Method, device and storage medium for determining caliper clamping force

Abstract

The present application discloses a method, device and storage medium for determining the clamping force of a caliper, the method comprising: when the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold, collecting the voltage value and current value of the motor; obtaining multiple motor parameter groups collected within a preset time period; each motor parameter group includes a collection time, a voltage value corresponding to the collection time, and a current value corresponding to the collection time; the preset time period is a time period with a first moment as the starting moment and a second moment as the ending moment; constructing a current-time relationship according to the collection time and the current value corresponding to the collection time; determining the working state of the motor according to the current-time relationship and the voltage value corresponding to the collection time; if the working state of the motor indicates that the motor is in a normal working state, determining the clamping force of the caliper fixedly connected to the motor. The present application improves the accuracy and reliability of the calculation results of the clamping force of the caliper.

Description

Technical Field

[0001] The present application relates to the field of electronic parking brake control, and in particular to a method, device and storage medium for determining caliper clamping force. Background Art

[0002] There are two main types of electronic parking brake systems, namely, wire-pull type and integrated type. In recent years, the integrated electronic parking brake system has been widely popularized due to its compact structure, fast response speed, and intelligent and automated control, and has become the standard configuration of current vehicles. Most of the current electronic parking brake systems use an integrated system, that is, the motor is directly integrated with the brake caliper, and the motor drives the gear and screw reduction mechanism to drive the caliper, thereby realizing the clamping and releasing functions of the caliper.

[0003] At present, the estimation of the clamping force of the integrated electronic parking brake system during clamping is basically based on the one-to-one correspondence between the current and the clamping force collected in advance at room temperature, and the clamping force is obtained by looking up the table of the current fed back by the DC motor during clamping. However, this method requires the use of pressure sensors on the equipment in advance to test different types of calipers and record the correspondence between current and clamping force. Although the calipers are of the same type, the correspondence between current and clamping force is slightly different, especially under different temperatures. The clamping force obtained by this table lookup method and the actual clamping force will have a more obvious error. Because for the integrated electronic parking brake system, its motor is close to the brake disc. When braking for a long time, the temperature around the motor will change greatly. The temperature will affect the internal resistance and torque constant of the motor, change the performance of the motor, and thus affect the correspondence between current and caliper clamping force. The clamping force found by the table lookup method is the clamping force obtained by testing at a specific temperature before, so there is a certain error with the clamping force at high temperature, which leads to problems in controlling the clamping of the parking caliper. For example, insufficient clamping force can cause serious problems such as vehicle sliding down a slope. Summary of the invention

[0004] The present application provides a method, device and storage medium for determining the clamping force of a caliper, which can improve the accuracy and reliability of the calculation results of the clamping force of the caliper.

[0005] In one aspect, the present application provides a method for determining a caliper clamping force, the method comprising:

[0006] When the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold, the voltage value and current value of the motor are collected; the motor is used to drive the caliper to clamp;

[0007] Acquire multiple groups of motor parameter groups collected within a preset time period; each of the motor parameter groups includes a collection time, a voltage value corresponding to the collection time, and a current value corresponding to the collection time; the preset time period is a time period starting at a first moment and ending at a second moment; the first moment is a moment when the current of the motor is at a peak value; the second moment is a moment when the current of the motor tends to be stable;

[0008] Constructing a current-time relationship according to the acquisition time and the current value corresponding to the acquisition time;

[0009] Determining the working state of the motor according to the current-time relationship and the voltage value corresponding to the acquisition time;

[0010] If the working state of the motor indicates that the motor is in a normal working state, a clamping force of the caliper fixedly connected to the motor is determined.

[0011] In an exemplary embodiment, constructing a current-time relationship according to the acquisition time and the current value corresponding to the acquisition time includes:

[0012] Obtaining a current value when the current of the motor is in a stable state to obtain a stable current value;

[0013] Constructing a preliminary current-time relationship according to the current value corresponding to the acquisition time and the stable current value;

[0014] Fitting the acquisition time and the preliminary current-time relationship to obtain an average value of the acquisition time and an average value of the current value corresponding to the acquisition time;

[0015] Determine a slope and an intercept according to an average value of the acquisition time and an average value of the current value corresponding to the acquisition time;

[0016] The current-time relationship is constructed according to the slope and the intercept.

[0017] In an exemplary embodiment, determining the working state of the motor according to the current-time relationship and the voltage value corresponding to the acquisition time includes:

[0018] Determine a state parameter corresponding to the motor according to the current-time relationship and the voltage value corresponding to the acquisition time; the state parameter includes a state coefficient corresponding to the motor;

[0019] Determining a first state parameter according to a state coefficient corresponding to the motor;

[0020] If the first state parameter is greater than or equal to a first state parameter threshold, determining that the motor is in a normal working state, and controlling the motor to continue working;

[0021] If the first state parameter is less than the first state parameter threshold, it is determined that the motor is in a fault state, and the motor is controlled to stop working.

[0022] In an exemplary embodiment, the state parameter further includes the resistance of the motor, the mechanical time constant of the motor, and the electrical time constant of the motor; and determining the state parameter corresponding to the motor according to the current-time relationship and the voltage value corresponding to the acquisition time includes:

[0023] Determine a state coefficient corresponding to the motor according to the acquisition time, the average value of the acquisition time, the current value corresponding to the acquisition time, and the average value of the current value corresponding to the acquisition time;

[0024] determining a relationship constant of the motor according to the intercept;

[0025] Determining a mechanical time constant of the motor according to the slope;

[0026] The electrical time constant of the motor and the resistance value of the motor are determined according to the relationship constant of the motor, the voltage value corresponding to the acquisition time, and the mechanical time constant of the motor.

[0027] In an exemplary embodiment, if the first state parameter is greater than or equal to a first state parameter threshold, it is determined that the motor is in a normal working state, and after controlling the motor to continue working, the method further includes:

[0028] Determining a second state parameter according to a mechanical time constant of the motor and an electrical time constant of the motor;

[0029] If the second state parameter is less than or equal to a second state parameter threshold, the state parameter corresponding to the motor at the first moment is calculated according to the voltage value and the current value at the first moment to obtain the current state parameter;

[0030] Determining the working state information of the motor according to a mechanical time constant corresponding to the current state parameter and an electrical time constant corresponding to the current state parameter;

[0031] If the working state information of the motor indicates that the motor is in a normal working state, the motor is controlled to continue working.

[0032] In an exemplary embodiment, determining the working state information of the motor according to a mechanical time constant corresponding to the current state parameter and an electrical time constant corresponding to the current state parameter includes:

[0033] determining a third state parameter according to a mechanical time constant corresponding to the current state parameter and an electrical time constant corresponding to the current state parameter;

[0034] If the third state parameter is greater than a third state parameter threshold, determining that the motor is in a normal working state, and controlling the motor to continue working;

[0035] If the third state parameter is less than or equal to the third state parameter threshold, it is determined that the motor is in a fault state, and the motor is controlled to stop working.

[0036] In an exemplary embodiment, if the working state of the motor indicates that the motor is in a normal working state, determining the clamping force of the caliper fixedly connected to the motor includes:

[0037] If the working state of the motor indicates that the motor is in a normal working state, obtaining a current voltage value and a current current value of the motor at a current moment;

[0038] The clamping force of the caliper fixedly connected to the motor is determined according to the current voltage value and the current current value of the motor.

[0039] On the other hand, a device for determining the clamping force of a caliper is provided, the device comprising:

[0040] A collection module, used for collecting the voltage value and current value of the motor when the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold; the motor is used to drive the caliper to clamp;

[0041] A motor parameter group acquisition module, used to acquire multiple motor parameter groups collected within a preset time period; each motor parameter group includes an acquisition time, a voltage value corresponding to the acquisition time, and a current value corresponding to the acquisition time; the preset time period is a time period starting at a first moment and ending at a second moment; the first moment is a moment when the current of the motor is at a peak value; the second moment is a moment when the current of the motor tends to be stable;

[0042] A current-time relationship determination module, configured to construct a current-time relationship according to the acquisition time and the current value corresponding to the acquisition time;

[0043] A working state determination module, used for determining the working state of the motor according to the current-time relationship and the voltage value corresponding to the acquisition time;

[0044] The clamping force determination module is used to determine the clamping force of the caliper fixedly connected to the motor if the working state of the motor indicates that the motor is in a normal working state.

[0045] On the other hand, an electronic device is provided, which includes a processor and a memory, wherein the memory stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded by the processor and executes the method for determining the clamping force of the caliper as described above.

[0046] On the other hand, a computer-readable storage medium is provided, wherein at least one instruction or at least one program is stored in the storage medium, and the at least one instruction or at least one program is loaded and executed by a processor to implement the method for determining the clamping force of the caliper as described above.

