汽车电动助力转向系统的自适应LQG控制

在对汽车电动助力转向系统(EPS)结构形式和性能进行分析的基础上,建立起3自由度的汽车动力学模型。 为克服实际EPS系统中存在的动态行为不确定性,采用自适应LQG控制策略。通过对模型参数的在线辩识,实现 系统的自适应LQG控制。在多种汽车行驶工况下,进行自适应LQG控制和LQG控制的仿真计算。仿真结果表明, 应用自适应LQG控制比LQG控制的EPS有更好的鲁棒性,且能有效改善EPS的助力特性及汽车的转向特性。为 验证仿真结果,还进行装有EPS系统的实车试验。试验结果充分证明了所提方法是正确和有效的,EPS系统可很 好改善汽车操纵性能。

ADAPTIVE LQG CONTROL FOR THE ELECTRIC POWER STEERING SYSTEM OF AN AUTOMOBILE

By analyzing the structure and dynamic characteristics of an electrical power steering system (EPS), the mathematical model of a three-degree of freedom is established. In order to overcome the uncertainties of the dynamic behavior of a practical EPS system, adaptive LQG control strategy is adopted. By identifying the model parameters on-line, adaptive LQG control is easy to be carried out. Under several running conditions of the automobile, the simulation of adaptive LQG and LQG control are implemented. The simulation results show that adaptive LQG control scheme is more effective and robustness is better than LQG control scheme. In order to verify simulation results, a test vehicle with an EPS mechanical and control system was experimented. The test results coincide closely with those obtained from simulation, and they exhibit good performance leading to improvement of steering and handling.