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

Abstract

The invention discloses a double-control EPB anti-lock control method and system based on indirect tire pressure monitoring, and belongs to the field of automobile anti-lock braking. The double-control EPB anti-lock control method comprises the following steps that S1, wheel speed signals of wheels are collected; s2, the wheel radius and the tire pressure deviation ratio are calculated based on the collected wheel speed, whether emergency braking is started or not is judged according to the tire pressure deviation ratio, if not, the step S1 is executed, and if yes, the vehicle speed is compensated, and the locking degree of each wheel is calculated based on the wheel radius; s3, initial holding force is applied to the left rear wheel and the right rear wheel; s4, according to the slip rate and the enclasping degree of the left rear wheel and the right rear wheel, the enclasping force of the left EPB caliper and the enclasping force of the right EPB caliper are dynamically adjusted; and S5, braking is finished. By the adoption of the double-control EPB anti-lock control method and system based on indirect tire pressure monitoring, when the tire pressure of the automobile is under-pressure, the automobile speed is compensated, and rear wheel anti-lock is achieved through emergency braking.

Description

Technical Field

[0001] The 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 parking system of a car plays a vital role. Its design and performance are directly related to driving safety and parking convenience.

[0003] Faced with the ever-increasing market demand for parking brake reliability, major automobile manufacturers (OEMs) continue to innovate and are committed to developing and applying parking system products with higher functional safety in order to meet industry standards and consumer expectations. In this context, tires are a key factor affecting the safety performance of vehicles, and their condition monitoring is particularly important. Among them, the indirect tire pressure monitoring system (TPMS) has become a popular solution due to its economic and efficient advantages. The system cleverly uses the existing vehicle wheel speed sensor to indirectly determine whether the tire pressure is within the safe range by analyzing the speed signal of each wheel. Compared with direct TPMS, the indirect TPMS system is easier to promote and apply on various models with its lower cost and higher popularization potential, which promotes the popularization of automobile safety technology.

[0004] However, ensuring the driving safety of the car under various complex road conditions requires more than just monitoring tire pressure. When it is detected that the tire pressure has dropped to an unsafe level, the advanced dynamic brake control system will intervene and effectively perform anti-lock control (ABS) through intelligent compensation of vehicle speed, even in emergency braking, to ensure the vehicle's handling stability and braking performance. This is particularly evident in the dual-control EPB (Electronic Parking Brake) anti-lock control system. The system can accurately control the braking force during vehicle driving, especially when the tire pressure drops abnormally or the wheel speed increases abnormally, to ensure that the vehicle can decelerate smoothly until it stops, greatly enhancing the driving safety factor.

[0005] Despite the continuous advancement of modern automotive braking technology, the control accuracy of rear wheel braking is still challenging in some cases. Specifically, when the rear wheels are locked during strong braking, the stability of the vehicle will be significantly reduced, which greatly increases the risk of loss of control and may even trigger a traffic accident, endangering the safety of passengers 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 the vehicle speed when the tire pressure of the vehicle 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 control method based on indirect tire pressure monitoring, comprising the following steps:

[0008] S1. Data collection: collecting wheel speed signals of the four wheels of the vehicle;

[0009] S2, data processing: calculating the wheel radius and tire pressure deviation ratio based on the collected wheel speed, judging whether to initiate emergency braking according to the tire pressure deviation ratio, if not, returning to step S1, if yes, compensating the vehicle speed, and calculating the locking degree of each wheel based on the wheel radius;

[0010] S3, initial brake intervention: control the left EPB caliper and the right EPB caliper to apply initial clamping force to the left rear wheel and the right rear wheel respectively;

[0011] S4, dynamically adjusting the brakes: dynamically adjusting the clamping force of the left EPB caliper and the right EPB caliper according to the slip rate and the clamping degree of the left rear wheel and the right rear wheel calculated in step S2, so as to prevent the left rear wheel and the right rear wheel from locking;

[0012] S5, braking end: when it is detected that the vehicle speed is lower than the set speed, the vehicle stops decelerating, or reaches the set wheel slip rate, braking is stopped, otherwise it returns to step S3.

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

[0014] S21. Calculate the center speed of the car:

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

[0016] In the formula, 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 radii 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, calculating tire pressure deviation ratio:

[0024]

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

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

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

[0028]

[0029] In the formula, δ RR ,δ LL are the slip ratios 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 They are the wheel speeds of the right rear wheel and the left rear wheel when the car is moving;

[0030] S26. Setting 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 clamping 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 kmm / h.

