Motor control method and vehicle

Abstract

The application discloses a motor control method and a vehicle, and relates to the technical field of vehicle control. The method comprises the following steps: acquiring an operation parameter of a motor; determining an operation state of a brake actuating mechanism driven by the motor based on the operation parameter; when the brake actuating mechanism is in a predetermined stroke stage, adopting an open-loop control strategy to generate a target output instruction of the motor; and controlling the motor to operate based on the target output instruction. The method adopts the open-loop control strategy in the predetermined stroke stage, does not correct the target output instruction through the feedback of the operation parameter, and directly generates the target output instruction according to the performance parameter of the motor. Compared with the closed-loop feedback control based on a target displacement or a target clamping force in the prior art, the method avoids the limitation of the feedback regulation on the motor speed and acceleration, can fully exert the dynamic output capacity of the motor, thereby shortens the duration of the brake actuating mechanism crossing the predetermined stroke, and effectively shortens the brake response time.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a motor control method and a vehicle. Background Technology

[0002] In brake-by-wire systems of motor vehicles, particularly electromechanical braking systems, the motor-driven brake calipers need to convert the rotational motion of the motor into linear displacement of the brake pads to achieve braking. Various strategies for controlling the motor have been proposed in the prior art, such as closed-loop control strategies based on target displacement or target clamping force.

[0003] However, with increasingly stringent requirements for active safety performance in vehicles, especially under emergency braking conditions, there is still a need for further optimization of the response speed of braking actuators. Particularly in the initial stage of the braking actuator's transition from a free state to a clamped state, how to more efficiently utilize the motor's output capacity to shorten the duration of this transition process is a key technical issue of concern in this field. Summary of the Invention

[0004] This application provides a motor control method and a vehicle, which aims to improve the motor output efficiency during the initial stage of the brake actuator's transition from a free state to a clamped state, thereby shortening the system response time.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] A motor control method, applied to a vehicle braking system, includes:

[0007] Obtain the motor's operating parameters;

[0008] Based on the operating parameters, the operating status of the braking actuator driven by the motor is determined;

[0009] When the braking actuator is in the predetermined stroke stage, an open-loop control strategy is adopted to generate the target output command of the motor;

[0010] Based on the target output command, control the operation of the motor.

[0011] Optionally, the operating parameters include actual displacement and target displacement;

[0012] Based on the operating parameters, the operating state of the braking actuator driven by the motor is determined, including:

[0013] The actual displacement is compared with a preset threshold.

[0014] When the actual displacement is less than the preset threshold, it is determined that the braking actuator driven by the motor is in the predetermined stroke stage.

[0015] Optionally, an open-loop control strategy is adopted to generate the target output command for the motor, including:

[0016] Obtain the performance parameters of the motor; the performance parameters include the maximum angular velocity and the system calculation cycle;

[0017] The target angular acceleration is determined based on the maximum angular velocity and the system calculation period.

[0018] Using the open-loop control strategy, the target output command for the motor is generated based on the target angular acceleration;

[0019] The open-loop control strategy is a control method that determines the target output command based on the performance parameters and does not correct it through feedback of the operating parameters.

[0020] Optionally, before obtaining the motor's operating parameters, the method further includes:

[0021] Obtain the target displacement of the motor;

[0022] When the vehicle is detected to be in an emergency braking condition and the target displacement is greater than a preset displacement threshold, the step of obtaining the motor's operating parameters is executed.

[0023] Optionally, the method further includes:

[0024] When the braking actuator has left the predetermined stroke stage, the system switches to a closed-loop control strategy to generate the target output command for the motor.

[0025] Optionally, switch to a closed-loop control strategy to generate the target output command for the motor, including:

[0026] Obtain the actual displacement and actual speed of the motor;

[0027] The target speed of the motor is determined based on the first deviation between the target displacement and the actual displacement;

[0028] Using the closed-loop control strategy, the target output command is generated based on the second deviation between the target speed and the actual speed.

[0029] The closed-loop control strategy is a control method that uses feedback adjustment based on deviation.

[0030] Optionally, determining the target speed of the motor based on a first deviation between the target displacement and the actual displacement includes:

[0031] Determine the displacement range in which the actual displacement is located;

[0032] When the actual displacement is within the first displacement range, the target rotation speed is corrected so that the corrected target rotation speed is greater than the original target rotation speed.

[0033] When the actual displacement is within the second displacement range, the target rotational speed is maintained unchanged.

[0034] Optionally, before generating the target output command for the motor using an open-loop control strategy, the method further includes:

[0035] Obtain historical operating data of the motor during the predetermined stroke phase;

[0036] Update the performance parameters based on the historical operating data.

[0037] Optionally, before determining the displacement range in which the actual displacement lies, the method further includes:

[0038] Obtain the wear status information of the braking actuator;

[0039] Based on the wear status information, adjust the boundary values ​​of the first displacement interval and / or the boundary values ​​of the second displacement interval.

[0040] A vehicle includes: a processor, a memory, and a bus; the processor and the memory are connected via the bus.

[0041] The memory is used to store the program, and the processor is used to run the program, wherein the program is executed by the processor to perform the above-described motor control method.

[0042] The technical solution provided in this application involves: acquiring the operating parameters of the motor; determining the operating state of the braking actuator driven by the motor based on the operating parameters; generating the target output command for the motor using an open-loop control strategy when the braking actuator is in a predetermined stroke stage; and controlling the motor operation based on the target output command. Unlike existing technologies that use closed-loop feedback strategies that suppress motor dynamic performance, the solution presented in this application employs an open-loop control strategy in the predetermined stroke stage. It does not rely on feedback from operating parameters for correction, but directly determines the target output command based on the motor's performance parameters. This differs from existing technologies where closed-loop feedback control based on target displacement or target pressure limits motor speed and acceleration. This application can fully utilize the motor's peak torque and maximum angular acceleration performance in the predetermined stroke stage, effectively shortening the duration for the braking actuator to cross the predetermined stroke stage, thereby reducing system response time. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a first flowchart illustrating a motor control method provided in an embodiment of this application;

[0045] Figure 2 This is a second flowchart illustrating a motor control method provided in an embodiment of this application;

[0046] Figure 3 A third flowchart illustrating a motor control method provided in an embodiment of this application;

[0047] Figure 4 A fourth flowchart illustrating a motor control method provided in an embodiment of this application;

[0048] Figure 5 A fifth flowchart illustrating a motor control method provided in an embodiment of this application;

[0049] Figure 6 A sixth flowchart illustrating a motor control method provided in an embodiment of this application;

[0050] Figure 7 A seventh flowchart illustrating a motor control method provided in an embodiment of this application;

[0051] Figure 8 The eighth flowchart of a motor control method provided in this application embodiment;

[0052] Figure 9 This is a schematic diagram of the architecture of a vehicle provided in an embodiment of this application. Detailed Implementation

[0053] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0055] like Figure 1 The diagram shown is a first flowchart of a motor control method provided in an embodiment of this application, applied to a vehicle braking system, and includes the following steps.

[0056] S101: Obtain the operating parameters of the motor.

[0057] Here, the motor is the drive element used to drive the brake actuator in the vehicle braking system, such as the wheel-end motor in an electro-mechanical braking (EMB) system. Operating parameters are information characterizing the real-time operating status of the motor.

[0058] In some examples, the motor's operating parameters can be acquired in real time using sensors built into the motor. These sensors include, but are not limited to, position sensors (such as resolvers, Hall effect sensors, and magnetic encoders) and speed sensors.

