Four-channel independent hydraulic anti-lock braking system and method based on multi-mode control

Abstract

The invention belongs to the technical field of braking, and discloses a four-channel independent hydraulic anti-lock braking system and method based on multi-mode control, the system comprises four wheel speed sensors, a hydraulic control unit and an ABS control unit, and the four wheel speed sensors and the hydraulic control unit are electrically connected with the ABS control unit; the four wheel speed sensors are used for collecting the wheel speeds of four wheels of the automobile respectively; the hydraulic control unit is used for generating brake pressure of four wheels of an automobile, and the brake pressure is used for conducting brake control on the wheels. The ABS control unit is used for generating an anti-lock control instruction of each wheel according to the wheel speed of each wheel and a preset multi-mode control strategy and sending the anti-lock control instruction to the hydraulic control unit so as to control the current brake pressure of each wheel to be in a preset state, and the preset state is a pressure increasing state, a pressure maintaining state or a pressure reducing state. According to the invention, independent and accurate brake pressure adjustment of wheels is realized, cross interference is eliminated, and accurate control is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of braking, and particularly relates to a four-channel independent hydraulic anti-lock braking system and method based on multimodal control. Background Art

[0002] During the braking process of an automobile, when the wheels lock and skid, the longitudinal adhesion coefficient between the wheels and the road surface decreases, and the lateral adhesion coefficient almost completely disappears. At this time, if the steering wheels lose their steering ability while the driving wheels are still moving, the handling stability of the automobile will be greatly reduced; if the driving wheels lock first while the front wheels are still rolling, the automobile will experience a sideslip (fishtailing) phenomenon. These are all extremely likely to cause serious traffic accidents.

[0003] In order to make full use of the adhesion performance between the tires and the ground to obtain the best braking effect, modern automobiles are equipped with an electronically controlled anti-lock braking system (Anti-lock Brake System, abbreviated as ABS). After the brake pedal is depressed, the hydraulic control unit calculates the master cylinder pressure according to the pedal angle signal, and the brake cylinder braking pressure is determined by the braking force distribution strategy. The braking pressure of the brake cylinder is adjusted by controlling the solenoid valve. At the same time, the pressure sensor feeds back the brake cylinder pressure signal to the ABS control unit, and combines other sensor signals to control the solenoid valve opening to achieve a new round of pressure output, thereby realizing the function of preventing wheel lock during braking. The anti-lock braking system of an automobile is a passive safety device and has been widely equipped on the automobile braking pressure control system. It can automatically adjust and regulate the braking force of the brakes during the braking process of the automobile, so that the automobile always maintains good handling stability during operation, avoiding dangerous states such as steering failure and rear axle sideslip, and reducing the occurrence of a large number of accidents.

[0004] When the ABS system works, the ABS controller sends control instructions to its actuators through the CAN bus, and realizes the anti-lock function by controlling the working mode of the brake cylinder pressure. Its working modes mainly include pressure increasing, pressure reducing, and pressure maintaining, and the slip ratio is controlled by switching these modes in real time. The execution structure of the ABS acts according to the control instructions sent by the ABS controller. The ABS control strategy is solidified in the ABS controller. For example: the logic threshold control LTCS (Logicthreshold control strategy). The braking system monitors the slip ratio and braking deceleration of the wheels in real time. When it detects that the slip ratio or wheel acceleration exceeds the set threshold value, corresponding actions of increasing, reducing, or maintaining the pressure of the wheel brake cylinder are performed, so that the acceleration and deceleration of the wheels are controlled within a certain range, and the wheel slip ratio is controlled near the optimal value.

[0005] However, since the logical threshold control does not have an accurate mathematical model and lacks the corresponding theoretical basis, and the stability of the logical threshold control is closely related to the selection of the threshold value, the accuracy and response speed are relatively low. Summary of the Invention

[0006] The object of the present invention is to provide a four-channel independent hydraulic anti-lock braking system and method based on multimodal control to solve the problems that the existing logical threshold control does not have an accurate mathematical model, lacks the corresponding theoretical basis, and the stability of the logical threshold control is closely related to the selection of the threshold value, resulting in relatively low accuracy and response speed.

