Dual-control EPB anti-lock braking control method and system based on indirect tire pressure monitoring

Abstract

The present invention discloses a dual-control EPB anti-lock braking control method and system based on indirect tire pressure monitoring, which belongs to the field of automobile anti-lock braking and includes the following steps: S1, collecting wheel speed signals; S2, calculating the wheel radius and tire pressure deviation ratio based on the collected wheel speed, and judging whether to initiate emergency braking based on the tire pressure deviation ratio. If not, the process returns to step S1; if so, the vehicle speed is compensated and the locking degree of each wheel is calculated based on the wheel radius; S3, applying an initial clamping force to the left and right rear wheels respectively; S4, dynamically adjusting the clamping force of the left and right EPB calipers based on the slip rate and the clamping degree of the left and right rear wheels; S5, ending braking. The present invention adopts the above-mentioned dual-control EPB anti-lock braking control method and system based on indirect tire pressure monitoring to achieve compensation for vehicle speed when the vehicle tire pressure is under-inflated, and to achieve rear wheel anti-lock braking through emergency braking.

Description

Technical Field

[0001] The present invention relates to the field of automobile anti-lock braking, and in particular to a dual-control EPB anti-lock braking control method and system based on indirect tire pressure monitoring. Background Art

[0002] As a core component of the vehicle's braking system, the car's parking system plays a vital role. Its design and performance are directly related to driving safety and parking convenience.

[0003] Faced with increasing market demand for parking brake reliability, major automakers (OEMs) are continuously innovating and developing and implementing parking systems with enhanced functional safety to meet industry standards and consumer expectations. In this context, tire condition monitoring is particularly crucial, as a key factor influencing vehicle safety performance. Indirect tire pressure monitoring systems (TPMS) have become a popular solution due to their cost-effectiveness. This system cleverly utilizes existing wheel speed sensors to indirectly determine whether tire pressure is within a safe range by analyzing the speed signals of each wheel. Compared to direct TPMS, indirect TPMS systems, with their lower cost and greater potential for widespread adoption, are easier to implement across a wide range of vehicle models, promoting the widespread adoption of automotive safety technology.

[0004] However, ensuring safe driving in complex road conditions requires more than just monitoring tire pressure. When tire pressure is detected to an unsafe level, the advanced Dynamic Braking Control system intervenes. By intelligently compensating for vehicle speed, it effectively activates anti-lock braking (ABS) to safeguard vehicle handling stability and braking performance, even in emergency braking situations. This is particularly evident in the dual-control EPB (Electronic Parking Brake) anti-lock braking system. This system precisely controls braking force while the vehicle is in motion, especially when tire pressure drops abnormally low or wheel speed increases abnormally high, ensuring smooth deceleration and a stop, significantly enhancing driving safety.

[0005] Despite continuous advancements in modern automotive braking technology, precise rear-wheel braking control remains challenging in certain situations. Specifically, when the rear wheels lock during heavy braking, vehicle stability can be significantly reduced, significantly increasing the risk of loss of control and potentially triggering a traffic accident, endangering the safety of occupants and other road users. Summary of the Invention

[0006] To solve the above problems, the present invention provides a dual-control EPB anti-lock braking control method and system based on indirect tire pressure monitoring, which can compensate for vehicle speed when the tire pressure is under-inflated and realize rear wheel anti-lock braking through emergency braking.

[0007] To achieve the above object, the present invention provides a dual-control EPB anti-lock braking system control method based on indirect tire pressure monitoring, comprising the following steps:

[0008] S1, data acquisition: collect wheel speed signals of the four wheels of the car;

[0009] S2. Data processing: Calculate the wheel radius and tire pressure deviation ratio based on the collected wheel speed, and determine whether to initiate emergency braking based on the tire pressure deviation ratio. If not, return to step S1. If so, compensate for the vehicle speed and calculate the locking degree of each wheel based on the wheel radius.

[0010] S3, preliminary brake intervention: Control the left and right EPB calipers to apply initial clamping force to the left and right rear wheels respectively;

[0011] S4. Dynamically adjust the brakes: Dynamically adjust the holding force of the left and right EPB calipers based on the slip ratio and the holding degree of the left and right rear wheels calculated in step S2 to prevent the left and right rear wheels from locking.

[0012] S5. Braking ends: When it is detected that the vehicle speed is lower than the set speed, the vehicle stops decelerating, or the slip rate of the set wheel is reached, braking is stopped, otherwise the process returns to step S3.

