Commercial vehicle intelligent braking cooperative control system

Abstract

The invention belongs to the technical field of vehicle electric appliance control, and particularly relates to a commercial vehicle intelligent braking cooperative control system which comprises a trigger unit, a control unit and an execution unit. The trigger unit performs filtering and threshold judgment on the trigger signal; the control unit establishes a non-linear relationship between the opening degree of a brake pedal and the target deceleration, and adopts a sectional PID (Proportion Integration Differentiation) to control and adjust the negative torque output of the execution unit; and the execution unit cooperatively outputs the braking torque and feeds back the actual deceleration to form closed-loop control. The brake performance and safety can be remarkably improved, and the beneficial effects of being accurate in response, flexible in control, high in applicability and the like are achieved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle electrical control technology, and in particular to an intelligent braking cooperative control system for commercial vehicles. Background Art

[0002] In traditional brake control systems, a linear or piecewise linear mapping relationship is used between the brake pedal opening and the target deceleration of the vehicle. However, the linear relationship has the following shortcomings in practical applications.

[0003] In the low opening range, linear mapping causes the braking response to be too sensitive, resulting in an abrupt increase in the vehicle's deceleration; in the high opening range, the driver's strong braking needs cannot be met due to insufficient linear growth; the sensitivity of linear mapping is fixed and it is difficult to adapt to different vehicle loads, road conditions or driver habits; under linear mapping, the system cannot accurately reflect the driver's braking intention at certain key opening points (such as the transition between light braking and emergency braking); the above problems lead to limited vehicle braking control accuracy, affecting driving comfort. Summary of the Invention

[0004] Based on the technical problems of the background technology, the present invention proposes an intelligent braking cooperative control system for commercial vehicles.

[0005] The present invention proposes an intelligent cooperative braking control system for commercial vehicles, comprising a trigger unit, a control unit and an execution unit; the trigger unit filters and performs threshold judgment on the trigger signal; the control unit establishes a nonlinear relationship between the brake pedal opening and the target deceleration, and adopts segmented PID control to adjust the negative torque output of the execution unit; the execution unit coordinates the output of the braking torque and feeds back the actual deceleration to form a closed-loop control.

[0006] Preferably, the trigger unit includes an engine system, a transmission system, a braking system and an instrument system; the control unit includes a vehicle control system; and the execution unit includes a retarder system and an in-cylinder braking system.

[0007] Preferably, the trigger unit performs filtering, time domain analysis and statistical characteristic analysis on the message and hard-wire signal.

[0008] Preferably, the target deceleration required for braking is in an exponential S-function relationship with the brake pedal opening.

[0009] Preferably, based on the target deceleration value, a PID controller is used to adjust the negative torque output of the execution unit.

[0010] Preferably, according to the error between the target deceleration and the actual deceleration, the error is segmented and the segmented PID control parameters are set.

[0011] Preferably, the segmented switching method uses an interpolation method to achieve smooth changes in parameters.

[0012] The beneficial effects of the present invention are:

[0013] 1. In the present invention, an exponential S-function model is established based on the brake pedal opening, and the pedal opening is nonlinearly associated with the target deceleration to achieve an accurate description of the braking demand. Secondly, by calculating the error between the target deceleration and the actual deceleration in real time, combined with segmented PID control, the PID parameters are dynamically adjusted according to different braking stages to control the negative torque output of the retarder. Finally, the auxiliary braking units are coordinated to work together to ensure smooth deceleration of the vehicle in the light braking stage and rapid response in the emergency braking stage. The present invention is suitable for commercial vehicle braking conditions, can significantly improve braking performance and safety, and has the advantages of precise response, flexible control, and strong applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a control flow chart of a commercial vehicle intelligent braking cooperative control system proposed by the present invention;

[0015] Figure 2 This is a relationship diagram between the brake pedal opening and target deceleration of a commercial vehicle intelligent brake cooperative control system proposed by the present invention. DETAILED DESCRIPTION

[0016] Reference Figure 1-Figure 2 , an intelligent braking cooperative control system for commercial vehicles, including a trigger unit, a control unit and an execution unit;

[0017] The trigger unit includes the engine system, transmission system, brake system and instrument system. The trigger unit filters the trigger signal and determines the threshold value;

[0018] The control unit includes a vehicle control system that establishes a nonlinear relationship between the brake pedal opening and the target deceleration, and uses segmented PID control to adjust the negative torque output of the actuator unit to achieve coordinated operation of the auxiliary brake unit.