[0047] On the other hand, a computer program product or a computer program is provided, the computer program product or the computer program comprising computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes to implement the method for determining the clamping force of a caliper as described above.

[0048] The present application provides a method, device and storage medium for determining the clamping force of a caliper, which have the following technical effects:

[0049] The present application collects the voltage value and current value of the motor when the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold; the motor is used to drive the caliper to clamp; multiple groups of motor parameter groups collected within a preset time period are obtained; each of the motor parameter groups includes a collection time, a voltage value corresponding to the collection time, and a current value corresponding to the collection time; the preset time period is a time period with a first moment as a starting moment and a second moment as an ending moment; the first moment is a moment when the current of the motor is at a peak value; the second moment is a moment when the current of the motor tends to be stable; a current-time relationship is constructed according to the collection time and the current value corresponding to the collection time; the working state of the motor is determined according to the current-time relationship and the voltage value corresponding to the collection time; if the working state of the motor indicates that the motor is in a normal working state, the clamping force of the caliper fixedly connected to the motor is determined. The present application first detects the state of the caliper and the working process of the motor to ensure that the motor is started in the correct state, thereby improving the stability of the electronic parking brake system; by real-time detection of the motor current, multiple groups of motor parameter groups within a preset time period are obtained to provide a reference basis for subsequent data processing, and the motor is ensured to enter a stable working state; by using multiple groups of motor parameter groups for subsequent data processing, this algorithm can calculate the caliper clamping force at different operating temperatures; by using the acquisition time and the acquired current value to establish a current-time relationship, a basis is provided for calculating the clamping force of the caliper; the acquired voltage value and the current-time relationship are combined to obtain the working state of the motor, and the clamping force of the caliper is calculated when the motor is in a normal working state, thereby realizing real-time acquisition of the working state of the motor, simplifying the calculation process, improving the practicability of the caliper clamping force algorithm, expanding the scope of application, improving the reliability of the electronic parking brake system, and improving the accuracy and reliability of the caliper clamping force calculation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 is a flow chart of a method for determining a clamping force of a caliper provided in an embodiment of this specification;

[0052] Figure 2 is a structural principle diagram of an integrated electronic parking brake system provided in an embodiment of this specification;

[0053] Figure 3 is a graph showing the relationship between the current of a motor and time provided in an embodiment of this specification;

[0054] Figure 4 It is a schematic diagram of a flow chart for constructing a current-time relationship provided in an embodiment of this specification;

[0055] Figure 5 It is a simplified schematic diagram of the circuit during the working process of the motor provided in the embodiment of this specification;

[0056] Figure 6 It is a flowchart of first state parameter determination provided by an embodiment of this specification;

[0057] Figure 7 is a schematic diagram of a flow chart of determining state parameters provided in an embodiment of this specification;

[0058] Figure 8 It is a flowchart of second state parameter determination provided by the embodiment of this specification;

[0059] Fig. 9 It is a schematic diagram of the process of determining the third state parameter provided in the embodiment of this specification;

[0060] Fig.10 is a schematic diagram of a flow chart for calculating the clamping force of a caliper provided in an embodiment of this specification;

[0061] Fig.11 It is a schematic diagram of the structure of a device for determining the clamping force of a caliper provided in an embodiment of this specification.

[0062] Fig.12 It is a structural schematic diagram of a server of a method for determining a caliper clamping force provided in an embodiment of this specification. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0064] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0065] The following describes a method for determining the clamping force of a caliper of the present application. Figure 1 It is a flowchart of a method for determining the clamping force of a caliper provided in an embodiment of this specification. This specification provides method operation steps as described in the embodiment or flowchart, but may include more or fewer operation steps based on conventional or non-creative labor. The order of steps listed in the embodiment is only one way of executing the steps among many orders, and does not represent the only order of execution. When the actual system or server product is executed, it can be executed in sequence or in parallel (for example, in a parallel processor or multi-threaded processing environment) according to the method shown in the embodiment or the drawings. Specifically, Figure 1 As shown, the method can be applied to a control unit in an integrated electronic parking brake system, and the method includes:

[0066] S101: When the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold, the voltage value and the current value of the motor are collected; the motor is used to drive the caliper to clamp.

[0067] In the embodiments of this specification, Figure 2 As shown, Figure 2The schematic diagram of the structure of an integrated electronic parking brake system is shown in FIG. 201, a motor, a gear, a rotating screw, a push rod, a push rod, four planetary pinions, a first-stage reduction gear, a second-stage reduction gear, and a third-stage reduction gear. T0 is the total torque output by the motor, T is the effective torque obtained by the push rod, and F is the thrust acting on the push rod, i.e., the clamping force of the caliper. During the operation of the integrated electronic parking brake system, the motor and the caliper are both electrically connected to the controller. When the caliper is in the process of changing from a released state to a clamped state, the motor drives the gear of the reduction transmission to rotate, thereby achieving the effect of reducing speed and increasing torque. Finally, the rotational torque is converted into a moving force by rotating the thread between the screw and the push rod, thereby pushing the caliper to clamp and achieve parking brake. The preset starting voltage threshold can be 2V. During the clamping process, the motor starts first, and the state of the caliper is read at this time. When the caliper state is released and the voltage value of the motor is greater than 2v, it means that the motor has started and started the clamping process. At this time, the voltage and current values ​​fed back to the controller by the caliper can be collected in real time every 1ms. By collecting the voltage and current values ​​of the motor when the motor starts and begins to clamp, it is easy to detect abnormal conditions of the motor and promptly confirm whether the motor is in the expected working state. At the same time, improvements can be made based on the collected data to reduce energy consumption.

[0068] S103: Acquire multiple groups of motor parameter groups collected within a preset time period; each of the motor parameter groups includes a collection time, a voltage value corresponding to the collection time, and a current value corresponding to the collection time; the preset time period is a time period starting at a first moment and ending at a second moment; the first moment is a moment when the current of the motor is at its peak; the second moment is a moment when the current of the motor tends to be stable.

[0069] In the embodiments of this specification, Figure 3 As shown, Figure 3 It is a graph showing the relationship between the motor current and time. During the acquisition process, the motor parameter group is acquired at intervals of 1ms, and the tth group of data collected represents the data at tms; the first moment may be t0, at which the motor current reaches its peak value; the second moment may be t1, at which the motor speed has not reached the maximum, that is, the motor current has not stabilized near a certain value, but tends to be stable; at this time, based on the preset time period from t0 to t1, n1 groups of motor parameter groups within the preset time period can be obtained, and data recording can be stopped. By obtaining multiple groups of motor parameter groups within the preset time period, it is easy to capture the dynamic process of the caliper clamping force changing with time, improve the accuracy of the caliper clamping force calculation results, and at the same time, detect abnormal conditions in time, and improve the reliability of the electronic parking brake system.

[0070] S105: constructing a current-time relationship according to the acquisition time and the current value corresponding to the acquisition time.

[0071] In the embodiments of this specification, by constructing a current-time relationship, it is possible to monitor the working status of the motor in real time and adjust the control strategy in time to ensure that the motor operates as expected. At the same time, by analyzing the current-time relationship, potential faults in the electronic parking brake system can be discovered early, reducing maintenance costs and improving the overall energy efficiency of the electronic parking brake system.

[0072] In the embodiment of this specification, a current-time relationship is constructed according to the acquisition time and the current value corresponding to the acquisition time, such as: Figure 4 As shown, Figure 4 A flow chart for constructing the current-time relationship includes:

[0073] S401: Acquire the current value of the motor when the current is in a stable state to obtain a stable current value.

[0074] In the embodiments of this specification, Figure 5 As shown, Figure 5 The simplified schematic diagram of the circuit during the motor working process can be combined with the simplified schematic diagram and the working process of the motor to construct a mechanical formula for theoretical calculation, where: Figure 5 In is the motor supply voltage, is the electromotive force generated during the operation of the motor, is the motor rotor, is the equivalent capacitance of the motor winding, is the motor speed, is the current flowing through the motor winding, For the motor, is the moment of inertia of the motor and transmission mechanism, is the inductance of the motor, is the resistance of the motor. For a known caliper, its and are all known fixed invariants that are not affected by temperature. During the clamping process, since the time is very short, about 1 second, it can be assumed that the temperature of the motor is constant during this process. , , The value of is also a constant, where is the back electromotive force constant, is the torque constant. According to the circuit equation:

[0075]

[0076] in, is the power supply voltage of the motor; is the inductance of the motor; is the first-order rate of change of current with time; is the current intensity in the motor; is the resistance of the motor; is the back electromotive force constant; is the angular velocity of the motor;

[0077] According to formula (1), the motor terminal voltage It is composed of three parts: motor inductance and the current change rate The induced voltage and the internal resistance of the motor The voltage drop on the motor and the back electromotive force generated by the motor rotation .