[0007] To achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present invention provides a four-channel independent hydraulic anti-lock braking system based on multimodal control. The system includes: four wheel speed sensors, a hydraulic control unit, and an ABS control unit. The four wheel speed sensors and the hydraulic control unit are both electrically connected to the ABS control unit; The four wheel speed sensors are used to collect the wheel speeds of the four wheels of the vehicle respectively; The hydraulic control unit is used to generate the braking pressure of the four wheels of the vehicle to control the braking of the wheels with the braking pressure; The ABS control unit is used to generate an anti-lock control instruction for each wheel according to the wheel speed of each wheel and a preset multimodal control strategy, and send the anti-lock control instruction to the hydraulic control unit to respectively control the current braking pressure of each wheel to be in a preset state, and the preset state is a pressure increasing state, a pressure maintaining state, or a pressure decreasing state.

[0008] Preferably, the hydraulic control unit includes: four hydraulic pipelines, and a pressure increasing valve and a pressure reducing valve are provided on each hydraulic pipeline; the multimodal control strategy includes a PID control strategy and a logical threshold control strategy, and the ABS control unit is a hybrid multimodal controller combining eight PID controllers and one logical threshold controller; The PID controller generates an adjustment instruction for a pressure increasing valve or an adjustment instruction for a pressure reducing valve based on the PID control strategy, and uses the adjustment instructions for the pressure increasing valves and the pressure reducing valves of each wheel as the anti-lock control instructions for each wheel; The logical threshold controller is used to determine the preset state in which the braking pressure of each wheel is located according to the logical threshold control strategy, so that the corresponding PID controller generates an adjustment instruction for a pressure increasing valve or an adjustment instruction for a pressure reducing valve.

[0009] Preferably, the logic threshold control strategy is as follows: during braking, obtain the vehicle speed of the vehicle, and determine the actual slip ratio of each wheel according to the vehicle speed and the wheel speed; determine whether the actual slip ratio of each wheel is equal to a preset target slip ratio. If so, the preset state is the pressure-holding state; if not, determine whether the actual slip ratio of each wheel is greater than the target slip ratio. If so, the preset state is the pressure-reducing state; if not, the preset state is the pressure-increasing state.

[0010] Preferably, the transfer function of the PID control strategy is: ; wherein, is the adjustment amount corresponding to the adjustment command of the pressure-increasing valve or the adjustment command of the pressure-reducing valve, is the proportional coefficient, is the integral coefficient, is the differential coefficient, t is the current moment, is the difference between the actual slip ratio at the current moment and the preset optimal slip ratio.

[0011] In a second aspect, the present invention provides a four-channel independent hydraulic anti-lock braking method based on multi-modal control. The method includes: Obtain the wheel speeds of the four wheels of the vehicle during braking; Generate an anti-lock control command for each wheel based on the wheel speed of each wheel and a preset multi-modal control strategy. The anti-lock control command for each wheel is used to adjust the current braking pressure of each wheel to a preset state, and the preset state is the pressure-increasing state, the pressure-holding state or the pressure-reducing state.

[0012] Preferably, the multi-modal control strategy includes a PID control strategy and a logic threshold control strategy. Generating an anti-lock control command for each wheel based on the wheel speed of each wheel and a preset multi-modal control strategy includes: Obtain the vehicle speed of the vehicle; Determine the actual slip ratio of each wheel according to the vehicle speed and the wheel speed; Determine the preset state in which the braking pressure of each wheel is located according to the actual slip ratio of each wheel and a preset target slip ratio; Generate an anti-lock control command for each wheel according to the current preset state of each wheel and based on the PID control strategy.

