Electromechanical brake release clearance control method and system and storage medium

Abstract

The invention relates to an electronic mechanical brake release clearance control method and system and a storage medium. The method comprises the steps that S1, a motor is controlled to rotate; s2, recording the Hall number of the current motor as a first motor Hall number when the state of the motor Hall sensor is stable; s3, calculating the Hall number of the initial position of the motor; s4, performing clamping force closed-loop control on the motor based on the Hall number of the initial position of the motor, and recording the Hall number of the clamping force output by the motor within a preset clamping force error band as a second motor Hall number; and S5, calculating a Hall number corresponding to the gap relieving position of the motor, performing Hall number closed-loop control on the motor, and controlling the motor to rotate to the gap relieving position. The initial position of the motor is quickly and accurately identified, the position of the relieving gap is positioned, the problem that the initial position of the motor is unknown when a braking system is powered on is effectively solved, and a stable initial position is provided for follow-up braking application.

Description

Technical Field

[0001] The present invention belongs to the technical field of rail vehicles, and in particular relates to an electronic mechanical brake relief gap control method, system and storage medium. Background Art

[0002] In the field of braking technology, electronic mechanical braking systems have gotten rid of their dependence on traditional transmission media such as hydraulic oil and compressed air. They are characterized by small equipment, space saving, low noise, and smooth, fast and precise braking effects, which greatly improves the electrification level of the braking system.

[0003] Electromechanical brake systems primarily control braking force output through a motor-driven lead screw and caliper arm. When the motor rotates forward, the transmission mechanism effectively applies braking force to the brake disc, achieving the braking function. Reverse rotation reduces braking force and creates an appropriate clearance between the brake components, ensuring proper operation of the brake system.

[0004] However, due to the unique operating principles of electromechanical braking systems, existing technologies often leave the initial motor position unknown when the system is powered on. This presents numerous potential issues for the entire braking system. For example, the inability to accurately determine the motor position can lead to unstable braking force control, making it difficult to precisely adjust the braking force output as expected during braking, impacting the reliability and safety of the braking effect. Furthermore, the braking force response speed can become unstable, making it impossible to quickly and accurately respond to the driver's braking commands, increasing the risk of vehicle emergency braking. Furthermore, operating the motor in an unknown initial position can damage the transmission mechanism, reducing its service life and increasing system maintenance costs and the risk of failure. Summary of the Invention

[0005] The purpose of the present invention is to solve one of the above-mentioned technical problems and to provide an electronic mechanical brake relief gap control method, system and storage medium. When the electronic mechanical brake system is powered on, the Hall sensor is used to accurately calculate the relief gap position suitable for the current system and control the motor to rotate to the corresponding relief gap position.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] An electronic mechanical brake relief gap control method comprises the following steps:

[0008] S1: controls the motor rotation;

[0009] S2: When the error between the current motor Hall sensor feedback value and the previous motor Hall sensor feedback value is less than a predetermined error value and lasts for a predetermined time, the current motor Hall number is recorded as a first motor Hall number;

[0010] S3: Calculating the Hall number of the motor initial position based on the Hall number of the first motor;

[0011] S4: performing closed-loop control of the clamping force of the motor based on the Hall value of the motor's initial position. When the clamping force output by the motor is within a predetermined clamping force error band, the Hall value of the current motor is recorded as the second motor Hall value.

[0012] S5: Calculate the Hall number corresponding to the motor relief gap position based on the Hall number of the second motor, perform Hall number closed-loop control on the motor based on the Hall number of the position corresponding to the motor relief gap, and control the motor to rotate to the relief gap position.

[0013] In some embodiments of the present invention, the specific implementation method of step S2 is:

[0014] Set a counter with an initial value of 0;

[0015] If the error between the current motor Hall sensor feedback value and the previous motor Hall sensor feedback value is less than the predetermined error value, the counter is incremented by 1, otherwise the counter is reset to zero.

[0016] When the counter reaches a predetermined count value, the Hall number of the current motor is recorded as the first motor Hall number.

[0017] In some embodiments of the present invention, the specific implementation method of step S1 is:

[0018] Output a predetermined PWM signal duty cycle D2 to the motor to control the motor to rotate in the forward direction;

[0019] In some embodiments of the present invention, step S1 further includes the following steps:

[0020] Before controlling the motor to rotate forward, a predetermined PWM signal duty cycle D1 is output to the motor to control the motor to rotate in the reverse direction for a predetermined time.

