The Kinematic Analyse of a New Waist's Joint Based on a Four Degree Parallel Manipulator

The reverse problem of the waist's joint parallel manipulator based on 4-RRR-RR is given through using analysis approach.The first order kinematic influence coefficient matrix is solved through using kinematic influence coefficient and the hypothesis of kinematics.The DOF of 4-RRR-RR parallel manipulator which providing 1 translation about a polar coordinate axis and 3 rotations is validated.The direct problem is approached through combining the reverse problem with the matrix of the first order kinematic influence coefficient.Through searching in polar coordinates,the workspace is searched by numerical approach.