[0013] Preferably, determining the preset state in which the braking pressure of each wheel is located according to the actual slip ratio of each wheel and a preset target slip ratio includes: Determine whether the actual slip ratio of each wheel is equal to the preset target slip ratio. If so, the preset state is the pressure-holding state; if not, determine whether the actual slip ratio of each wheel is greater than the target slip ratio. If so, the preset state is the pressure-reducing state; if not, the preset state is the pressure-increasing state.

[0014] Preferably, the calculation expression of the actual slip ratio is: ; where s is the actual slip ratio, is the vehicle speed, is the wheel speed.

[0015] In a third aspect, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned four-channel independent hydraulic anti-lock braking method based on multi-modal control is implemented.

[0016] In a fourth aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the above-mentioned four-channel independent hydraulic anti-lock braking method based on multi-modal control is implemented.

[0017] Beneficial effects: In the present invention, the wheel speeds of the four wheels are separately processed by four wheel speed sensors, and a multi-modal control strategy is adopted to generate anti-lock control instructions for each wheel, so as to realize independent and accurate braking pressure regulation of the wheels, eliminate cross-interference, and achieve precise control. Description of the drawings

[0018] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. They are used together with the following specific embodiments to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings: Figure 1 is a block diagram of a four-channel independent hydraulic anti-lock braking system based on multi-modal control provided by an embodiment of the present invention; Figure 2 is a flowchart of a four-channel independent hydraulic anti-lock braking method based on multi-modal control provided by an embodiment of the present invention. Specific embodiments

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the present invention in combination with the accompanying drawings and the descriptions of the embodiments or the prior art. Obviously, the following descriptions of the structures of the accompanying drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings. It should be noted here that the descriptions of these embodiments are used to help understand the present invention, but do not constitute a limitation to the present invention.

[0020] Embodiment 1 Figure 1 is a block diagram of a four-channel independent hydraulic anti-lock braking system based on multimodal control provided by an embodiment of the present invention. As Figure 1 shown, this embodiment provides that the system includes: four wheel speed sensors, a hydraulic control unit, and an ABS control unit. The four wheel speed sensors and the hydraulic control unit are both electrically connected to the ABS control unit; The four wheel speed sensors are used to respectively collect the wheel speeds of the four wheels of the vehicle; The hydraulic control unit is used to generate the braking pressures of the four wheels of the vehicle to perform braking control on the wheels with the braking pressures; The ABS control unit is used to generate anti-lock control instructions for each wheel according to the wheel speeds of each wheel and a preset multimodal control strategy, and send the anti-lock control instructions to the hydraulic control unit to respectively control the current braking pressure of each wheel to be in a preset state, and the preset state is a pressure increasing state, a pressure maintaining state, or a pressure reducing state.

[0021] In this embodiment, the hydraulic control unit mainly includes: four hydraulic pipelines, four brake wheel cylinders, a hydraulic pump and other devices. A pressure increasing valve and a pressure reducing valve are provided on each hydraulic pipeline. Secondly, the braking system of the vehicle further includes: a brake pedal, an ECU (electronic control unit), a brake master cylinder, and a brake. Taking any brake wheel cylinder as an example, a brief introduction to the pressure increasing, pressure maintaining, and pressure reducing working processes of the braking system is as follows: (1) Pressure increasing process: The driver steps on the brake pedal. The ECU decides the magnitude of the target braking pressure according to the received displacement information of the brake pedal, and controls the pressure increasing valve to open and the pressure reducing valve to close to increase the braking pressure of the brake wheel cylinder. The hydraulic pressure in the brake wheel cylinder increases, the brake generates a braking torque, and the wheel angular deceleration and the vehicle body linear deceleration begin to generate and increase (referring to the absolute values of both). In the pressure increasing process, the driver steps on the brake pedal to start braking, pushing the piston rod of the brake master cylinder to generate hydraulic pressure, which is transmitted to the brake wheel cylinder through the hydraulic regulation unit to generate braking force.