[0078] During the rotation process, according to the kinematic formula:

[0079]

[0080] in, is the torque constant; is the current intensity in the motor; It is the torque output by the motor when the push rod is unloaded during the caliper clamping process, that is, the torque generated by the motor when it is running without any external load; is the moment of inertia of the motor and transmission mechanism; is the angular acceleration, which indicates the rate of change of the motor angular velocity over time;

[0081] According to formula (2), the torque generated by the motor is Minus no-load torque Equal to the moment of inertia and angular acceleration In order to change its speed and generate angular acceleration, the motor must overcome its own moment of inertia. When the torque applied by the motor exceeds the no-load torque, the remaining torque will be used to accelerate the motor's rotor. If the motor has no load, that is, is zero, then the total torque generated by the motor Will be used to change the angular velocity of the motor.

[0082] According to the motor just started, that is Moment, its , , combining formula (1) and formula (2) to obtain:

[0083]

[0084] in, The current changes with time during the motor starting process The change function of The current intensity in the motor at It is the current when the motor reaches the highest speed when the ejector rod is unloaded; is the integral constant of the motor in the starting stage; is the integral constant when the motor is in the stable stage; and is the characteristic root, indicating the exponential growth or decay trend of the current over time; is a time variable, indicating the time elapsed from the start of the motor;

[0085] According to formula (3), the current when the motor starts is Over time Changes according to a specific exponential law.

[0086] in,

[0087]

[0088] in, are the two characteristic roots of the current changing with time during the motor starting process; is the resistance of the motor; is the inductance of the motor; is the back electromotive force constant; is the torque constant; is the moment of inertia of the motor and transmission mechanism;

[0089] According to formula (4), the characteristic root of the current changing with time is The resistance is the physical parameter of the motor. ,inductance , Back EMF constant , Torque constant and moment of inertia Calculated.

[0090]

[0091] in, is the integral constant of the motor in the starting stage; is the power supply voltage of the motor; is the inductance of the motor; and is the characteristic root of the current change rate during motor starting; It is the current when the motor reaches the maximum speed when the ejector rod is unloaded.

[0092] According to formula (5), the integral constant of the current changing with time during the motor starting process is The specific calculation method of the motor supply voltage , Inductance , Current And two characteristic roots and , we can solve , which makes it easier to describe the change of current over time during motor starting.

[0093]

[0094] in, is the integral constant of the motor in the starting stage; is the integral constant when the motor is in the stable stage; It is the current when the motor reaches the highest speed when the ejector rod is unloaded;

[0095] According to formula (6), the integral constant of the current change during motor starting is Through the known current and the integral constant of the motor in the startup phase , the integral constant of the motor in the stable stage can be determined These two integral constants together determine the complete form of the current variation over time during the motor starting process. Once and Once determined, the time-varying behavior of the current during motor starting can be fully described.

[0096] In general, there are ,in, is the motor time constant, is the electrical time constant, and because it is a DC motor, when the motor internal resistance and mechanical loss are ignored, we have:

[0097]

[0098] According to formula (7), for some motors, the back electromotive force constant is and torque constant are equal and can be expressed using the same constant It helps to simplify some calculations when analyzing motor performance.

[0099] According to formula (3)-formula (7), we can simplify:

[0100]

[0101] in, The current changes with time during the motor starting process The change function of It is the current when the motor reaches the highest speed when the ejector rod is unloaded; is the comprehensive integral constant of the motor current changing with time; is a time variable, indicating the time elapsed from the start of the motor; is the motor time constant; is the electrical time constant;

[0102] According to formula (8), the change of current consists of three parts: current , exponential decay term and another exponential decay term .

[0103] in,

[0104]

[0105] in, is the comprehensive integral constant of the motor current changing with time; is the power supply voltage of the motor; is the resistance of the motor; It is the current when the motor reaches the highest speed when the ejector rod is unloaded; is the motor time constant; is the electrical time constant;

[0106] According to formula (9), the integral constant is It is a key parameter used to describe the law of current change over time during motor starting. ,resistance , Current and two time constants and The solution is obtained.

[0107]

[0108] in, The current changes with time during the motor starting process The change function of It is the current when the motor reaches the highest speed when the ejector rod is unloaded; is the comprehensive integral constant of the motor current changing with time; is the time variable; is the motor time constant;

[0109] According to formula (10), The current over time According to the motor time constant The attenuated part.

[0110]

[0111] in, The current changes with time during the motor starting process part of the variation function of ; It is the current when the motor reaches the highest speed when the ejector rod is unloaded; is the comprehensive integral constant of the motor current changing with time; is the time variable; is the electrical time constant;

[0112] According to formula (11), The current over time According to the electrical time constant The attenuated part.

[0113] The change of current over time during the motor starting process is as follows Figure 3 As shown. Figure 3 It can be seen that The change process is determined by the motor time constant caused by and the electrical time constant Caused by The electrical time constant is small and quickly becomes stable, so when After the maximum value, After a while, you can think , and at startup time When it is 0, The value of , The value of .

[0114] At this time, the relationship between current and time can be obtained through theoretical calculation. When the current value of the motor is in a stable state, the stable current value is obtained. , and we can assume that Moment, after which the data from the multiple motor parameter groups actually collected are used to obtain the actual current-time relationship. By performing the next calculation after the current reaches a stable state, when the rate of change of the current tends to zero, the change of the current over time becomes simpler, reducing the complexity of the calculation, and improving the reliability of the subsequent caliper clamping force calculation results, which helps to better analyze the working state of the motor and improve the overall efficiency of the integrated electronic parking brake system.

[0115] S402: constructing a preliminary current-time relationship according to the current value corresponding to the acquisition time and the stable current value.

[0116] In the embodiment of this specification, when the motor starts to move and the caliper starts to clamp, the voltage and current values ​​fed back by the caliper to the controller, that is, the voltage and current values ​​of the motor, are recorded, and the collection time interval is 1ms. It is assumed that n1 sets of motor parameter groups are collected in the time period from the current peak t0 to the constant speed t1. The current values ​​in the collected n1 sets of motor parameter groups are calculated. Processing, assuming:

[0117]

[0118] in, is the current value collected; is the current value corresponding to the acquisition time; is the stable current value;

[0119] The preliminary current-time relationship is obtained from formula (10):

[0120]

[0121] in, is the current value collected; is the comprehensive integral constant of the motor current changing with time; is the collection time; is the motor time constant;

[0122] According to formula (13), by combining formula (10) and formula (12), the exponential expression is converted into a linear form, which is convenient for linear regression analysis. When the current decays exponentially with time, the logarithmic transformation can simplify the data analysis and make the data present a linear relationship, which is convenient for further processing and understanding.

[0123] S403: performing fitting processing on the acquisition time and the preliminary current-time relationship to obtain an average value of the acquisition time and an average value of the current value corresponding to the acquisition time.

[0124] In the embodiment of this specification, the acquisition time and the current value corresponding to the acquisition time in the n1 group of motor parameter groups, that is, The data were fitted with a univariate linear regression using the least squares method, and the formula is as follows:

[0125]

[0126] in, is the average value of the acquisition time; is the total number of motor parameter groups collected; For the The value at each time point;

[0127] According to formula (14), by calculating the average value of the acquisition time, we can better understand the time characteristics of the current change during the motor startup process and provide a basis for subsequent data processing and analysis.

[0128]

[0129] in, is the average value of the current value corresponding to the acquisition time; is the total number of motor parameter groups collected; For the The current value at a certain time point is the current value obtained according to formula (13).

[0130] According to formula (15), by calculating the average value of the current value corresponding to the acquisition time, the logarithmic characteristics of the current change during the motor startup process can be better understood.

[0131] Calculating the average value of the acquisition time and the average value of the acquired current helps to simplify the data processing process, reduce the impact of noise and fluctuations in the data, improve the stability of the data, and provide a basis for subsequent data processing.

[0132] S404: Determine a slope and an intercept according to an average value of the acquisition time and an average value of the current value corresponding to the acquisition time.

[0133] In the embodiments of this specification,

[0134]

[0135] in, is the slope; For the The value at each time point; is the average value of the acquisition time; For the The current value at a time point; is the average value of the current value corresponding to the acquisition time; is the total number of motor parameter groups collected; is the motor time constant;

[0136] According to formula (16), the slope is calculated by the least squares method: and the motor time constant through this slope Make connections.