[0021] In some embodiments of the present invention, the calculation formula for the Hall number of the motor initial position is:

[0022] Hall_Counter_Start=Hall_Counter_Init-△Hall1;

[0023] Where Hall_Counter_Start is the Hall counter of the motor's initial position, Hall_Counter_Init is the first motor Hall counter, and ΔHall1 is the first predetermined Hall counter difference determined based on the motor's mechanical structure. The calculation formula for ΔHall1 is:

[0024] △Hall1=K1*K2*K3;

[0025] Wherein, K1 is the transmission efficiency of the gear train, K2 is the transfer function coefficient of the ball screw, and K3 is the first predetermined magnification.

[0026] In some embodiments of the present invention, the calculation formula for the Hall number corresponding to the motor relief gap position is:

[0027] Hall_Counter_R=Hall_Counter_PI-△Hall2;

[0028] Where Hall_Counter_R is the Hall number corresponding to the motor gap relief position, Hall_Counter_PI is the Hall number of the second motor, and △Hall2 is the second predetermined Hall number difference determined based on the motor mechanical structure; the calculation formula of △Hall2 is:

[0029] △Hall2=K1*K2*K4;

[0030] Wherein, K1 is the transmission efficiency of the gear train, K2 is the transfer function coefficient of the ball screw, and K4 is the second predetermined magnification.

[0031] In some embodiments of the present invention, step S5 further includes the following steps:

[0032] Set the stable error band of Hall number closed-loop control to -△Hall_Error to Hall_Error;

[0033] When the motor is subjected to closed-loop control of the Hall number, when the difference between the current Hall number of the motor and the Hall number at the position corresponding to the motor relief gap is within a stable error band, it is determined that the motor has rotated to the relief gap position.

[0034] In some embodiments of the present invention, in step S4, PI control is used to perform closed-loop control of the clamping force of the motor.

[0035] Some embodiments of the present invention further provide an electronic mechanical brake relief clearance control system, comprising:

[0036] at least one processor;

[0037] at least one memory for storing at least one program;

[0038] When at least one program is executed by at least one processor, the at least one processor implements the above-mentioned electronic mechanical brake relief gap control method.

[0039] Some embodiments of the present invention further provide a storage medium storing a program executable by a processor. The program executable by the processor is used to implement the above-mentioned electronic mechanical brake relief gap control method when executed by the processor.

[0040] The beneficial effects of the present invention are:

[0041] 1. The present invention can quickly and accurately identify the initial position of the motor and locate the clearance relief position, effectively solving the problem of unknown initial position of the motor when the brake system is powered on, and providing a stable initial position for subsequent brake application;

[0042] 2. The present invention controls the motor to rotate in the reverse direction for a predetermined time before controlling the motor to rotate forward, so that the clamping force can be quickly relieved when the motor is under high clamping force, thereby preventing the problem of the motor Hall sensor feedback value remaining unchanged at a low duty cycle due to the hysteresis of the mechanical structure, thereby improving positioning accuracy.

[0043] 3. The present invention calculates the Hall number of the motor's initial position based on the feedback state of the Hall sensor during the motor's rotation, ensuring the consistency of the motor during PI clamping force closed-loop control, enabling the motor to quickly apply the clamping force to a stable error band, and improving the speed and stability of the motor's initial position positioning.

[0044] 4. The present invention performs closed-loop control of the clamping force of the motor and performs positioning to alleviate the gap without causing obvious deformation of the transmission mechanism, which can significantly improve the versatility and accuracy of the method.

[0045] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures indicated in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0047] Figure 1 is a structural diagram of an electromechanical braking system;

[0048] Figure 2 This is a flow chart of the electronic mechanical brake relief gap control method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0051] In order to better illustrate the solution of the present invention, the electromechanical brake system is first described.

