Permanent magnet synchronous motor position closed-loop control system and method for brake-by-wire electric control master cylinder

Abstract

The invention provides a permanent magnet synchronous motor position closed-loop control system and method for a brake-by-wire electric control master cylinder. The system is composed of a position instruction generation module, a parameter converter module, a feedforward control value-added device module, a feedforward controller module, a PID controller module, a PID limiter module, a current instruction converter module, a voltage instruction generation module, a current sensor module and a control system module. Baseline torque is provided through the feedforward controller, the motor is preliminarily sent to a target position, then fine adjustment is conducted through the PID controller, and the problem of overshoot or undershoot caused by the influence of static friction force is effectively avoided. Segmented feedforward and PID parameters are adopted to adapt to the exponential relation between the position and the load torque, low-position small parameters and high-position large parameters. And particularly, feed-forward parameters are improved in a low-speed low-position area, so that the motor is prevented from being clamped by static friction force. A speed ring is omitted, and system reaction delay caused by speed feedback filtering is reduced. The simplified control algorithm is suitable for equipment which is low in computing power and needs a high-frequency control loop.

Description

Technical Field

[0001] The present invention relates to the field of automotive electronic control technology, and particularly to a permanent magnet synchronous motor position closed-loop control system and method for an electronically controlled master cylinder of a brake-by-wire system. Background Art

[0002] Automotive electronic control refers to the application of electronic technology in automobiles to control various functions of the vehicle, such as engine management, brake control, steering control, driver assistance systems, etc. With the progress of technology and the pursuit of safety and comfort, the application of electronic control in automobiles is becoming more and more widespread. The electronically controlled brake system is a part of it, which mainly uses electronic technology to achieve the braking function of the vehicle, rather than the traditional hydraulic or pneumatic method.

[0003] Among them, the motor position closed-loop control system of the electronically controlled master cylinder of the brake-by-wire system is a subsystem of the electronic brake system, mainly used to control the position of the motor of the electronically controlled master cylinder during the braking process of the vehicle. The motor provides power so that the master cylinder can generate sufficient braking pressure, which is then applied to the wheels to achieve the braking function. The purpose of this system is to ensure that the position of the motor can be accurately controlled under any circumstances, so as to provide a stable, reliable and efficient braking effect for the driver.

[0004] In a traditional hydraulic braking system, the braking force of the brake pedal is amplified by a vacuum booster, and then transmitted to the brake caliper through the brake fluid master cylinder. However, in a brake-by-wire electro-hydraulic braking system, the vacuum booster is removed, and the connection between the brake pedal and the master cylinder is separated. The braking force on the master cylinder is completely driven by the motor. Although the design details of the master cylinder may vary, the basic working principle is that a servo motor drives a rotary translation transmission device to amplify the torque and drive the piston to move in the hydraulic cylinder. The entire mechanical structure makes the hydraulic pressure proportional to the piston position (depth in the cylinder), and the piston position is proportional to the position of the motor (rotation angle). Therefore, from the perspective of the motor, the hydraulic pressure forms a load torque (negative torque), and a specific motor position corresponds to a specific hydraulic pressure. Due to the limitation of the mechanical structure, the motor can only rotate within a specific position range.

[0005] In actual operation, although the basic principle of motor position control is relatively simple, the characteristics of the load torque make the traditional three-loop (position -> speed -> torque / current) PID motor position control strategy less than ideal. The specific problems are reflected in the response time and accuracy. First, the behavior of this load torque is similar to a spring. When we try to increase the pressure (forward rotation), the motor has to provide positive torque. However, when reducing the pressure (reverse rotation), the motor mainly reduces the torque rather than truly providing negative torque. In addition, when the motor tries to maintain a certain position, a constant torque needs to be provided to balance this load torque. Different from an ordinary spring, the relationship between position and torque in this system shows exponential growth. Moreover, the static friction force existing in the master cylinder mechanism also poses challenges to control. When the torque of the motor is less than the static friction force at a certain position, the motor will stop. But once the torque is sufficient to overcome this static friction, the friction force quickly changes to a smaller dynamic friction force, which causes the motor to suddenly jerk forward until it is blocked by the static friction force again, resulting in a stepped change in the position even though the torque change of the motor is linear, as Figure 11 shown. In summary, a simple linear torque control strategy cannot meet the linear control requirements of the motor position. Summary of the Invention

[0006] The object of the present invention is to solve the disadvantages existing in the prior art, and to propose a permanent magnet synchronous motor position closed-loop control system and method for a wire-controlled electronic control master cylinder.

[0007] The permanent magnet synchronous motor position closed-loop control system for the wire-controlled electronic control master cylinder of the present invention mainly consists of a position command generation module, a parameter converter module, a feedforward control incrementer module, a feedforward controller module, a PID controller module, a PID limiter module, a current command converter module, a voltage command generation module, a current sensor module, and a control system module;

[0008] The position command generation module generates a motor position command by inputting a target position;

[0009] The parameter converter module performs parameter conversion based on the motor position command and the position command speed to generate PID controller parameters and feedforward controller parameters; the feedforward control incrementer module performs parameter increment based on the motor position command, the position command speed, and the first feedforward controller parameter to generate feedforward control increment parameters;

[0010] The feedforward controller module linearizes based on the motor position command and the feedforward control increment parameters according to the static relationship diagram of the motor position and the load torque, and determines the feedforward controller torque command to generate a feedforward output;

[0011] The PID controller module performs fine-tuning of the motor based on the motor position command and the actual position feedback, and generates a PID controller torque command by using the PID algorithm according to the PID controller parameters;

[0012] The PID limiter module processes the PID controller torque command output by the PID controller module, limits the PID controller torque command within the absolute value of the feedforward control increment parameter, and outputs it;

[0013] The current command converter module combines the feedforward controller torque command and the PID controller torque command to convert and output the q-axis current command;

[0014] The voltage command generation module obtains the voltage command by weighted summation based on the position command, the PID output, and the conversion parameters;

[0015] The current sensor module monitors the three-phase current of the motor in real time through a current sensor to obtain current feedback;

[0016] The control system module performs inverse Park transformation based on the voltage command and the current feedback, and generates the three-phase voltage output of the motor through a voltage inverter to achieve accurate position control of the motor.

