A motor angle correction method for an electromechanical brake system based on model compensation

Abstract

The present invention discloses a method for correcting the rotation angle of a motor of an electronic mechanical brake system based on model compensation, the method comprising: obtaining target parameters of the motor, the target parameters comprising current and rotation angle; determining friction load according to the target parameters of the motor; calculating the speed change rate of the motor according to the current and the friction load; calculating the average speed within a control output delay time according to the speed change rate of the motor; and calculating the rotation angle calibration value according to the average speed within the control output delay time. The present invention takes into account that the motor speed signal also changes within the control step time, and therefore calculates the speed change rate of the motor through a system dynamics model, and integrates the speed change rate of the motor within the control step time to obtain a more accurate correction angle.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicles, and in particular relates to a method for correcting a motor rotation angle of an electronic mechanical brake system based on model compensation. Background Art

[0002] Usually, motors are installed on vehicles, and motors can be used for braking. In the FOC (Field Oriented Control) control process of the motor, the current motor angle is required. Since there is an irreconcilable time difference between the acquisition, calculation and output of the angle signal, when the motor speed is high, there is an error in the speed signal used for control. The current method is to make corrections based on the product of the motor speed in the previous cycle and the control step length. However, the motor speed signal also changes within the control step length, so the angle corrected by the above method will still have a certain error and low accuracy. Summary of the invention

[0003] An object of the present invention is to provide a method for correcting the rotation angle of a motor of an electronic mechanical brake system based on a model compensation, which can solve the technical problem of low accuracy in correcting the rotation angle of a motor in the prior art.

[0004] According to a first aspect of the present invention, a method for correcting a motor rotation angle of an electronic mechanical brake system based on model compensation is provided, the method comprising:

[0005] Acquire target parameters of the motor, wherein the target parameters include current and rotation angle;

[0006] determining a friction load according to target parameters of the motor;

[0007] Calculating a speed change rate of the motor according to the current and the friction load;

[0008] Calculate the average speed within the control output delay time according to the speed change rate of the motor;

[0009] The rotation angle calibration value is calculated according to the average rotation speed within the control output delay time.

[0010] Optionally, determining the friction load according to the target parameters of the motor includes:

[0011] Performing a plate-touching detection on the motor;

[0012] If no disc contact occurs, use a fixed friction load;

[0013] If disc contact occurs, the friction load is calculated based on the brake system model.

[0014] Optionally, calculating the friction load according to the brake system model includes:

[0015] The brake clamping force is calculated according to the rotation angle of the motor, and the calculation formula is as follows:

[0016] ;

[0017] in, is the brake clamping force, , , is the system stiffness constant, is the rotation angle of the motor;

[0018] The load torque applied to the screw is calculated based on the brake clamping force, and the calculation formula is as follows:

[0019] ;

[0020] in, is the load torque applied to the screw, is the screw lead constant, is the screw efficiency constant, is the brake clamping force;

[0021] The load torque applied to the motor shaft is calculated based on the load torque applied to the screw rod. The calculation formula is as follows:

[0022] ;

[0023] in, is the load torque applied to the motor shaft, is the load torque applied to the screw, is the reduction ratio constant of the reduction mechanism, is the efficiency constant of the reduction mechanism.

[0024] Optionally, calculating the speed change rate of the motor according to the current and the friction load includes:

[0025] The driving torque of the motor is calculated according to the current of the motor, and the calculation formula is as follows:

[0026] ;

[0027] in, is the driving torque of the motor, is the torque constant of the motor, is the current of the motor;

[0028] The speed change rate of the motor is calculated according to the driving torque of the motor and the friction load of the motor, and the calculation formula is as follows:

[0029] ;

[0030] in, is the speed change rate of the motor, is the driving torque of the motor, is the load torque applied to the motor shaft, is the total friction torque constant, is the total moment of inertia of the system.

