一种新型五自由度混联机械手的概念设计及尺度综合

摘要

研究了一种新型的五自由度混联机械手,该机械手由一个三自由度并联机构和一个二自由度旋转头串接而成。在建立三自由度并联机构全雅可比矩阵的基础上,考察机构外力、外力矩对支链驱动力及约束力的映射关系,提出在给定载荷下,支链驱动力及约束力全域最大值均值最小的机构传动性能评价指标。给定机构期望工作空间,并以全局条件数、速度、精度为机构的操作性能指标,研究三自由度并联机构的尺度综合问题。通过单调性分析得到机构尺度参数对上述各指标的影响规律图谱,获得其优化设计区域,根据实际设计要求确定了参数变量。最后给出一组算例,验证了%A novel 5 degree-of-freedom（DOF） hybrid manipulator were presented.The manipulator was composed of a 3-DOF parallel mechanism which was serially connected with a 2-DOF rotating head.On the basis of the formulation of the overall Jacobian matrix of the parallel mechanism,the mapping characteristics among the external force and moment applied on the moving platform and actuation and constraint forces of the links were investigated,and a transmission capability index was proposed for minimizing the maximum actuation and constraint forces of the links for a given set of external force and moment.Dimensional synthesis of the 3-DOF parallel mechanism was carried out under various geometrical and performance constrains in term of global conditioning index,linear velocity and accuracy for a given task space.The results of the optimal kenimatic design were given via examples.