超冗余液压振动台的模态空间解耦控制

Modal space decoupling control for a hyper redundant hydraulic shaking table

摘要:

为解决超冗余振动台在带负载工作时自由度间出现耦合运动的现象,提出一种基于模态空间的解耦控制策略. 建立液压伺服系统的线性化模型,将液压缸视为液压弹簧,分析超冗余振动台的振动模态方程；通过标准模态矩阵及其逆矩阵,将超冗余振动台由自由度空间转到无耦合的模态空间进行控制；在模态空间应用三状态反馈控制,通过极点配置,实现自由度间的解耦控制. 仿真结果表明,该模态解耦控制策略在时域和频域内均可有效降低超冗余振动台自由度间的动力学耦合,提高位姿的跟踪精度.

Abstract:

To solve the problem of coupling movements between degrees of freedom(DOF) of hyper-redundant shaking table while working with a load, a novel decoupling control strategy based on modal space is proposed. Linear model of hydraulic servo system is established and modal equation of hyper-redundant shaking table is given by considering hydraulic cylinder as a hydraulic spring. By standard modal matrix and its inverse matrix, the hyper-redundant shaking table is controlled in non-coupling modal space instead of DOF space. Three variables feedback control is employed in modal space to achieve decoupling control by pole placement. Simulation results show that the proposed decoupling control strategy can effectively improve tracking accuracy and reduce the dynamic coupling among DOF in both time and frequency domain.