Braking clearance and clamping force control method and system of electronic mechanical braking system

Abstract

The present invention relates to a brake clearance and clamping force control method and system of an electronic mechanical brake system. The system of the present invention comprises a self-learning module, an input arbitration module and a feedback arbitration module. The self-learning module is used for self-learning a critical absolute angle. The input arbitration module is used for selecting one of a reference absolute angle calculated by the self-learning module, a reference absolute angle converted by the brake clearance, and a reference absolute angle converted by the reference clamping force as input. The feedback arbitration module is used for selecting one of an actual absolute angle calculated by the absolute angle calculation module and an actual absolute angle converted by the actual clamping force as feedback. The present invention adopts a critical absolute angle self-learning method based on force feedback, which can improve the accuracy and consistency of critical absolute angle acquisition, and at the same time, can eliminate the influence of brake friction pad wear on clamping force control accuracy and response speed.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic mechanical brake systems, and in particular to a method and system for controlling brake clearance and clamping force of electronic mechanical brake systems. Background Art

[0002] With the development of electrification and intelligence of new energy vehicles, especially the development of unmanned driving technology, the requirements for chassis braking performance are getting higher and higher. Traditional chassis braking is achieved through hydraulics, which has the disadvantages of complex design, inconvenient installation, high cost, slow response, etc. In order to meet the development requirements of automobile intelligence and electrification and overcome the shortcomings of traditional chassis braking, the electronic mechanical braking system (EMB) came into being. This braking system has fast response, high precision, simple structure and easy installation.

[0003] like Figure 1 As shown, a typical EMB system includes a motor 11, a first reduction mechanism 12, a second reduction mechanism 13, a first brake friction pad 14, a brake disc 15, a caliper housing 16, and a second brake friction pad 17. The motor 11 outputs a controllable torque, and the output of the motor 11 is decelerated and torque-increased by the first reduction mechanism 12, and then further decelerated and torque-increased by the second reduction mechanism 13, while converting the rotary motion into a linear motion. The second reduction mechanism 13 acts on the first brake friction pad 14 through a piston, and the first brake friction pad 14 clamps the brake disc 15 after eliminating the brake clearance, thereby generating a clamping force to achieve vehicle braking. In the non-braking state, in order to avoid residual braking force that affects the normal driving of the car, a certain gap needs to be left between the first brake friction pad 14, the second brake friction pad 17, and the brake disc 15. In the braking state, the brake clearance needs to be eliminated before the clamping force can be generated, so there will be a certain delay in vehicle braking. It can be seen that the control of the brake clearance has an important influence on the reliability, rapidity and accuracy of braking, and the brake clearance will shift with the wear of the brake friction pad.

[0004] A prior Chinese patent (application number: 202310819624.5, invention name: A method for self-adapting pressure zero point of an electronic mechanical brake system) discloses a method for self-adapting pressure zero point of an electronic mechanical brake system. After the power-on initialization is completed, the method executes the pressure zero point adaptive control algorithm, and determines the completion of the pressure zero point adaptive by monitoring the q-axis current and motor speed feedback. The invention enables the pressure zero point to be adaptive, overcoming the effects of different pressure zero points due to different mechanical parts and the pressure zero point offset caused by wear of the automobile brake pads. The method has high requirements for the q-axis current and motor speed signals. Since the clamping force signal cannot be obtained, there is also a large deviation between the established zero point and the actual zero point.

[0005] Another prior Chinese patent (application number: 202410306615.0, invention name: A method for estimating and adjusting the brake clearance of an electronic mechanical brake system) discloses a method for estimating and adjusting the brake clearance of an electronic mechanical brake system. This method collects motor angle information and current information during the braking process, and inputs them into the contact function of the contact criterion between the brake caliper and the brake disc, thereby estimating the brake clearance; after the braking stroke is completed, the brake clearance is corrected to the set range and the brake clearance value is provided to the clamping force estimation module to solve the problem of decreased clamping force estimation accuracy caused by wear and other reasons. This method has high requirements on the parameters in the contact function of the contact criterion between the brake caliper and the brake disc. When the system parameters change or there is a large disturbance in the system, it is difficult to accurately estimate the contact criterion. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a method and system for controlling the braking clearance and clamping force of an electronic mechanical braking system, so as to solve the problems that the existing methods have large deviations and the acquisition of the critical absolute angle is highly dependent on the reliability of the physical model parameters. When the physical model parameters vary greatly, it is difficult to ensure the consistency of the critical absolute angle.