[0052] As attached Figure 1 As shown in the figure, in an electromechanical braking system, the controller collects signals from the position sensor and controls the forward and reverse rotation of the motor rotor, driving the speed change mechanism. The speed change mechanism then rotates the lead screw mechanism, which converts the rotation into linear motion. The braking force, amplified by the lever structure, is applied to the brake pads to complete the braking action. The application and release of the entire system are determined by the action of the motor. The system applies braking force when the motor rotor is rotating forward, and releases it when the motor rotor is rotating backward.

[0053] The relief gap position is the distance between the brake pad and the brake disc of the rail vehicle in a non-contact state. At this distance, the brake pad and the brake disc have no contact wear, and the braking system can quickly respond to the braking demand so that the brake pad and the brake disc fit together to form braking force.

[0054] However, due to the zero drift problem of the force sensor and the different mechanical characteristics of different clamps, the existing method of determining the absolute position of the motor corresponding to the gap of the clamp has low accuracy and versatility.

[0055] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0056] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and the accompanying drawings.

[0057] As attached Figure 2As shown, in an illustrative embodiment of an electronic mechanical brake clearance control method, system, and storage medium of the present invention, the clearance control method is used to obtain the initial position of the motor when the electronic mechanical brake system is powered on, and control the motor to rotate to the clearance position. The method includes the following steps.

[0058] S1: Control the motor rotation.

[0059] In some embodiments of the present invention, step S1 specifically includes the following steps.

[0060] S11: The controller is set to output a predetermined PWM signal duty cycle D=D1 to the motor, controlling the motor to rotate in the reverse direction and lasting for ΔT1.

[0061] Because the initial motor position is unknown, if the motor is in a high-torque output state, it is necessary to briefly control the motor to reduce its output torque. Controlling the motor to briefly reverse for a predetermined period of time allows the clamping force to be quickly relieved when the motor is under high clamping force. This prevents the Hall effect sensor feedback value from remaining unchanged at low duty cycles due to the mechanical structure's hysteresis, which reduces positioning accuracy.

[0062] Among them, D1 and △T1 are determined based on the physical characteristics of the motor.

[0063] S12: The controller is set to output a predetermined PWM signal duty cycle D=D2 to the motor to control the motor to rotate in the forward direction.

[0064] Controlling the motor to rotate in the forward direction can effectively eliminate the influence of the motor's idle stroke. Regardless of whether the motor is at the end away from the gate piece or the end close to the gate piece, the motor position can be locked in the applied state through the continuous movement of the motor.

[0065] S2: When the error between the current motor Hall sensor feedback value and the previous motor Hall sensor feedback value is less than the predetermined error value △Hall_Error and lasts for a predetermined time, that is, when the feedback state of the Hall sensor in this cycle is basically the same as that in the previous cycle and lasts for a predetermined time, the Hall number of the current motor is recorded as the first motor Hall number.

[0066] In some embodiments of the present invention, the specific implementation method of step S2 includes the following steps.

[0067] Set a counter with an initial value of 0.

[0068] If the error between the current motor Hall sensor feedback value and the previous motor Hall sensor feedback value is less than the predetermined error value, the counter is incremented by 1, otherwise the counter is reset to zero.

[0069] When the counter reaches the predetermined count value COUNTER1, the Hall number of the current motor is recorded as the first motor Hall number Hall_Counter_Init:

[0070] Hall_Counter_Init=Hall_Counter.

[0071] It should be noted that the Hall number of the motor's Hall sensor represents the electrical angle of the motor. When the motor's electrical angle remains unchanged, it means that the motor is in a state of torque and resistance balance. Since the motor's characteristics are consistent, the torque output by different motors at the same duty cycle is relatively small. Therefore, the position of the motor when the motor is in a torque-resistance balance state is also relatively small. Determining the Hall number of the motor when it is in a torque-resistance balance state is conducive to improving the versatility of the control method provided by the present invention in controlling electronic mechanical brake systems of the same series but with different numbers.

[0072] S3: Calculate the Hall number of the motor initial position based on the Hall number of the first motor.

[0073] In some embodiments of the present invention, the calculation formula for the Hall number of the motor initial position is:

[0074] Hall_Counter_Start=Hall_Counter_Init-ΔHall1.

[0075] Where Hall_Counter_Start is the Hall counter of the motor's initial position, Hall_Counter_Init is the first motor Hall counter, and ΔHall1 is the first predetermined Hall counter difference determined based on the motor's mechanical structure. The calculation formula for ΔHall1 is:

[0076] △Hall1=K1*K2*K3.

