake pad reaches the second pad position comprises:

in response to determining that the pressure is less than a second pressure threshold, determining that the brake piston reaches the end, wherein the brake pad reaches the second pad position.

8. The method of claim 7, wherein extracting the brake fluid from within the brake cylinder comprises:

and closing the pipelines of the brake fluid storage tank and the brake pump so that only the brake fluid in the brake cylinder is pumped into the brake pump.

9. The method of claim 5, wherein driving the brake piston comprises:

Determining the first lining position as the position of the brake lining when the brake piston is at the end within the brake cylinder; and

the brake fluid is supplied into the brake cylinder to bring the brake linings into contact with the brake disk via the brake piston.

10. The method of claim 9, wherein determining that the brake pad reaches the second pad position comprises:

in response to determining that the pressure is greater than a first pressure threshold, determining that the brake lining reaches the second lining position in contact with the brake disc.

11. The method of claim 1, further comprising:

a plurality of brake pistons of a vehicle are moved such that a plurality of brake pads attached to the plurality of brake pistons respectively abut against corresponding brake discs.

12. The method of claim 11, wherein driving the brake piston comprises:

driving one of the plurality of brake pistons; and

the other brake pistons of the plurality of brake pistons are held in place.

13. An apparatus for determining wear of a brake pad, comprising:

a pressure detection module configured to detect a pressure of brake fluid for driving a brake piston in response to a brake lining of the brake piston being moved from a first lining position;

A position determination module configured to determine a second liner position reached by the brake liner in response to detecting that the pressure satisfies a preset condition;

a distance determination module configured to determine a first distance from the first liner position to the second liner position; and

a wear determination module configured to determine wear information for the brake pads based on the first distance and a calibrated distance.

14. A controller, comprising:

at least one processor; and

a memory coupled to the at least one processor and having instructions stored thereon that, when executed by the at least one processor, cause the controller to perform the method of any of claims 1-13.

15. A computer readable storage medium having stored thereon computer executable instructions, wherein the computer executable instructions are executed by a processor to implement the method of any of claims 1 to 13.