[0007] The technical solution to achieve the above purpose is:

[0008] The present invention provides a method for controlling the brake clearance and clamping force of an electronic mechanical brake system, comprising the following steps:

[0009] Determine whether the critical absolute angle self-learning is completed;

[0010] If not completed, the reference absolute angle in the critical absolute angle self-learning process is selected as the equivalent reference absolute angle of the three-loop control, and the actual absolute angle calculated based on the default zero angle is selected as the equivalent actual absolute angle of the three-loop control;

[0011] If it has been completed, further determine whether there is a clamping force request. If not, select the angle corresponding to the set reference braking clearance as the equivalent reference absolute angle of the three-ring control. If so, select the angle corresponding to the clamping force request as the equivalent reference absolute angle of the three-ring control. Further determine whether the current clamping force is greater than the critical clamping force. If not, select the actual absolute angle calculated based on the critical absolute angle as the reference zero position as the equivalent actual absolute angle of the three-ring control. If so, select the angle corresponding to the current clamping force as the equivalent actual absolute angle of the three-ring control.

[0012] A further improvement of the brake clearance and clamping force control method of the electronic mechanical brake system of the present invention is that it also includes:

[0013] receiving a self-learning activation signal;

[0014] The critical absolute angle is self-learned according to the received self-learning activation signal.

[0015] A further improvement of the brake clearance and clamping force control method of the electronic mechanical brake system of the present invention is that the self-learning of the critical absolute angle includes the following steps:

[0016] S11, obtaining the current clamping force;

[0017] S12, determining whether the current clamping force is less than the critical clamping force, if so, increasing the reference absolute angle by a set value, if not, decreasing the reference absolute angle by a set value;

[0018] S13, determine whether the current clamping force is within the critical reference range. If so, use the current reference absolute angle as the critical absolute angle, and update the critical absolute angle self-learning state to completion; if not, repeat step S12.

[0019] A further improvement of the brake clearance and clamping force control method of the electronic mechanical brake system of the present invention is that before taking the current reference absolute angle as the critical absolute angle, it also includes judging whether the current clamping force is stable. If so, the current reference absolute angle is taken as the critical absolute angle. If not, step S12 is repeated.

[0020] A further improvement of the brake clearance and clamping force control method of the electronic mechanical brake system of the present invention is that judging whether the current clamping force is stable comprises the following steps:

[0021] According to the set cycle period, whether the current clamping force is in the critical reference interval is cyclically judged, and if the current clamping force is in the critical reference interval, counting is performed;

[0022] If the count reaches the set threshold, the current clamping force is determined to be stable, otherwise the current clamping force is determined to be unstable.

[0023] The present invention also provides a brake clearance and clamping force control system of an electronic mechanical brake system, comprising:

[0024] An acquisition module, used for acquiring a current clamping force of an electronic mechanical brake system;

[0025] A self-learning module, connected to the acquisition module, for self-learning the critical absolute angle;

[0026] An absolute angle calculation module, connected to the self-learning module, for calculating the actual absolute angle;

[0027] An input arbitration module, connected to the self-learning module and the three-loop control module, for selecting the reference absolute angle of the self-learning module in the self-learning process as an equivalent reference absolute angle to be input to the three-loop control module when the self-learning of the self-learning module is not completed, and for further determining whether there is a clamping force request when the self-learning of the self-learning module is completed, if not, selecting the angle corresponding to the set reference braking clearance as the equivalent reference absolute angle to be input to the three-loop control module, if yes, selecting the angle corresponding to the clamping force request as the equivalent reference absolute angle to be input to the three-loop control module;

[0028] A feedback arbitration module is connected to the acquisition module, the absolute angle calculation module and the three-ring control module, and is used for selecting the actual absolute angle calculated by the absolute angle calculation module based on the default zero position angle as the equivalent actual absolute angle to be input to the three-ring control module when the self-learning of the self-learning module is not completed, and is used for further judging whether the current clamping force is greater than the critical clamping force when the self-learning of the self-learning module is completed. If not, the actual absolute angle calculated by the absolute angle calculation module based on the critical absolute angle as the reference zero position is selected as the equivalent actual absolute angle to be input to the three-ring control module; if so, the angle corresponding to the current clamping force is selected as the equivalent actual absolute angle to be input to the three-ring control module.