[0013] Preferably, step S2 specifically includes the following steps:

[0014] S21. Calculate the vehicle center speed:

[0015] v=(v FR +v FL +v RR +v RL ) / 4 (1);

[0016] Where, v FR 、v FL 、v RR 、v RL Respectively represent the wheel speeds of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car;

[0017] S22. Calculate tire radius:

[0018] r FR =v / w FR (2);

[0019] r FL =v / w FL (3);

[0020] r RR =v / w RR (4);

[0021] v RL =v / w RL (5);

[0022] Where v is the center speed of the car; r FR 、r FL 、r RR 、r RL Respectively represent the radius of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car; w FR 、w FL 、w RR 、w RL Respectively represent the angular velocities of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car;

[0023] S23. Calculate tire pressure deviation ratio:

[0024]

[0025] Where, ∝ represents the tire pressure deviation ratio;

[0026] S24, determine whether to activate emergency braking: when the deviation ratio ∝≠1, activate emergency braking and execute step S25;

[0027] S25. Calculate the slip ratio of the rear wheels relative to the front wheels:

[0028]

[0029] Where, δ RR , δ LL are the slip rates of the right rear wheel relative to the right front wheel and the left rear wheel relative to the left front wheel respectively; Vt FR 、Vt FL are the wheel speeds of the right front wheel and the left front wheel when the car is moving; Va RR 、Va RL are the wheel speeds of the right rear wheel and the left rear wheel when the car is moving;

[0030] S26. Set the corresponding relationship between the locking degree and the slip ratio: the locking degree is equal to the slip ratio.

[0031] Preferably, in step S3, the initial clamping force is set to 0.2 mg.

[0032] Preferably, in step S4, the calculation formula of the holding force F is as follows:

[0033]

[0034] Where m is the mass of the vehicle; g is the acceleration of gravity; θ is the slope angle of the vehicle; R is the rolling radius of the wheel; μ is the friction coefficient between the tire and the ground; and r is the effective radius of the caliper.

[0035] Preferably, in step S5, the vehicle speed is set to 3 km / h.

[0036] A system for a dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring includes a dual-control EPB controller, wheel speed sensors for respectively collecting wheel speed signals of the vehicle's four wheels, an indirect tire pressure monitoring module for monitoring the tire pressures of the vehicle's four wheels, and left and right EPB calipers. The dual-control EPB controller is connected to the wheel speed sensors and the indirect tire pressure monitoring module, respectively, and the indirect tire pressure monitoring module is connected to the left and right EPB calipers, respectively. The left and right EPB calipers are used to lock and decelerate the left and right rear wheels of the vehicle, respectively.

[0037] The dual-control EPB controller includes a first MCU controller and a second MCU controller that interact with each other. The first MCU controller and the second MCU controller are electrically connected to the first car battery power supply and the second car battery power supply respectively. The first MCU controller is also connected to the EPB switch.

[0038] Preferably, the first MCU controller and the second MCU controller communicate with each other via the SPI protocol;

[0039] The first MCU controller and the wheel speed sensor, as well as the second MCU controller and the wheel speed sensor, communicate via the CAN bus.

[0040] Preferably, the operating voltage range of the first automobile battery power source and the second automobile battery power source is 9V-16V.

[0041] The present invention has the following beneficial effects:

[0042] The optimized braking system can finely adjust the braking force on the rear wheels during emergency braking to prevent locking, maintain vehicle controllability even under extreme conditions, avoid accidents, and further consolidate the line of defense for driving safety.

[0043] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of a dual-control EPB anti-lock braking system control method based on indirect tire pressure monitoring according to the present invention;

[0045] Figure 2The present invention is a block diagram of the structure of a dual-control EPB anti-lock braking system based on indirect tire pressure monitoring. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions.

[0047] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0048] Like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not require further definition or explanation in subsequent drawings.

[0049] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0050] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0051] like Figure 1 As shown, a dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring includes the following steps:

[0052] S1, data acquisition: collect wheel speed signals of the four wheels of the car;

[0053] S2. Data processing: Calculate the wheel radius and tire pressure deviation ratio based on the collected wheel speed, determine whether to initiate emergency braking based on the tire pressure deviation ratio, and if not, return to step S1. If so, compensate for vehicle speed (implementing a method whereby when low tire pressure is detected, if the wheel speed is low, speed compensation is performed on the tire with the low speed based on the remaining normal wheel speeds, so that the wheel speeds of all four wheels are consistent), and calculate the degree of locking of each wheel based on the wheel radius;

[0054] Step S2 specifically includes the following steps:

[0055] S21. Calculate the vehicle center speed:

[0056] v=(v FR +v FL +v RR +v RL ) / 4 (1);