[0137]

[0138] in, is the intercept; is the average value of the current value corresponding to the acquisition time; is the slope; is the average value of the acquisition time; is the comprehensive integral constant of the motor current changing with time;

[0139] According to formula (17), the intercept is calculated by the least squares method: , and through this intercept and Make connections.

[0140] Calculating the slope and intercept by the least squares method helps detect whether there are abnormal conditions during the motor startup process. At the same time, the accurate current change law can be used to optimize the motor control strategy, improve the response speed and stability of the integrated electronic parking brake system, and facilitate subsequent data processing and analysis.

[0141] S405: constructing the current-time relationship according to the slope and the intercept.

[0142] In the embodiment of this specification, according to the slope and the intercept , so as to construct the current-time relationship, as shown below:

[0143]

[0144] in, is the current value collected; is the intercept; is the slope; is the collection time;

[0145] According to formula (18), the current value can be described by the linear regression model With the collection time The changing law of the current is obtained by collecting the time and the stable current value, and a preliminary current-time relationship is constructed. Then, the collected collection time and current value are fitted through the collection time and the preliminary current-time relationship, and the average value of the collection time and the average value of the current value are obtained. The slope and intercept are further derived, and finally the current-time relationship is constructed. Through such a processing process, the complexity of data processing is simplified, the stability of the data is improved, it is helpful to more accurately describe the changing law of current over time, improve the accuracy of data analysis, and facilitate subsequent data processing to calculate the clamping force of the caliper.

[0146] S107: Determine the working state of the motor according to the current-time relationship and the voltage value corresponding to the acquisition time.

[0147] In the embodiments of the present specification, the key parameters of the motor are determined by the current-time relationship and the voltage value corresponding to the acquisition time, thereby determining the working state of the motor, which not only improves the accuracy of the parameter calculation results, but also improves the stability of the integrated electronic parking brake system, facilitates fault diagnosis and prevention, and can adapt to temperature changes.

[0148] In the embodiment of this specification, the working state of the motor is determined according to the current-time relationship and the voltage value corresponding to the acquisition time, such as Figure 6 As shown, Figure 6 The flowchart of the first state parameter judgment is as follows:

[0149] S601: Determine a state parameter corresponding to the motor according to the current-time relationship and the voltage value corresponding to the acquisition time; the state parameter includes a state coefficient corresponding to the motor.

[0150] In the embodiments of this specification, the state parameter may include a state coefficient corresponding to the motor, which is an indicator of the degree of fit and credibility. The subsequent determination of the running state of the motor by the state coefficient can not only effectively predict motor failures and improve the safety performance of the electronic parking brake system, but also help calculate the clamping force of the caliper and improve the reliability of the calculation results.

[0151] In the embodiment of this specification, the state parameter also includes the resistance of the motor, the mechanical time constant of the motor and the electrical time constant of the motor; the state parameter corresponding to the motor is determined according to the current-time relationship and the voltage value corresponding to the acquisition time, such as Figure 7 As shown, Figure 7 A flow chart for determining state parameters, including:

[0152] S701: Determine a state coefficient corresponding to the motor according to the acquisition time, an average value of the acquisition time, the current value corresponding to the acquisition time, and the average value of the current value corresponding to the acquisition time.

[0153] In the embodiment of this specification, the state parameter may include a state coefficient corresponding to the motor. , this coefficient is the linear regression fitting coefficient, which is an indicator of the degree of fitting and credibility, and The value of is between 0 and 1. The larger the value, the better the linear regression model fits. The formula is as follows:

[0154]

[0155] in, is the state coefficient corresponding to the motor; is the total number of motor parameter groups collected; For the The value at each time point; is the average value of the acquisition time; For the The current value at a time point; is the average value of the current value corresponding to the acquisition time;

[0156] According to formula (19), evaluating the goodness of fit of the current-time relationship obtained based on the linear regression model by using the state coefficient is helpful to determine the working state of the motor and improve the reliability of the electronic parking brake system.

[0157] S702: Determine a relationship constant of the motor according to the intercept.

[0158] In the embodiment of this specification, the relationship constant is the comprehensive integral constant of the motor current changing with time, and the formula for obtaining the relationship constant is as follows:

[0159]

[0160] in, is the relation constant; is the intercept;

[0161] According to formula (20), the intercept in the linear regression model To calculate the relation constant , which helps to intuitively understand the change pattern of current over time during motor startup and provides a basis for subsequent data processing and analysis.

[0162] S703: Determine a mechanical time constant of the motor according to the slope.

[0163] In the embodiments of this specification, the mechanical time constant, i.e., the motor time constant, is a time scale for the motor current to decay over time, reflecting the effect of the motor's internal inductance and resistance on the current change. The calculation formula of the mechanical time constant is as follows:

[0164]

[0165] in, is the mechanical time constant of the motor; is the slope;

[0166] According to formula (21), the slope in the linear regression model To calculate the mechanical time constant , by obtaining accurate mechanical time constants to detect faults in the motor and evaluate the performance of the motor, the response speed and stability of the electronic parking brake system are improved.

[0167] S704: Determine the electrical time constant of the motor and the resistance value of the motor according to the relationship constant of the motor, the voltage value corresponding to the acquisition time, and the mechanical time constant of the motor.

[0168] In the embodiment of this specification, at the peak Moment and stability The voltages collected at time are , , because in to During the period of time, the voltage is basically stable. For a constant voltage DC motor, the voltage at this time is It can be considered as a constant value and is expressed as:

[0169]

[0170] in, is the average voltage value; is the voltage value collected at the first moment; is the voltage value collected at the second moment;

[0171] And because:

[0172]

[0173] in, is the electrical time constant of the motor; is the inductance of the motor; is the resistance of the motor;

[0174]

[0175] in, is the mechanical time constant of the motor; is the resistance of the motor; is the back electromotive force constant; is the torque constant; is the moment of inertia of the motor and transmission mechanism; is the motor constant;

[0176] Then the mechanical time constant of the motor can be obtained by combining equations (9), (20)-(24): , the electrical time constant of the motor , the resistance of the motor , Motor constant Specifically, due to the mechanical time constant of the motor Already passed the slope The moment of inertia is calculated , Back EMF constant , Torque constant All are known quantities. First, substitute formula (21)-(22) into formula (9) to obtain the electrical time constant of the motor: for:

[0177]

[0178] in, is the electrical time constant of the motor; is the mechanical time constant of the motor; is the relation constant; is the average voltage value; is the resistance of the motor; is the stable current value;

[0179] Combining equations (23) and (24) to obtain the resistance of the motor for:

[0180]

[0181] in, is the resistance of the motor; is the mechanical time constant of the motor; is the back electromotive force constant; is the torque constant; is the moment of inertia of the motor and transmission mechanism;

[0182] At the same time, according to formula (24), we can get

[0183]

[0184] in, is the motor constant; is the back electromotive force constant; is the torque constant;

[0185] By calculating the state parameters, the accurate resistance value of the motor is obtained, which helps to control the output torque of the motor; the accurate motor constant is obtained, which helps to control the movement speed of the caliper; the mechanical time constant and electrical time constant of the motor are obtained, which helps to optimize the response time of the motor, so that the caliper can complete the clamping action more quickly; at the same time, obtaining accurate state parameters can not only help prevent the motor from overshooting during the start-stop process, improve the stability of the electronic parking brake system, and ensure the stable performance of the caliper clamping process, but also timely understand the working status of the motor, enhance the practicality of the caliper clamping force calculation algorithm, avoid errors caused by environmental factors, and improve the accuracy and reliability of the caliper clamping force calculation results.

[0186] S602: Determine a first state parameter according to a state coefficient corresponding to the motor.

[0187] In the embodiment of this specification, the first state parameter, i.e., the state coefficient , which is used to judge the working status of the motor and improve the accuracy of the calculation results of the caliper clamping force.

[0188] S603: If the first state parameter is greater than or equal to a first state parameter threshold, determine that the motor is in a normal working state, and control the motor to continue working.

[0189] In the embodiment of this specification, the first state parameter threshold can be , that is, the coefficient of determination threshold based on the linear regression model, when the first state parameter Greater than or equal to the first state parameter threshold When the motor is initially determined to be working properly, and the motor continues to work, the subsequent judgment process is entered. By setting multiple judgment processes, it is helpful to improve the accuracy and reliability of the caliper clamping force calculation results.

[0190] In the embodiment of this specification, if the first state parameter is greater than or equal to the first state parameter threshold, it is determined that the motor is in a normal working state, and after the motor is controlled to continue working, Figure 8 As shown, Figure 8 The flowchart of the second state parameter determination is shown in FIG. 1 , wherein the method further includes:

[0191] S801: Determine a second state parameter according to a mechanical time constant of the motor and an electrical time constant of the motor.

