3自由度并联柔索驱动变刚度操作臂的刚度控制

利用柔索的弹性及驱动冗余性构造了一种3自由度并联柔索驱动变刚度操作臂,在静力学与刚度分析的基础上,进行刚度控制研究。首先,将柔索驱动力映射到关节空间,并分析等效关节力与柔索张力和外力的关系, 提出该操作臂的三维力矢量闭合原理。根据微分变换原理进行刚度分析,得到关节刚度矩阵及操作手刚度矩阵, 并进行数值算例分析,结果表明:刚度与柔索的张力有关,调节柔索张力可以改变系统刚度。最后,采用位置与张力混合控制的策略,对该变刚度操作臂进行了刚度控制,并进行了仿真验证。

STATICS AND STIFFNESS STUDY ON A 3-DOF PARALLEL WIRE DRIVEN FLEXIBLE MANIPULATOR

A 3-DOF parallel wire driven stiffness-variable manipulator is presented by making use of the elasticity of wires and the redundant actuation. Based on static and stiffness analysis,the study on stiffness control is made. Firstly, by pro-jecting the tension of wires into the joint space, the relation between joint forces and tension of wires and that between joint forced and resultant forces are studied, and a 3 dimension force vector closure theory is presented. Then, the joint stiffness matrix and the manipulating stiffness matrix are deduced according to differential transform theory, and a numerical example is given subsequently. The result shows that the stiffness relates not only to stiffness of wires but also to tension of wires. So it can be changed by regulating the tension of wires. Finally, stiffness control to this stiffness-variable manipulator is studied by separating position control and tension control, and a numerical example is done for verifying it.