[0022] (2) Pressure maintaining process: In the initial stage of braking, the pressure in the brake wheel cylinder continuously increases, causing the frictional braking force between the brake and the brake disc to continuously rise. When this braking force exceeds the maximum adhesion force provided by the ground, the wheels tend to lock. At this time, the ECU controls the pressure regulating unit to receive the wheel state signal transmitted by the sensor, and calculates and analyzes to control the charging valve to be energized and in the closed state, and the pressure reducing valve is not energized and also in the closed state, and the pressure in the brake wheel cylinder is maintained.

[0023] During the pressure holding process, the brake fluid in the brake wheel cylinder is isolated from the oil circuit, and the brake pressure in the brake wheel cylinder remains unchanged.

[0024] (3)Pressure reducing process: During the pressure holding stage, the angular deceleration and slip ratio of the wheels continuously change. When they exceed the specified threshold value, the wheels show the phenomenon of locked dragging. When the brake pedal is released or the control strategy decides to reduce the pressure in the brake wheel cylinder, the upper controller issues an instruction to make the system brake enter the pressure reducing state, and the lower controller receives the pressure reducing instruction and controls the on-off of the high-speed switching valve group to release pressure. During the pressure holding process, the electronic control unit controls the pressure reducing valve to open and the charging valve to close. During this process, the brake fluid flows back to the liquid storage tank in the master cylinder, and the pressure in the brake wheel cylinder decreases to complete the pressure reducing process.

[0025] Therefore, in order to achieve precise adjustment of the braking pressure of each wheel of the vehicle and the response speed of the adjustment, the multi-modal control strategy includes a PID control strategy and a logic threshold control strategy, and the ABS control unit is a hybrid multi-modal controller combining eight PID controllers and one logic threshold controller; The PID controller generates an adjustment instruction for the charging valve or an adjustment instruction for the pressure reducing valve based on the PID control strategy, and uses the adjustment instructions for the charging valve and the pressure reducing valve of each wheel as the anti-lock braking control instructions for each wheel; at this time, the pressure reducing valve and the charging valve on each hydraulic pipeline are separately controlled by a PID controller to eliminate cross-interference and achieve precise control.

[0026] The logic threshold controller is used to determine the preset state of the braking pressure of each wheel according to the logic threshold control strategy, so that the corresponding PID controller generates an adjustment instruction for the charging valve or an adjustment instruction for the pressure reducing valve.

[0027] In this embodiment, the transfer function of the PID control strategy is: ; In the formula, is the adjustment amount corresponding to the adjustment instruction for the charging valve or the adjustment instruction for the pressure reducing valve, is the proportional coefficient, is the integral coefficient, is the differential coefficient, t is the current moment, It is the difference between the actual slip ratio at the current moment and the preset optimal slip ratio.

[0028] In this embodiment, the logic threshold control strategy is as follows: during braking, obtain the vehicle speed of the vehicle, and determine the actual slip ratio of each wheel according to the vehicle speed and the wheel speed; judge whether the actual slip ratio of each wheel is equal to the preset target slip ratio. If so, the preset state is the pressure-holding state; if not, judge whether the actual slip ratio of each wheel is greater than the target slip ratio. If so, the preset state is the pressure-reducing state, and if not, the preset state is the pressure-increasing state.

[0029] In this embodiment, the definition of the slip ratio is that when the tire generates traction or braking force, relative movement will occur between the tire and the ground. The braking process of the vehicle from pure rolling to locked dragging is a gradual process, experiencing three stages: pure rolling, rolling and sliding, and pure sliding. In order to evaluate the proportion of the slip degree component of the vehicle wheel, its definition is as follows: ; In the formula, s is the actual slip ratio, is the vehicle speed, is the wheel speed.

[0030] Among them, when and are almost the same, the wheel speed is the vehicle speed, s is equal to 0, and the vehicle is in pure rolling. When has a relatively large value, but is relatively small and is 0, then s is equivalent to equal to 1. The state of the vehicle is that the vehicle keeps moving forward, but the wheels do not rotate. At this time, the vehicle has a vehicle speed, but the wheels do not rotate.