[0059] In a possible implementation, for a motor without a speed sensor, the actual rotational speed can be calculated from the differential value of the actual displacement.

[0060] It should be noted that obtaining operating parameters is a prerequisite for determining the operating status of the braking actuator and selecting the appropriate control strategy in subsequent steps. Real-time acquisition of operating parameters through sensors enables the braking system to promptly grasp the current state of the motor and braking actuator, providing a data foundation for subsequent closed-loop or open-loop control.

[0061] Optionally, before obtaining the motor's operating parameters, embodiments of this application may also utilize... Figure 8 The steps shown define the triggering conditions for the motor control method shown in this application.

[0062] S102: Determine the operating status of the braking actuator driven by the motor based on the operating parameters.

[0063] The braking actuator is a mechanical component driven by an electric motor to achieve the braking function, including but not limited to brake calipers, brake pistons, and friction pads. The operating states include a first state where the braking actuator is in a predetermined stroke phase, and a second state where the braking actuator has moved out of the predetermined stroke phase.

[0064] Optionally, the operating parameters include actual displacement and target displacement. The process of determining the operating state of the braking actuator based on these operating parameters can be found in [reference needed]. Figure 2 The steps shown are explained below.

[0065] In some examples, the actual displacement of the braking actuator can be calculated from the angular displacement of the motor rotor and the transmission ratio of the transmission mechanism. For example, if the angular displacement of the motor rotor is θ and the transmission ratio of the transmission mechanism is R (i.e., the conversion coefficient between the rotation angle of the motor rotor and the linear displacement of the braking actuator), then the actual displacement of the braking actuator is D_actual = θ × R.

[0066] It should be noted that by comparing the actual displacement with the preset threshold to determine whether the braking actuator is in the predetermined stroke stage or has left the predetermined stroke stage, the physical position state of the braking actuator can be quantified into a discernible electrical signal, providing a clear logical criterion for the selection of subsequent control strategies.

[0067] S103: When the brake actuator is in the predetermined stroke stage, an open-loop control strategy is adopted to generate the target output command for the motor.

[0068] The predetermined stroke phase is the mechanical clearance phase during which the brake actuator moves from its initial release position to the point of physical contact with the brake disc. During this predetermined stroke phase, the resistance experienced by the brake actuator is essentially constant and much less than that during the clamping phase, and the motor output torque is mainly used to overcome internal friction and inertia of the system.

[0069] Open-loop control is a control method that determines the target output command based on the motor's performance parameters and does not rely on feedback from operating parameters for correction. Unlike closed-loop control, open-loop control does not depend on feedback signals from operating parameters such as actual displacement and actual speed to correct the output command in real time during the generation of the target output command. Instead, it directly determines the target output command based on the inherent performance parameters of the motor, thereby avoiding the limitation of motor output capability by feedback regulation.

[0070] Optionally, an open-loop control strategy can be used. For details on the specific implementation process of generating the target output command for the motor, please refer to [link / reference]. Figure 3 The steps shown are explained below.

[0071] Optionally, before generating the target output command for the motor using an open-loop control strategy, it is also possible to utilize... Figure 6 The steps shown update the performance parameters to improve their reliability.

[0072] In some examples, when the brake actuator is in the predetermined stroke stage, it means that the friction pads have not yet contacted the brake disc. At this time, the brake actuator needs to quickly overcome the mechanical gap to establish braking force. Since the magnitude of the braking force does not need to be precisely controlled during this stage, an open-loop control strategy is adopted. The target output command is generated directly based on the inherent performance parameters of the motor, so that the motor drives the brake actuator to accelerate with maximum dynamic output capability, thereby shortening the time to overcome the mechanical gap.

[0073] It should be noted that an open-loop control strategy is employed during the predetermined stroke phase, avoiding the limitations on motor speed and acceleration imposed by closed-loop feedback control in existing technologies. In closed-loop control, to prevent overshoot or ensure position tracking accuracy, the controller typically imposes limits on the motor's speed and acceleration. However, in open-loop control, since it does not rely on feedback signals for correction, the motor can freely output within its physical limits, thereby fully utilizing the motor's peak torque and maximum angular acceleration performance.

[0074] S104: Controls motor operation based on target output commands.

[0075] The target output command is a control signal used to instruct the motor to output a corresponding drive quantity. The target output command includes, but is not limited to, at least one of the target torque command, target speed command, and target current command.

[0076] In some examples, controlling motor operation means sending a target output command to the motor's drive circuit or motor controller, which then generates a corresponding drive signal based on the target output command to control the motor's actual output torque, speed, or current.

[0077] In a possible implementation, when the target output command is a target torque command, the motor drive circuit adjusts the armature current according to the target torque command to make the motor output the target torque. When the target output command is a target speed command, the motor drive circuit adjusts the armature voltage or current according to the target speed command to make the actual speed of the motor follow the target speed.

[0078] It should be noted that the type of target output command can be flexibly selected according to the specific architecture of the motor control system. For example, a target torque command can be used in torque control mode, a target speed command in speed control mode, and a target current command in current control mode. Different types of target output commands are equivalent in engineering implementation and can all achieve control over the motor's operating state.

[0079] Optionally, when the braking actuator has moved beyond the predetermined stroke stage, the system switches to a closed-loop control strategy to generate the target output command for the motor. For details on its implementation, please refer to [link to relevant documentation]. Figure 4 The steps shown are explained below.

[0080] The processes described in S101-S104 above employ an open-loop control strategy during the predetermined stroke phase, enabling the motor to accelerate with maximum dynamic output during the mechanical gap phase and quickly traverse the predetermined stroke. Compared to closed-loop feedback control based on target displacement or target clamping force in existing technologies, this avoids the limitations on motor speed and acceleration caused by feedback adjustment, fully utilizing the motor's peak torque and maximum angular acceleration performance. This shortens the duration for the braking actuator to traverse the predetermined stroke, effectively reducing braking response time. Simultaneously, switching to a closed-loop control strategy after the braking actuator leaves the predetermined stroke phase ensures accurate tracking of the target displacement during the clamping phase, balancing the requirements of rapid response and control accuracy.

[0081] like Figure 2 The diagram shown is a second flowchart of a motor control method provided in an embodiment of this application, including the following steps.

[0082] S201: Compare the actual displacement with the preset threshold.

[0083] The actual displacement is the actual distance or angle that the motor rotor or braking actuator moves relative to its initial position at the current moment, which can be obtained through the position sensor built into the motor. The preset threshold is a pre-set critical value used to distinguish whether the braking actuator is in a predetermined stroke stage.

[0084] In this embodiment, the position where the braking actuator just contacts the brake disc is defined as the zero displacement point, with the direction of free travel being negative and the direction of clamping being positive.

[0085] In some examples, the actual displacement can be obtained by the actual rotation angle of the motor rotor through the motor's built-in rotary transformer or magnetic encoder, and then the rotation angle of the rotor can be converted into the linear displacement of the braking actuator according to the transmission ratio of the transmission mechanism.

[0086] In a possible implementation, the preset threshold can be pre-calibrated based on the mechanical structural parameters of the braking system and stored in the vehicle controller. For example, the preset threshold could be equal to the mechanical clearance travel of the brake actuator from its initial release position to its position just touching the brake disc. This mechanical clearance travel is a fixed parameter determined during the design of the braking system, and different braking systems have different mechanical clearance travel values.

