Four-wheel hub electric vehicle electro-hydraulic composite brake anti-lock coordinated optimal control method

Abstract

The invention discloses a coordinated optimal control method for electro-hydraulic composite braking and anti-lock braking of a four-wheel hub electric vehicle, which belongs to the technical field of vehicle engineering. The purpose of the invention is to obtain empirically expected optimal slip rates of front and rear wheels according to road condition information, design a slip rate model prediction controller in the upper layer, and use the motor speed and remaining battery power as constraints in the lower layer. A coordinated and optimal control method for the electro-hydraulic composite braking and anti-lock braking of wheel hub electric vehicles. The steps of the invention are: establishing a four-wheel hub electric vehicle braking system model, identifying road adhesion conditions and optimal slip rate, designing an upper slip rate tracking controller, and a lower regenerative braking and friction braking distribution controller. The invention can quickly and accurately control the tire slip rate, effectively shorten the braking distance and braking time, improve the safety and reliability of emergency braking, and improve the energy feedback efficiency in the emergency braking process.

Description

technical field [0001] The invention belongs to the technical field of vehicle engineering. Background technique [0002] Compared with traditional internal combustion engine vehicles, electric vehicles have added a motor braking system. Under emergency braking conditions, how to coordinate the regenerative braking system and the friction braking system to improve safety and energy efficiency is an important research problem. In the traditional hydraulic braking system, the hydraulic pressure can be controlled by adjusting the solenoid valve through the pulse width modulation signal, so as to avoid the wheel lock. With the change of hydraulic pressure, the hydraulic braking torque can obtain a large relative working range, but due to the low carrier pulse frequency of the traditional anti-lock braking system (ABS), the dynamic change of the friction braking torque is slow, and during the operation process There is always a noticeable transient delay response in the fuse, wh...

AI Technical Summary

Problems solved by technology

As the hydraulic pressure changes, the hydraulic braking torque can obtain a large relative working range. However, due to the low carrier pulse frequency of the traditional anti-lock braking system (ABS), the dynamic change of the frictional braking torque is slow. There is always a noticeable delayed response to transients, which can seriously affect anti-lock control performance

In addition, traditional hydraulic brakes will have greater vibration and noise during ABS work, which will affect braking stability and comfort

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