轮毂电机驱动电动汽车主动悬架μ综合鲁棒控制研究

μ-Synthesis Robust Control for Active Suspension of In-wheel-motor-driven Electric Vehicles

针对现有研究较少考虑轮毂悬架系统中非簧载质量增加及轮毂电机力矩在车轮处波动导致的车辆振动恶化问题,考虑轮毂主动悬架系统的簧上质量、悬架刚性和阻尼等参数不确定性及高阶非线性未建模动态等影响,采用线性分式变换(Linear fractional translation, LFT)方法建立面向μ综合鲁棒控制的定向轮毂悬置吸振式(Dynamic vibration absorber,DVA)主动悬架混合不确定系统动力学模型。在广义μ综合鲁棒控制系统的统一框架下,根据鲁棒μ综合奇异值理论设计轮毂主动悬架增广系统下的μ综合鲁棒控制器,并通过D-G-K迭代方法进行求解,μ综合分析显示,设计的μ综合控制器能在拥有良好稳定裕度的条件下保证主动悬架闭环系统的鲁棒稳定性和鲁棒性能,并降低传统H_(∞)控制器的保守性。在Matlab/Simulink环境中通过频域和时域响应对控制器的可行性和有效性进行验证,仿真结果表明,设计的DVA-μ控制系统的综合性能优于DVA-H_(∞),DVA-μ控制器能有效抑制轮毂主动悬架系统的垂向振动,即使在外界干扰和多参数摄动下仍能较好地提高车辆行驶的平顺性及乘坐舒适性,有助于后续电动汽车主动悬架系统减振设计的理论借鉴。

Aiming at the existing researches that rarely consider the deterioration of vehicle vibration caused by the increase of unsprung mass and the torque fluctuation of the wheel motor at the wheel in-wheel active suspension system,the influences of the sprung mass,suspension rigidity,suspension damping and high-order nonlinear unmodeled dynamics of the in-wheel active suspension system are considered.The LFT method is used to establish the oriented hybrid uncertain active suspension dynamic model,in which in-wheel motor is suspended as dynamic vibration absorber(DVA).Under the unified framework of the generalizedμsynthesis system,theμsynthesis robust controller about the active suspension augmentation system is designed according to the robustμsynthesis singular value theory,and solved by the D-G-K iterative method.Theμsynthesis analysis reveals that the designedμsynthesis controller can ensure the robust stability and robust performance of the closed-loop active suspension system under a good stability margin,and reduce the conservativeness of the traditional H_(∞)controller.In the Matlab/Simulink environment,the feasibility and effectiveness of the controller are verified through frequency domain and time domain responses.The simulation results show that the comprehensive performance of designed DVA-μcontrol system is better than the DVA-H_(∞),it can effectively suppress the vertical vibration of the active suspension system and still improve the ride comfort and road-holding ability even if external interference and multi-parameter perturbations exist,which is helpful for the theoretical reference of the vibration reduction design of the active suspension system of electric vehicles.