A Novel Method for Jacobian Analysis of Lower-Mobility Parallel Mechanism

This paper presents a method for the forward/reverse velocity analysis of N-DoF (N<6) parallel manipulator which is developed from kinematic influence coefficient method (KIC). With this method, a 6timesN Jacobian will be achieved for an N-DoF parallel manipulator. The selection of an instantaneous coordinate frame for a configuration of the mechanism is the key of this method. In the instantaneous coordinate frame, there are 6-N zero components in the velocity vector of end-effector. Similar with the KIC method, the method has uniform formulas, which is convenient for programming. In the rear part of the paper, a 4-DoF 4-RURR mechanism is taken as the mechanism example