分布式驱动电动汽车回馈制动失效的液压补偿控制

Hydraulic Compensation Control of Distributed Drive Electric Vehicle with Regenerative Braking Failure

分布式驱动电动汽车各驱动轮转速和转矩可以单独精确控制,便于实现整车动力学控制和制动能量回馈,从而提升车辆的主动安全性和行驶经济性。但车辆在回馈制动过程中,一旦1台电机突发故障,其他电机产生的制动力矩将对整车形成附加横摆力矩,从而造成车辆失稳,此时虽可通过截断异侧对应电机制动力矩输出来保证行驶方向,但会使车辆制动力大幅衰减或丧失,同样不利于行车安全。为了解决此问题,提出并验证一种基于电动助力液压制动系统的制动压力补偿控制方法,力图有效保证整车制动安全性。以轮毂电机驱动汽车为例,首先建立了整车动力学模型以及轮毂电机模型,通过仿真验证了回馈制动失效的整车失稳特性以及电机转矩截断控制的不足;然后,建立了电动助力液压制动系统模型,并通过原理样机的台架试验验证了模型的准确性;接着,基于滑模控制算法设计了制动压力补偿控制器,并在单侧电机再生制动失效后的转矩截断控制基础上完成了液压制动补偿控制效果仿真验证;最后,通过实车试验证明了所提控制方法的有效性和实用性。研究结果表明:在分布式驱动电动汽车单侧电机再生制动失效工况下,通过异侧电机转矩截断控制和制动系统的液压主动补偿,能够使车辆快速恢复稳定行驶并满足制动强度需求。

The speed and torque of each drive wheel of a distributed drive electric vehicle can be individually and accurately controlled,which facilitates the realization of vehicle dynamics control and braking energy feedback.This improves both the vehicle’s active safety and driving economy.However,in the process of regenerative braking of the vehicle,if one motor suddenly fails,the braking torque generated by the other motors will form an additional yaw moment to the entire vehicle,causing it to become unstable.The other motors’ braking torque can be truncated to ensure the vehicle driving direction.However,it would greatly attenuate or lose the braking force of the vehicle,which is also detrimental to driving safety.To solve this problem,this study proposes and verifies a brake pressure compensation control method based on the electronic booster hydraulic braking system to ensure the vehicle brake safety effectively.The study took an in-wheel motors drive vehicle as an example.The vehicle dynamics model and the in-wheel motor model were first established.Through simulations,the instability characteristics of the vehicle with regenerative braking failure and the lack of motor braking torque cutoff control were verified.The electronic hydraulic braking system model was developed,and principle prototype bench tests were used to verify the accuracy of the model.Additionally,the brake pressure compensation controller of the hydraulic braking system was designed based on the sliding mode control algorithm.Based on the motor’s braking torque cutoff control after one side motor regenerative braking failure,the hydraulic brake compensation control effect was simulated and verified.Finally,the effectiveness and practicability of the proposed control method were proved through vehicle tests.The study shows that when the regenerative braking of the unilateral motor of the distributed drive electric vehicle fails,the torque cutoff control of the opposite-side motor and the active and rapid compensation of the pressure of the hydraulic braking system can make the vehicle quickly resume stability and meet braking strength requirements.