[0017] As a permanent magnet synchronous motor position closed-loop control system for a wire-controlled electro-hydraulic master cylinder according to the present invention, the position command generation module includes a target input sub-module and a position encoding sub-module; the feedforward controller module includes a static relationship diagram sub-module and a feedforward calculation sub-module; the PID controller module includes a feedback acquisition sub-module, a PID algorithm sub-module, and a torque command output sub-module; the parameter converter module includes a data reception sub-module, a data conversion sub-module, and a data output sub-module; the voltage command generation module includes a parameter aggregation sub-module, a calculated voltage sub-module, and a voltage output sub-module; the current sensor module includes a current detection sub-module, a current data processing sub-module, and a current feedback output sub-module; the control system module includes a data integration sub-module, an inverse Park transformation sub-module, and an inverter output sub-module.

[0018] As a permanent magnet synchronous motor position closed-loop control system for a wire-controlled electro-hydraulic master cylinder according to the present invention, the target input sub-module obtains the target position through system signals and generates target position data; the position encoding sub-module encodes the position based on the target position data to meet the motor control requirements and generates an encoded position command.

[0019] As a permanent magnet synchronous motor position closed-loop control system for the electronic control master cylinder of the wire control brake in the present invention, the static relationship diagram sub-module generates static relationship diagram data according to the characteristic curves of the motor and the load; the feed-forward calculation sub-module uses the feed-forward control increment parameter and the static relationship diagram data to perform feed-forward calculation, determines the torque command of the feed-forward controller, and generates the feed-forward parameter output.

[0020] As a permanent magnet synchronous motor position closed-loop control system for the electronic control master cylinder of the wire control brake in the present invention, the feedback acquisition sub-module obtains the actual position of the motor through the position sensor and generates the actual position data;

[0021] The PID algorithm sub-module calculates using the PID algorithm based on the actual position data and the encoded position command, and generates the PID output parameter; the torque command output sub-module calculates based on the PID output parameter and the feed-forward parameter output, and generates the torque command output data.

[0022] As a permanent magnet synchronous motor position closed-loop control system for the electronic control master cylinder of the wire control brake in the present invention, the data reception sub-module receives the motor position command and the position command speed, and transfers them to the data conversion sub-module; the data conversion sub-module performs torque ratio conversion based on the parameter data to be converted and generates the converted parameter data; the data output sub-module generates and outputs the PID controller parameter and the feed-forward controller parameter according to the converted parameter data.

[0023] As a permanent magnet synchronous motor position closed-loop control system for the electronic control master cylinder of the wire control brake in the present invention, the parameter aggregation sub-module collects the encoded position command, the fine-tuning output data and the formatted conversion parameter, and generates the aggregated data; the voltage calculation sub-module calculates the required voltage command based on the aggregated data and generates the voltage command data; the voltage output sub-module formats the voltage command data for motor control use and generates the formatted voltage command; the current detection sub-module uses the sensor to monitor the three-phase current of the motor in real time and generates the raw current data; the current data processing sub-module filters and amplifies the raw current data and generates the processed current data; the current feedback output sub-module formats and outputs for the control system module based on the processed current data and generates the formatted current feedback; the data integration sub-module integrates the formatted voltage command and the formatted current feedback and generates the integrated data; the inverse Park conversion sub-module performs inverse Park conversion based on the integrated data and generates the converted voltage data; the inverter output sub-module generates a three-phase voltage output through the voltage inverter according to the converted voltage data to achieve accurate position control of the motor.

[0024] The present invention also provides a permanent magnet synchronous motor position closed-loop control method for a wire-controlled electronic master cylinder, which can be executed based on any one of the above-mentioned wire-controlled electronic master cylinder permanent magnet synchronous motor position closed-loop control systems, and mainly includes the following steps:

[0025] S1: Obtain the static relationship diagram of the motor position and the load torque, divide the motor position into several segments, and the number of segments is determined according to the exponential nature of the relationship diagram. The higher the exponential nature, the more segments. Make the motor position and the load torque in the segment linear, and divide the segment into two parts:

[0026] N segments x1 (covering θ start to θ x1 ), x2 (covering θ x1 to θ x2 ),... to xN (covering θ x(N-1) to θ max ) when the position is rising;

[0027] M segments y1 (covering θ start to θ y1 ), y2 (covering θ y1 to θ y2 ),... to yM (covering θ y(M-1) to θ max ) when the position is falling;

[0028] Among them, the number of segments N and M are not equal, θ start is the position where the load torque starts to show an exponential growth trend, and θ max is the highest position allowed by the master cylinder mechanical structure;

[0029] For the xN and yM segments, the parameter calculation is as follows:

[0030]

[0031] The median value θ mid,segxn / ym of the segment position is calculated as follows:

[0032]

[0033] T segxn / ym is the corresponding load torque of the median value θ segxn / ym of the segment position in the relationship diagram; thus, the determination of the K FFC parameters is completed;

[0034] S2: Define P as the parameter combination of the segments:

[0035] P = {K P , K I , K D , K FFC} (3)

[0036] The parameter converter module generates and outputs the PID controller parameters and the feedforward controller parameters according to the following equations:

[0037] if θ * < θ start ,

[0038] P inuse = P segz

[0039] if (θ * ≥ θ start ) and (ω * > 0),

[0040]

[0041] if (θ * ≥ θ start ) and (ω * < 0), (4)

[0042]

[0043] S3: The feedforward control incrementer module increments the feedforward controller parameters according to the following equation and outputs the feedforward control increment parameters:

[0044]