[0192] In the embodiment of this specification, according to the mechanical time constant of the motor and the electrical time constant of the motor , the second state parameter can be obtained , which reflects the comparison of the motor's mechanical and electrical response speeds. In fact, if , it indicates that the motor's mechanical response speed is relatively slow; if , it means that the motor's electrical response speed is relatively slow. and , you can understand the dynamic characteristics of the motor when it starts or responds to changes in external torque.

[0193] S802: If the second state parameter is less than or equal to a second state parameter threshold, calculate the state parameter corresponding to the motor at the first moment according to the voltage value and the current value at the first moment to obtain the current state parameter.

[0194] In the embodiment of this specification, the second state parameter threshold value may be 10. When it is less than or equal to 10, it indicates that the electrical response speed is faster than the mechanical response speed. At this time, the state parameter results calculated based on the linear regression model are unreliable, and the first moment is used. The voltage value collected at any time And the current value , using the collection results at the peak moment to recalculate the state parameters of the motor, we have:

[0195]

[0196] in, For current At the point in time The first derivative of represents the rate of change of current with time; is the integral constant of the motor in the starting stage; is the integral constant when the motor is in the stable stage; and is the characteristic root of the current change rate during motor starting; For the first moment;

[0197] It can be seen that formula (25) describes the first-order derivative of the current changing with time during the motor starting process at a specific time point expression.

[0198] in:

[0199]

[0200] It can be seen that formula (26) has an effect on the voltage value Assignment, the voltage value at the first moment .

[0201]

[0202] in, and Both represent the first moment The current value; is the stable current value; is the integral constant of the motor in the starting stage; is the integral constant when the motor is in the stable stage; and is the characteristic root of the current change rate during motor starting; For the first moment;

[0203] It can be seen that formula (27) represents the composition of the current value at the first moment.

[0204] Combining the above equations (4)-(6) and (23)-(27), we can also solve the mechanical time constant of the motor: , the electrical time constant of the motor , the resistance of the motor , Motor constant , thus forming the current state parameters. By combining the data at the peak moment to calculate the state parameters, the accuracy and reliability of the calculation results are improved and the calculation process is simplified.

[0205] S803: Determine the working state information of the motor according to the mechanical time constant corresponding to the current state parameter and the electrical time constant corresponding to the current state parameter.

[0206] In the embodiments of the present specification, judging the working state of the motor by using the mechanical time constant corresponding to the current state parameters and the electrical time constant corresponding to the current state parameters helps to improve the accuracy and reliability of the detection results and enhance the safety performance of the electronic parking brake system.

[0207] In the embodiment of this specification, the working state information of the motor is determined according to the mechanical time constant corresponding to the current state parameter and the electrical time constant corresponding to the current state parameter, such as Fig. 9 As shown, Fig. 9 The flowchart of the third state parameter judgment is as follows:

[0208] S901: Determine a third state parameter according to a mechanical time constant corresponding to the current state parameter and an electrical time constant corresponding to the current state parameter.

[0209] In the embodiment of this specification, according to the mechanical time constant corresponding to the current state parameter And the electrical time constant corresponding to the current state parameter , we can get the third state parameter .

[0210] S902: If the third state parameter is greater than a third state parameter threshold, it is determined that the motor is in a normal working state, and the motor is controlled to continue working.

[0211] In the embodiment of this specification, the third state parameter threshold value may be 4. If it is greater than 4, it means that the working state of the motor is normal and the motor continues to work. By judging the working state of the motor, it is helpful to improve the sensitivity and reliability of fault detection, obtain the state of the motor in time, and improve the reliability of the electronic parking brake system.

[0212] S903: If the third state parameter is less than or equal to the third state parameter threshold, determine that the motor is in a fault state, and control the motor to stop working.

[0213] In the embodiment of this specification, if the third state parameter If it is less than or equal to 4, it means that the motor is in a fault state and the motor stops working. By timely obtaining the working status of the motor, it is helpful to take timely measures when there is a fault in the motor, improve the reliability and safety of the motor operation, reduce the losses caused by the fault, enhance the safety performance of the electronic parking brake system, enter the subsequent calculation process when the motor is working normally, and improve the reliability of the caliper clamping force calculation result.

[0214] S804: If the working state information of the motor indicates that the motor is in a normal working state, control the motor to continue working.

[0215] In the embodiments of the present specification, the working state of the motor is determined after judgment, and the motor continues to work when the motor is in a normal working state; through the strategy of multiple judgments, the accuracy and reliability of the obtained motor state results are improved, which is helpful for the subsequent calculation of the clamping force of the caliper, and at the same time, the occurrence of faults can be prevented, thereby improving the reliability of the electronic parking brake system.

[0216] S604: If the first state parameter is less than the first state parameter threshold, determine that the motor is in a fault state, and control the motor to stop working.

[0217] In the embodiment of this specification, when the first state parameter Less than the first state parameter threshold When the motor is determined to be faulty, it is unreliable to use the state parameter calculated at this time to calculate the clamping force of the caliper, and the motor stops working. By judging the size of the first state parameter to determine whether the motor is faulty, the reliability and safety of the motor operation are improved, which is helpful for fault diagnosis and prevention. At the same time, the reliability of the clamping force calculation of the caliper is improved to avoid obtaining a clamping force calculation result with errors.

[0218] S109: If the working state of the motor indicates that the motor is in a normal working state, determine the clamping force of the caliper fixedly connected to the motor.

[0219] In the embodiments of this specification, through multiple judgment strategies, when it is finally determined that the motor is in a normal working state, it is indicated that the state parameters at this time can be used to calculate the clamping force of the caliper, thereby ensuring the accuracy and reliability of the calculation results of the caliper clamping force.

[0220] In the embodiment of the present specification, if the working state of the motor indicates that the motor is in a normal working state, determining the clamping force of the caliper fixedly connected to the motor includes:

[0221] If the working state of the motor indicates that the motor is in a normal working state, a current voltage value and a current current value of the motor at a current moment are obtained.

[0222] In the embodiment of the present specification, when it is determined that the motor is in a normal working state, the current value and voltage value of the motor at the current moment are obtained to provide a basis for the subsequent calculation of the clamping force of the caliper.

[0223] The clamping force of the caliper fixedly connected to the motor is determined according to the current voltage value and the current current value of the motor.

[0224] In the embodiments of this specification, the clamping force of the caliper can be calculated by combining the voltage value of the motor at the current moment, the current value at the current moment, and the kinematic formula of the transmission mechanism between the motor and the caliper. Specifically, according to the kinematic formula:

[0225]

[0226] in, is the total torque output by the motor; is the moment of inertia of the motor and transmission mechanism; is the angular acceleration; It is the torque output by the motor when the ejector rod is unloaded during the clamping process of the caliper; is the transmission ratio from the motor to the rotating screw; The mechanical efficiency of the entire transmission system from the motor to the ram; is the effective torque obtained by the ejector rod;

[0227] And because:

[0228]

[0229] in, is the total torque output by the motor; is the torque constant; is the current current value; is the motor constant;

[0230] According to the kinematic principle of thread transmission:

[0231]

[0232] in, is the effective torque obtained by the ejector rod; is the effective diameter of the screw; is the helix angle of the screw; is the thrust acting on the ejector rod, i.e. the clamping force of the caliper;

[0233] And because:

[0234]

[0235] in, is the helix angle of the screw; is the effective diameter of the screw; is the pitch of the screw;

[0236] Then, by combining formulas (1), (2) and (28)-(31), we can obtain:

[0237]

[0238] in, is the thrust acting on the ejector rod, i.e. the clamping force of the caliper; is the motor constant; is the current current value; is the stable current value; is the resistance of the motor; is the moment of inertia of the motor and transmission mechanism; is the first-order rate of change of current with time; is the second-order rate of change of current with time; is the inductance of the motor; is the transmission ratio from the motor to the rotating screw; The mechanical efficiency of the entire transmission system from the motor to the ram; is the pitch of the screw;

[0239] Among them, since the time interval between two collected data is small, only 1ms, we have:

[0240]

[0241] in, is the first-order rate of change of current with time; is the difference between two adjacent data points;

[0242] According to formula (33), when the time interval is very short, for example, 1 ms, the current change rate is It can be approximated as the current change Divide by the change in time In practical applications, it is difficult to directly measure the instantaneous rate of change. , the difference between two adjacent data points is usually used to estimate the rate of change, that is, , which is convenient for calculating the clamping force of the caliper. By real-time monitoring of the current and voltage values ​​of the motor and combining the kinematic formula of the transmission mechanism, the clamping force of the caliper is calculated, which helps to quickly respond to changes in the working state of the motor and adjust the control strategy in time to ensure that the clamping force of the caliper is always within the optimal range. At the same time, it improves the accuracy and reliability of the calculation results of the clamping force of the caliper, simplifies the calculation process, and avoids the influence of temperature through this algorithm. It has a wide range of applications and can be applied to various calipers, which improves the practicality of this set of algorithms.