[0029] A further improvement of the brake clearance and clamping force control system of the electronic mechanical brake system of the present invention is that it also includes an activation module connected to the self-learning module;

[0030] The activation module is used to form a self-learning activation signal, and send the self-learning activation signal to the self-learning module so that the self-learning module performs self-learning of a critical absolute angle.

[0031] A further improvement of the brake clearance and clamping force control system of the electronic mechanical brake system of the present invention is that the self-learning module is used to receive the current clamping force obtained by the acquisition module, and determine whether the current clamping force is less than the critical clamping force, if so, increase the reference absolute angle by a set value, if not, decrease the reference absolute angle by a set value;

[0032] It is also used to determine whether the current clamping force is within the critical reference range. If so, the current reference absolute angle is used as the critical absolute angle, and the critical absolute angle self-learning state is updated to completion; if not, repeat the step of determining whether the current clamping force is less than the critical clamping force.

[0033] A further improvement of the braking clearance and clamping force control system of the electronic mechanical braking system of the present invention is that the self-learning module is also used to determine whether the current clamping force is stable before taking the current reference absolute angle as the critical absolute angle. If so, the current reference absolute angle is taken as the critical absolute angle; if not, the step of determining whether the current clamping force is less than the critical clamping force is repeated.

[0034] A further improvement of the brake clearance and clamping force control system of the electronic mechanical brake system of the present invention is that the self-learning module is used to perform cyclic judgment on whether the current clamping force is in a critical reference interval according to a set cycle period when judging whether the current clamping force is stable, and counts if the current clamping force is in the critical reference interval;

[0035] If the count reaches the set threshold, the current clamping force is determined to be stable, otherwise the current clamping force is determined to be unstable.

[0036] The beneficial effects of the brake clearance and clamping force control method and system of the electronic mechanical brake system of the present invention are as follows:

[0037] The present invention considers the coordination of critical absolute angle self-learning, gap control and clamping force control from a system level, solves the problems of gap acquisition, rapid gap elimination and unified control of clamping force control from a system level, improves the consistency of critical absolute angle acquisition, the rapidity and stability of clamping force control, and avoids the wear of brake friction pads due to residual clamping force and unnecessary driving losses.

[0038] The present invention adopts a critical absolute angle self-learning method based on force feedback, which can improve the accuracy and consistency of critical absolute angle acquisition and eliminate the influence of brake friction pad wear on clamping force control accuracy and response speed.

[0039] In the braking state, the present invention converts the clamping force request into a reference absolute angle as the input of the three-loop control, and converts the actual current clamping force into an actual absolute angle as the feedback of the three-loop control. Through the same conversion relationship, the precise control of the clamping force can be achieved. In the non-braking state, the reference angle equivalent to the reference brake clearance is used as the input of the three-loop control, and the calculated actual absolute angle is used as the feedback of the three-loop control, which can ensure the precise control of the brake clearance and avoid the generation of residual clamping force.

[0040] After the critical absolute angle self-learning of the present invention is completed, the continuity from the elimination of the brake clearance to the clamping force control is guaranteed, the clamping force response time is shortened, and the brake response speed is improved.

[0041] The present invention converts the relative angle measured by the angle sensor into an absolute angle through an absolute angle calculation module, thereby ensuring accurate control of the braking clearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of a typical existing EMB system.

[0043] Figure 2 It is a functional architecture design diagram of the brake clearance and clamping force control system of the electronic mechanical brake system of the present invention.

[0044] Figure 3 This is a logic flow chart of the critical angle self-learning of the present invention.

[0045] Figure 4 It is a logic flow chart of the input arbitration module of the present invention.

[0046] Figure 5 It is a logic flow chart of the feedback arbitration module of the present invention.