[0036] A system of a dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring, comprising a dual-control EPB controller, a wheel speed sensor for respectively collecting wheel speed signals of four wheels of a vehicle, an indirect tire pressure monitoring module for monitoring tire pressures of four wheels of the vehicle, a left EPB caliper and a right EPB caliper, the dual-control EPB controller being connected to the wheel speed sensor and the indirect tire pressure monitoring module respectively, and the indirect tire pressure monitoring module being connected to the left EPB caliper and the right EPB caliper respectively, and the left EPB caliper and the right EPB caliper being used to hold and decelerate the left rear wheel and the right rear wheel 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 a first vehicle battery power source and a second vehicle battery power source, 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, thereby maintaining the controllability of the vehicle even under extreme conditions, avoiding accidents and further consolidating 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 It is a flow chart of a dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring of the present invention;

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

[0046] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in conjunction with 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 reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

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

[0048] Like reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0049] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention 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 direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0050] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to 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 collection: collecting wheel speed signals of the four wheels of the vehicle;

[0053] S2, data processing: Calculate the wheel radius and tire pressure deviation ratio based on the collected wheel speed, determine whether to start emergency braking based on the tire pressure deviation ratio, if not, return to step S1, if yes, compensate for the vehicle speed (when the tire pressure is detected to be low, if the wheel speed is low, the speed of the tire with low wheel speed is compensated based on the other normal wheel speeds as a reference, so that the wheel speeds of the four wheels are consistent), and calculate the locking degree of each wheel based on the wheel radius;

[0054] Step S2 specifically includes the following steps:

[0055] S21. Calculate the center speed of the car:

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

[0057] In the formula, 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 radii 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, calculating tire pressure deviation ratio:

[0065]

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

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

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

[0069]

[0070] In the formula, δ RR ,δ LL are the slip ratios 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 They 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 locking degree and the slip ratio: the locking degree is equal to the slip ratio, that is, when the slip ratio is 0, the wheel rolls purely on the road and the locking degree 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 locking degree 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, initial brake intervention: control the left EPB caliper and the right EPB caliper to apply initial clamping force to the left rear wheel and the right rear wheel respectively;

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

[0074] S4, dynamically adjusting the brakes: dynamically adjusting the clamping force of the left EPB caliper and the right EPB caliper according to the slip rate and the clamping degree of the left rear wheel and the right rear wheel calculated in step S2, so as to prevent the left rear wheel and the right rear wheel from locking;

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

[0076]

[0077] In the formula, 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 RL ; μ is the friction coefficient between the tire and the ground; r is the effective radius of the caliper.

[0078] S5, braking end: when it is detected that the vehicle speed is lower than the set speed, the vehicle stops decelerating, or reaches the set wheel slip rate, braking is stopped, otherwise it 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 of a dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring includes a dual-control EPB controller, a wheel speed sensor for respectively collecting wheel speed signals of four wheels of a vehicle, an indirect tire pressure monitoring module for monitoring the tire pressure of 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, and the left EPB caliper and the right EPB caliper are used to hold and decelerate the left rear wheel and the right rear wheel 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 a first vehicle battery power source and a second vehicle battery power source, 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 automobile battery power source and the second automobile battery power source is 9V-16V.

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

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. 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 solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring, characterized in that: The following steps are involved: S1. Data collection: collecting wheel speed signals of the four wheels of the vehicle; S2, data processing: calculating the wheel radius and tire pressure deviation ratio based on the collected wheel speed, judging whether to initiate emergency braking according to the tire pressure deviation ratio, if not, returning to step S1, if yes, compensating the vehicle speed, and calculating the locking degree of each wheel based on the wheel radius; S3, initial brake intervention: control the left EPB caliper and the right EPB caliper to apply initial clamping force to the left rear wheel and the right rear wheel respectively; S4, dynamically adjusting the brakes: dynamically adjusting the clamping force of the left EPB caliper and the right EPB caliper according to the slip rate and the clamping degree of the left rear wheel and the right rear wheel calculated in step S2, so as to prevent the left rear wheel and the right rear wheel from locking; S5, braking end: when it is detected that the vehicle speed is lower than the set speed, the vehicle stops decelerating, or reaches the set wheel slip rate, braking is stopped, otherwise it returns to step S3.

2. The dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring according to claim 1, characterized in that: Step S2 specifically includes the following steps: S21. Calculate the center speed of the car: v=(v FR +v FL +v RR +v RL ) / 4 (1); In the formula, 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 radii 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, calculating tire pressure deviation ratio: Where, ∝ represents tire pressure deviation ratio; S24, determine whether to start emergency braking: when the deviation ratio ∝≠1, start emergency braking and execute step S25; S25. Calculate the slip rate of the rear wheels of the vehicle relative to the front wheels: In the formula, δ RR , δ LL are the slip ratios 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 They 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.

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

4. The dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring according to claim 3, characterized in that: In step S4, the calculation formula of the clamping 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.

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

6. The system of the dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring according to any one of claims 1 to 5, 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 hold 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 a first vehicle battery power source and a second vehicle battery power source, respectively. The first MCU controller is also connected to the EPB switch.

7. The system of the dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring according to claim 6, 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.

8. The system of the dual-control EPB anti-lock braking control method based on indirect tire pressure monitoring according to claim 6, characterized in that: The operating voltage range of the first automobile battery power source and the second automobile battery power source is 9V-16V.

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