[0087] It should be noted that comparing the actual displacement with the preset threshold is the process of quantifying the physical position of the braking actuator into a processable digital signal. The comparison result can clearly distinguish whether the braking actuator is currently in the predetermined stroke stage (i.e., not yet in contact with the brake disc) or the clamping stage (i.e., already in contact with the brake disc).

[0088] S202: When the actual displacement is less than the preset threshold, the braking actuator driven by the motor is determined to be in the predetermined stroke stage.

[0089] The predetermined stroke stage is the stage before the brake actuator moves from the initial release position to the point of physical contact with the brake disc, i.e., the mechanical clearance stroke stage.

[0090] In some examples, when the preset threshold is set to 0, an actual displacement less than 0 indicates that the brake actuator is in the no-travel stage (i.e., has not yet contacted the brake disc), an actual displacement equal to 0 indicates that the brake actuator has just contacted the brake disc, and an actual displacement greater than 0 indicates that the brake actuator is in the clamping state. Therefore, when the actual displacement is less than 0, the brake actuator is determined to be in the predetermined travel stage.

[0091] Furthermore, the comparison result between the actual displacement and the preset threshold has the following correspondence with the physical state of the braking actuator: when the actual displacement is less than the preset threshold (for example, the preset threshold is 0), it means that the braking actuator is in the no-stroke stage and the friction pad has not yet contacted the brake disc; when the actual displacement is equal to the preset threshold, it means that the braking actuator has just contacted the brake disc; when the actual displacement is greater than the preset threshold, it means that the braking actuator is in the clamping state and the friction pad has been pressed onto the brake disc.

[0092] It should be noted that the actual displacement equals the preset threshold at the critical point between the idle travel phase and the clamping phase. Before this critical point, the braking actuator only needs to overcome internal system friction and inertia, resulting in a relatively small load; after this critical point, the braking actuator needs to build up braking force, leading to a sharp increase in load. By accurately identifying the comparison between the actual displacement and the preset threshold, the physical state of the braking actuator can be precisely determined, providing accurate criteria for subsequently activating the open-loop control strategy during the idle travel phase and the closed-loop control strategy during the clamping phase.

[0093] In possible implementations, the preset threshold can also be set to other values ​​according to actual needs. For example, in order to enter the open-loop control strategy in advance, the preset threshold can be set to a small positive value greater than 0, so that the braking actuator has already entered the open-loop control logic of the predetermined stroke stage when it is about to contact the brake disc but has not yet contacted the brake disc.

[0094] It should also be noted that by comparing the actual displacement with the preset threshold and determining whether the braking actuator is in the predetermined stroke stage, the braking system can monitor the stroke position of the braking actuator in real time, providing accurate criteria for selecting an open-loop control strategy in the predetermined stroke stage and a closed-loop control strategy in the clamping stage.

[0095] The process shown in S201-S202 above achieves an accurate judgment on whether the braking actuator is in the predetermined stroke stage by comparing the actual displacement with the preset threshold. This judgment result is the basis for the selection of control strategy in subsequent steps, ensuring that the open-loop control strategy is only activated in the predetermined stroke stage, and avoiding the incorrect use of open-loop control in inappropriate stages.

[0096] like Figure 3 The diagram shown is a third flowchart of a motor control method provided in an embodiment of this application, including the following steps.

[0097] S301: Obtain the performance parameters of the motor.

[0098] The performance parameters include the maximum angular velocity and the system calculation cycle.

[0099] It should be noted that the maximum angular velocity is the maximum angular velocity value that the motor can achieve under factory calibration conditions, and it is one of the inherent performance parameters of the motor. The system calculation cycle is the cycle time for the vehicle controller to execute the control algorithm.

[0100] In some examples, the maximum angular velocity can be determined and provided by the motor manufacturer using testing equipment such as a dynamometer, and is usually recorded in the motor's product specifications. The system calculation cycle is determined by the vehicle controller's hardware architecture and software scheduling strategy. For example, if the controller runs the control algorithm at a fixed frequency of 1000Hz, the system calculation cycle is 0.001 seconds.

[0101] S302: Determine the target angular acceleration based on the maximum angular velocity and the system calculation period.

[0102] The target angular acceleration is determined as follows: It is calculated based on the maximum angular velocity and the desired time to reach that maximum angular velocity. This target time is preset according to actual needs and is an integer multiple of the system calculation cycle. For example, if the motor is expected to reach its maximum angular velocity within N system calculation cycles, then the target angular acceleration = maximum angular velocity / (N × system calculation cycle), where N is a positive integer defined according to actual needs. The value of N can be calibrated according to specific application scenarios and performance requirements; for example, when N=5, it means the motor is expected to reach its maximum angular velocity within 5 system calculation cycles.

[0103] It should be noted that the value of N determines how quickly the motor reaches its maximum angular velocity. The smaller the value of N, the shorter the time required for the motor to reach its maximum angular velocity and the shorter the duration of the predetermined stroke phase, but the higher the acceleration capability required of the motor. The value of N can be comprehensively calibrated based on the actual peak torque capability of the motor, the length of the system calculation cycle, and the mechanical characteristics of the braking system to achieve the optimal response speed within the physical limits of the motor.

[0104] For example, if the maximum angular velocity is 1000 radians / second, the system calculation period is 0.001 seconds, and N is set to 5, then the target duration = 5 × 0.001 = 0.005 seconds, and the target angular acceleration = 1000 / 0.005 = 200000 radians / second. 2 .

[0105] In a possible implementation, the moment of inertia and resistance torque of the motor are also considered when determining the target angular acceleration. The moment of inertia is the equivalent moment of inertia of the motor rotor and transmission mechanism referred to the motor shaft, and the resistance torque is the internal frictional resistance torque that the motor needs to overcome during the predetermined stroke phase. Both the moment of inertia and resistance torque are inherent physical parameters of the motor and can be obtained by the motor manufacturer through dynamometer testing.

[0106] S303: Employs an open-loop control strategy to generate the target output command for the motor based on the target angular acceleration.

[0107] Among them, the open-loop control strategy is a control method that determines the target output command based on performance parameters and does not make corrections through feedback of operating parameters.

[0108] In some examples, when the target output command is a target torque command, the target output command is generated by determining the target torque based on the motor's moment of inertia and target angular acceleration. Specifically, target torque = moment of inertia × target angular acceleration + resistance torque, where moment of inertia and resistance torque are inherent performance parameters of the motor. This calculation process does not rely on feedback from actual displacement, actual speed, or other operating parameters for correction, therefore it belongs to an open-loop control method.

[0109] For example, if the moment of inertia of the motor is 0.01 kg·m 2 The target angular acceleration is 200,000 radians / second. 2 If the resistance torque is 0.5 N·m, then the target torque = 0.01 × 200000 + 0.5 = 2000.5 N·m.

[0110] In possible implementations, the method for generating the target output command is adjusted accordingly when the target output command is a target speed command or a target current command. For example, the target speed command can be determined based on the target angular velocity obtained by integrating the target angular acceleration with time, and the target current command can be determined based on the proportional relationship between the target torque and the motor torque constant.

[0111] It should be noted that during the predetermined stroke phase, the target angular acceleration is determined based on the motor's maximum angular velocity, system calculation cycle, and other inherent performance parameters. This results in the generation of a target output command, enabling the motor to accelerate at its maximum angular acceleration from startup, thus reaching maximum angular velocity in the shortest possible time. Because this control process does not rely on feedback signals for correction, it avoids the response delay caused by feedback adjustment in closed-loop control, fully utilizing the motor's peak torque capability.