[0045] where, and are the low-speed threshold and the low-position threshold, ΔK FFC is the increment of the feedforward controller parameters;

[0046] S4: The feedforward controller module calculates the torque command through the following calculation equation to generate the feedforward output:

[0047]

[0048] is the torque command of the feedforward controller, K FFC is the feedforward control increment parameter, θ * is the motor position command;

[0049] S5: The PID controller torque command in the PID limiter module is limited by the following equation within the absolute value of :

[0050]

[0051] S6: The torque commands of the PID limiter module and the feedforward controller module are combined through the following equation and then input into the current command converter module:

[0052]

[0053] Torque command T * After passing through the q-axis current command converter in the current command converter module, the position loop directly outputs the torque command T * , T * to The conversion equation is as follows:

[0054]

[0055] The calculation of the conversion coefficient is as follows:

[0056]

[0057] Where, T rated and i rated are the rated torque and current of the motor respectively;

[0058] The current command converter module outputs the converted current command

[0059] S7: Based on the current command and the real-time current feedback, use a PI controller to generate a voltage command. Through inverse Park transformation, the voltage command is transferred from the dq coordinate system to the abc coordinate system to generate a voltage command for actual motor control, and then sent back to the control system to form a closed-loop control.

[0060] As a permanent magnet synchronous motor position closed-loop control method for a wire-controlled electro-hydraulic master cylinder according to the present invention, the step S1 further includes a step of debugging segmented parameters. According to the dynamic relationship between the motor position and the load torque, through re-debugging to confirm the adaptability of the parameters to the dynamic relationship, use a trajectory planning method for testing. In the trajectory, the rising segment is used as the position target, from θ zer o to θ xn / ym , stay, and then return to θ zero , for normal to high-speed testing; first judge whether there is overshoot or undershoot when the motor stops during the trajectory. Overshoot indicates that the K FFC of this segment is too large, and undershoot means it is too small; repeat adjusting the K FFC parameter until there is no overshoot or undershoot when stopping; then judge whether there is jamming during rising or falling. If so, it means that the PID parameter of the segment where the jamming position belongs is too small, and if there is overshoot, it means that the PID parameter is too large, and adjust the PID parameter accordingly.

[0061] As a permanent magnet synchronous motor position closed-loop control method for the electronic control master cylinder of the wire control brake of the present invention, in step S1, when the main cylinder mechanical structure is at the low position from θ zero to θ start , only one segment z is used to cover it; in segment z, the feedforward controller module is turned off, K FFC,segz is set to 0, and the PID limiter module does not perform limit processing on the torque command .

[0062] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0063] In the present invention, the feedforward controller provides the baseline torque, which can roughly send the motor to the target position, and then the PID controller is used for fine-tuning. This combination avoids the overshoot or undershoot problems that are likely to occur when only using the PID controller, especially under the conditions where the static friction has a significant impact. Since the relationship between position and torque grows exponentially, this solution adapts to the requirements of different positions by using segmented feedforward controller parameters. Small feedforward parameters are used at low positions, and large feedforward parameters are used at high positions. In the low-speed and low-position regions, friction becomes the main influencing factor. Increasing the feedforward controller parameters can effectively prevent the motor from getting stuck due to static friction. By omitting the speed loop, the delay that may be introduced by the speed filter is reduced, thus achieving a faster response speed. The amount of calculation required during the execution of this solution is relatively small, and most of the complexity is solved in the experimental stage of parameter adjustment, which makes it very suitable for low-end devices with limited computing power and applications that require high-frequency control loops. Brief Description of the Drawings

[0064] Figure 1 is the main system flow chart of the present invention;

[0065] Figure 2 is the system block diagram of the present invention;

[0066] Figure 3 is the schematic diagram of the method steps of the present invention;

[0067] Figure 4 is the static relationship diagram of the motor position and load torque of the present invention;

[0068] Figure 5 is the schematic diagram of the position rising segment of the present invention;

[0069] Figure 6 is the flow chart of the schematic diagram of the position falling segment of the present invention;

[0070] Figure 7 is the schematic diagram of the parameter segment summary of the present invention;

[0071] Figure 8Data flow diagram of the motor control method of the present invention;

[0072] Figure 9 Flow chart of the motor control method of the present invention;

[0073] Figure 10 Traditional motor position PID closed-loop control design in the prior art;

[0074] Figure 11 Shows the step phenomenon of the static friction of the master cylinder generated in the traditional control technology;

[0075] Figure 12 Shows the effect comparison diagram before and after the parameter improvement of the present invention;

[0076] Figure 13 and Figure 14 Shows the influence comparison diagram of adjusting the parameters of the feedforward controller of the present invention. Detailed implementation manners

[0077] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0078] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, in the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0079] Please first refer to Figure 10 , which is a traditional permanent magnet synchronous motor position PID closed-loop control design in the prior art, and mainly includes the following content:

[0080] 1. Compare the motor position command θ * and the motor position feedback θ to obtain the motor position error Δθ, and process and output the position command speed ω with a PID controller *

[0081] 2. Compare the position command speed ω * and the position speed feedback ω to obtain the motor position error Δω, and process and output the torque command T with a PID controller *

[0082] 3. T * Convert to iq current command through coefficient id current command Maintain 0 to determine the maximum torque of the motor output

[0083] 4. Compare with id and iq current feedback i d and i q Calculate the id and iq current errors Δi d and Δi q . Then transmit the error value to the PI controller to obtain the dq voltage command and

[0084] 5. Use the inverse Park transformation to convert the previous voltage reference from the dq coordinate system to the αβ coordinate system to obtain the αβ voltage command and

[0085] 6. Then use the SVPWM module and the three-phase inverter to transmit the actually output voltage to the motor through the current sensor

[0086] 7. Through the Park and Clarke transformations, the measured three-phase current feedback i of the motor u , i v , and i w becomes i d and i q . And the measured θ and ω are transmitted back to the control system to form a closed loop

