Hybrid Vibration Control Adapting to State Variation of Suspension System

为了从几何角度验证悬架刚度的变化，应用多体动力学理论对悬架进行了分析。仿真结果验证了其行程端周围的刚度比标称状态下的刚度要高。同时，对冲程末端的冲击量进行了估计，并对抑制冲击的方法进行了研究。从标称阻尼到更高阻尼的切换控制可能会使加速度响应变差。研究发现，在悬架接近其行程结束之前激活执行器是非常重要的。采用滑模变结构控制方法设计控制系统，使其在行程端刚度发生变化时仍能保持标称性能。设计了变结构系统观测器来估计四分之一汽车悬架系统的状态，并进行了实验。实验装置采用直线电机作致动器，交流伺服电机作激振器产生路面扰动。VSS观测器利用了车辆的加速度，不需要随着行程接近终点而变化的刚度。利用直线电机对悬架刚度的非线性力进行仿真。通过仿真和实验，验证了实验结果与仿真结果吻合良好，所设计的控制器能够适应悬架系统非线性状态的变化。

In order to verify variation of suspension stiffness by considering its geometry, the suspension was analyzed using multi-body dynamics theory. It was verified from the simulation results that the stiffness at around its stroke end becomes higher than that in the nominal state. Also, the amount of shock at the stroke end was estimated and the method to suppress the shock was examined. The switching control from nominal damping to higher damping may make the acceleration response worse. It was found out that it is important to activate the actuator before the suspension approaches to its stroke end.By using sliding-mode control method, the control system was designed in order to improve the nominal performance and maintain it even when the stiffness changes in the stroke end. VSS (variable structural system) observer was designed to estimate the state of the quarter-car suspension system and the experiments are performed. A linear motor was used as the actuator in the experimental setup and the AC servo motor was used as the shaker to generate the road disturbance. VSS observer utilized the acceleration of the vehicle and did not need the stiffness force varying as the stroke approaches the end. The nonlinear force of the suspension stiffness was simulated by the linear motor. By carrying out simulations and experiments it was verified that the experimental results coincide with the simulation results and the controller designed was adaptable to the state varying according to the nonlinearity of the suspension system.