[0019] The execution unit includes a retarder system and an in-cylinder brake system. The execution unit outputs braking torque in a coordinated manner and feeds back the actual deceleration to form a closed-loop control;

[0020] The torque distribution ratio of each execution unit is optimized according to the vehicle configuration and operating status. When an execution unit fails, the system automatically increases the torque output of other units to ensure braking effectiveness. Combined with dynamic parameters such as vehicle load, road conditions, and vehicle speed, the torque distribution between the retarder and the in-cylinder brake is optimized to ensure maximum braking efficiency under multiple working conditions, while avoiding overload of a single execution unit and improving system reliability.

[0021] In the present invention, the trigger unit performs signal processing operations such as filtering, time domain analysis, and statistical characteristic analysis on messages and hard-wired signals. Through signal denoising and smoothing, the reliability of the input signal is improved, false braking triggering or response delay caused by signal interference is avoided, and the stability of the control system is ensured.

[0022] In the present invention, the target deceleration required for braking and the brake pedal opening are in an exponential S-function relationship:

[0023] The brake pedal opening x is the normalized value of the pedal displacement applied by the driver, ranging from [0,1]; the target deceleration a target The brake pedal opening x is described by an exponential S function;

[0024] Furthermore, in the initial stage (x→0): within the low opening range, the target deceleration increases slowly. This stage mainly satisfies the driver's slight braking needs and ensures smooth response.

[0025] Furthermore, in the intermediate stage (x≈x0), the target deceleration increases rapidly near the equilibrium point x0 of the curve. This stage significantly reflects the driver's braking intention and is suitable for conventional driving scenarios.

[0026] Further, saturation stage (x→1): In the high opening range, the target deceleration area saturation value a max , to avoid exceeding the system’s capabilities while meeting the driver’s strong braking needs;

[0027] Compared with traditional linear mapping, the exponential S-function makes the target deceleration increase slowly in the low opening range, ensuring the smoothness of light braking; it tends to saturation in the high opening range to avoid system overload, while meeting emergency braking needs and accurately reflecting the driver's braking intention.

[0028] In the present invention, based on the target deceleration value, a PID controller is used to adjust the negative torque output of the execution unit; through PID closed-loop control, the target deceleration and the actual deceleration are compared in real time, and the negative torque output is dynamically adjusted to improve the accuracy and response speed of braking control.

[0029] In the present invention, according to the error between the target deceleration and the actual deceleration, the error is segmented and the segmented PID control parameters are set:

[0030] Based on the deceleration error, the error is segmented and the K is set by the tuning method in each segment. p , K i , K d ;

[0031] Furthermore, when the deceleration error is small (|e|<a s ), strengthen K iTo ensure steady-state accuracy;

[0032] Furthermore, when the deceleration error is moderate (a s ≤|e|≤a l ), balance response and steady-state accuracy;

[0033] Furthermore, when the deceleration error is large (|e|>a l ), enhanced K p , weaken K i With quick response;

[0034] Based on the error characteristics of different braking stages (light, medium and heavy braking), the PID parameters are dynamically adjusted (such as enhancing the proportional term for rapid response when the error is large, and strengthening the integral term to ensure accuracy when the error is small), which significantly improves the smoothness and control stability of the braking process.

[0035] In the present invention, the segmented switching method uses an interpolation method to achieve smooth changes in parameters and reduce oscillations caused by switching.