[0087] Traditional designs assume that the dynamic characteristics of the system are linear, but this is clearly not applicable to the situation mentioned in the background

[0088] Please refer to Figures 1 to 9 , the present invention provides a technical solution: the permanent magnet synchronous motor position closed-loop control system of the wire-controlled electro-hydraulic master cylinder is composed of a position command generation module, a parameter converter module, a feed-forward control booster module, a feed-forward controller module, a PID controller module, a PID limiter module, a current command converter module, a voltage command generation module, a current sensor module, and a control system module

[0089] The position command generation module generates a motor position command by inputting a target position

[0090] The parameter converter module performs parameter conversion based on the motor position command and the position command speed to generate PID controller parameters and feed-forward controller parameters

[0091] The feedforward control incrementer module increments parameters based on the motor position command, the position command speed, and the first feedforward controller parameters to generate feedforward control increment parameters;

[0092] The feedforward controller module linearizes based on the motor position command and the feedforward control increment parameters according to the static relationship diagram of the motor position and the load torque, and determines the feedforward controller torque command to generate a feedforward output;

[0093] The PID controller module performs fine-tuning of the motor based on the motor position command and the actual position feedback using the PID algorithm according to the PID controller parameters to generate a PID controller torque command;

[0094] The PID limiter module limits the PID controller torque command output by the PID controller module within the absolute value of the feedforward control increment parameter and outputs it;

[0095] The current command converter module has a q-axis current command converter, combines the feedforward controller torque command and the PID controller torque command to convert and output the q-axis current command;

[0096] The voltage command generation module obtains the voltage command by weighted summation based on the position command, the PID output, and the conversion parameters;

[0097] The current sensor module monitors the three-phase current of the motor in real time through a current sensor to obtain current feedback;

[0098] The control system module performs inverse Park transformation based on the voltage command and the current feedback, and generates the three-phase voltage output of the motor through a voltage inverter to achieve accurate position control of the motor.

[0099] An accurate position command is generated through the position command generation module, the feedforward controller module provides stable control parameters, the PID controller module achieves fine-tuning, the parameter converter module optimizes the control signal, and the voltage command generation module generates a suitable voltage command. At the same time, the current sensor module monitors the motor current in real time, and the control system module performs inverse Park transformation and voltage inverter operation to achieve precise position control. Such integration makes the system have high precision and high reliability, can adapt to different loads and motion requirements, and achieve stable motion performance and accurate position control.

[0100] Please refer to Figure 2 , as an embodiment of the present invention, the position command generation module may include a target input sub-module and a position encoding sub-module;

[0101] The feedforward controller module may include a static relationship diagram sub-module and a feedforward calculation sub-module;

[0102] The PID controller module may include a feedback acquisition sub-module, a PID algorithm sub-module, and a torque command output sub-module;

[0103] The parameter converter module may include a data reception sub-module, a data conversion sub-module, and a data output sub-module;

[0104] The voltage command generation module may include a parameter aggregation sub-module, a calculated voltage sub-module, and a voltage output sub-module;

[0105] The current sensor module may include a current detection sub-module, a current data processing sub-module, and a current feedback output sub-module;

[0106] The control system module may include a data integration sub-module, an inverse Park transformation sub-module, and an inverter output sub-module.

[0107] The position command generation module can output a position command, the feedforward controller module provides stable control parameters, the PID controller module realizes fine tuning, the parameter converter module optimizes the control signal, and the voltage command generation module generates appropriate voltage commands. At the same time, the current sensor module monitors the motor current in real time, and the control system module performs inverse Park transformation and voltage inverter operations to achieve precise position control.

[0108] The target input sub-module obtains the target position through the system signal and generates target position data;

[0109] The position encoding sub-module encodes the position based on the target position data to meet the motor control requirements and generates an encoded position command.

[0110] The position encoding sub-module converts the target position data into an accurate position command to ensure that the motor can be precisely controlled according to the expected position.

[0111] The static relationship diagram sub-module generates static relationship diagram data according to the characteristic curves of the motor and the load; for example, a data fitting algorithm can be used to process the static relationship diagram of the development main cylinder, divide the motor position and the load torque into multiple linear relationship segments, use the exponential clustering algorithm to determine the number of each relationship segment, and divide the segments of position rising and position falling into two groups to generate a position-torque static relationship mapping chart; the feedforward calculation sub-module uses the feedforward control parameters and the encoded position command to perform feedforward calculation and generate a feedforward parameter output.

[0112] Based on the data generated by the static relationship graph sub-module, the system can accurately understand the characteristic curve relationship between the motor and the load, providing an important reference for subsequent control. The feedforward calculation sub-module uses the feedforward control parameters generated by the parameter determination sub-module and the encoded position command to perform feedforward calculations to achieve load compensation and precise position tracking. The feedback acquisition sub-module obtains the actual position of the motor through a position sensor and generates actual position data;

[0113] The PID algorithm sub-module calculates using the PID algorithm based on the actual position data and the encoded position command to generate PID output parameters;

[0114] The torque command output sub-module performs calculations based on the PID output parameters and the feedforward parameter output to generate torque command output data. Through the feedback acquisition sub-module, the system can obtain the actual position data of the motor, achieve closed-loop control, and provide accurate feedback information. The PID algorithm sub-module uses the actual position data and the encoded position command to calculate using the PID control algorithm to generate PID output parameters. The advantage of this is that it can automatically adjust according to the current error, error change rate, and error accumulation value to achieve precise position control and stable response capabilities.

[0115] The data reception sub-module receives the motor position command and the position command speed and transfers them to the data conversion sub-module;

[0116] The data conversion sub-module calculates the parameters for each segment using algorithms such as linear regression based on the position-torque static relationship mapping chart. For the segments with low positions, the PID control strategy is used, and for other segments, the PID and feedforward control strategies are combined to generate segment parameters; then, the conversion coefficient of the parameter converter can be calculated according to the rated torque and current of the motor using the segment parameters and the parameter standardization method to obtain the parameter conversion coefficient; based on the segment parameters and the parameter conversion coefficient, the parameter data to be converted is subjected to torque ratio conversion to generate the converted parameter data;

[0117] The data output sub-module generates and outputs the PID controller parameters and the feedforward controller parameters according to the converted parameter data.