[0077] Wherein, K1 is the transmission efficiency of the gear train, K2 is the transfer function coefficient of the ball screw, and K3 is the first predetermined magnification. The value of K3 can be obtained through experimental verification. In this embodiment, K3=1.

[0078] S4: Based on the Hall number of the motor's initial position, PI control is used to perform closed-loop control of the motor's clamping force. The target clamping force is F1. When the clamping force output by the motor is within the predetermined clamping force error band ±△F, the Hall number of the current motor is recorded as the second motor Hall number Hall_Counter_PI.

[0079] It should be noted that due to the zero drift phenomenon of the force sensor, when the force sensor feedback is near the zero position, the actual corresponding motor position is not at the contact point between the motor and the brake pad. Therefore, the clamping force output by the motor is controlled at F1 using a closed-loop control of the clamping force. When the force sensor feedback value is F1 after filtering through a low-pass filter, the zero drift value of the force sensor has a relatively small impact (the zero drift value is generally around 0-F2). F1 also means that the clamping force output is small, and the clamp transmission mechanism does not produce significant deformation, which is conducive to improving the accuracy of the motor position for back-thrust clearance relief.

[0080] Furthermore, due to the different physical properties of clamps with different serial numbers within the same batch, the corresponding relationship between deformation and position will also be different. Therefore, positioning to alleviate the gap without causing significant deformation of the transmission mechanism can significantly improve the versatility and accuracy of the control method provided by the present invention.

[0081] S5: Calculate the Hall number corresponding to the motor relief gap position based on the Hall number of the second motor, perform Hall number closed-loop control on the motor based on the Hall number of the position corresponding to the motor relief gap, and control the motor to rotate to the relief gap position.

[0082] In some embodiments of the present invention, the calculation formula for the Hall number corresponding to the motor relief gap position is:

[0083] Hall_Counter_R=Hall_Counter_PI-ΔHall2.

[0084] Where Hall_Counter_R is the Hall number corresponding to the motor gap relief position, Hall_Counter_PI is the Hall number of the second motor, and △Hall2 is the second predetermined Hall number difference determined based on the motor mechanical structure; the calculation formula of △Hall2 is:

[0085] △Hall2=K1*K2*K4.

[0086] Wherein, K1 is the transmission efficiency of the gear train, K2 is the transfer function coefficient of the ball screw, and K4 is the second predetermined magnification. The value of K4 can be obtained through experimental verification. In this embodiment, K4=2.

[0087] In some embodiments of the present invention, step S5 further includes the following steps.

[0088] Set the stable error band of Hall closed-loop control to -△Hall_Error r To △Hall_Error.

[0089] When position closed-loop control is used to perform Hall number closed-loop control on the motor, when the difference between the current Hall number of the motor and the Hall number at the position corresponding to the motor relief gap is within the stable error band, it is determined that the motor has rotated to the relief gap position.

[0090] In the above-mentioned schematic embodiment, the single running time of the gap relief control process is within 30 seconds, which realizes the rapid and accurate identification of the initial position of the motor and positioning of the gap relief position, effectively solving the problem of unknown initial position of the motor when the braking system is powered on, and providing a stable initial position for subsequent braking application.

[0091] During actual application, the relief gap was measured multiple times using a feeler gauge after the above control method was completed. The relief gap error was stable within 0.2 mm, and the gap result was stable and highly accurate.

[0092] The above control method was verified using different batches of clamp transmission mechanisms. A feeler gauge was used to measure the relief gap of different clamps after the above control method was completed. The relief gap error was still stable within 0.2mm. The gap result was stable and accurate, that is, the above control method has high versatility and accuracy.

[0093] Some embodiments of the present invention further provide an electronic mechanical brake relief clearance control system, comprising:

[0094] At least one processor.

[0095] At least one memory is used to store at least one program.

[0096] When at least one program is executed by at least one processor, the at least one processor implements the above-mentioned electronic mechanical brake relief gap control method.

[0097] Some embodiments of the present invention further provide a storage medium storing a program executable by a processor. The program executable by the processor is used to implement the above-mentioned electronic mechanical brake relief gap control method when executed by the processor.