[0031] Optionally, the calculating the average speed within the control output delay time according to the motor speed change rate includes:

[0032] Calculating the rotation speed of the motor according to the target parameters of the motor;

[0033] The average speed during the control output delay period is calculated according to the following formula:

[0034] ;

[0035] in, is the average speed within the control output delay time, For a fixed delay time, is the speed of the motor, is the speed change rate of the motor.

[0036] Optionally, the calculating the rotation angle calibration value according to the average rotation speed within the control output delay time includes:

[0037] The rotation angle calibration value is calculated according to the following formula:

[0038] ;

[0039] in, is the angle calibration value, is the rotation angle of the motor, is the average speed within the control output delay time, is a fixed delay time.

[0040] According to a second aspect of the present invention, there is provided a device for correcting a motor rotation angle of an electronic mechanical brake system based on model compensation, comprising:

[0041] An acquisition module, used for acquiring target parameters of the motor, wherein the target parameters include current and rotation angle;

[0042] A first calculation module, configured to determine a friction load according to a target parameter of the motor;

[0043] A second calculation module, used for calculating the speed change rate of the motor according to the current and the friction load;

[0044] A third calculation module, used for calculating the average speed within the control output delay time according to the speed change rate of the motor;

[0045] The fourth calculation module is used to calculate the rotation angle calibration value according to the average rotation speed within the control output delay time.

[0046] According to a third aspect of the present invention, an electronic device is provided, comprising a processor and a memory, wherein the memory stores programs or instructions that can be executed on the processor, and when the program or instructions are executed by the processor, the steps of a method for correcting the motor angle of an electronic mechanical braking system based on model compensation as described in the first aspect of the present invention are implemented.

[0047] According to a fourth aspect of the present invention, a vehicle is provided, comprising an electronic device according to the third aspect of the present invention.

[0048] According to a fifth aspect of the present invention, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of a method for correcting the motor angle of an electronic mechanical braking system based on model compensation as described in the first aspect of the present invention are implemented.

[0049] The beneficial effect of the present invention is that: the present invention takes into account that the motor speed signal also changes within the control step time, and therefore calculates the motor speed change rate through the system dynamics model, and integrates the motor speed change rate within the control step time to obtain a more accurate correction angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a flowchart of a method for correcting a motor rotation angle of an electronic mechanical brake system based on model compensation in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0052] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0053] The techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered as part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0054] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0055] In the specification and claims of the present invention, if the term "first" or "second" is involved, it may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the related objects are in an "or" relationship.

[0056] like Figure 1 As shown, this embodiment introduces a method for correcting the motor rotation angle of an electronic mechanical brake system based on model compensation, and the method includes steps 1100-1500.

[0057] Step 1100: Obtain target parameters of the motor, where the target parameters include current and rotation angle.

[0058] The motor of the present invention is a motor in a vehicle braking system. In the vehicle braking system, the motor controls the caliper to apply a brake clamping force to the wheel to achieve braking of the vehicle. When the vehicle is not braked, there is a certain distance between the caliper and the wheel. When the vehicle needs to be braked, the motor controls the caliper to move so that the caliper hits the wheel and applies a brake clamping force to the wheel. The motor can be detected by various detection devices to obtain the target parameters of the motor.

[0059] Step 1200: Determine the friction load according to the target parameters of the motor.

[0060] When the caliper hits the wheel, friction is generated between the caliper and the wheel. The friction between the caliper and the wheel is transmitted through the screw, generating a load torque on the motor shaft. The friction load is the load torque applied to the motor shaft. The load torque applied to the motor shaft is related to the size of the brake clamping force. The greater the brake clamping force, the greater the load torque applied to the motor shaft.

[0061] Step 1300: Calculate the speed change rate of the motor according to the current and the friction load.

[0062] Here, the speed change rate of the motor is calculated to find out the speed change rate of the motor within the control output delay time.

[0063] Specifically, step 1300 includes steps 1310-1320.

[0064] Step 1310: Calculate the driving torque of the motor according to the current of the motor, and the calculation formula is as follows.

[0065] .