[0243] In an exemplary embodiment, Fig.10 As shown, Fig.10 A schematic diagram of a process for calculating the clamping force of a caliper is shown, including:

[0244] S1001: Data cleaning and initialization.

[0245] In the embodiment of the present specification, when it is necessary to calculate the clamping force of the caliper, it is necessary to first clean and initialize the historically stored data to facilitate subsequent data collection, recording, analysis and calculation.

[0246] S1002: Determine whether the caliper is in a released state and whether the voltage value of the motor is greater than 2V; if the caliper is not in a released state or the voltage value of the motor is less than or equal to 2V, continue to detect the state of the caliper and the voltage value of the motor until the caliper is in a released state and the voltage value of the motor is greater than 2V.

[0247] In the embodiment of this specification, the stored caliper state is first read. When the caliper state is in the released state and the voltage value of the motor is greater than 2V, it indicates that the motor has started and started the clamping process. At this time, the current voltage value and current value fed back to the controller by the caliper are recorded in real time every 1ms. By confirming whether the motor is in the clamping process before performing various processing on subsequent data, the working efficiency of the electronic parking brake system is improved.

[0248] S1003: Determine whether the current of the motor is the maximum value; if the current of the motor is not the maximum value, continue to detect until the current of the motor reaches the maximum value.

[0249] In the embodiment of the present specification, when it is detected that the collected current value is the maximum value, the time when the current is the maximum value is set as time t0, which is convenient for subsequent data calculation and improves the accuracy and reliability of the caliper clamping force calculation result.

[0250] S1004: Determine whether the current collection time is less than t1; if the current collection time is less than t1, go to S1011;

[0251] In the embodiment of this specification, time t1 is the time when the set motor speed has not reached the maximum, that is, the current has not stabilized near a certain value. By collecting data from time t0 to time t1, the number of samples for subsequent data calculation is expanded, the calculation error is reduced, and the calculation accuracy is improved.

[0252] S1005: Perform least squares linear regression on the n1 group of data to obtain motor parameters.

[0253] In the embodiment of this specification, when the current acquisition time is greater than or equal to t1, it is assumed that n1 sets of data are acquired from time t0 to time t1, and each set of data includes the acquisition time, the acquisition voltage value, and the acquisition current value. At this time, the least squares linear regression calculation is performed on the n1 sets of data to obtain the state parameters of the motor, where the state parameters include the mechanical time constant of the motor , the electrical time constant of the motor , the resistance of the motor , Motor constant , linear regression fitting coefficient By obtaining these parameters, it is helpful to conduct subsequent data analysis to determine the status of the motor, detect whether the motor has faults in time, and improve the safety performance of the electronic parking brake system. At the same time, it also avoids the electronic parking brake system being affected by temperature, which makes the subsequent caliper calculation force result have errors.

[0254] S1006: Determine whether the linear regression fitting coefficient is less than the determination coefficient threshold; if the linear regression fitting coefficient is less than the determination coefficient threshold, go to S1012;

[0255] In the embodiments of this specification, is the determination coefficient threshold of linear regression, and the linear regression fitting coefficient The coefficient of determination threshold for linear regression By making a comparison, it is possible to determine whether the parameters obtained by linear regression are reliable for calculating the clamping force of the caliper and the working state of the motor at this time, thereby improving the safety performance of the electronic parking brake system and the reliability of the calculation result of the caliper clamping force.

[0256] S1007: Determine whether the ratio of the mechanical time constant to the electrical time constant is less than or equal to 10. If the ratio of the mechanical time constant to the electrical time constant is greater than 10, go to S1013;

[0257] In the embodiment of this specification, when the linear regression fitting coefficient Greater than or equal to the coefficient of determination threshold for linear regression , to determine that the motor is not faulty at this time, and then enter the secondary judgment. The mechanical time constant of the motor It is an indicator of the motor's response time to an input signal. It determines the time required for the motor to reach a steady-state response. The electrical time constant of the motor It involves the time response characteristics of the motor drive circuit. By determining the mechanical time constant of the motor The electrical time constant of the motor The ratio of is used to judge whether the calculation strategy is reliable, so as to improve the reliability of the caliper clamping force calculation results.

[0258] S1008: Calculate the updated motor parameters using the highest point of the current curve.

[0259] In the embodiment of this specification, the mechanical time constant of the motor is The electrical time constant of the motor Ratio Less than or equal to 10, it can be inferred that it is unreliable to use the current calculation results for subsequent data processing, and enter the three judgment steps. When the maximum current is used The voltage and current values ​​at the moment are used to recalculate the state parameters of the motor and obtain The motor parameters updated at all times include The mechanical time constant of the motor at the moment , the electrical time constant of the motor , the resistance of the motor , Motor constant These parameters are used for subsequent data analysis, which improves the reliability of the motor status detection results and the reliability of the caliper clamping force calculation results.

[0260] S1009: Determine whether the ratio of the updated mechanical time constant to the updated electrical time constant is greater than 4; if the ratio of the updated mechanical time constant to the updated electrical time constant is less than or equal to 4, go to S1012;

[0261] In the embodiment of this specification, the mechanical time constant of the motor at the maximum current is used. The electrical time constant of the motor Ratio To judge, in fact, When it is less than or equal to 4, it means that the motor time constant is small relative to the electrical time constant, and the motor response may not be fast enough to meet the system's requirements for fast response. In addition, it may also indicate that there may be some abnormal conditions in the motor or its drive circuit, such as excessive load, motor aging or damage, etc., which may cause the motor response speed to decrease. At this time, the electronic parking brake system reports a motor fault and stops the motor from working, avoiding potential safety hazards and improving the safety performance of the electronic parking brake system. When it is greater than 4, this indicates that the ratio of the motor time constant to the electrical time constant is within an acceptable range, and the motor should be able to operate as expected. At this time, the motor is controlled to continue working and subsequent data processing is performed to obtain effective caliper clamping force calculation results, thereby improving the efficiency of the calculation process and the effectiveness of the calculation results.

[0262] S1010: Calculate the value of the caliper clamping force according to the current current and voltage.

[0263] In the embodiments of this specification, when When it is greater than 4, the motor is in normal working condition. The clamping force of the caliper can be obtained by using the current and voltage values ​​of the motor and combining the kinematic formula of the transmission mechanism between the motor and the caliper. Moreover, due to the layer-by-layer judgment strategy, the calculation result at this time is more reliable and accurate.

[0264] S1011: record the current and voltage of group n1;

[0265] In the embodiment of this specification, when the current acquisition time is less than At this time, the voltage and current values ​​of the motor are continuously collected every 1ms, which expands the sample capacity of the data, facilitates subsequent data analysis and processing, reduces the error caused by a single measurement, and improves the accuracy of the calculation results.

[0266] S1012: The motor stops and reports a fault;

[0267] In the embodiments of this specification, when it is determined that the motor is faulty, the motor is promptly controlled to stop working and the fault is reported, which helps to avoid secondary damage and timely troubleshoot the fault to improve the reliability of the electronic parking brake system and extend the service life of the equipment.

[0268] S1013: Use , The clamping force of the caliper is determined as a parameter of the electric motor.

[0269] In the embodiments of this specification, when When it is greater than 10, there is no fault in the motor and the resistance of the motor can be directly calculated by linear regression. ,constant The calculation of the clamping force of the caliper is performed to simplify the calculation process and improve the reliability of the calculation results.