[0098] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0099] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to preferred embodiments, persons skilled in the art should understand that the specific implementation methods of the present invention may still be modified or some technical features may be replaced by equivalents without departing from the spirit of the technical solutions of the present invention, and all of these should fall within the scope of the technical solutions claimed for protection by the present invention.

Claims

1. An electronic mechanical brake relief gap control method, characterized in that: The following steps are involved: S1: controls the motor rotation; S2: When the error between the current motor Hall sensor feedback value and the previous motor Hall sensor feedback value is less than a predetermined error value and lasts for a predetermined time, the current motor Hall number is recorded as a first motor Hall number; S3: Calculating the Hall number of the motor initial position based on the Hall number of the first motor; S4: performing closed-loop control of the clamping force of the motor based on the Hall value of the initial position of the motor, and when the clamping force output by the motor is within a predetermined clamping force error band, recording the current Hall value of the motor as the second motor Hall value; S5: Calculate the Hall number corresponding to the motor relief gap position based on the Hall number of the second motor, perform Hall number closed-loop control on the motor based on the Hall number of the position corresponding to the motor relief gap, and control the motor to rotate to the relief gap position.

2. The electronic mechanical brake relief gap control method according to claim 1, characterized in that: The specific implementation method of step S2 is: Set a counter with an initial value of 0; If the error between the current motor Hall sensor feedback value and the previous motor Hall sensor feedback value is less than the predetermined error value, the counter is incremented by 1, otherwise the counter is reset to zero. When the counter reaches a predetermined count value, the Hall number of the current motor is recorded as the first motor Hall number.

3. The electronic mechanical brake relief gap control method according to claim 1, characterized in that: The specific implementation method of step S1 is: A predetermined PWM signal duty cycle is output to the motor to control the motor to rotate in the forward direction.

4. The electronic mechanical brake relief gap control method according to claim 3, characterized in that: Step S1 further includes the following steps: Before controlling the motor to rotate forward, a predetermined PWM signal duty cycle is output to the motor to control the motor to rotate in the reverse direction for a predetermined time.

5. The electronic mechanical brake relief gap control method according to claim 1, characterized in that: The calculation formula of the Hall number of the motor initial position is: Hall_Counter_Start=Hall_Counter_Init-△Hall1; Where Hall_Counter_Start is the Hall counter of the motor's initial position, Hall_Counter_Init is the first motor Hall counter, and ΔHall1 is the first predetermined Hall counter difference determined based on the motor's mechanical structure. The calculation formula for ΔHall1 is: △Hall1=K1*K2*K3; Wherein, K1 is the transmission efficiency of the gear train, K2 is the transfer function coefficient of the ball screw, and K3 is the first predetermined magnification.

6. The electronic mechanical brake relief gap control method according to claim 1, characterized in that: The calculation formula for the Hall number corresponding to the motor relief gap position is: Hall_Counter_R=Hall_Counter_PI-△Hall2; Where Hall_Counter_R is the Hall number corresponding to the motor gap relief position, Hall_Counter_PI is the Hall number of the second motor, and △Hall2 is the second predetermined Hall number difference determined based on the motor mechanical structure; the calculation formula of △Hall2 is: △Hall2=K1*K2*K4; Wherein, K1 is the transmission efficiency of the gear train, K2 is the transfer function coefficient of the ball screw, and K4 is the second predetermined magnification.

7. The electronic mechanical brake relief gap control method according to claim 1, characterized in that: Step S5 further includes the following steps: Set the stable error band of Hall closed-loop control to -△Hall_Error to △Hall_Error; When the motor is subjected to closed-loop control of the Hall number, when the difference between the current Hall number of the motor and the Hall number of the position corresponding to the motor relief gap is within the stable error band, it is determined that the motor has rotated to the relief gap position.

8. The electronic mechanical brake relief gap control method according to claim 1, characterized in that: In step S4, PI control is used to perform closed-loop control of the clamping force of the motor.

9. An electronic mechanical brake relief gap control system, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the electronic mechanical brake relief gap control method according to any one of claims 1 to 8.

10. A storage medium storing a program executable by a processor, characterized in that: The processor-executable program is used to implement the electronic mechanical brake relief gap control method according to any one of claims 1 to 8 when executed by the processor.

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