空间4-UPU并联机器人的运动学研究

运用自然坐标法研究了空间4-UPU（万向铰-移动铰-万向铰）并联机器人的运动学正解问题．通过共用并联机器人两两构件间的公共点或公共向量的笛卡尔坐标减少自然坐标的数量，从而简化了整个分析过程．在用自然坐标法处理多体机器人系统时，由于变量仅仅引进了末端执行器上关键点的笛卡尔坐标，因此，约束方程或者是二次的或者是线性的，这就使得并联机器人的运动学分析中不会出现任何超越函数．该建模过程方法简单、统一，非常有利于计算机编程处理．

Investigation on kinematics of a 4-UPU spatial parallel manipulator

This paper presents a forward kinematics model with natural coordinates for a 4-UPU(universal joint-prismatic joint-universal joint) spatial parallel manipulator.The fact that the total number of coordinates for the whole system may be significantly reduced by sharing a certain points or vectors at the kinematic couples between bodies of a parallel manipulator can reduce the total number of variables,and therefore can facilitate the whole analysis.Moreover,when dealing with multibody systems with natural coordinates,the constraint equations are either quadratic or linear because only the Cartesian coordinates of the key points on the end-effector are utilized,which will not induce any transcendental functions in the kinematics analysis.This method is simple and unitive and especially adapted to programming at a computer.