[0118] The data reception sub-module ensures that the parameters output by the feedforward controller module are accurately received, providing the necessary parameter data for the system. This can ensure the complete transfer of parameters and avoid control problems caused by data loss or errors. The data conversion sub-module performs torque ratio conversion to convert the parameters into a form suitable for system operation. This conversion helps to maintain the consistency of the parameters, enabling effective parameter exchange and collaboration between different systems. At the same time, the converted parameters also meet the operation requirements of the system, providing suitable inputs for subsequent control.

[0119] The feedforward control incrementer module can adopt a threshold determination algorithm. Based on the low-speed threshold, the low-position threshold, and the parameter conversion coefficient table, it determines the feedforward controller parameter increment, generates and outputs the feedforward parameter increment.

[0120] The PID limiter module, based on the logical constraint determination rule, combines the feedforward parameters, and determines the torque command limit range of the PID controller according to the set limit conditions, generating a limited torque command.

[0121] Combine and linearly weighted synthesize the segmented parameters, the feedforward parameter increment, and the limited torque command to generate the final torque command.

[0122] The parameter aggregation sub-module collects the encoded position command, the fine-tuning output data, and the conversion parameters to generate aggregated data;

[0123] The voltage calculation sub-module calculates the required voltage command based on the aggregated data, generating voltage command data;

[0124] The voltage output sub-module supplies the voltage command data for motor control, generating a voltage command.

[0125] The parameter aggregation sub-module can ensure the integrity and consistency of the parameters, integrating parameters from different sources together for convenient subsequent processing and calculation. The voltage calculation sub-module calculates based on the aggregated data to generate the required voltage command to achieve an accurate control effect. The voltage output sub-module is responsible for outputting the voltage command data and ensuring accurate transmission and proper motor control.

[0126] The current detection sub-module uses a sensor to monitor the three-phase current of the motor in real time, generating raw current data;

[0127] The current data processing sub-module filters and amplifies the raw current data, generating processed current data;

[0128] The current feedback output sub-module outputs for use by the control system module based on the processed current data, generating a current feedback.

[0129] Please refer to Figure 2 , the data integration sub-module integrates the voltage command and the current feedback to generate integrated data;

[0130] The inverse Park conversion sub-module performs an inverse Park conversion based on the integrated data, generating the converted voltage data;

[0131] The inverter output sub-module generates a three-phase voltage output through a voltage inverter according to the converted voltage data to achieve accurate position control of the motor.

[0132] The current detection sub-module can monitor the three-phase current of the motor in real time and provide accurate original current data as feedback. The current data processing sub-module filters and amplifies the original current data to improve the data quality and reliability. By filtering out noise and interference, the current data more accurately reflects the working state of the motor. The current feedback output sub-module outputs the processed current data for use by the control system module.

[0133] In some embodiments, the data output sub-module, the voltage output sub-module, and the current feedback output sub-module can also be built with a formatting output function, which can perform formatting output according to the converted parameter data to meet the requirements of the system for output parameters. Through formatting output, the parameters can be presented in a unified format and standard, facilitating the use and processing by subsequent control modules or external devices. This can improve the compatibility and scalability of the system, making the system more seamlessly dock and interact with other devices or platforms.

[0134] The added feedforward controller module of the present invention uses the motor position command θ * as an input, multiplies it by the parameter K FFC of the feedforward controller, and then outputs the FFC torque command Thereby, it can achieve (1) effectively dealing with the nature of the load. More specifically, it solves the problem of requiring a constant torque to maintain a specific position. Regardless of Δθ, the motor will provide a constant torque proportional to θ * to counteract the load torque. In contrast, the traditional PID controller will change the torque as Δθ changes, and finally will cause the position θ of the motor to swing back and forth and never fully reach θ * . (2) Real-time torque response. As long as θ * changes, the torque will immediately change. (3) The real-time torque response also helps to overcome static friction because the torque increases / decreases rapidly. If only the PID controller and Δθ are not large enough and the proportional unit cannot immediately provide enough torque, the system will need to wait for the integral unit to slowly accumulate until the torque is large enough to overcome static friction. Through the judgment of the feedforward control booster module of the present invention, when the absolute value of the position command speed ω * is less than the absolute value of the low-speed threshold , K FFC is equal to (K FFC +ΔK FFC ). It is used to help the motor overcome static friction when starting from rest to start moving, or to prevent premature stopping due to static friction before reaching θ * during deceleration. Increasing K FFC will result in a greater in order to delay the time when static friction overwhelms the motor torque and stops the motor.

[0135] The present invention uses a PID limiter module to limit the ratio between and the PID torque command within the absolute value of . This avoids dominating the combined torque command T * , and the integral and derivative units of the PID may cause disproportionately large causing the motor to deviate significantly from θ * , or even oscillate. This limitation avoids this problem.

[0136] The parameter converter module of the present invention changes the PID parameters K * , K * , K p , K i , K d and K FFC according to the input θ * and ω * . To adapt to the non - linear hydraulic load and static friction properties. The load torque increases with the position, but the relationship is non - linear. The same description also applies to static friction. The non - linear nature means that a single set of parameters cannot adapt to different θ * . This new arrangement divides the entire position range into multiple segments, each segment containing its own set of K p , K i , K d and K FFC matched to the load characteristics at that time. When the characteristic curve of θ and the load torque is missing, the segmented design is more convenient for debugging. And the number of segments does not need to be excessive because the PID controller itself has adaptability. In addition, according to whether ω * is positive or negative, there is a corresponding set of segments to handle the offset nature of the load. Finally, when θ * is below only the PID threshold , there is only relatively little friction and load torque, and the feed - forward controller module will turn off, leaving only the PID controller module working. This is because when θ * is small enough, the hydraulic pressure is small enough to be negligible. Within this range, it is sufficient to handle only through the PID controller module.

