融合主动转向功能的电动助力转向系统H_∞控制

H_∞ Control for Electric Power Steering System Integrated with Function of Active Steering

针对传统电动助力转向(EPS)系统不能在车辆极限工况行驶时实施主动转向,也不能对驾驶员的转向误操作进行主动补偿的问题,建立了融合主动转向功能的EPS整车操纵动力学模型,并以转向轻便性、灵敏性、回正特性及整车操纵稳定性为系统评价输出,运用H∞鲁棒控制策略对基于整车操纵稳定性控制的汽车EPS系统控制特性进行了仿真分析。仿真结果表明,集成主动转向功能的EPS控制系统,既能够实现EPS系统的传统控制特性,又能够根据汽车极限运行工况时整车操纵稳定性的要求实施主动转向,从而有效降低车身横摆角速度和质心侧偏角,并最大程度地发挥EPS的功能调节范围。

Aiming at the problems that traditional electric power steering （EPS） system cannot implement active steering when vehicles running in limiting condition and also can＇t actively compensate on the driver＇s steering misuse, the full vehicle handling dynamic model of EPS integrated with the function of active steering is established in this paper. Then taking the steering portability, sensitivity, return ability and handling stability as the system evaluation outputs, the control characteristics of EPS based on full vehicle handling stability is simulated using the strategy of H∞ robust control. The simulation results show that the EPS integrated active steering not only can realize the traditional EPS control characteristics, but also can implement the active steering according to the vehicle steering stability requirements in the limiting operation condition. Thus, the vehicle yaw rate and side-slip angle are reduced effectively and the function adjusting range of EPS is played furthest.