[0066] in, is the driving torque of the motor, is the torque constant of the motor, is the current of the motor.

[0067] Step 1320: Calculate the speed change rate of the motor according to the driving torque of the motor and the friction load of the motor, and the calculation formula is as follows.

[0068] .

[0069] in, is the speed change rate of the motor, is the driving torque of the motor, is the load torque applied to the motor shaft, is the total friction torque constant, is the total moment of inertia of the system.

[0070] Step 1400: Calculate the average speed within the control output delay time according to the speed change rate of the motor.

[0071] Specifically, the step 1400 includes: calculating the rotation speed of the motor according to the target parameters of the motor; and calculating the average rotation speed within the control output delay time according to the following formula.

[0072] .

[0073] in, is the average speed within the control output delay time, For a fixed delay time, is the speed of the motor, is the speed change rate of the motor.

[0074] The motor speed is related to the motor current. The motor speed is calculated based on the motor current and motor load. The rate of change of motor speed Indicates the degree of change in the motor's speed.

[0075] In the present invention, it is considered that during the delay time The speed of the internal motor changes linearly. So for any moment in the delay time , the motor speed The expression is as follows.

[0076] .

[0077] In the above formula, The value is between 0 and The motor speed It is the speed calculated based on the collected target parameters of the motor, and the corresponding moment is 0.

[0078] According to the above formula, the motor speed at the end of the delay time can be obtained .

[0079] .

[0080] Then the average speed of the motor during the control output delay time is the motor speed The speed of the motor at the end of the delay time The average value of .

[0081] .

[0082] Step 1500: Calculate the rotation angle calibration value according to the average rotation speed within the control output delay time.

[0083] The control output delay time indicates the delay time between collecting the motor angle and outputting the control signal. The average speed of the motor during the control output delay time can reflect the change of the motor angle during the control output delay time. By making corrections based on the change of the motor angle during the delay time, a more accurate motor angle can be obtained.

[0084] The present invention takes into account that the motor speed signal also changes within the control step time, and therefore calculates the motor speed change rate through a system dynamics model, and integrates the motor speed change rate within the control step time to obtain a more accurate correction angle.

[0085] In this embodiment, step 1200 includes steps 1210-1230.

[0086] Step 1210: Perform a plate-touching detection on the motor.

[0087] The motor contact detection is to detect whether the caliper touches the wheel. When the vehicle does not need to be braked, the caliper does not touch the wheel. When the vehicle needs to be braked, the caliper touches the wheel, and the motor applies the brake clamping force to the wheel through the caliper.

[0088] The brake system includes a motor, a lead screw and a caliper. The lead screw can convert the motor's rotational motion into linear motion, which in turn drives the caliper to move, controls the caliper to contact the wheel, and achieves vehicle braking. The position of the caliper can be calculated based on the motor's rotation angle, and whether the caliper is in contact with the wheel can be determined to achieve disc contact detection.

[0089] Step 1220: If no plate contact occurs, use a fixed friction load.

[0090] When there is no contact with the disc, there is a certain distance between the caliper and the wheel, the caliper does not touch the wheel, and there is no friction between the caliper and the wheel. In this case, a pre-set fixed friction load is used. The fixed friction load is determined according to the vehicle's braking system and can be calibrated on a real vehicle.

[0091] Step 1230: If the disc hits, calculate the friction load according to the brake system model.

[0092] When the disc hits the wheel, friction occurs between the caliper and the wheel. The friction load is related to the brake clamping force and needs to be calculated based on the actual situation of the motor.

[0093] In this embodiment, step 1230 includes steps 1231-1233.

[0094] Step 1231: Calculate the brake clamping force according to the rotation angle of the motor, and the calculation formula is as follows.

[0095] .

[0096] in, is the brake clamping force, , , is the system stiffness constant, is the rotation angle of the motor.

[0097] is the measured value of the rotation angle of the motor, that is, the rotation angle in the target parameter of the motor. , , is the stiffness constant determined according to the vehicle braking system. Brake clamping force The force applied by the caliper to the wheel in the vehicle's braking system.