[0137] Compared with the traditional position -> speed -> current 3 - loop design, the present invention removes the speed - loop PID controller, improving the system's response ability. Since the speed loop depends on ω, but without a dedicated speed sensor, ω can only be calculated from the derivative of θ, and any slight noise in θ will be amplified. Therefore, ω must be filtered to make it usable. However, filtering will suppress the change of feedback, making the controller respond slowly. In contrast, θ does not have this problem. Although there is still noise, the signal - to - noise ratio is relatively small. Even without filtering, the controller can perform well, and more importantly, the response time will not be affected by any filtering. Please refer to Figures 3 to 9, A permanent magnet synchronous motor position closed-loop control method for a wire-controlled electronic master cylinder. The permanent magnet synchronous motor position closed-loop control method for the wire-controlled electronic master cylinder can be executed based on the above-mentioned permanent magnet synchronous motor position closed-loop control system for the wire-controlled electronic master cylinder, and includes the following steps:

[0138] Remove the speed loop on the basis of the traditional three-loop PID permanent magnet synchronous motor's motor position control method, and add the torque command T * to the q-axis current command Converter, the position loop directly outputs the torque command T * . T * to The conversion equation is as follows:

[0139]

[0140] The calculation of the conversion coefficient is as follows:

[0141]

[0142] T rated and i rated are the rated torque and current of the motor respectively.

[0143] After that, based on the current command and the real-time current feedback, use a PI controller to generate a voltage command. Through the inverse Park transformation, transfer the voltage command from the dq coordinate system to the abc coordinate system, generate a voltage command for actual motor control, and send it back to the control system to form a closed-loop control.

[0144] In this embodiment, taking the motor for development as an example, T rated = 4.8 Nm, i rated = 103.6 A, so

[0145] Use the no-load motor to preliminarily estimate the parameters K P,init , K I,init , K D,init . Taking the motor for development as an example, K P,init = 1.2, K I,init = 0.0001, K D,init = 0.

[0146] Add a feedforward controller. The calculation equation is:

[0147]

[0148] is the torque command of the feedforward controller, K FFC is the parameter of the feedforward controller, θ *Is the motor position command.

[0149] Determine K FFC Parameter:

[0150] Obtain the static relationship diagram of the motor position and the load torque. Taking the master cylinder for development as an example, see Figure 4 .

[0151] Divide the position into several segments. The number of segments is based on the exponential nature of the relationship diagram. The higher the exponential nature, the more segments are required. Try to make the motor position and the load torque linear in each segment. Due to the hysteresis phenomenon seen in the relationship diagram, the segments need to be further divided into two parts:

[0152] N segments x1 when the position is rising (covering θ start to θ x1 ), x2 (covering θ x1 to θ x2 ), … to xN (covering θ x(N-1) to θ max ).

[0153] M segments y1 when the position is falling (covering θ start to θ y1 ), y2 (covering θ y1 to θ y2 ), … to yM (covering θ y(M-1) to θ max ).

[0154] Note that the number of segments N and M do not need to be the same. θ start Is the position where the load torque begins to show an exponential growth trend. θ max Is the highest position allowed by the mechanical structure of the master cylinder. At a low position (the zero position of the mechanical structure of the master cylinder θ zero to θ start ), it can be covered by only one segment z.

[0155] In segment z, because the load is relatively linear and there is only relatively little friction and load torque, only a PID controller is required, and the feedforward controller can be turned off.

[0156] K FFC,seg z = 0

[0157] For the remaining xN and yM segments, the parameter calculation is as follows:

[0158]

[0159] The median θ of the segment position mid,seg xn / ym Is calculated as follows:

[0160]

[0161] T seg xn / ym is the median position θ of the segments in the relationship diagram seg xn / ym of the corresponding load torque.

[0162] Add a parameter converter. First, define P as the parameter combination of the segments:

[0163] P = {K P , K I , K D , K FFC}

[0164] Temporarily use the parameters obtained in the steps calculated by the feedforward controller as the PID controller parameters for all segments.

[0165] The equation of the parameter converter is as follows:

[0166] if θ * < θ start ,

[0167] P in use = P seg z

[0168] if(θ * ≥ θ start ) and (ω * > 0),

[0169]

[0170] if(θ * ≥ θ start ) and (ω * < 0),

[0171]

[0172] K P,in use , K I,in use , K D,in use , P in use respectively represent the parameters of the currently active segment and their combinations, plus the feedforward controller parameter incrementer. The equation of the incrementer is as follows:

[0173]

[0174] and are the low-speed threshold and the low-position threshold. ΔK FFC is the feedforward controller parameter increment. They can be set to 0 first and then adjusted in the next step. K FFC,in use is the feedforward controller parameter currently in effect.

[0175] Add the PID controller torque command Limiter. Limit Within the absolute value of (not applicable to segmented z):

[0176]

[0177] Torque command combining PID and feedforward controllers:

[0178]

[0179] Debug segmented parameters. Since the relationship diagram in the parameter determination step only describes the static relationship between the motor position and the load torque, it is necessary to debug again to confirm the adaptability of the parameters to the dynamic relationship. It is recommended to use any common trajectory planning such as trapezoidal velocity trajectory, S-shaped velocity trajectory for testing. The trajectory uses the rising segment as the position target, from θ FFC to θ zero to θ xn / ym , stays, and then returns to θ zero . Test from normal to high speed (depending on the application). First, pay attention to whether there is overshoot / undershoot of the motor when the trajectory stays. Overshoot indicates that the K FFC of this segment is too large, and undershoot indicates that it is too small. Repeat after adjustment until there is no overshoot / undershoot when staying. Then pay attention to whether there is jamming during rising / falling. If there is, it means that the PID parameters of the segment where the jamming occurs are too small, but if there is overshoot, it means that the PID parameters are too large. If the change between parameters is too significant when crossing from one segment to another, it may cause sudden vibration of the motor. Then a transition paragraph can be added between the two to achieve a smooth transition. In the corresponding paragraph with a smaller θ * , the proportion of PID parameters should be heavier because the influence of hydraulics is relatively small.

