【摘要】 电动助力转向系统性能直接影响汽车整车性能,为提高整车操纵稳定性及驾驶安全性,对转向系统进行建模并对关键结构参数进行分析及优化设计。首先,简单介绍了电动助力转向系统的构成及工作原理,在对电动助力转向系统进行简化的基础上,利用动力学理论建立数学模型,整车采用二自由度模型,推导出了系统传递函数,并对电动机参数和减速机构参数对汽车转向性能的影响进行了分析。然后,以MATLAB/Simulink与Carsim联合建模对汽车运动状态随电机转动惯量与减速机构减速比的变化进行仿真分析。由此可得,减速比增大,可提高汽车转向响应速度,但减速比和转动惯量的增加会导致汽车转向稳定性变差。以此,利用遗传算法,以操纵稳定性为条件,对系统参数进行优化,优化结果可大大提高系统稳定性。更多还原

【Abstract】 The vehicle performance is directly affected by electric power steering system performance. To improve the vehicle handling stability and driving safety,the steering system modeling was built,the key structure parameters were analyzed and the design was optimized. Firstly,the basic structure and working principle of the electric power steering system were introduced. On the basis of the simplified electric power system,a mathematical model based on dynamics theory was established and a two-degree freedom model was used for the vehicle. The transfer function of system was deduced,and the affect of the parameters of the motor and reduction gear on the performance of vehicle steering were analyzed. Then,on the basis of the joint simulation of MATLAB/Simulink and Carsim,the changing of vehicle movement state along with motor inertia and the ratio of reduction gear were analyzed. To this end,with reduction ratio increases,the automotive steering response speed can be improved,while with the increase of reduction ratio,the motor inertia can lead to the deterioration in vehicle steering stability. Thus,for handing stability condition,optimizing the system parameters with the genetic algorithm can improve the system stability.更多还原