[0270] This embodiment first performs data processing and initialization to confirm whether the caliper is in the released state and whether the motor voltage exceeds the preset threshold of 2V to determine whether the motor has started and started the clamping process. Next, the electronic parking brake system detects whether the motor current reaches the maximum value and records this moment as .exist After a period of time, the system collects Perform linear regression analysis on the collected data to obtain the mechanical time constant of the motor , the electrical time constant of the motor , the resistance of the motor , Motor constant , the inductance of the motor , linear regression fitting coefficient First, the linear regression coefficients The value of is used to judge whether the result of linear regression is reliable and the working status of the motor; if the result of linear regression is reliable, continue to The value of is used to make a second judgment on whether the calculation result is reliable. If it is not reliable, a third judgment is made. Finally, the clamping force of the caliper is calculated when the motor is in normal working condition, and the process returns to the starting state after the process is completed, waiting for the next clamping task. Through data processing and initialization, the motor is ensured to start in the correct state, which improves the stability of the electronic parking brake system. By detecting the peak value of the motor current and recording the time point, a reference is provided for subsequent calculations. By collecting a certain number of data samples, the accuracy of linear regression analysis is guaranteed. Linear regression analysis is used to establish a relationship model between the motor current and time, which provides a basis for calculating the clamping force. By calculating the state parameters of the motor to evaluate the dynamic response capability of the motor, ensure that the motor works within a reasonable range, realize the real-time detection and early warning function of the motor fault, enhance the safety performance of the electronic parking brake system, realize accurate calculation of the clamping force of the caliper, ensure the braking effect, and improve the reliability of the electronic parking brake system.

[0271] This specification also provides a device for determining the clamping force of the caliper, such as Fig.11 As shown, the device comprises:

[0272] The acquisition module 1101 is used to acquire the voltage value and current value of the motor when the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold; the motor is used to drive the caliper to clamp;

[0273] The motor parameter group acquisition module 1102 is used to acquire multiple groups of motor parameter groups collected within a preset time period; each of the motor parameter groups includes a collection time, a voltage value corresponding to the collection time, and a current value corresponding to the collection time; the preset time period is a time period starting at a first moment and ending at a second moment; the first moment is a moment when the current of the motor is at a peak value; the second moment is a moment when the current of the motor tends to be stable;

[0274] A current-time relationship determination module 1103 is used to construct a current-time relationship according to the acquisition time and the current value corresponding to the acquisition time;

[0275] A working state determination module 1104, configured to determine the working state of the motor according to the current-time relationship and the voltage value corresponding to the acquisition time;

[0276] The clamping force determination module 1105 is configured to determine the clamping force of the caliper fixedly connected to the motor if the working state of the motor indicates that the motor is in a normal working state.

[0277] In some embodiments, the current-time relationship determination module further includes:

[0278] The stable current value determination submodule is used to obtain the current value of the motor when the current is in a stable state, so as to obtain the stable current value.

[0279] The preliminary current-time relationship constructing submodule is used to construct a preliminary current-time relationship according to the current value corresponding to the acquisition time and the stable current value.

[0280] The average value acquisition submodule is used to perform fitting processing on the acquisition time and the preliminary current-time relationship to obtain the average value of the acquisition time and the average value of the current value corresponding to the acquisition time.

[0281] The determination submodule is used to determine the slope and the intercept according to the average value of the acquisition time and the average value of the current value corresponding to the acquisition time.

[0282] The current-time relationship constructing submodule is used to construct the current-time relationship according to the slope and the intercept.

[0283] In some embodiments, the working status determination module further includes:

[0284] The state parameter determination submodule is used to determine the state parameter corresponding to the motor according to the current-time relationship and the voltage value corresponding to the acquisition time; the state parameter includes a state coefficient corresponding to the motor.

[0285] The first state parameter determination submodule is used to determine the first state parameter according to the state coefficient corresponding to the motor.

[0286] The first continuing operation submodule is used to determine that the motor is in a normal working state and control the motor to continue working if the first state parameter is greater than or equal to a first state parameter threshold.

[0287] The first stop-operation submodule is used to determine that the motor is in a fault state and control the motor to stop working if the first state parameter is less than the first state parameter threshold.

[0288] In some embodiments, the state parameter determination submodule further includes:

[0289] A state coefficient determination unit is used to determine a state coefficient corresponding to the motor according to the acquisition time, the average value of the acquisition time, the current value corresponding to the acquisition time, and the average value of the current value corresponding to the acquisition time.

[0290] A relationship constant determination unit is used to determine the relationship constant of the motor according to the intercept.

[0291] A mechanical time constant determining unit is used to determine the mechanical time constant of the motor according to the slope.

[0292] A determination unit is used to determine the electrical time constant of the motor and the resistance value of the motor according to the relationship constant of the motor, the voltage value corresponding to the acquisition time, and the mechanical time constant of the motor.

[0293] In some embodiments, the apparatus further comprises:

[0294] The second state parameter determination module is used to determine the second state parameter according to the mechanical time constant of the motor and the electrical time constant of the motor.

[0295] The current state parameter determination module is used to calculate the state parameter corresponding to the motor at the first moment according to the voltage value and the current value at the first moment if the second state parameter is less than or equal to the second state parameter threshold, so as to obtain the current state parameter.

[0296] The working state information determination module is used to determine the working state information of the motor according to the mechanical time constant corresponding to the current state parameter and the electrical time constant corresponding to the current state parameter.

[0297] The continuing operation module is used to control the motor to continue to operate if the operating state information of the motor indicates that the motor is in a normal operating state.

[0298] In some embodiments, the working status information determination module further includes:

[0299] The third state parameter determination submodule is used to determine the third state parameter according to the mechanical time constant corresponding to the current state parameter and the electrical time constant corresponding to the current state parameter.

[0300] The second continuing operation submodule is used to determine that the motor is in a normal working state and control the motor to continue working if the third state parameter is greater than a third state parameter threshold.

[0301] The second stop-work submodule is used to determine that the motor is in a fault state and control the motor to stop working if the third state parameter is less than or equal to the third state parameter threshold.

[0302] In some embodiments, the clamping force determination module further includes:

[0303] The current data acquisition submodule is used to acquire the current voltage value and the current current value of the motor at the current moment if the working state of the motor indicates that the motor is in a normal working state.

[0304] The calculation submodule is used to determine the clamping force of the caliper fixedly connected to the motor according to the current voltage value and the current current value of the motor.

[0305] The device and method embodiments in the described device embodiments are based on the same inventive concept.

[0306] An embodiment of the present specification provides an electronic device related to an integrated electronic parking brake system, the device including a processor and a memory, the memory storing at least one instruction or at least one program, the at least one instruction or at least one program being loaded and executed by the processor to implement a method for determining a caliper clamping force as provided in the above method embodiment.

[0307] An embodiment of the present application also provides a computer storage medium, which can be set in a terminal to store at least one instruction or at least one program related to a method for determining a caliper clamping force in a method embodiment. The at least one instruction or at least one program is loaded and executed by the processor to implement the method for determining the caliper clamping force provided in the above method embodiment.

[0308] The embodiment of the present application also provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes to implement the method for determining the clamping force of the caliper provided in the above method embodiment.

[0309] The memory described in the embodiments of this specification can be used to store software programs and modules, and the processor executes various functional applications and data processing by running the software programs and modules stored in the memory. The memory may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, application programs required for functions, etc.; the data storage area may store data created according to the use of the device, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage device. Accordingly, the memory may also include a memory controller to provide the processor with access to the memory.

[0310] The method for determining the clamping force of a caliper provided in the embodiments of this specification can be executed in a mobile terminal, a computer terminal, a server or a similar computing device. Taking running on a server as an example, Fig.12 1 is a hardware structure block diagram of a server of a method for determining the clamping force of a caliper provided in an embodiment of this specification. Fig.12As shown, the server 1200 may have relatively large differences due to different configurations or performances, and may include one or more central processing units (CPU) 1210 (the central processing unit 1210 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA), a memory 1230 for storing data, and one or more storage media 1220 (such as one or more mass storage devices) for storing application programs 1223 or data 1222. Among them, the memory 1230 and the storage medium 1220 can be short-term storage or permanent storage. The program stored in the storage medium 1220 may include one or more modules, each of which may include a series of instruction operations on the server. Furthermore, the central processing unit 1210 may be configured to communicate with the storage medium 1220 and execute a series of instruction operations in the storage medium 1220 on the server 1200. The server 1200 may also include one or more power supplies 1260, one or more wired or wireless network interfaces 1250, one or more input and output interfaces 1240, and / or one or more operating systems 1221, such as Windows ServerTM, Mac OS XTM, UnixTM, LinuxTM, FreeBSDTM, etc.

[0311] The input / output interface 1240 may be used to receive or send data via a network. A specific example of the network may include a wireless network provided by a communication provider of the server 1200. In one example, the input / output interface 1240 includes a network adapter (Network Interface Controller, NIC), which may be connected to other network devices via a base station so as to communicate with the Internet. In one example, the input / output interface 1240 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0312] It can be understood by those skilled in the art that Fig.12 The structure shown is only for illustration and does not limit the structure of the above electronic device. Fig.12 More or fewer components as shown, or with Fig.12 Different configurations are shown.