[0047] Figure 6 It is a logic flow chart of the three-loop control of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0049] The present invention provides a method and system for controlling the brake clearance and clamping force of an electronic mechanical brake system, which is used to solve the problem that the existing method only describes the method for obtaining the critical absolute angle (the position point where the brake friction pad and the brake disc just touch each other) or the position control method, and does not propose a solution from the clearance elimination to the clamping force control at the system level. It is also used to solve the problem that the critical absolute angle acquisition method relies heavily on the reliability of the physical model parameters, and when the physical model parameters vary greatly, it is difficult to ensure the consistency of the critical absolute angle. The present invention detects the current clamping force through a clamping force sensor, and considers the coordinated control of the critical absolute angle self-learning, clearance control and clamping force control from the system function level. Through the present invention, the problems of clearance acquisition, clearance rapid elimination, and unified control of clamping force control are solved from the system level, and the consistency of critical absolute angle acquisition, the rapidity and stability of clamping force control are improved, and the wear of the brake friction pad by the residual clamping force and unnecessary driving loss are avoided. The brake clearance and clamping force control method and system of the electronic mechanical brake system of the present invention are described below in conjunction with the accompanying drawings.

[0050] See also Figure 2 , shows the functional architecture design diagram of the brake clearance and clamping force control system of the electronic mechanical brake system of the present invention. Figure 2 , the brake clearance and clamping force control system of the electronic mechanical brake system of the present invention is described.

[0051] like Figure 2As shown, the brake clearance and clamping force control system of the electronic mechanical brake system of the present invention includes an acquisition module 21, a self-learning module 22, an absolute angle calculation module 23, an input arbitration module 24 and a feedback arbitration module 25; wherein the acquisition module 21 is used to acquire the current clamping force of the electronic mechanical brake system (EMB system); the self-learning module 22 is connected to the acquisition module 21, and the self-learning module 22 is used to self-learn the critical absolute angle; the absolute angle calculation module 23 is connected to the self-learning module 22, and the absolute angle calculation module 23 is used to calculate the actual absolute angle; the input arbitration module 24 is connected to the self-learning module 22 and the three-loop control module 26, and the input arbitration module 24 is used to select the reference absolute angle of the self-learning module 22 in the self-learning process as the equivalent reference absolute angle input to the three-loop control module 26 when the self-learning of the self-learning module 22 is not completed, and is used to further determine whether there is a clamping force request when the self-learning of the self-learning module 22 is completed. If not, select the set The angle corresponding to the reference braking gap is input as an equivalent reference absolute angle to the three-ring control module. If any, the angle corresponding to the clamping force request is selected as the equivalent reference absolute angle to be input to the three-ring control module; the feedback arbitration module 25 is connected to the acquisition module 21, the absolute angle calculation module 23 and the three-ring control module 26. The feedback arbitration module 25 is used to select the actual absolute angle calculated by the absolute angle calculation module 23 based on the default zero position angle as the equivalent actual absolute angle to be input to the three-ring control module 26 when the self-learning module 22 has not completed self-learning. It is used to further determine whether the current clamping force is greater than the critical clamping force (that is, determine whether the gap is eliminated) when the self-learning module 22 completes self-learning. If not, the actual absolute angle calculated by the absolute angle calculation module 23 based on the critical absolute angle as the reference zero position is selected as the equivalent actual absolute angle to be input to the three-ring control module 26. If so, the angle corresponding to the current clamping force is selected as the equivalent actual absolute angle to be input to the three-ring control module 26.

[0052] In a specific embodiment of the present invention, the system of the present invention also includes an activation module connected to the self-learning module 22; the activation module is used to form a self-learning activation signal, and send the self-learning activation signal to the self-learning module so that the self-learning module performs self-learning of the critical absolute angle.

[0053] The activation module serves as a self-learning switch of the self-learning module 22, and is used to activate the self-learning module 22 to perform self-learning of the critical absolute angle. The critical absolute angle is Figure 1The position point where the brake friction pad (including the first brake friction pad and the second brake friction pad) just touches the brake disc, that is, the position point after the first brake friction pad moves, and the position is expressed by angle. An angle sensor is provided at the motor to detect the rotation angle of the motor. The rotation of the motor 11 pushes the first brake friction pad 14 toward the brake disc 15 through the deceleration of the first deceleration mechanism 12 and the second deceleration mechanism 13.