[0112] The processes shown in S301-S303 above employ an open-loop control strategy during the predetermined stroke phase, using inherent performance parameters such as the maximum angular velocity of the motor as the control basis. This allows the motor to drive the braking actuator to quickly cross the predetermined stroke with maximum acceleration during the mechanical gap phase, thereby maximally compressing the duration of the predetermined stroke phase and providing core technical support for shortening the braking response time.

[0113] like Figure 4 The diagram shown is a fourth flowchart of a motor control method provided in an embodiment of this application, including the following steps.

[0114] S401: Obtain the actual displacement and actual speed of the motor.

[0115] The actual displacement refers to the actual position of the motor rotor or braking actuator at the current moment. The actual rotational speed refers to the actual angular velocity of the motor rotor at the current moment.

[0116] In some examples, the actual displacement can be obtained using position sensors built into the motor (such as resolvers, Hall effect sensors, or magnetic encoders). The actual rotational speed can be obtained using speed sensors built into the motor, or calculated by differentiating the actual displacement, or estimated using current or back electromotive force signals in the motor drive circuit.

[0117] In a possible implementation, for a motor without a speed sensor, the actual rotational speed can be obtained by differentiating the actual displacement signal. Specifically, the actual rotational speed = Δactual displacement / Δtime, where Δactual displacement is the change in actual displacement between two adjacent sampling times, and Δtime is the time interval between two adjacent sampling times.

[0118] It should be noted that step S401 is performed after the braking actuator has left the predetermined stroke stage, and is used to obtain the feedback signal required by the closed-loop control strategy. The actual displacement is compared with the target displacement to form the first deviation, and the actual rotational speed is compared with the target rotational speed to form the second deviation.

[0119] S402: Determine the target speed of the motor based on the first deviation between the target displacement and the actual displacement.

[0120] The target displacement is the desired position that the braking actuator is expected to reach under the current braking condition. The target displacement can be determined based on the driver's braking intention (e.g., brake pedal opening) or the braking requirements of the upper-level controller (e.g., the target deceleration requested by the vehicle's braking system). The first deviation is the difference between the target displacement and the actual displacement, reflecting the gap between the current position and the desired position of the braking actuator.

[0121] Optionally, the specific process for determining the target speed of the motor based on the first deviation between the target displacement and the actual displacement can be found in [reference needed]. Figure 5 The steps shown are explained below.

[0122] In some examples, the target rotational speed is determined based on the first deviation by using a proportional-integral-derivative (PID) control algorithm to adjust the first deviation and output the target rotational speed. For example, the target rotational speed = Kp × e(t) + Ki × ∫e(t)dt + Kd × de(t) / dt, where e(t) is the first deviation, Kp is the proportional coefficient of the displacement loop, Ki is the integral coefficient of the displacement loop, and Kd is the derivative coefficient of the displacement loop. The output of this PID control is the target rotational speed, which drives the braking actuator to move in the target displacement direction.

[0123] In possible implementations, other closed-loop control algorithms can also be used to determine the target speed based on the first deviation, such as fuzzy control, sliding mode control, or model predictive control. The core idea of ​​these algorithms is to generate speed commands based on displacement deviations, so that the braking actuator can approach the target position.

[0124] It should be noted that S402 constitutes the outer loop (i.e., the displacement loop) in the closed-loop control strategy. The outer loop takes the displacement deviation as input and the target speed as output, and its function is to make the actual displacement of the braking actuator follow the target displacement.

[0125] It should also be noted that the coordination relationship between the displacement loop and the speed loop (mentioned later) is as follows: the displacement loop calculates the target speed based on the first deviation between the target displacement and the actual displacement, and uses this target speed as the expected input value of the speed loop; the speed loop calculates the target output command based on the second deviation between the target speed and the actual speed. In other words, the output of the displacement loop is the input of the speed loop, and the two form a cascaded control link. In each control cycle, the displacement loop's calculation is executed first to update the target speed, and then the speed loop's calculation is executed to update the target output command.

[0126] S403: Employs a closed-loop control strategy to generate a target output command based on the second deviation between the target speed and the actual speed.

[0127] The closed-loop control strategy is a control method based on feedback adjustment according to the deviation. The second deviation is the difference between the target speed and the actual speed.

[0128] In some examples, a closed-loop control strategy is employed. Based on the second deviation, the target output command is generated by adjusting the second deviation using a PID control algorithm to output the target torque command. For example, the target torque = Kp_v × e_v(t) + Ki_v × ∫e_v(t)dt + Kd_v × de_v(t) / dt, where e_v(t) is the second deviation, Kp_v is the proportional coefficient of the speed loop, Ki_v is the integral coefficient of the speed loop, and Kd_v is the derivative coefficient of the speed loop. The output of this PID control is the target torque command, used to control the actual torque output of the motor, ensuring that the actual motor speed follows the target speed.

[0129] In possible implementations, the target output command is not limited to a target torque command, but may also include a target current command or a target voltage command. The specific type of output command used depends on the specific architecture of the motor control system.

[0130] It should be noted that S403 constitutes the inner loop (i.e., the speed loop) in the closed-loop control strategy. The inner loop takes the speed deviation as input and the target output command as output, and its function is to make the actual speed of the motor follow the target speed. The outer loop of S402 and the inner loop of S403 together form a dual closed-loop control structure. The outer loop is responsible for displacement tracking, and the inner loop is responsible for speed stabilization. The two work together to achieve precise control of the displacement of the braking actuator.

[0131] The process described in S401-S403 switches to a closed-loop control strategy after the braking actuator disengages from the predetermined stroke stage. During the clamping stage, the braking actuator has already contacted the brake disc and needs to establish precise braking force; therefore, a closed-loop control strategy based on deviation feedback adjustment is adopted. Through the dual closed-loop structure of displacement and speed loops, it is ensured that the braking actuator accurately reaches the target displacement, achieving precise tracking of the target braking force. Compared to the open-loop control strategy in the predetermined stroke stage, which prioritizes rapid response, the closed-loop control strategy in the clamping stage prioritizes precise control. Both strategies perform their respective functions in different stages, jointly achieving a balance between speed and precision throughout the braking process.

[0132] like Figure 5 The diagram shown is a fifth flowchart of a motor control method provided in an embodiment of this application, which includes the following steps.

[0133] S501: Determine the displacement range in which the actual displacement is located.

[0134] The displacement range is a pre-defined numerical range based on the physical characteristics of the braking actuator. Different displacement ranges correspond to different load characteristics and control requirements of the braking actuator.

[0135] Optionally, before determining the displacement range in which the actual displacement occurs, it is also possible to utilize... Figure 7 The steps shown adjust the boundary values ​​of the displacement interval to improve the reliability of the displacement interval determination results.

[0136] Generally speaking, the upper limit of the first displacement interval and the lower limit of the second displacement interval are the same boundary value (i.e., the preset boundary value). This boundary value corresponds to the turning point of the caliper stiffness characteristics: when the actual displacement is within the range of [0, preset boundary value], the caliper stiffness is small, and the rate of change of braking force with displacement is low, at which point the braking force has not yet been fully established; when the actual displacement is greater than the preset boundary value, the caliper stiffness is large, the rate of change of braking force with displacement is high, and the braking force has entered the rapid establishment stage.

