考虑迟滞及变形影响的主被动混合驱动绳驱空间机械臂运动学建模及求解

在绳驱空间机械臂的非结构化环境灵巧作业中，驱动绳索拉伸和臂段形变给机械臂的精确控制带来了困难。为此，本文提出一种改进运动学模型。首先，建立机械臂“驱动绳索长度－关节角度－末端位姿”的多重映射运动学模型；进一步考虑绳索迟滞、运动方向切换和臂段变形3种因素耦合影响，改进“驱动绳索长度－关节角”的映射模型。其次，设计试验平台，开展不同负载下的绳索迟滞量测定试验。最后，对比改进运动学模型仿真结果和绳驱空间机械臂样机试验数据。与理想几何模型的比较结果表明，长1110 mm的两段绳驱空间机械臂的末端绝对位置误差可减小15.2 mm；末端绝对位置误差减小61.4%，证明了改进运动学模型的有效性。

Kinematics Modeling and Solution of Hybrid Active-Passive Cable-driven Space Manipulator Considering the Effects of Hysteresis and Deformation

For dexterous tasks of cable-driven space manipulators in an unstructured environment, stretch of the driving cable and segment deformation hamper the precise control of these manipulators. To solve this problem, an improved kinematics model is proposed. Firstly, a kinematics model is set up on multiple mapping among the length of driving cable, the joint angle, and the end pose of the manipulator. Further, the coupling effects of three factors are considered, including the cable hysteresis, the movement direction switching and the segment deformation, and consequently the model of mapping between the length of driving cable and the joint angle is improved. Secondly, a test platform is designed, and the cable hysteresis is measured under different loads. Finally, the test data of the cable-driven space manipulator prototype are compared with the simulation results of the improved kinematics model. Comparison results with the ideal geometric model show that, the absolute position error can be reduced by 15.2 mm at the end of the two-segment cable-driven space manipulator with a length of 1110 mm, while the absolute position error of the end can be reduced by 61.4%, which proves the effectiveness of the improved kinematics model.