[0054] Specifically, when the electronic mechanical brake system is powered on (i.e., the car starts or the driving cycle begins), the activation module generates a self-learning activation signal to allow the self-learning module to perform self-learning. This achieves self-learning of the critical absolute angle for each driving cycle. The activation module is also connected to the host computer, receives instructions from the host computer, and generates a self-learning activation signal according to the instructions of the host computer to allow the self-learning module to perform self-learning. The host computer can generate instructions to the activation module when the brake is repaired, maintained, or replaced.

[0055] Furthermore, if Figure 3 As shown, the self-learning module 22 is used to receive the current clamping force obtained by the acquisition module 21, and determine whether the current clamping force is less than the critical clamping force. If so, the reference absolute angle is increased by a set value, and if not, the reference absolute angle is decreased by a set value; the self-learning module 22 is also used to determine whether the current clamping force is within the critical reference interval. If so, the current reference absolute angle is used as the critical absolute angle, and the critical absolute angle self-learning state is updated to completion; if not, the step of determining whether the current clamping force is less than the critical clamping force is repeated. The reference absolute angle can be a set angle, and the set value can be a specific angle value such as 1°, 2°, etc. Through step-by-step adjustment, the current clamping force can approach the critical reference interval.

[0056] Furthermore, the self-learning module 22 is also used to determine whether the current clamping force is stable before taking the current reference absolute angle as the critical absolute angle. If so, the current reference absolute angle is taken as the critical absolute angle. If not, the step of determining whether the current clamping force is less than the critical clamping force is repeated.

[0057] Specifically, when judging whether the current clamping force is stable, the self-learning module 22 is used to perform cyclic judgment on whether the current clamping force is in a critical reference interval according to a set cycle period. If the current clamping force is in the critical reference interval, counting is performed; if the count reaches the set threshold, the current clamping force is judged to be stable, otherwise, the current clamping force is judged to be unstable.

[0058] The cycle period can be set to be the same as the clamping force closed-loop control period, such as 2ms, that is, every cycle period, it is judged whether the current clamping force is in the critical reference interval. If so, the count is increased by 1. A counter can be set. When the current clamping force is in the critical reference interval, the counter is accumulated by 1. When the value of the counter reaches the set threshold, it is determined that the current clamping force is stable.

[0059] That is, when the current clamping force is within the critical reference interval and is stable, the current absolute angle is taken as the critical absolute angle and sent to the absolute angle calculation module, and the self-learning state is updated to completion.

[0060] When the self-learning module starts self-learning, the self-learning state is updated to incomplete, so that the input arbitration module 24 and the feedback arbitration module 25 can query the self-learning state.

[0061] Furthermore, the critical reference interval and the critical clamping force are set values, which can be determined according to the transmission parameters. For example, the critical clamping force can be set to 500 Newtons, and the critical reference interval can be set to 500 Newtons to 550 Newtons.

[0062] Furthermore, a clamping force sensor is provided inside the second speed reduction mechanism 13 , and the current clamping force is detected by the clamping force sensor. The clamping force sensor is connected to the acquisition module 21 and can send the detected current clamping force to the acquisition module 21 .

[0063] The self-learning module of the present invention accurately obtains the critical clamping force and the critical absolute angle of the caliper, and can establish an absolute angle reference for accurate control of brake clearance, rapid clearance elimination, and rapid clamping force response.

[0064] In a specific embodiment of the present invention, the absolute angle calculation module is used to calculate the actual absolute angle. When the self-learning state of the self-learning module is not completed, the absolute angle calculation module uses the default angle as a reference to calculate the absolute angle. The default angle is a set angle, which can be 0°. When the self-learning state of the self-learning module is completed, the critical absolute angle is used as a reference zero position, and the absolute angle is recalculated based on the reference zero position. After the reference is confirmed, the absolute angle is calculated using the following formula: ang_abs = ang_abs_old + ang_rel_dlt,

[0065] In the above formula, ang_abs is the current absolute angle, and ang_abs_old is the absolute angle of the previous calculation cycle.

[0066] Absolute angle, ang_rel_dlt is the angle increment calculated based on the relative angle input by the angle sensor. The angle sensor is set at the motor to detect the rotation angle of the motor.