[0031] When the actual slip ratio is 0, the lateral anti-skid ability of the vehicle is the strongest; When the actual slip ratio is 1, the lateral anti-skid ability of the vehicle is the weakest; Based on the above theory, the ABS anti-lock braking system prevents the wheels of the vehicle from locking during braking and keeps the actual slip ratio of the wheels within the range of 10% - 30%, so as to ensure good longitudinal and lateral adhesion between the wheels and the road surface, effectively prevent phenomena such as vehicle side slip, tail swing, and loss of steering during braking, and improve the directional stability of the vehicle during braking.

[0032] In this embodiment, a logic threshold control strategy is used to determine whether the vehicle needs to intervene in the ABS control. When a certain wheel needs to intervene in the ABS control, the two PID controllers corresponding to that wheel are started. The PID controller takes the difference between the actual slip ratio at the current moment and the preset optimal slip ratio (i.e., in the range of 10% - 30%) as the input, and outputs the anti-lock control instruction for that wheel, that is, the adjustment instruction for the pressure increasing valve or the pressure reducing valve on the hydraulic pipeline configured for that wheel, so that the braking pressure of the wheel is in the pressure increasing state, pressure maintaining state or pressure reducing state.

[0033] In this embodiment, through the non-linear control method of the logic threshold control strategy, the dynamic parameters of the wheel (such as the slip ratio) are monitored in real time and compared with the preset threshold value (target slip ratio), triggering different braking pressure adjustment actions (pressure increasing / pressure maintaining / pressure reducing). Then, through the independent pressure increasing valve, pressure reducing valve and the hydraulically controlled unit with unified adjustment configured for each wheel, the braking pressure of each wheel is independently closed-loop adjusted to form a closed-loop pressure control loop, eliminating cross-interference to achieve precise control. Secondly, the PID control strategy has the advantages of higher precision and faster response speed.

[0034] Therefore, the combination of the two control strategies, the PID control strategy can make up for the problems of the logic threshold control strategy relying on the setting of empirical thresholds, lacking dynamic adaptability, resulting in low response speed and low precision, while the logic threshold control strategy can make up for the high sensitivity of the PID control strategy to the control parameters of the non-linear system and insufficient robustness to achieve independent and precise braking pressure adjustment of the wheels.

[0035] The multi-modal control strategy of the present invention can effectively avoid vehicle locking and skidding, control the slip ratio near the optimal slip ratio, ensure that the vehicle will not lose steerability and stability during emergency braking, and at the same time shorten the braking distance.

[0036] Embodiment 2 Figure 2 is a flowchart of a four-channel independent hydraulic anti-lock braking method based on multi-modal control provided by an embodiment of the present invention. As Figure 2 shown, this embodiment provides a four-channel independent hydraulic anti-lock braking method based on multi-modal control, and the method includes: Step S10: Obtain the wheel speeds of the four wheels of the vehicle during braking; in this embodiment, the wheel speeds of each wheel are collected by the wheel speed sensors installed on the four wheels of the vehicle.

[0037] Step S20: Generate anti-lock control instructions for each wheel based on the wheel speeds of each wheel and the preset multi-modal control strategy, and the anti-lock control instructions for each wheel are used to adjust the current braking pressure of each wheel to a preset state, and the preset state is a pressure increasing state, a pressure maintaining state or a pressure reducing state.

[0038] In this embodiment, the multimodal control strategy includes a PID control strategy and a logic threshold control strategy. Therefore, generating an anti-lock control instruction for each wheel based on the wheel speed of each wheel and the preset multimodal control strategy includes: Step S201: Obtain the vehicle speed of the vehicle, and the vehicle speed of the vehicle can be obtained through the ECU of the vehicle.

[0039] Step S202: Determine the actual slip ratio of each wheel according to the vehicle speed and the wheel speed; the calculation expression of the actual slip ratio in this embodiment is: ; In the formula, s is the actual slip ratio, is the vehicle speed, is the wheel speed.