[0137] In some examples, the preset boundary values ​​are pre-calibrated based on the caliper's stiffness characteristic curve. The caliper's stiffness characteristic curve characterizes the relationship between braking force and the displacement of the braking actuator, and can be obtained through bench testing or simulation analysis. In the stiffness characteristic curve, the displacement value corresponding to the first time the rate of change of braking force with displacement reaches the preset stiffness threshold is the preset boundary value.

[0138] It should be noted that by setting this boundary value within the clamping stage, the clamping stage is further subdivided into an initial clamping sub-stage with lower caliper stiffness and a later clamping sub-stage with higher caliper stiffness. In these two sub-stages, the control objectives differ: the initial clamping sub-stage focuses on rapidly establishing braking force, while the later clamping sub-stage focuses on stably tracking the target displacement. This refined stage division based on caliper stiffness characteristics allows the control strategy to better match the physical characteristics of the braking actuator.

[0139] In some examples, the displacement range is defined based on the caliper's stiffness characteristics. In the initial clamping phase (when the friction pads just contact the brake disc), the caliper stiffness is low, and the rate of change of braking force with displacement is low. In the later clamping phase (when the friction pads are fully clamped), the caliper stiffness is high, and the rate of change of braking force with displacement is high. Therefore, by determining the displacement range in which the actual displacement occurs, different control strategies can be employed for different caliper stiffness states.

[0140] In a possible implementation, the displacement interval includes a first displacement interval and a second displacement interval. The first displacement interval corresponds to the initial clamping stage, and its range is where the actual displacement is greater than or equal to a first boundary value and less than a second boundary value. The second displacement interval corresponds to the later clamping stage, and its range is where the actual displacement is greater than or equal to the second boundary value. The first and second boundary values ​​are pre-calibrated based on the mechanical structural parameters of the braking system and the caliper stiffness characteristics.

[0141] For example, the first boundary value can be set to 0 (i.e., zero displacement), the second boundary value can be set to 0.5mm, the first displacement interval is [0, 0.5mm), and the second displacement interval is [0.5mm, ∞).

[0142] It should be noted that the accurate division of the displacement range has a significant impact on the subsequent speed correction strategy. If the boundary values ​​of the displacement range are not set appropriately, the correction strategy will be activated at inappropriate stages, affecting the control effect.

[0143] S502: When the actual displacement is in the first displacement range, the target speed is corrected so that the corrected target speed is greater than the original target speed.

[0144] The first displacement range corresponds to the initial clamping stage when the brake actuator just contacts the brake disc. During this initial clamping stage, the caliper stiffness is relatively low, and the rate of change of braking force with displacement is also low. Therefore, the speed of brake force build-up can be accelerated by appropriately increasing the target rotational speed, thereby further shortening the pressurization time.

[0145] In some examples, the target speed is corrected by multiplying it by a correction factor greater than 1. For example, the corrected target speed = target speed × k, where k is the correction factor and k > 1. The correction factor can be pre-calibrated based on the actual stiffness characteristics of the caliper. Generally speaking, the smaller the caliper stiffness, the larger the correction factor can be set.

[0146] In some examples, the correction factor k ranges from [1.0, 1.5], and preferably from [1.0, 1.3]. The specific value of the correction factor k can be calibrated through bench testing: on a braking bench, the control motor drives the brake actuator to perform clamping action with different correction factors, and the pressure build-up time required from contacting the brake disc (i.e., contacting the brake disc) to reaching the target braking force is measured. The correction factor with the shortest pressure build-up time and without causing brake force overshoot is determined as the calibration value.

[0147] For example, if the target speed before correction is 1000 rpm and the correction coefficient k = 1.2, then the target speed after correction is 1000 × 1.2 = 1200 rpm. This correction process enables the motor to drive the brake actuator at a higher speed during the initial clamping phase, thus accelerating the establishment of braking force.

[0148] In a possible implementation, the correction factor can also be dynamically adjusted according to the specific position of the actual displacement within the first displacement interval. For example, when the actual displacement just enters the first displacement interval, the correction factor takes a larger value, and as the actual displacement approaches the second displacement interval, the correction factor gradually decreases to 1.

[0149] In a possible implementation, the correction coefficient k(d) = 1 + (k_max - 1) × (1 - d / d_max), where d is the offset of the actual displacement relative to the starting point of the first displacement interval, d_max is the width of the first displacement interval, and k_max is the preset maximum correction coefficient. When d = 0, k(d) = k_max; when d = d_max, k(d) = 1. Thus, the correction coefficient gradually decreases from its maximum value at the starting point of the interval to 1 at the end point, achieving a smooth transition. The value of k_max is determined based on the stiffness characteristics and calibration requirements of the caliper; for example, k_max can be set to 1.3.

[0150] It should be noted that the amplification correction of the target rotational speed during the initial clamping stage is based on the physical characteristics of the caliper having relatively low stiffness and a low rate of change of braking force with respect to displacement during this stage. Since a moderate increase in the target rotational speed during this stage will not cause a drastic jump in braking force, the response speed can be further optimized without affecting stability.

[0151] S503: When the actual displacement is in the second displacement range, maintain the target rotational speed unchanged.

[0152] The second displacement range corresponds to the later clamping stage where the braking actuator has been fully clamped. In this later clamping stage, the caliper stiffness is relatively high, the rate of change of braking force with respect to displacement is high, and even a small change in the target rotational speed can lead to a large fluctuation in the braking force.

[0153] In some examples, maintaining the target speed unchanged means not performing the correction process in S502, and directly using the target speed determined by the displacement loop based on the first deviation as the final target speed. That is, in the second displacement interval, the correction coefficient for the target speed can be defaulted to 1.

[0154] It should be noted that maintaining a constant target speed in the later stages of clamping is important because the caliper stiffness is high during this phase, and any additional speed amplification could lead to braking force overshoot or system oscillation. Maintaining a constant target speed ensures stable tracking of the target displacement, guaranteeing the smoothness and safety of the braking process.

[0155] The processes shown in S501-S503 above achieve differentiated control of different sub-stages within the clamping stage by subdividing the clamping stage into a first displacement interval and a second displacement interval. The target rotational speed is amplified and corrected in the first displacement interval, while the target rotational speed is maintained constant in the second displacement interval. This control strategy fully considers the nonlinear characteristics of caliper stiffness in different displacement intervals, further optimizes the response speed in the initial clamping stage, and ensures the stability of the control system in the later clamping stage, thus achieving a balance between response speed and stability throughout the entire clamping stage.

[0156] like Figure 6 The diagram shown is a sixth flowchart of a motor control method provided in an embodiment of this application, including the following steps.

[0157] S601: Obtain historical operating data of the motor during the predetermined stroke phase.

[0158] Historical operating data refers to the data recorded by the motor during historical braking events when it was in the predetermined stroke phase. Historical operating data includes, but is not limited to, data on changes in actual displacement over time, data on changes in actual rotational speed over time, and data on actual output torque.

[0159] In some examples, historical operational data is stored in the vehicle controller's non-volatile memory. After each braking event, the vehicle controller stores the relevant operational data for the predetermined travel phase of that braking event into memory for subsequent braking events.

[0160] In a possible implementation, historical operating data can be stored as time-series data in chronological order. For example, using the system calculation cycle as the sampling interval, the actual displacement value, actual rotational speed value, and actual output torque value at each sampling moment in a predetermined stroke stage are recorded to form a time-series record.

[0161] It should be noted that the step shown in S601 is executed before the target output command is generated using the open-loop control strategy. By acquiring historical operating data, a data foundation is provided for subsequent performance parameter updates.