[0067] In a specific embodiment of the present invention, Figure 4 As shown, the input arbitration module 24 of the present invention is used to select an equivalent reference absolute angle as the input of the three-loop control module 26. Specifically, the input arbitration module 24 determines whether the critical absolute angle self-learning is completed. If not, the input arbitration module selects the reference absolute angle calculated by the self-learning module as the three-loop control input. The reference absolute angle calculated by the self-learning module is the angle adjusted by the step increase or step decrease of the reference absolute angle during the self-learning process.

[0068] If the critical absolute angle self-learning has been completed, it is further determined whether there is a clamping force request. If there is no clamping force request, the input arbitration module selects a reference absolute angle equivalent to the reference brake gap. The reference brake gap is a set gap, for example, it can be set at the position of the critical absolute angle so that the motor 11 moves back n turns to form a gap, where n is an integer greater than 1, such as 2 turns, 3 turns, etc. The system of the present invention is preset with a conversion relationship comparison table of the reference brake gap and the reference absolute angle, and the corresponding angle can be obtained from the comparison table according to the specific gap value.

[0069] If the critical absolute angle self-learning has been completed and there is a clamping force request, the input arbitration module selects the reference absolute angle converted with the reference clamping force. The clamping force request comes from the host computer, which provides the clamping force target. The clamping force target is regarded as the reference clamping force. Specifically, the corresponding reference absolute angle can be obtained according to the conversion relationship comparison table between the clamping force and the reference absolute angle.

[0070] In a specific embodiment of the present invention, Figure 5 As shown, the feedback arbitration module 25 is used to select the equivalent actual absolute angle as the feedback of the three-loop control module 26. Specifically, the feedback arbitration module 25 determines whether the critical absolute angle self-learning is completed. If not, the feedback arbitration module selects the actual absolute angle three-loop control feedback of the absolute angle calculation module 23 (at this time, the calculation basis of the angle calculation module 23 is the default zero angle).

[0071] If the critical absolute angle self-learning has been completed, it is further determined whether the current clamping force is greater than the critical clamping force. If it is not greater than the critical clamping force, the feedback arbitration module selects the actual absolute angle of the absolute angle calculation module 23 as the three-loop control feedback (at this time, the calculation basis of the angle calculation module 23 is the critical absolute angle as the reference zero position).

[0072] If the critical absolute angle self-learning has been completed and the current clamping force is greater than the critical clamping force, the input arbitration module selects the actual absolute angle converted with the actual clamping force. The actual clamping force is detected by the clamping force sensor, and the corresponding angle can be obtained according to the conversion relationship table between the clamping force and the reference absolute angle.

[0073] like Figure 6 As shown, the three-loop control module 26 of the present invention includes a current loop, a speed loop and a position loop, wherein the current loop is an inner loop and the position loop is an outer loop. The control of the motor 11 by the three-loop control module 26 is the same as the specific control method of the three-loop control module in the prior art.

[0074] The input arbitration module and the feedback arbitration module of the present invention need to maintain a consistent conversion relationship between the equivalent reference absolute angle and the equivalent actual absolute angle, so that the clamping force can be accurately controlled. The conversion relationship can be achieved by measuring the clamping force corresponding to different absolute angles and establishing a data table to ensure the equivalent accuracy of the conversion.

[0075] Regarding the critical absolute angle self-learning method, there are multiple counting modes for judging whether the current clamping force is within the critical reference clamping force range and is stable. If the counting condition is met, a certain value is increased, and if it is not met, a certain value is decreased. Before reaching the threshold condition, the clamping force is within the critical reference clamping force range and is stable.

[0076] Regarding the design method of the input arbitration module and the output arbitration module, the conversion relationship between the reference clamping force and the reference absolute angle, the actual clamping force and the actual absolute angle can be achieved by measuring the clamping forces corresponding to different absolute angles to establish a data table, or by function fitting.

[0077] The present invention also provides a method for controlling the brake clearance and clamping force of an electronic mechanical brake system, which is described below.