[0098] Step 1232: Calculate the load torque applied to the screw rod according to the brake clamping force, and the calculation formula is as follows.

[0099] .

[0100] in, is the load torque applied to the screw, is the screw lead constant, is the screw efficiency constant, is the brake clamping force.

[0101] Screw lead constant And the screw efficiency constant Determined according to the specific model of the screw.

[0102] Step 1233: Calculate the load torque applied to the motor shaft according to the load torque applied to the screw rod, and the calculation formula is as follows.

[0103] .

[0104] in, is the load torque applied to the motor shaft, is the load torque applied to the screw, is the reduction ratio constant of the reduction mechanism, is the efficiency constant of the reduction mechanism.

[0105] In this embodiment, the step 1500 includes: calculating the rotation angle calibration value according to the following formula.

[0106] .

[0107] in, is the angle calibration value, is the rotation angle of the motor, is the average speed within the control output delay time, is a fixed delay time. The fixed delay time is usually very small, for example, the fixed delay time is at the microsecond level, which can be obtained through actual measurement.

[0108] After calculating the average speed during the control output delay time, the rotation angle is corrected. Calculating the average speed during the control output delay time With fixed delay time The product of The change value of the motor angle is compared with the detected value of the motor angle. Add them together to get the angle calibration value.

[0109] This embodiment introduces a motor angle correction device for an electronic mechanical brake system based on model compensation, including: an acquisition module, used to acquire target parameters of the motor, the target parameters including current and angle; a first calculation module, used to determine the friction load according to the target parameters of the motor; a second calculation module, used to calculate the speed change rate of the motor according to the current and the friction load; a third calculation module, used to calculate the average speed within the control output delay time according to the speed change rate of the motor; and a fourth calculation module, used to calculate the angle calibration value according to the average speed within the control output delay time.

[0110] This embodiment introduces an electronic device, including a processor and a memory, wherein the memory stores programs or instructions that can be run on the processor, and when the program or instructions are executed by the processor, the steps of a method for correcting the motor angle of an electronic mechanical braking system based on model compensation as described in any embodiment of the present invention are implemented.

[0111] This embodiment introduces a vehicle, including an electronic device described in an embodiment of the present invention.

[0112] This embodiment introduces a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of a method for correcting the motor angle of an electronic mechanical brake system based on model compensation as described in any embodiment of the present invention are implemented.

[0113] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

[0114] Those of ordinary skill in the art will appreciate that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0115] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and equipment can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0116] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0117] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0118] In addition, each functional module in the embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0119] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the energy-saving signal sending / receiving method of each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0120] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

[0121] It should be understood that the size of the sequence number of each step in the content of the invention and the embodiments of the present invention does not absolutely mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention. For the purpose of example and description, the foregoing description of the implementation of the present disclosure has been given. The foregoing description is not exhaustive and is not intended to limit the present disclosure to the exact form disclosed. Various deformations and modifications may exist according to the above teachings, or various deformations and modifications may be obtained from the practice of the present disclosure. These embodiments are selected and described to illustrate the principles of the present disclosure and its practical application, so that those skilled in the art can use the present disclosure in various embodiments and various modifications suitable for the specific purpose conceived.