[0057] Where, v FR 、v FL 、v RR 、v RL Respectively represent the wheel speeds of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car;

[0058] S22. Calculate tire radius:

[0059] r FR =v / w FR (2);

[0060] r FL =v / w FL (3);

[0061] r RR =v / w RR (4);

[0062] r RL =v / w RL (5);

[0063] Where v is the center speed of the car; r FR 、r FL 、r RR 、r RL Respectively represent the radius of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car; w FR 、w FL 、w RR 、w RL Respectively represent the angular velocities of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car;

[0064] S23. Calculate tire pressure deviation ratio:

[0065]

[0066] Where, ∝ represents the tire pressure deviation ratio;

[0067] S24, determine whether to activate emergency braking: when the deviation ratio ∝≠1, activate emergency braking and execute step S25;

[0068] S25. Calculate the slip ratio of the rear wheels relative to the front wheels:

[0069]

[0070] Where, δ RR , δ LL are the slip rates of the right rear wheel relative to the right front wheel and the left rear wheel relative to the left front wheel respectively; Vt FR 、Vt FL are the wheel speeds of the right front wheel and the left front wheel when the car is moving; Va RR 、Va RL are the wheel speeds of the right rear wheel and the left rear wheel when the car is moving;

[0071] S26. Set the corresponding relationship between the degree of locking and the slip ratio: the degree of locking is equal to the slip ratio, that is, when the slip ratio is 0, the wheel rolls purely on the road and the degree of locking is 0; when the vehicle brakes, the difference between the wheel speed and the slip ratio becomes larger and larger. When the wheel speed is 0, the slip ratio is 100%, and the degree of locking is set to 100%. At this time, the wheel is completely locked and the vehicle is purely sliding on the road, and so on.

[0072] S3, preliminary brake intervention: Control the left and right EPB calipers to apply initial clamping force to the left and right rear wheels respectively;

[0073] In step S3, the initial clamping force is set to 0.2 mg.

[0074] S4. Dynamically adjust the brakes: Dynamically adjust the holding force of the left and right EPB calipers based on the slip ratio and the holding degree of the left and right rear wheels calculated in step S2 to prevent the left and right rear wheels from locking.

[0075] In step S4, the calculation formula of the holding force F is as follows:

[0076]

[0077] Where m is the mass of the vehicle; g is the acceleration of gravity; θ is the slope angle of the vehicle; R is the rolling radius of the wheel, that is, R is r FR 、r FL 、rRR or r RL ; μ is the friction coefficient between the tire and the ground; r is the effective radius of the caliper.

[0078] S5. Braking ends: When it is detected that the vehicle speed is lower than the set speed, the vehicle stops decelerating, or the slip rate of the set wheel is reached, braking is stopped, otherwise the process returns to step S3.

[0079] In step S5 , the vehicle speed is set to 3 km / h.

[0080] like Figure 2 As shown, a system for a dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring includes a dual-control EPB controller, wheel speed sensors for respectively collecting wheel speed signals of the vehicle's four wheels, an indirect tire pressure monitoring module for monitoring the tire pressures of the vehicle's four wheels, and left and right EPB calipers. The dual-control EPB controller is connected to the wheel speed sensors and the indirect tire pressure monitoring module, respectively, and the indirect tire pressure monitoring module is connected to the left and right EPB calipers, respectively. The left and right EPB calipers are used to lock and decelerate the left and right rear wheels of the vehicle, respectively.

[0081] The dual-control EPB controller includes a first MCU controller and a second MCU controller that interact with each other. The first MCU controller and the second MCU controller are electrically connected to the first car battery power supply and the second car battery power supply respectively. The first MCU controller is also connected to the EPB switch.

[0082] The first MCU controller and the second MCU controller communicate with each other via the SPI protocol; the first MCU controller and the wheel speed sensor, as well as the second MCU controller and the wheel speed sensor, communicate with each other via the CAN bus.

[0083] The operating voltage range of the first car battery power source and the second car battery power source is 9V-16V.

[0084] It should be noted that when the present invention is applied to a rear-wheel drive or four-wheel drive new energy vehicle, energy recovery of the new energy vehicle is stopped when the system is running.