[0078] The coordinated control method of the present invention comprises the following steps:

[0079] Determine whether the critical absolute angle self-learning is completed;

[0080] If not completed, the reference absolute angle in the critical absolute angle self-learning process is selected as the equivalent reference absolute angle of the three-loop control, and the actual absolute angle calculated based on the default zero angle is selected as the equivalent actual absolute angle of the three-loop control;

[0081] If it has been completed, further determine whether there is a clamping force request. If not, select the angle corresponding to the set reference braking gap as the equivalent reference absolute angle of the three-ring control. If yes, select the angle corresponding to the clamping force request as the equivalent reference absolute angle of the three-ring control. Further determine whether the current clamping force is greater than the critical clamping force (that is, determine whether the gap is eliminated). If not, select the actual absolute angle calculated based on the critical absolute angle as the reference zero position as the equivalent actual absolute angle of the three-ring control. If so, select the angle corresponding to the current clamping force as the equivalent actual absolute angle of the three-ring control.

[0082] Furthermore, it also includes: receiving a self-learning activation signal; and performing self-learning of a critical absolute angle according to the received self-learning activation signal.

[0083] Specifically, a self-learning activation signal can be generated when the electronic mechanical brake system is powered on (that is, the car is started or the driving cycle begins) to allow the self-learning module to perform self-learning, so that self-learning of the critical absolute angle is performed once in each driving cycle. A self-learning activation signal can also be generated through instructions from the host computer to allow the self-learning module to perform self-learning. For example, the host computer can generate instructions when the brake is repaired, maintained, or replaced to allow the system to generate a self-learning activation signal.

[0084] In a specific embodiment of the present invention, the self-learning of the critical absolute angle includes the following steps:

[0085] S11, obtaining the current clamping force;

[0086] S12, determining whether the current clamping force is less than the critical clamping force, if so, increasing the reference absolute angle by a set value, if not, decreasing the reference absolute angle by a set value;

[0087] S13, determine whether the current clamping force is within the critical reference range. If so, use the current reference absolute angle as the critical absolute angle, and update the critical absolute angle self-learning state to completion; if not, repeat step S12.

[0088] Furthermore, before taking the current reference absolute angle as the critical absolute angle, it is also included to determine whether the current clamping force is stable. If so, the current reference absolute angle is taken as the critical absolute angle. If not, step S12 is repeated.

[0089] Furthermore, judging whether the current clamping force is stable includes the following steps:

[0090] According to the set cycle period, whether the current clamping force is in the critical reference interval is cyclically judged, and if the current clamping force is in the critical reference interval, counting is performed;

[0091] If the count reaches the set threshold, the current clamping force is determined to be stable, otherwise the current clamping force is determined to be unstable.

[0092] That is, when the current clamping force is within the critical reference interval and is stable, the current absolute angle is taken as the critical absolute angle and sent to the absolute angle calculation module, and the self-learning state is updated to completion.

[0093] The present invention is described in detail above in conjunction with the embodiments of the accompanying drawings. A person skilled in the art can make various variations of the present invention according to the above description. Therefore, certain details in the embodiments should not constitute a limitation of the present invention, and the scope of protection of the present invention shall be defined by the scope of the attached claims.

Claims

1. A method for controlling brake clearance and clamping force of an electronic mechanical brake system, characterized in that: The steps include: Determine whether the critical absolute angle self-learning is completed; If not completed, the reference absolute angle in the critical absolute angle self-learning process is selected as the equivalent reference absolute angle of the three-loop control, and the actual absolute angle calculated based on the default zero angle is selected as the equivalent actual absolute angle of the three-loop control; If it has been completed, further determine whether there is a clamping force request. If not, select the angle corresponding to the set reference brake clearance as the equivalent reference absolute angle of the three-ring control. If yes, select the angle corresponding to the clamping force request as the equivalent reference absolute angle of the three-ring control. Further determine whether the current clamping force is greater than the critical clamping force. If not, select the actual absolute angle calculated based on the critical absolute angle as the reference zero position as the equivalent actual absolute angle of the three-ring control. If yes, select the angle corresponding to the current clamping force as the equivalent actual absolute angle of the three-ring control. Also includes: receiving a self-learning activation signal; Performing self-learning of a critical absolute angle according to a received self-learning activation signal; The self-learning of critical absolute angles includes the following steps: S11, obtaining the current clamping force; S12, determining whether the current clamping force is less than the critical clamping force, if so, increasing the reference absolute angle by a set value, if not, decreasing the reference absolute angle by a set value; S13, determining whether the current clamping force is within the critical reference interval, if so, taking the current reference absolute angle as the critical absolute angle, and updating the critical absolute angle self-learning state to completion; if not, repeating step S12; The critical absolute angle refers to the point where the brake friction pad just touches the brake disc; The reference absolute angle is the set angle; The default zero angle is the default angle, which is another set angle; The critical clamping force is the set value.