[0162] S602: Update performance parameters based on historical operating data.

[0163] The performance parameters are the inherent physical parameters of the motor, including but not limited to maximum angular velocity, moment of inertia, and resistance torque. Although these parameters are calibrated at the factory, the actual performance of the motor may drift due to factors such as temperature changes, mechanical wear, and changes in lubrication conditions during long-term use.

[0164] In some examples, performance parameters are updated based on historical operating data by reverse-engineering the actual moment of inertia and actual resistance torque of the motor in the current state, using the actual acceleration and actual output torque from the historical operating data. For example, based on Newton's second law (torque = moment of inertia × angular acceleration + resistance torque), multiple sets of torque-acceleration data points from historical operating data are used to estimate the current actual moment of inertia and actual resistance torque through parameter identification methods (such as the least squares method), and the original performance parameters are updated using the estimation results.

[0165] In a possible implementation, the performance parameters can be updated recursively, that is, the performance parameters are slightly modified after each braking event, rather than being changed drastically all at once. For example, the updated performance parameter = original performance parameter × (1-α) + estimated performance parameter × α, where α is the update step size (0 < α < 1), used to control the update speed and avoid drastic fluctuations in parameters due to single estimation errors.

[0166] In some examples, the update step size α ranges from [0.1, 0.3]. A larger α value results in a faster response of the performance parameters to the latest estimation, but also a higher sensitivity to single estimation errors. A smaller α value results in smoother changes in the performance parameters, but a slower tracking speed of actual performance drift. The specific value of α can be determined by combining the motor's performance parameter drift rate and the estimated noise level. For example, for a motor with a slow performance parameter drift rate, α can be 0.1, while for a motor with a fast performance parameter drift rate, α can be 0.3.

[0167] For example, if the original moment of inertia is 0.01 kg·m 2The current actual moment of inertia, estimated based on historical operating data, is 0.0105 kg·m. 2 If the update step size α = 0.3, then the updated moment of inertia = 0.01 × 0.7 + 0.0105 × 0.3 = 0.007 + 0.00315 = 0.01015 kg·m 2 .

[0168] It should be noted that the step shown in S602 is also executed before generating the target output command using the open-loop control strategy. By updating the performance parameters before executing open-loop control, the performance parameters used to determine the target angular acceleration in S301 are the actual current performance parameters of the motor, thereby improving the accuracy of the target angular acceleration and thus improving the precision and reliability of the open-loop control strategy.

[0169] The processes shown in S601-S602 above update the motor's performance parameters based on historical operating data during each braking event, ensuring that the performance parameters upon which the open-loop control strategy is based remain consistent with the motor's current actual state. Since an open-loop control strategy is used during the predetermined stroke phase, its control accuracy depends entirely on the accuracy of the performance parameters. If the performance parameters drift due to motor aging or wear, the accuracy of the open-loop control will be affected. By using feedback from historical operating data to adaptively update the performance parameters, the problem of accuracy degradation of fixed performance parameters due to aging, wear, and other factors during long-term motor use is overcome, ensuring the consistency and reliability of the open-loop control strategy throughout its entire lifecycle.

[0170] like Figure 7 The diagram shown is a seventh flowchart of a motor control method provided in an embodiment of this application, which includes the following steps.

[0171] S701: Obtain wear status information of the brake actuator.

[0172] Among them, the wear status information characterizes the degree of wear of the braking actuator, especially the wear of the brake friction pads. During use, the brake friction pads gradually wear and thin, causing the zero-point displacement of the braking actuator to drift under different degrees of wear.

[0173] In some examples, wear status information can be obtained in multiple ways. Specifically, method one: directly acquiring the degree of wear through wear detection sensors integrated on the brake friction pads. Method two: obtaining the degree of wear by statistically estimating the cumulative number of braking operations or cumulative braking energy of the braking actuator. Method three: indirectly inferring the degree of wear by analyzing the trend of zero-point displacement changes in historical braking events.

[0174] In a possible implementation, wear status information can be represented as the remaining thickness of the friction pad or the wear ratio. For example, when the initial thickness of the friction pad is 10 mm and the current remaining thickness is 8 mm, the wear ratio is 20%. A preset correspondence exists between the zero-point offset of the brake actuator and this wear ratio, which can be pre-calibrated through bench testing. When the wear ratio increases by 10%, the zero-point offsets by 0.02 mm in the direction of increasing displacement, and the boundary values ​​of the first and second displacement intervals are correspondingly offset by 0.02 mm in the direction of increasing displacement.

[0175] In a possible implementation, the wear detection sensor can be a resistive or inductive sensor embedded inside the friction pad. When the friction pad wears down to the sensor position, the sensor output signal changes, indicating the degree of wear. The cumulative braking count can be calculated by incrementing a braking count counter by 1 after each braking event. When the cumulative braking count reaches a preset maintenance threshold, the wear level is determined to have reached the point where the adjustment interval boundary value is required. The displacement zero-point change trend analysis can be performed by recording the displacement value when the actual displacement changes from negative to zero during each braking event. If this displacement value shows a monotonic change trend over time, the current degree of wear can be estimated based on this trend.

[0176] It should be noted that step S701 is performed before determining the displacement range in which the actual displacement lies. By acquiring wear status information, a basis is provided for subsequent adjustment of the boundary values ​​of the displacement range. Since the wear of the friction pads is a gradual process, acquiring wear status information in each braking event and adjusting the range boundary values ​​accordingly ensures that the division of the displacement range is always synchronized with the current physical state of the braking actuator.

[0177] S702: Adjust the boundary values ​​of the first displacement range and / or the boundary values ​​of the second displacement range based on the wear condition information.

[0178] The boundary values ​​between the first and second displacement intervals are threshold values ​​used to divide the different displacement intervals, such as... Figure 5 The steps shown are explained in the accompanying instructions.

[0179] In some examples, when the acquired wear status information indicates that the brake pads have worn to a certain extent, it is necessary to shift the boundary values ​​of the first displacement interval and / or the second displacement interval in the direction of increasing displacement to compensate for the change in the zero displacement point caused by the thinning of the friction pads. For example, if the wear of the friction pads causes the zero displacement point to shift from 0 to +0.05mm, then the boundary values ​​of both the first and second displacement intervals are shifted by 0.05mm in the direction of increasing displacement, so that the division of the displacement intervals remains unchanged relative to the actual physical contact state.

[0180] For example, if the first displacement range before wear is [0, 0.5 mm) and the second displacement range is [0.5 mm, ∞), and wear causes the zero displacement point to shift by +0.05 mm, then the adjusted first displacement range is [0.05 mm, 0.55 mm) and the adjusted second displacement range is [0.55 mm, ∞).

[0181] In a possible implementation, when the wear of the friction pads is minor, the boundary values ​​of the displacement range may not be adjusted temporarily to avoid instability in the control logic due to overly frequent adjustments. The boundary value adjustment operation is only performed when the wear exceeds a preset adjustment threshold.

[0182] It should be noted that by adjusting the boundary values ​​of the displacement range based on wear status information, the problem of inaccurate displacement range division caused by zero-point drift due to friction plate wear is avoided. If the boundary values ​​of the displacement range are not adjusted with wear, the first displacement range, which originally corresponds to the initial stage of clamping, may incorrectly cover the idle travel stage or the later stage of clamping, causing the speed correction strategy to be activated or not activated at inappropriate stages, affecting the control effect. Through adaptive boundary value adjustment, the effectiveness of the displacement range-based correction strategy is ensured throughout the entire vehicle lifecycle.