Claims

1. A method for correcting the motor rotation angle of an electronic mechanical brake system based on model compensation, characterized in that: The method comprises: Acquire target parameters of the motor, wherein the target parameters include current and rotation angle; determining a friction load according to target parameters of the motor; Calculating a speed change rate of the motor according to the current and the friction load; Calculate the average speed within the control output delay time according to the speed change rate of the motor; Calculating a rotation angle calibration value according to the average rotation speed within the control output delay time; The determining of the friction load according to the target parameters of the motor comprises: Performing a plate-touching detection on the motor; If no disc contact occurs, use a fixed friction load; If disc contact occurs, calculate the friction load based on the brake system model; The calculating the friction load according to the brake system model comprises: The brake clamping force is calculated according to the rotation angle of the motor, and the calculation formula is as follows: ； in, is the brake clamping force, is the system stiffness constant, is the rotation angle of the motor; The load torque applied to the screw is calculated based on the brake clamping force, and the calculation formula is as follows: ； in, is the load torque applied to the screw, is the screw lead constant, is the screw efficiency constant, is the brake clamping force; The load torque applied to the motor shaft is calculated based on the load torque applied to the screw rod. The calculation formula is as follows: ； in, is the load torque applied to the motor shaft, is the load torque applied to the screw, is the reduction ratio constant of the reduction mechanism, is the efficiency constant of the reduction mechanism.

2. The method according to claim 1, characterized in that The calculating the speed change rate of the motor according to the current and the friction load includes: The driving torque of the motor is calculated according to the current of the motor, and the calculation formula is as follows: ； in, is the driving torque of the motor, is the torque constant of the motor, is the current of the motor; The speed change rate of the motor is calculated according to the driving torque of the motor and the friction load of the motor, and the calculation formula is as follows: ； in, is the speed change rate of the motor, is the driving torque of the motor, is the load torque applied to the motor shaft, is the total friction torque constant, is the total moment of inertia of the system.

3. The method according to claim 2, characterized in that The step of calculating the average speed within the control output delay time according to the motor speed change rate comprises: Calculating the rotation speed of the motor according to the target parameters of the motor; The average speed during the control output delay period is calculated according to the following formula: ； in, is the average speed within the control output delay time, For a fixed delay time, is the speed of the motor, is the speed change rate of the motor.

4. The method according to claim 3, characterized in that The calculating of the rotation angle calibration value according to the average rotation speed within the control output delay time comprises: The rotation angle calibration value is calculated according to the following formula: ； in, is the angle calibration value, is the rotation angle of the motor, is the average speed within the control output delay time, is a fixed delay time.

5. A motor angle correction device for an electronic mechanical brake system based on model compensation, characterized in that: include: An acquisition module, used for acquiring target parameters of the motor, wherein the target parameters include current and rotation angle; A first calculation module, configured to determine a friction load according to a target parameter of the motor; A second calculation module, used for calculating the speed change rate of the motor according to the current and the friction load; A third calculation module, used for calculating the average speed within the control output delay time according to the speed change rate of the motor; A fourth calculation module, used for calculating the rotation angle calibration value according to the average rotation speed within the control output delay time; The first calculation module is also used for: Performing a plate-touching detection on the motor; If no disc contact occurs, use a fixed friction load; If disc contact occurs, calculate the friction load based on the brake system model; The brake clamping force is calculated according to the rotation angle of the motor, and the calculation formula is as follows: ； in, is the brake clamping force, is the system stiffness constant, is the rotation angle of the motor; The load torque applied to the screw is calculated based on the brake clamping force, and the calculation formula is as follows: ； in, is the load torque applied to the screw, is the screw lead constant, is the screw efficiency constant, is the brake clamping force; The load torque applied to the motor shaft is calculated based on the load torque applied to the screw rod. The calculation formula is as follows: ； in, is the load torque applied to the motor shaft, is the load torque applied to the screw, is the reduction ratio constant of the reduction mechanism, is the efficiency constant of the reduction mechanism.

6. An electronic device, characterized in that: It includes a processor and a memory, wherein the memory stores programs or instructions that can be run on the processor, and when the programs or instructions are executed by the processor, the steps of a method for correcting the motor angle of an electronic mechanical brake system based on model compensation as described in any one of claims 1 to 4 are implemented.

7. A vehicle, characterized in that: An electronic device comprising the electronic device described in claim 6.

8. A readable storage medium, characterized in that: The readable storage medium stores a program or instruction, and when the program or instruction is executed by the processor, the steps of the method for correcting the motor angle of an electronic mechanical brake system based on model compensation as described in any one of claims 1 to 4 are implemented.

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