[0040] Step S203: Determine the preset state of the braking pressure of each wheel according to the actual slip ratio of each wheel and the preset target slip ratio; the method for determining the preset state of the braking pressure of each wheel is: judge whether the actual slip ratio of each wheel is equal to the preset target slip ratio, if so, the preset state is the pressure holding state; if not, judge whether the actual slip ratio of each wheel is greater than the target slip ratio, if so, the preset state is the pressure reducing state, if not, the preset state is the pressure increasing state.

[0041] Step S204: Generate an anti-lock control instruction for each wheel according to the current preset state of each wheel and based on the PID control strategy.

[0042] In this embodiment, the logic threshold control strategy is used to judge whether the vehicle needs to intervene in the ABS control. When a certain wheel needs to intervene in the ABS control, the two PID controllers corresponding to that wheel are started. The PID controller takes the difference between the actual slip ratio at the current moment and the preset optimal slip ratio (i.e., in the range of 10% - 30%) as the input, and outputs an anti-lock control instruction for that wheel, that is, an adjustment instruction for the pressure increasing valve or the pressure reducing valve on the hydraulic pipeline configured for that wheel, so that the braking pressure of the wheel is in the pressure increasing state, the pressure holding state or the pressure reducing state.

[0043] In this embodiment, through the non-linear control method of the logic threshold control strategy, the dynamic parameters of the wheel (such as the slip ratio) are monitored in real time, compared with the preset threshold value (target slip ratio), and different braking pressure adjustment actions (pressure increasing / pressure holding / pressure reducing) are triggered. Then, through a hydraulic control unit with independent pressure increasing valves, pressure reducing valves and unified adjustment configured for each wheel, the braking pressure of each wheel is independently closed-loop adjusted to form a closed-loop pressure control loop to eliminate cross interference for precise control. Secondly, the PID control strategy has the advantages of higher accuracy and faster response speed.

[0044] Therefore, the combination of the two control strategies enables the PID control strategy to make up for the problems of the logic threshold control strategy, which relies on the setting of empirical thresholds, lacks dynamic adaptability, results in low response speed and low accuracy. The logic threshold control strategy, in turn, can make up for the high sensitivity of the PID control strategy to the control parameters of non-linear systems and its insufficient robustness, so as to achieve independent and precise braking pressure regulation for the wheels.

[0045] The multi-modal control strategy of the present invention can effectively avoid vehicle locking and skidding, control the slip ratio near the optimal slip ratio, ensure that the vehicle does not lose its steerability and stability during emergency braking, and at the same time shorten the braking distance.

[0046] Embodiment III This embodiment also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the four-channel independent hydraulic anti-lock braking method based on multi-modal control in Embodiment II.

[0047] This embodiment also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the four-channel independent hydraulic anti-lock braking method based on multi-modal control in Embodiment II.

[0048] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0049] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, so that the instructions executed by the processors of the computer or other programmable data processing devices generate means for implementing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0050] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A four-channel independent hydraulic anti-lock braking system based on multi-modal control, characterized in that, The system includes: four wheel speed sensors, a hydraulic control unit, and an ABS control unit. The four wheel speed sensors and the hydraulic control unit are both electrically connected to the ABS control unit; The four wheel speed sensors are used to respectively collect the wheel speeds of the four wheels of the vehicle; The hydraulic control unit is used to generate the braking pressures of the four wheels of the vehicle to perform braking control on the wheels with the braking pressures; The ABS control unit is used to generate anti-lock control commands for each wheel according to the wheel speeds of each wheel and a preset multimodal control strategy, and send the anti-lock control commands to the hydraulic control unit to respectively control the current braking pressure of each wheel to be in a preset state, and the preset state is a pressure increasing state, a pressure maintaining state, or a pressure reducing state.