[0183] The processes described in S701-S702 above acquire wear state information of the braking actuator before determining the displacement range, and adaptively adjust the boundary values ​​of the displacement range based on the wear state information, ensuring that the division of the displacement range is synchronized with the current physical state of the braking actuator. This process overcomes the problem of inaccurate range division caused by fixed displacement range boundary values ​​after friction pad wear, ensuring the accuracy and reliability of the speed correction strategy based on the displacement range throughout its entire life cycle, and further improving the robustness of the control method during long-term vehicle use.

[0184] like Figure 8 The diagram shown is an eighth flowchart of a motor control method provided in an embodiment of this application, which includes the following steps.

[0185] S801: Obtain the target displacement of the motor.

[0186] The target displacement is the desired position that the braking actuator expects to reach under the current braking condition. The target displacement can be determined based on the driver's braking intention (e.g., brake pedal opening) or the braking requirements of the upper-level controller (e.g., the target deceleration requested by the Automatic Emergency Braking (AEB) system).

[0187] In some examples, the target displacement can be obtained from a higher-level controller (such as an autonomous driving domain controller or a vehicle stability controller) through the vehicle controller's communication interface. The higher-level controller calculates the target displacement corresponding to the current braking demand based on environmental perception information or driver operation information, and sends the target displacement to the motor controller.

[0188] In a possible implementation, the target displacement can also be directly calculated by the motor controller based on the brake pedal opening signal. Specifically, there is a preset mapping relationship between the brake pedal opening and the target displacement, which can be stored in the motor controller's memory in the form of a lookup table. When the motor controller detects a change in the brake pedal opening, it obtains the target displacement corresponding to the current brake pedal opening by querying the lookup table.

[0189] It should be noted that step S801 is performed before acquiring the motor's operating parameters. The target displacement is one of the input parameters for determining whether to trigger the control logic of this application, and its accuracy directly affects the reliability of the trigger condition determination.

[0190] S802: Determine whether the vehicle is in an emergency braking condition and whether the target displacement is greater than a preset displacement threshold.

[0191] The emergency braking condition includes both the vehicle braking system activation state and the driver's emergency braking state. The vehicle braking system activation state includes braking triggered by the AEB system. The preset displacement threshold is a pre-set critical value used to determine whether the current braking demand exceeds the idle travel.

[0192] In some examples, the method for determining whether a vehicle is in an emergency braking condition is as follows: when a braking request signal is received from the AEB system, the vehicle is determined to be in an emergency braking condition; or, when the rate of change of the brake pedal travel is detected to be greater than a preset rate of change of the travel threshold, or the rate of change of the brake pedal force is detected to be greater than a preset rate of change of the pedal force threshold, the driver is determined to be in an emergency braking state.

[0193] In a possible implementation, the preset displacement threshold can be pre-calibrated based on the mechanical clearance stroke of the brake actuator. Specifically, if the mechanical clearance stroke of the brake actuator is 0.5 mm, then the preset displacement threshold is calibrated to 0.5 mm. When the target displacement is greater than 0.5 mm, it indicates that the current braking demand exceeds the idle stroke of the brake actuator, and it is necessary to enter the effective brake clamping stage. For different braking systems, the mechanical clearance stroke may be different, and the preset displacement threshold should be calibrated according to the braking system parameters of the specific vehicle model.

[0194] In possible implementations, the order of judgment of the two conditions in step S802 can be flexibly adjusted. For example, it can be determined first whether the vehicle is in an emergency braking condition, and then the target displacement is obtained and a threshold comparison is performed after the determination is made. Alternatively, the target displacement can be obtained first and a threshold comparison is performed, and then it can be determined whether the vehicle is in an emergency braking condition after the target displacement is greater than a preset displacement threshold.

[0195] For example, if the vehicle has triggered the AEB system and the target displacement corresponding to the braking request is 0.8mm, and the preset displacement threshold is 0.5mm, then 0.8mm > 0.5mm, and the vehicle is in an emergency braking condition. Both conditions are met, and the control logic of this application is triggered.

[0196] It should be noted that the two triggering conditions in step S802 together form a logical "AND" relationship, meaning that the control logic of this application is triggered only when both conditions are met. By setting dual triggering conditions of emergency braking and target displacement, the open-loop control strategy is only activated under extreme conditions. In normal braking conditions, the braking response time requirement is relatively lenient, and the conventional control strategy can meet the requirements; however, in emergency braking conditions, by activating the open-loop control strategy to quickly cross the predetermined stroke, the braking response time can be effectively shortened. At the same time, the setting of dual triggering conditions avoids the frequent activation of the open-loop control strategy in unnecessary scenarios, which helps to reduce system power consumption and motor losses.

[0197] S803: When it is detected that the vehicle is in an emergency braking condition and the target displacement is greater than the preset displacement threshold, the step of obtaining the motor's operating parameters is executed.

[0198] The steps for obtaining the motor's operating parameters are as follows: Figure 1 The S101 step shown means that after the triggering condition is met, the subsequent process of the motor control method provided in this application is started.

[0199] In a possible implementation, when the triggering condition is met, the motor controller begins to execute the steps shown in S101, obtains the operating parameters of the motor, and then sequentially executes the following steps: determining the operating state of the braking actuator based on the operating parameters, generating a target output command using an open-loop control strategy during a predetermined stroke phase, and controlling the motor operation based on the target output command, so as to achieve rapid pressure build-up under emergency braking conditions.

[0200] Optionally, when it is detected that the vehicle is not in an emergency braking condition, or the target displacement is not greater than a preset displacement threshold, the step of obtaining the motor's operating parameters is not executed, and braking control can be performed according to the conventional control strategy.

[0201] For example, if the current braking is normal braking by the driver (non-emergency braking), even if the target displacement is large, the open-loop control strategy of this application will not be triggered. Instead, braking will be performed according to the conventional closed-loop feedback control strategy to ensure the smoothness and comfort of the braking process.

[0202] It should be noted that step S803 is the final output action of the trigger condition judgment. When both conditions in step S802 are met, step S803 will redirect the control flow to subsequent control steps of this application (such as...). Figure 1 (S101-S104 shown). Through this pre-triggered judgment mechanism, the control method of this application can be precisely activated in emergency situations requiring extreme response speed, while remaining uninterrupted in normal operating conditions. This improves active safety performance while also ensuring the comfort of daily driving and the durability of the system.

[0203] The processes described in S801-S803 above establish a trigger condition judgment step before acquiring the motor's operating parameters. The trigger conditions are whether the vehicle is in an emergency braking condition and whether the target displacement exceeds a preset displacement threshold. The subsequent open-loop control process is initiated only when both conditions are met. This process ensures that the open-loop control strategy is only activated under extreme conditions such as emergency braking, avoiding excessive intervention in conventional braking. Simultaneously, it achieves rapid pressure build-up response under extreme conditions, improving the vehicle's active safety performance.

[0204] like Figure 9 The diagram shown is a schematic representation of a vehicle architecture according to an embodiment of this application. The vehicle includes a processor 901, a memory 902, and a bus 903. The processor 901 and the memory 902 are connected via the bus 903. The memory 902 is used to store programs, and the processor 901 is used to run the programs. When the programs run, they execute the motor control method provided in this application, including the following steps:

[0205] Obtain the motor's operating parameters;

[0206] Based on the operating parameters, the operating status of the braking actuator driven by the motor is determined;

[0207] When the braking actuator is in the predetermined stroke stage, an open-loop control strategy is adopted to generate the target output command of the motor;

[0208] Based on the target output command, control the operation of the motor.

