考虑铰间间隙和重力影响的空间机械臂轨迹跟踪控制
Trajectory tracking control of space manipulator considering joint clearance and gravity

以在轨服务高精度操控任务为背景, 研究了铰间间隙和重力对空间机械臂末端轨迹跟踪精度的耦合影响, 并设计了间隙补偿控制器. 通过分析不同重力环境下含铰间间隙机构的运动特性, 基于铰间间隙的Kelvin-Voigt线 性弹簧阻尼假设, 建立了地面装调及空间服役两种不同工况下的近似间隙等效模型. 以二自由度空间机械臂为例, 利用牛顿欧拉法推导了重力及重力释放条件下的含间隙机械臂动力学模型, 并分离出了间隙补偿项. 最后, 通过轨 迹跟踪控制仿真研究, 给出了含间隙机械臂在不同重力环境下的动力学行为差异, 同时验证了间隙补偿控制器的有 效性.
Taking the on-orbit servicing high precision manipulation task as background, we investigate the coupling effect of joint clearance and gravity on the accuracy of trajectory tracking for space manipulator, and design the clearance compensation controller. By analyzing the motion characteristics about mechanism with joint clearance under different gravity environments, we build approximate clearance equivalent models for ground alignment as well as for space applications, on the basis of Kelvin-Voigt linear spring damping assumption. Taking a two degree-of-freedom (DOF) manipulator as an example, we use Newton–Euler method to derive the dynamic model of space manipulator with joint clearance in the gravity and gravity release conditions, and isolate the clearance compensation. Through the simulation studies of trajectory tracking control, the differences between the dynamic behaviors of space manipulator in different gravity environments are explored and the effectiveness of the clearance compensation controller is demonstrated.