EBS shaft module pressure control method based on high-frequency PWM

Abstract

The invention relates to the field of automobile brake system control, and discloses an EBS shaft module pressure control method based on high-frequency PWM, which comprises the following steps of: 1, acquiring a target pressure value Pt output by a foot brake valve and a current actual pressure Pb output by a brake chamber pressure sensor, and calculating a pressure difference delta P by taking a difference value between the target pressure value Pt and the current actual pressure Pb; 2, according to the pressure difference delta P obtained through calculation, the state in which the shaft module needs to enter is judged, and when delta P is larger than or equal to 0.1 bar, the shaft module enters the pressurization control state; when delta P is smaller than or equal to-0.1 bar, the shaft module enters a decompression control state, and when delta P is-0.1 bar; [delta] Plt; and when the voltage is 0.1 bar, the shaft module is in a pressure maintaining state, and the pressurizing / depressurizing electromagnetic valve does not act. According to the method, by adjusting the duty ratio of the high-frequency PWM signal, the driving current of the electromagnetic valve can be changed, the electromagnetic valve element is made to be in the middle position of the on-off state, the opening degree of the electromagnetic valve element can be dynamically adjusted, fine adjustment of the pressure of the brake chamber is achieved, the pressure control precision is improved, the response speed is increased, and overshoot is reduced.

Description

technical field [0001] The invention belongs to the field of vehicle braking system control, and in particular relates to a high-frequency PWM-based EBS shaft module pressure control method. Background technique [0002] The Electronically Controlled Brake System (EBS) is developed on the ABS anti-lock braking system. Compared with the conventional braking system, the commercial vehicle EBS adopts the electronically controlled air brake, which can achieve faster braking. Dynamic response time, more reasonable braking force distribution, and more comprehensive braking system control can effectively improve the braking efficiency of the vehicle and greatly improve the safety and comfort of the vehicle driver. Based on EBS, a variety of system functions can also be expanded, such as vehicle stability control (ESC), adaptive cruise (ACC), automatic emergency braking (AEB) and other functions. [0003] In the current electric control brake system (EBS) of commercial vehicles, th...

AI Technical Summary

Problems solved by technology

At the same time, because the switch solenoid valve only has two states of on and off, the flow adjustment function of the proportional solenoid valve cannot be realized, so in the pressure control of the brake chamber, there are low control accuracy, large overshoot, and poor brake pedal feel. , severe fever, etc.

[0004] At present, there are also some high-speed switching solenoid valve pressure control methods based on high-frequency PWM, but most of them are aimed at hydraulic systems. Patent authorization number CN105889603B and application number 201610356795.9 disclose a PWM control method for improving the proportional characteristics of high-speed switching solenoid valves. Improve the proportional control range of the flow rate and pressure controlled by the high-speed switching solenoid valve, and realize the fine adjustment of the opening of the valve port. However, this method is aimed at the hydraulic high-speed switching solenoid valve, and does not consider the pressure difference between the inlet and outlet of the solenoid valve on the valve core. Effect of opening

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