主动悬架的二阶滑模容错控制研究

Second Order Sliding Mode Fault Tolerant Control of Active Suspension Systems

针对主动悬架执行器故障,基于终端滑模和二阶超螺旋滑模算法,研究不同路面激励及不同执行器故障下悬架系统特性,实现主动悬架容错控制的目的。首先建立了七自由度悬架模型和非线性液压执行器模型,将悬架系统分为簧载质量运动的内部动力学和含有执行器子系统的外部动力学;然后引入非奇异快速终端滑模控制器来抑制簧载质量运动加速度,并利用超螺旋滑模控制器来跟踪终端滑模产生的期望控制力,使主动悬架在外部干扰及执行器故障工况下仍能保持期望性能;最后利用Lyapunov方程证明了超螺旋滑模控制器的稳定性。仿真结果表明:控制算法能有效提升车辆振动系统的性能;相比于传统的H∞控制,二阶滑模能更有效地提升系统的可靠性。

To improve the vibration performance of active suspension systems subject to actuator faults and disturbances,a terminal sliding mode and super twisting sliding mode-based fault tolerant controller was presented.Firstly,a 7-DOF suspension model and a nonlinear hydraulic actuator model were built for accurate control.The 3-DOF subsystem representing sprung mass motions was considered as the internal dynamics of the suspension system,and the subsystem with 4-DOF including unsprung masses,hydraulic actuators and external disturbances was considered as the external dynamics of the system.Then the proposed controller was implemented in two stages to provide a fault tolerant approach.A nonsingular fast terminal sliding mode based sliding manifold was designed for the internal system to suppress the sprung mass motions arising from road disturbances,and a super twisting algorithm was introduced for the external system to track the desired forces generated by the terminal sliding mode controller.Moreover,the stability of the controller was proved by the strong Lyapunov functions.Simulation results indicate that compared with traditional H∞approach,the proposed controller can achieve better performance under both faulty and healthy conditions.