[0036] A control method of a commercial vehicle intelligent brake cooperative control system is:

[0037] Step 1: The engine system provides a speed signal, the transmission system provides a gear position signal, the instrument system provides a vehicle speed signal, the body system provides an auxiliary brake switch signal, and the EBS braking system provides a brake pedal opening signal. After the trigger signals undergo signal processing and other operations, the activation threshold and deactivation threshold are set according to actual needs.

[0038] Step 2: The vehicle control system receives the trigger signal. If the activation condition of the control system is not met, the auxiliary braking request signal is not output; if the activation condition of the control system is met, the braking request signal is output.

[0039] Step 3: Build Figure 2 The exponential S-function target deceleration model shown in the figure establishes the target deceleration a according to the variation range of the brake pedal opening x [0, 1]. target Exponential S-function relationship with pedal opening.

[0040] Furthermore, set the maximum deceleration a in the low opening section max1 and the low opening segment curve gain parameter α; set the maximum deceleration a in the high opening segment max2 and the steepness parameter β of the curve in the high opening section.

[0041] Furthermore, set the segmentation point x c The equilibrium point x0 with the high opening section.

[0042] Furthermore, by adjusting the function model parameters, the vehicle can achieve smooth braking requirements when the brake pedal is at a low opening range, and quickly increase the braking force to meet emergency braking needs when the brake pedal is at a high opening range.

[0043] Step 4: Construct a segmented PID model to control the negative torque output.

[0044] Furthermore, according to the calculated target deceleration a target and the actual deceleration a actual , calculate the deceleration error e(t), and adjust the negative torque output T of the brake device in the execution unit through the segmented PID control method break .

[0045] Furthermore, when e(t)<a s When the small error segment PID parameters are used to adjust the negative torque output T break ; when a s ≤e(t)≤a l When the middle error segment PID parameters are used to adjust the negative torque output T break ;When e(t)>a l When the middle error segment PID parameters are used to adjust the negative torque output T break .

[0046] Furthermore, the interpolation method is used to smoothly transition the K p , K i , K d Parameter value to reduce the oscillation caused by switching.

[0047] Step 5: Finally, a braking request signal is sent to control the auxiliary brake execution unit to perform braking. The retarder system and the in-cylinder brake system constitute the execution unit, which linearly outputs the braking torque according to the braking request.

[0048] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A commercial vehicle intelligent braking cooperative control system, characterized in that: It includes a trigger unit, a control unit and an execution unit; The trigger unit filters and determines the threshold value of the trigger signal; The control unit establishes a nonlinear relationship between the brake pedal opening and the target deceleration, and uses segmented PID control to adjust the negative torque output of the actuator; The execution units coordinate to output braking torque and feed back the actual deceleration to form a closed-loop control.

2. The intelligent brake cooperative control system for commercial vehicles according to claim 1, characterized in that: The trigger unit includes an engine system, a transmission system, a brake system and an instrument system; The control unit includes a vehicle control system; The execution unit includes a retarder system and an in-cylinder braking system.

3. The intelligent brake cooperative control system for commercial vehicles according to claim 2, characterized in that: The trigger unit performs filtering, time domain analysis and statistical characteristic analysis on the message and hard-wire signal.

4. The intelligent brake coordination control system for commercial vehicles according to any one of claims 2 to 3, characterized in that: The target deceleration required for braking has an exponential S-function relationship with the brake pedal opening.

5. The intelligent brake coordination control system for commercial vehicles according to claim 4, characterized in that: Based on the target deceleration value, the negative torque output of the actuator is adjusted using a PID controller.

6. The intelligent brake coordination control system for commercial vehicles according to claim 5, characterized in that: According to the error between the target deceleration and the actual deceleration, the error is segmented and the segmented PID control parameters are set.

7. The intelligent brake coordination control system for commercial vehicles according to claim 6, characterized in that: The segmented switching method uses interpolation to achieve smooth changes in parameters.

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