不同重力条件下含铰间间隙空间机械臂PDμ-SMC轨迹跟踪控制

摘要

研究了重力对含铰间间隙空间机械臂的轨迹跟踪控制的影响.针对空间机械臂在安装、调试阶段处于地面重力环境,在应用过程中处于空间微重力环境,重力环境的改变会使得在地面设计、装配、调试好的控制器在空间应用时达不到良好的控制精度和效果的问题,设计了不需被控对象模型的分数阶PD滑模控制器(PDμ-SMC)对含铰间间隙空间机械臂进行控制,并基于李亚普诺夫理论证明了渐近稳定性.仿真结果表明该控制策略能有效地抑制外部干扰,实现含铰间间隙空间机械臂在不同重力环境及存在外部扰动情况下仍然能对期望轨迹进行准确快速跟踪.%The influence of gravity on the trajectory tracking control of a space manipulator with joint clearance was studied.Considering that the assembly and debugging of a manipulator is conducted under the ground gravity, while in space application it is influenced by the micro-gravity, so a manipulator well designed, assembled and debugged on the ground fails to achieve the expected control precision and effect in its space application, the study designed a fractional order PD sliding mode controller (PDμ-SMC) without a need of controlled subject model for control of a space manipulator with joint clearance.Based on the Lyapunov theory, the asymptotic stability of the closed-loop system was proved.The simulation results show that the control strategy can effectively suppress the external disturbance and successfully realize the fast and accurate tracking of the expected trajectory toward the space manipulator with joint clearance under different gravity conditions and external disturbance.