[0085] Therefore, the present invention adopts the above-mentioned dual-control EPB anti-lock braking control method and system based on indirect tire pressure monitoring, which realizes compensation of vehicle speed when the tire pressure of the vehicle is under-inflated, and realizes rear wheel anti-lock braking through emergency braking.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A dual-control EPB anti-lock braking system based on indirect tire pressure monitoring, characterized by: The following steps are involved: S1, data acquisition: collect wheel speed signals of the four wheels of the car; S2. Data processing: Calculate the wheel radius and tire pressure deviation ratio based on the collected wheel speed, and determine whether to initiate emergency braking based on the tire pressure deviation ratio. If not, return to step S1. If so, compensate for the vehicle speed and calculate the locking degree of each wheel based on the wheel radius. Step S2 specifically includes the following steps: S21. Calculate the vehicle center speed: v=(v FR +v FL +v RR +v RL ) / 4 (1); Where, v FR 、v FL 、v RR 、v RL Respectively represent the wheel speeds of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car; S22. Calculate tire radius: r FR =v / w FR (2); r FL =v / w FL (3); r RR =v / w RR (4); r RL =v / w RL (5); Where v is the center speed of the car; r FR 、r FL 、r RR 、r RL Respectively represent the radius of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car; w FR 、w FL 、w RR 、w RL Respectively represent the angular velocities of the right front wheel, left front wheel, right rear wheel and left rear wheel of the car; S23. Calculate tire pressure deviation ratio: Where, ∝ represents the tire pressure deviation ratio; S24, determine whether to activate emergency braking: when the deviation ratio ∝≠1, activate emergency braking and execute step S25; S25. Calculate the slip ratio of the rear wheels relative to the front wheels: Where, δ RR , δ LL are the slip rates of the right rear wheel relative to the right front wheel and the left rear wheel relative to the left front wheel respectively; Vt FR 、Vt FL are the wheel speeds of the right front wheel and the left front wheel when the car is moving; Va RR 、Va RL are the wheel speeds of the right rear wheel and the left rear wheel when the car is moving; S26. Setting the corresponding relationship between the locking degree and the slip ratio: the locking degree is equal to the slip ratio; S3, preliminary brake intervention: Control the left and right EPB calipers to apply initial clamping force to the left and right rear wheels respectively; S4. Dynamically adjust the brakes: Dynamically adjust the holding force of the left and right EPB calipers based on the slip ratio and the holding degree of the left and right rear wheels calculated in step S2 to prevent the left and right rear wheels from locking. S5. Braking ends: When it is detected that the vehicle speed is lower than the set speed, the vehicle stops decelerating, or the slip rate of the set wheel is reached, braking is stopped, otherwise the process returns to step S3.

2. The dual-control EPB anti-lock braking system control method based on indirect tire pressure monitoring according to claim 1, characterized in that: In step S3, the initial clamping force is set to 0.2 mg.

3. The dual-control EPB anti-lock braking system control method based on indirect tire pressure monitoring according to claim 2, characterized in that: In step S4, the calculation formula of the holding force F is as follows: Where m is the mass of the vehicle; g is the acceleration of gravity; θ is the slope angle of the vehicle; R is the rolling radius of the wheel; μ is the friction coefficient between the tire and the ground; and r is the effective radius of the caliper.

4. The dual-control EPB anti-lock braking system control method based on indirect tire pressure monitoring according to claim 3, characterized in that: In step S5 , the vehicle speed is set to 3 km / h.

5. The system of the dual-control EPB anti-lock braking system based on indirect tire pressure monitoring according to any one of claims 1 to 4, characterized in that: It includes a dual-control EPB controller, a wheel speed sensor for respectively collecting wheel speed signals of the four wheels of the vehicle, an indirect tire pressure monitoring module for monitoring the tire pressure of the four wheels of the vehicle, a left EPB caliper and a right EPB caliper. The dual-control EPB controller is connected to the wheel speed sensor and the indirect tire pressure monitoring module respectively, and the indirect tire pressure monitoring module is connected to the left EPB caliper and the right EPB caliper respectively. The left EPB caliper and the right EPB caliper are used to clamp and decelerate the left rear wheel and the right rear wheel of the vehicle respectively; The dual-control EPB controller includes a first MCU controller and a second MCU controller that interact with each other. The first MCU controller and the second MCU controller are electrically connected to the first car battery power supply and the second car battery power supply respectively. The first MCU controller is also connected to the EPB switch.

6. The system of the dual-control EPB anti-lock braking system based on indirect tire pressure monitoring according to claim 5, characterized in that: The first MCU controller and the second MCU controller communicate with each other via the SPI protocol; The first MCU controller and the wheel speed sensor, as well as the second MCU controller and the wheel speed sensor, communicate via the CAN bus.

7. The system of the dual-control EPB anti-lock braking system based on indirect tire pressure monitoring according to claim 5, characterized in that: The operating voltage range of the first car battery power source and the second car battery power source is 9V-16V.

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