[0209] Optionally, the operating parameters include actual displacement and target displacement;

[0210] Based on the operating parameters, the operating state of the braking actuator driven by the motor is determined, including:

[0211] The actual displacement is compared with a preset threshold.

[0212] When the actual displacement is less than the preset threshold, it is determined that the braking actuator driven by the motor is in the predetermined stroke stage.

[0213] Optionally, an open-loop control strategy is adopted to generate the target output command for the motor, including:

[0214] Obtain the performance parameters of the motor; the performance parameters include the maximum angular velocity and the system calculation cycle;

[0215] The target angular acceleration is determined based on the maximum angular velocity and the system calculation period.

[0216] Using the open-loop control strategy, the target output command for the motor is generated based on the target angular acceleration;

[0217] The open-loop control strategy is a control method that determines the target output command based on the performance parameters and does not correct it through feedback of the operating parameters.

[0218] Optionally, before obtaining the motor's operating parameters, the method further includes:

[0219] Obtain the target displacement of the motor;

[0220] When the vehicle is detected to be in an emergency braking condition and the target displacement is greater than a preset displacement threshold, the step of obtaining the motor's operating parameters is executed.

[0221] Optionally, the method further includes:

[0222] When the braking actuator has left the predetermined stroke stage, the system switches to a closed-loop control strategy to generate the target output command for the motor.

[0223] Optionally, switch to a closed-loop control strategy to generate the target output command for the motor, including:

[0224] Obtain the actual displacement and actual speed of the motor;

[0225] The target speed of the motor is determined based on the first deviation between the target displacement and the actual displacement;

[0226] Using the closed-loop control strategy, the target output command is generated based on the second deviation between the target speed and the actual speed.

[0227] The closed-loop control strategy is a control method that uses feedback adjustment based on deviation.

[0228] Optionally, determining the target speed of the motor based on a first deviation between the target displacement and the actual displacement includes:

[0229] Determine the displacement range in which the actual displacement is located;

[0230] When the actual displacement is within the first displacement range, the target rotation speed is corrected so that the corrected target rotation speed is greater than the original target rotation speed.

[0231] When the actual displacement is within the second displacement range, the target rotational speed is maintained unchanged.

[0232] Optionally, before generating the target output command for the motor based on the motor's performance parameters using an open-loop control strategy, the method further includes:

[0233] Obtain historical operating data of the motor during the predetermined stroke phase;

[0234] Update the performance parameters based on the historical operating data.

[0235] Optionally, before determining the displacement range in which the actual displacement lies, the method further includes:

[0236] Obtain the wear status information of the braking actuator;

[0237] Based on the wear status information, adjust the boundary values ​​of the first displacement interval and / or the boundary values ​​of the second displacement interval.

[0238] In summary, this application employs an open-loop control strategy during the predetermined stroke phase, determining the target output command based on the inherent performance parameters of the motor. This avoids the limitations on motor speed and acceleration imposed by closed-loop feedback control in existing technologies, fully leveraging the motor's dynamic output capability and effectively shortening the duration of the braking actuator crossing the predetermined stroke phase, thereby reducing braking response time. Simultaneously, switching to a closed-loop control strategy after the braking actuator leaves the predetermined stroke phase ensures accurate tracking of the target displacement during the clamping phase. Furthermore, updating performance parameters based on historical operating data and adjusting displacement interval boundary values ​​based on wear status information further improves control accuracy and reliability throughout the vehicle's lifecycle. The performance parameter update scheme shown in S601-S602 and the wear compensation scheme shown in S701-S702 can be implemented independently or in combination. When implemented in combination, the performance parameter update ensures the accuracy of the open-loop feedforward control, while the adjustment of displacement interval boundary values ​​ensures the effectiveness of the speed correction strategy based on the displacement interval. Both improve the robustness and reliability of the control strategy throughout the vehicle's lifecycle from both control parameter and physical boundary dimensions. The motor control method provided in this application is particularly suitable for extreme conditions such as vehicle braking system triggering or driver emergency braking, and can effectively shorten braking distance and improve the active safety performance of the vehicle.

[0239] While several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this application. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0240] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A motor control method, characterized in that, Applied to vehicle braking systems, including: Obtain the motor's operating parameters; Based on the operating parameters, the operating status of the braking actuator driven by the motor is determined; When the braking actuator is in the predetermined stroke stage, an open-loop control strategy is adopted to generate the target output command of the motor; Based on the target output command, control the operation of the motor.

2. The method according to claim 1, characterized in that, The operating parameters include actual displacement and target displacement; Based on the operating parameters, the operating state of the braking actuator driven by the motor is determined, including: The actual displacement is compared with a preset threshold. When the actual displacement is less than the preset threshold, it is determined that the braking actuator driven by the motor is in the predetermined stroke stage.

3. The method according to claim 1, characterized in that, An open-loop control strategy is adopted to generate the target output command for the motor, including: Obtain the performance parameters of the motor; the performance parameters include the maximum angular velocity and the system calculation cycle; The target angular acceleration is determined based on the maximum angular velocity and the system calculation period. Using the open-loop control strategy, the target output command for the motor is generated based on the target angular acceleration; The open-loop control strategy is a control method that determines the target output command based on the performance parameters and does not correct it through feedback of the operating parameters.

4. The method according to claim 1, characterized in that, Before obtaining the motor's operating parameters, the method further includes: Obtain the target displacement of the motor; When the vehicle is detected to be in an emergency braking condition and the target displacement is greater than a preset displacement threshold, the step of obtaining the motor's operating parameters is executed.

5. The method according to claim 2, characterized in that, The method further includes: When the braking actuator has left the predetermined stroke stage, the system switches to a closed-loop control strategy to generate the target output command for the motor.

6. The method according to claim 5, characterized in that, Switch to closed-loop control strategy and generate target output commands for the motor, including: Obtain the actual displacement and actual speed of the motor; The target speed of the motor is determined based on the first deviation between the target displacement and the actual displacement; Using the closed-loop control strategy, the target output command is generated based on the second deviation between the target speed and the actual speed. The closed-loop control strategy is a control method that uses feedback adjustment based on deviation.

7. The method according to claim 6, characterized in that, Determining the target speed of the motor based on a first deviation between the target displacement and the actual displacement includes: Determine the displacement range in which the actual displacement is located; When the actual displacement is within the first displacement range, the target rotation speed is corrected so that the corrected target rotation speed is greater than the original target rotation speed. When the actual displacement is within the second displacement range, the target rotational speed is maintained unchanged.

8. The method according to claim 3, characterized in that, Before generating the target output command for the motor using an open-loop control strategy, the method further includes: Obtain historical operating data of the motor during the predetermined stroke phase; Update the performance parameters based on the historical operating data.

9. The method according to claim 7, characterized in that, Before determining the displacement range in which the actual displacement lies, the method further includes: Obtain the wear status information of the braking actuator; Based on the wear status information, adjust the boundary values ​​of the first displacement interval and / or the boundary values ​​of the second displacement interval.

10. A vehicle, characterized in that, include: Processor, memory, and bus; The processor and the memory are connected via the bus; The memory is used to store a program, and the processor is used to run the program, wherein the program is executed by the processor to perform the motor control method according to any one of claims 1-9.

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