[0180] In an embodiment of the present application, taking the electric master cylinder for development as an example, θ start =

[0181] 3.1 turns, θ max = 19.7 turns. Please refer to Tables 1 to 3 for the parameters used.

[0182]

[0183]

[0184]

[0185]

[0186] In summary, the present invention can indeed obtain the following beneficial effects:

[0187] 1. As Figure 12As shown, the present invention can provide accurate position control without overshoot / undershoot. As previously mentioned, the load torque is like a spring, and the motor needs to provide a constant torque to maintain the position. The feedforward controller provides the baseline torque for the load torque, sending the motor to the approximate position of the command, and then the PID controller fine-tunes the error caused by friction. In a traditional position loop with only a PID controller, the torque command decreases as the position error decreases, causing the motor to be stuck by static friction before reaching the commanded position. When the integral unit of the controller accumulates to a certain extent, it will suddenly rush forward, constantly cycling between these two states.

[0188] 2. Since the position and torque have an exponential growth relationship, only one feedforward controller parameter cannot be suitable for all position commands. If the parameter is too small, the motor cannot reach a high position; if the parameter is too large, it will cause overshoot of the position feedback when processing low position commands. As Figure 13 shown, the present invention overcomes this problem by using segmented parameters. At lower positions, the relationship between position and torque is relatively linear, and a smaller feedforward controller parameter can be used, mainly letting the PID controller control. But at higher positions, the load torque rises exponentially, so a larger feedforward controller parameter is used to increase the influence of the feedforward controller on the final torque command.

[0189] 3. At low speeds and low positions, friction dominates the load, and the motor is easily stuck by the static friction of the master cylinder until the motor torque is sufficient to break free, and then the motor will suddenly rush forward. As Figure 14 shown, increasing the feedforward controller parameter in this case can effectively prevent the motor from getting stuck.

[0190] 4. By omitting the speed loop, a fast response time is achieved, avoiding the delay caused by the speed filter.

[0191] 5. The requirement for computing resources is low. The amount of calculation required during execution is small, and most complex parameters are pre-adjusted to generate a position-torque static relationship map. This is beneficial for implementation on low-end devices and high-frequency operation control loops.

[0192] The above are only the preferred embodiments of the present invention, and do not limit the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A permanent magnet synchronous motor position closed-loop control system for a wire-controlled electro-hydraulic master cylinder, characterized in that: The permanent magnet synchronous motor position closed-loop control system of the electronic control master cylinder for wire-controlled braking is composed of a position command generation module, a parameter converter module, a feedforward control booster module, a feedforward controller module, a PID controller module, a PID limiter module, a current command converter module, a voltage command generation module, a current sensor module, and a control system module; The position command generation module generates a motor position command by inputting a target position; The parameter converter module converts parameters based on the motor position command and the position command speed to generate PID controller parameters and feedforward controller parameters; The feedforward control booster module performs parameter boosting based on the motor position command, the position command speed, and the first feedforward controller parameter to generate feedforward control boost parameters; The feedforward controller module linearizes based on the motor position command and the feedforward control boost parameters according to the static relationship diagram of the motor position and the load torque, determines the feedforward controller torque command, and generates a feedforward output; The PID controller module performs fine-tuning of the motor using the PID algorithm based on the motor position command and the actual position feedback, and generates a PID controller torque command; The PID limiter module processes the PID controller torque command output by the PID controller module, limits the PID controller torque command within the absolute value of the feedforward control boost parameter, and outputs it; The current command converter module combines the feedforward controller torque command and the PID controller torque command to convert and output the q-axis current command; The voltage command generation module obtains the voltage command through weighted summation based on the position command, the PID output, and the conversion parameters; The current sensor module monitors the three-phase current of the motor in real time through a current sensor to obtain current feedback; The control system module performs inverse Park transformation based on the voltage command and the current feedback, and generates the three-phase voltage output of the motor through a voltage inverter to achieve accurate position control of the motor.

2. The permanent magnet synchronous motor position closed-loop control system of the electronic control master cylinder for wire control braking according to claim 1, wherein: The position command generation module includes a target input sub-module and a position encoding sub-module; The feedforward controller module includes a static relationship diagram sub-module and a feedforward calculation sub-module; The PID controller module includes a feedback acquisition sub-module, a PID algorithm sub-module, and a torque command output sub-module; The parameter converter module includes a data reception sub-module, a data conversion sub-module, and a data output sub-module; The voltage command generation module includes a parameter aggregation sub-module, a calculated voltage sub-module, and a voltage output sub-module; The current sensor module includes a current detection sub-module, a current data processing sub-module, and a current feedback output sub-module; The control system module includes a data integration sub-module, an inverse Park transformation sub-module, and an inverter output sub-module.

3. The permanent magnet synchronous motor position closed-loop control system of the wire-controlled electronic master cylinder according to claim 2, characterized in that: The target input sub-module obtains the target position through a system signal and generates target position data; The position encoding sub-module encodes the position based on the target position data to meet the motor control requirements and generates an encoded position command.

4. The permanent magnet synchronous motor position closed-loop control system of the wire-controlled electronic master cylinder according to claim 2, wherein: The static relationship diagram sub-module generates static relationship diagram data according to the characteristic curves of the motor and the load; The feedforward calculation sub-module uses the feedforward control increment parameter and the static relationship diagram data to perform feedforward calculation, determine the torque command of the feedforward controller, and generate the feedforward parameter output.