2. The method of the four-channel independent hydraulic anti-lock braking system based on multimodal control according to claim 1, wherein The hydraulic control unit includes: four hydraulic pipelines, and a pressure increasing valve and a pressure reducing valve are arranged on each hydraulic pipeline; the multimodal control strategy includes a PID control strategy and a logic threshold control strategy, and the ABS control unit is a hybrid multimodal controller combining eight PID controllers and one logic threshold controller; The PID controller generates an adjustment command for a pressure increasing valve or an adjustment command for a pressure reducing valve based on the PID control strategy, and uses the adjustment commands for the pressure increasing valves and the pressure reducing valves of each wheel as the anti-lock control commands for each wheel; The logic threshold controller is used to determine the preset state in which the braking pressure of each wheel is located according to the logic threshold control strategy, so that the corresponding PID controller generates an adjustment command for a pressure increasing valve or an adjustment command for a pressure reducing valve.

3. The four-channel independent hydraulic anti-lock braking system based on multi-modal control according to claim 2, characterized in that, The logic threshold control strategy is: during braking, obtain the vehicle speed of the vehicle, and determine the actual slip ratio of each wheel according to the vehicle speed and the wheel speed; judge whether the actual slip ratio of each wheel is equal to a preset target slip ratio. If so, the preset state is the pressure maintaining state; if not, judge whether the actual slip ratio of each wheel is greater than the target slip ratio. If so, the preset state is the pressure reducing state, and if not, the preset state is the pressure increasing state.

4. The four-channel independent hydraulic anti-lock braking system based on multimodal control according to claim 2, wherein The transfer function of the PID control strategy is: ； In the formula, is the adjustment amount corresponding to the adjustment command of the supercharging valve or the adjustment command of the pressure reducing valve, is the proportionality coefficient, is the integral coefficient, is the differential coefficient, t is the current time, is the difference between the actual slip ratio at the current time and the preset optimal slip ratio.

5. A four-channel independent hydraulic anti-lock braking method based on multimodal control, characterized in that, The method includes: Obtain the wheel speeds of the four wheels of the vehicle during braking; Generate anti-lock control commands for each wheel based on the wheel speeds of each wheel and a preset multimodal control strategy. The anti-lock control commands for each wheel are used to adjust the current braking pressure of each wheel to be in a preset state, and the preset state is a pressure increasing state, a pressure maintaining state, or a pressure reducing state.

6. The four-channel independent hydraulic anti-lock braking method based on multi-modal control according to claim 5, characterized in that The multimodal control strategy includes a PID control strategy and a logic threshold control strategy. Generating anti-lock control commands for each wheel based on the wheel speeds of each wheel and a preset multimodal control strategy includes: Obtain the vehicle speed of the vehicle; Determine the actual slip ratio of each wheel according to the vehicle speed and the wheel speed; Determine the preset state in which the braking pressure of each wheel is located according to the actual slip ratio of each wheel and a preset target slip ratio; Generate anti-lock control commands for each wheel according to the current preset state of each wheel and based on the PID control strategy.

7. The four-channel independent hydraulic anti-lock braking method based on multi-modal control according to claim 6, characterized in that, Determining the preset state in which the braking pressure of each wheel is located according to the actual slip ratio of each wheel and a preset target slip ratio includes: Determine whether the actual slip ratio of each wheel is equal to the preset target slip ratio. If so, the preset state is the pressure holding state; if not, determine whether the actual slip ratio of each wheel is greater than the target slip ratio. If so, the preset state is the pressure reducing state; if not, the preset state is the pressure increasing state.

8. The four-channel independent hydraulic anti-lock braking method based on multimodal control according to claim 7 or 6, characterized in that The calculation expression of the actual slip ratio is as follows: ； where s is the actual slip ratio, is the vehicle speed, is the wheel speed.

9. An electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the four-channel independent hydraulic anti-lock braking method based on multimodal control described in any one of claims 5-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the four-channel independent hydraulic anti-lock braking method based on multimodal control described in any one of claims 5-8.

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