VGT空间机械臂地面悬吊系统二自由度控制

为了在地表环境下对多节双八面体变几何桁架空间机械臂进行空间环境模拟研究，需要把机械臂悬吊起来进行重力补偿.根据机械臂的正向运动学和张力吊挂原理，设计了悬吊系统二自由度控制器.该控制器其中一个自由度由机械臂的正向运动学得出前馈控制信号，另一个自由度根据张力的偏移信号，采用PI控制得出反馈控制信号，结合两个自由度的信号对吊索长度进行收放控制，从而使吊索保持恒定张力.实验表明，该控制器能快速、稳定、可靠地控制机械臂吊索张力，既能补偿前馈控制无法消除的结构误差，又能解决反馈控制响应过慢的问题，控制性能远远优于单自由度控制

2 DOF Control of on Ground Suspension System for VGT Space Manipulator

To do on ground research on a multisection double octahedral variable geometry truss (VGT) space manipulator, suspension system is needed to compensate the gravity of the manipulator. A 2 DOF controller for the system is designed based on the forward kinematics of the manipulator and force analysis. On one DOF, the feed forward signal is calculated by the forward kinematics; on the other DOF, the feedback signal is obtained based on tension difference with PI algorithm. Via combining the two signals to control the length of the cable, the tension is kept constant. The proposed controller not only compensates the structure error that feed forward controller cannot eliminate, but also solves the lag of response of feedback controller. Experiments show that the controller can rapidly regulate the tension with good performances in stability and reliability, which are much better than one dof controller