2. The method for controlling the brake clearance and clamping force of an electronic mechanical brake system according to claim 1, characterized in that: Before taking the current reference absolute angle as the critical absolute angle, it is also necessary to determine whether the current clamping force is stable. If so, the current reference absolute angle is taken as the critical absolute angle. If not, step S12 is repeated.

3. The method for controlling the brake clearance and clamping force of an electronic mechanical brake system according to claim 2, characterized in that: Judging whether the current clamping force is stable includes the following steps: According to the set cycle period, whether the current clamping force is in the critical reference interval is cyclically judged, and if the current clamping force is in the critical reference interval, counting is performed; If the count reaches the set threshold, the current clamping force is determined to be stable, otherwise the current clamping force is determined to be unstable.

4. A brake clearance and clamping force control system for an electromechanical brake system, characterized in that: include: An acquisition module, used for acquiring a current clamping force of an electronic mechanical brake system; A self-learning module, connected to the acquisition module, for self-learning the critical absolute angle; An absolute angle calculation module, connected to the self-learning module, for calculating the actual absolute angle; An input arbitration module, connected to the self-learning module and the three-loop control module, for selecting the reference absolute angle of the self-learning module in the self-learning process as an equivalent reference absolute angle to be input to the three-loop control module when the self-learning of the self-learning module is not completed, and for further determining whether there is a clamping force request when the self-learning of the self-learning module is completed, if not, selecting the angle corresponding to the set reference braking clearance as the equivalent reference absolute angle to be input to the three-loop control module, if yes, selecting the angle corresponding to the clamping force request as the equivalent reference absolute angle to be input to the three-loop control module; A feedback arbitration module, connected to the acquisition module, the absolute angle calculation module and the three-loop control module, for selecting the actual absolute angle calculated by the absolute angle calculation module based on the default zero position angle as an equivalent actual absolute angle to be input to the three-loop control module when the self-learning of the self-learning module is not completed, and for further judging whether the current clamping force is greater than the critical clamping force when the self-learning of the self-learning module is completed, and if not, selecting the actual absolute angle calculated by the absolute angle calculation module based on the critical absolute angle as the reference zero position as an equivalent actual absolute angle to be input to the three-loop control module, and if so, selecting the angle corresponding to the current clamping force as the equivalent actual absolute angle to be input to the three-loop control module; Also includes an activation module connected to the self-learning module; The activation module is used to form a self-learning activation signal, and send the self-learning activation signal to the self-learning module so that the self-learning module performs self-learning of the critical absolute angle; The self-learning module is used to receive the current clamping force obtained by the acquisition module, and determine whether the current clamping force is less than the critical clamping force. If so, the reference absolute angle is increased by a set value, and if not, the reference absolute angle is decreased by a set value. It is also used to determine whether the current clamping force is within the critical reference interval. If so, the current reference absolute angle is used as the critical absolute angle, and the critical absolute angle self-learning state is updated to completion; if not, the step of determining whether the current clamping force is less than the critical clamping force is repeated; The critical absolute angle refers to the point where the brake friction pad just touches the brake disc; The reference absolute angle is the set angle; The default zero angle is the default angle, which is another set angle; The critical clamping force is the set value.

5. The brake clearance and clamping force control system of the electromechanical brake system according to claim 4, characterized in that: The self-learning module is also used to determine whether the current clamping force is stable before taking the current reference absolute angle as the critical absolute angle. If so, the current reference absolute angle is taken as the critical absolute angle. If not, the step of determining whether the current clamping force is less than the critical clamping force is repeated.

6. The brake clearance and clamping force control system of the electromechanical brake system according to claim 5, characterized in that: When judging whether the current clamping force is stable, the self-learning module is used to perform cyclic judgment on whether the current clamping force is in a critical reference interval according to a set cycle period, and if the current clamping force is in the critical reference interval, counting is performed; If the count reaches the set threshold, the current clamping force is determined to be stable, otherwise the current clamping force is determined to be unstable.

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