[0313] It can be seen from the embodiments of the method, device and storage medium for determining the clamping force of the caliper provided by the present application that, when the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold, the present application collects the voltage value and current value of the motor; the motor is used to drive the caliper to clamp; multiple groups of motor parameter groups collected within a preset time period are obtained; each of the motor parameter groups includes a collection time, a voltage value corresponding to the collection time, and a current value corresponding to the collection time; the preset time period is a time period with a first moment as the starting moment and a second moment as the ending moment; the first moment is a moment when the current of the motor is at its peak; the second moment is a moment when the current of the motor tends to be stable; a current-time relationship is constructed according to the collection time and the current value corresponding to the collection time; the working state of the motor is determined according to the current-time relationship and the voltage value corresponding to the collection time; if the working state of the motor indicates that the motor is in a normal working state, the clamping force of the caliper fixedly connected to the motor is determined. When the clamping force of the caliper needs to be calculated, the state of the caliper and the working process of the motor are first judged to determine whether the motor has started and started the clamping process, which improves the stability of the electronic parking brake system and ensures that the motor starts in the correct state; by detecting the current of the motor, a reference basis is provided for subsequent calculations to ensure that the motor enters a stable working state; by collecting multiple groups of motor parameter groups and using linear regression analysis to establish a current-time relationship, it provides a basis for calculating the clamping force and avoids collecting data in advance; by evaluating the goodness of fit of linear regression, the data quality is ensured and the calculation accuracy is improved; by calculating the ratio of the mechanical time constant and the electrical time constant, the dynamic response capability of the motor is evaluated to ensure that the motor works within a reasonable range, and the real-time detection and early warning function of the motor fault is realized, which enhances the safety of the electronic parking brake system, so that the clamping force of different types of calipers can be accurately calculated at different temperatures, ensuring the braking effect, improving the reliability of the electronic parking brake system, and enabling the electronic parking brake system to continuously monitor and control the clamping force of the caliper to ensure that the electronic parking brake system is always in a good working state.

[0314] It should be noted that the above sequence of the embodiments of this specification is for description only and does not represent the advantages and disadvantages of the embodiments. The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0315] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device, equipment, and storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0316] A person skilled in the art will appreciate that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0317] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for determining the clamping force of a caliper, characterized in that: The method comprises: When the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold, the voltage value and current value of the motor are collected; the motor is used to drive the caliper to clamp; Acquire multiple groups of motor parameter groups collected within a preset time period; each of the motor parameter groups includes a collection time, a voltage value corresponding to the collection time, and a current value corresponding to the collection time; the preset time period is a time period starting at a first moment and ending at a second moment; the first moment represents the moment when the current of the motor is at a peak value; the second moment represents the moment when the current of the motor tends to be stable; Constructing a current-time relationship according to the acquisition time and the current value corresponding to the acquisition time; Determining the working state of the motor according to the current-time relationship and the voltage value corresponding to the acquisition time; If the working state of the motor indicates that the motor is in a normal working state, the clamping force of the caliper fixedly connected to the motor is determined; the calculation formula of the clamping force of the caliper is as follows: in, is the thrust acting on the ejector rod, i.e. the clamping force of the caliper; is the motor constant; is the current current value; is the stable current value; is the resistance of the motor; is the moment of inertia of the motor and transmission mechanism; is the first-order rate of change of current with time; is the second-order rate of change of current with time; is the inductance of the motor; is the transmission ratio from the motor to the rotating screw; The mechanical efficiency of the entire transmission system from the motor to the ram; is the pitch of the screw.

2. The determination method according to claim 1, characterized in that: The constructing a current-time relationship according to the acquisition time and the current value corresponding to the acquisition time includes: Obtaining a current value when the current of the motor is in a stable state to obtain a stable current value; Constructing a preliminary current-time relationship according to the current value corresponding to the acquisition time and the stable current value; Fitting the acquisition time and the preliminary current-time relationship to obtain an average value of the acquisition time and an average value of the current value corresponding to the acquisition time; Determine a slope and an intercept according to an average value of the acquisition time and an average value of the current value corresponding to the acquisition time; The current-time relationship is constructed according to the slope and the intercept.

3. The determination method according to claim 2, characterized in that: The determining the working state of the motor according to the current-time relationship and the voltage value corresponding to the acquisition time includes: Determine a state parameter corresponding to the motor according to the current-time relationship and the voltage value corresponding to the acquisition time; the state parameter includes a state coefficient corresponding to the motor; Determining a first state parameter according to a state coefficient corresponding to the motor; If the first state parameter is greater than or equal to a first state parameter threshold, determining that the motor is in a normal working state, and controlling the motor to continue working; If the first state parameter is less than the first state parameter threshold, it is determined that the motor is in a fault state, and the motor is controlled to stop working.

4. The determination method according to claim 3, characterized in that: The state parameters also include the resistance of the motor, the mechanical time constant of the motor, and the electrical time constant of the motor; the state parameters corresponding to the motor are determined according to the current-time relationship and the voltage value corresponding to the acquisition time, including: Determine a state coefficient corresponding to the motor according to the acquisition time, the average value of the acquisition time, the current value corresponding to the acquisition time, and the average value of the current value corresponding to the acquisition time; determining a relation constant of the motor according to the intercept; Determining a mechanical time constant of the motor according to the slope; The electrical time constant of the motor and the resistance value of the motor are determined according to the relationship constant of the motor, the voltage value corresponding to the acquisition time, and the mechanical time constant of the motor.

5. The determination method according to claim 4, characterized in that: If the first state parameter is greater than or equal to the first state parameter threshold, it is determined that the motor is in a normal working state, and after controlling the motor to continue working, the method further includes: Determining a second state parameter according to a mechanical time constant of the motor and an electrical time constant of the motor; If the second state parameter is less than or equal to a second state parameter threshold, the state parameter corresponding to the motor at the first moment is calculated according to the voltage value and the current value at the first moment to obtain the current state parameter; Determining the working state information of the motor according to a mechanical time constant corresponding to the current state parameter and an electrical time constant corresponding to the current state parameter; If the working state information of the motor indicates that the motor is in a normal working state, the motor is controlled to continue working.

6. The determination method according to claim 5, characterized in that: The determining the working state information of the motor according to the mechanical time constant corresponding to the current state parameter and the electrical time constant corresponding to the current state parameter comprises: determining a third state parameter according to a mechanical time constant corresponding to the current state parameter and an electrical time constant corresponding to the current state parameter; If the third state parameter is greater than a third state parameter threshold, determining that the motor is in a normal working state, and controlling the motor to continue working; If the third state parameter is less than or equal to the third state parameter threshold, it is determined that the motor is in a fault state, and the motor is controlled to stop working.

7. The determination method according to claim 1, characterized in that: If the working state of the motor indicates that the motor is in a normal working state, determining the clamping force of the caliper fixedly connected to the motor includes: If the working state of the motor indicates that the motor is in a normal working state, obtaining a current voltage value and a current current value of the motor at a current moment; The clamping force of the caliper fixedly connected to the motor is determined according to the current voltage value and the current current value of the motor.

8. A device for determining the clamping force of a caliper, characterized in that: The device comprises: A collection module, used for collecting the voltage value and current value of the motor when the caliper is in a released state and the voltage value of the motor is greater than a preset starting voltage threshold; the motor is used to drive the caliper to clamp; A motor parameter group acquisition module, used to acquire multiple motor parameter groups collected within a preset time period; each motor parameter group includes a collection time, a voltage value corresponding to the collection time, and a current value corresponding to the collection time; the preset time period is a time period starting at a first moment and ending at a second moment; the first moment represents the moment when the current of the motor is at a peak value; the second moment represents the moment when the current of the motor tends to be stable; A current-time relationship determination module, configured to construct a current-time relationship according to the acquisition time and the current value corresponding to the acquisition time; A working state determination module, used for determining the working state of the motor according to the current-time relationship and the voltage value corresponding to the acquisition time; The clamping force determination module is used to determine the clamping force of the caliper fixedly connected to the motor if the working state of the motor indicates that the motor is in a normal working state; the calculation formula of the clamping force of the caliper is as follows: in, is the thrust acting on the ejector rod, i.e. the clamping force of the caliper; is the motor constant; is the current current value; is the stable current value; is the resistance of the motor; is the moment of inertia of the motor and transmission mechanism; is the first-order rate of change of current with time; is the second-order rate of change of current with time; is the inductance of the motor; is the transmission ratio from the motor to the rotating screw; The mechanical efficiency of the entire transmission system from the motor to the ram; is the pitch of the screw.

9. An electronic device, characterized in that: The device includes a processor and a memory, wherein the memory stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded by the processor and executes the method for determining the clamping force of the caliper as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded and executed by the processor to implement the method for determining the clamping force of the caliper as described in any one of claims 1-7.

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