5. The permanent magnet synchronous motor position closed-loop control system of the wire-controlled electronic control master cylinder according to claim 2, characterized in that: The feedback acquisition sub-module obtains the actual position of the motor through the position sensor and generates the actual position data; The PID algorithm sub-module calculates using the PID algorithm based on the actual position data and the encoded position command, and generates the PID output parameter; The torque command output sub-module calculates based on the PID output parameter and the feedforward parameter output, and generates the torque command output data.

6. The permanent magnet synchronous motor position closed-loop control system of the wire-controlled electronic master cylinder according to claim 2, characterized in that: The data reception sub-module receives the motor position command and the position command speed, and transfers them to the data conversion sub-module; The data conversion sub-module performs torque ratio conversion based on the parameter data to be converted, and generates the converted parameter data; The data output sub-module generates and outputs the PID controller parameter and the feedforward controller parameter according to the converted parameter data.

7. The permanent magnet synchronous motor position closed-loop control system of the wire-controlled electronic master cylinder according to claim 2, wherein: The parameter aggregation sub-module collects the encoded position command, the fine-tuning output data, and the formatted conversion parameter, and generates the aggregated data; The voltage calculation sub-module calculates the required voltage command based on the aggregated data, and generates the voltage command data; The voltage output sub-module formats the voltage command data for motor control use, and generates the formatted voltage command; The current detection sub-module uses the sensor to monitor the three-phase current of the motor in real time, and generates the raw current data; The current data processing sub-module filters and amplifies the raw current data, and generates the processed current data; The current feedback output sub-module formats and outputs for the control system module based on the processed current data, and generates the formatted current feedback; The data integration sub-module integrates the formatted voltage command and the formatted current feedback, and generates the integrated data; The inverse Park conversion sub-module performs inverse Park conversion based on the integrated data, and generates the converted voltage data; The inverter output sub-module generates a three-phase voltage output through the voltage inverter according to the converted voltage data, and realizes the accurate position control of the motor.

8. The permanent magnet synchronous motor position closed-loop control method for the electronically controlled master cylinder of the wire-controlled braking system, characterized in that It includes the following steps: S1: Obtain the static relationship diagram of the motor position and the load torque, divide the motor position into several segments, the number of segments is determined according to the exponential nature of the relationship diagram, the higher the exponential nature, the more segments, and make the motor position and the load torque linear in the segment. Then divide the segment into two parts: N segments x1 when the position rises (covering θ start to θ x1 ), x2 (covering θ x1 to θ x2 ), … to xN (covering θ x(N-1) to θ max ); The M segments y1 (covering θ start to θ y1 ), y2 (covering θ y1 to θ y2 ), … to yM (covering θ y(M-1) to θ max ); Among them, the number of segments N and M are not equal, and θ start is the position where the load torque begins to show an exponential growth trend, and θ max is the highest position allowed by the master cylinder mechanical structure; xN and yM segments, and the parameter calculation is as follows: Median θ of the segmentation position mid，seg xn / ym It is calculated as follows: T seg xn / ym is the corresponding load torque of the median θ of the segmented position in the relationship diagram; thus completing the determination of the K seg xn / ym parameter; FFC ​ S2: Define P as the parameter combination of the segment: P = {K P , K I , K D , K FFC} (3) The parameter converter module generates and outputs the PID controller parameter and the feedforward controller parameter according to the following equation: S3: The feedforward control incrementer module increments the parameter of the feedforward controller according to the following equation and outputs the feedforward control increment parameter: Among them, and are the low-speed threshold and the low-position threshold, and ΔK FFC is the incremental value of the feedforward controller parameter; S4: The feedforward controller module calculates the torque command through the following calculation equation and generates the feedforward output: is the torque command for the feedforward controller, K FFC is the feedforward control increment parameter, θ * is the motor position command; S5: PID controller torque command in the PID limiter module The limiter limits by the following equation within the absolute value of: S6: The torque commands of the PID limiter module and the feedforward controller module are combined through the following equation and then input to the current command converter module: Torque command T * The q-axis current command in the current command converter module Converter, the position loop directly outputs the torque command T * , T * to The conversion equation is as follows: The calculation of the conversion coefficient is as follows: Among them, T rated and i rated are the rated torque and current of the motor, respectively; The current command converter module outputs the converted current command S7: Based on the current command and the real-time current feedback, a PI controller is used to generate a voltage command. Through the inverse Park transformation, the voltage command is transformed from the dq coordinate system to the abc coordinate system to generate a voltage command for actual motor control, which is sent back to the control system to form a closed-loop control.

9. A permanent magnet synchronous motor position closed-loop control method for a wire-controlled electro-hydraulic master cylinder according to claim 8, characterized in that, The step S1 further includes a step of debugging the segmentation parameters. According to the dynamic relationship between the motor position and the load torque, re-debugging is performed to confirm the adaptability of the parameters to the dynamic relationship, and the trajectory planning method is used for testing. Taking the rising segment of the trajectory as the position target, from θ zero to θ xn / ym , staying, and then returning to θ zero , to perform normal to high-speed testing; first, judge whether there is overshoot or undershoot when the motor stops during the trajectory. Overshoot indicates that the K FFC of this segment is too large, and undershoot indicates that it is too small; repeatedly adjust the K FFC parameter until there is no overshoot or undershoot when staying; then judge whether there is jamming during rising or falling. If there is, it means that the PID parameter of the segment where the jamming position belongs is too small, and if there is overshoot, it means that the PID parameter is too large, and adjust the PID parameter accordingly.

10. A permanent magnet synchronous motor position closed-loop control method for a wire-controlled electronic master cylinder according to claim 8 or 9, characterized in that In step S1, when the mechanical structure of the master cylinder is at the low position from θ zero to θ start , only one segment z is used to cover it; In segment z, turn off the feedforward controller module, set K FFC，segz = 0, and the PID limiter module does not perform limit processing on the torque command .

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