A Performance Analysis of a Mobile Parallel Mechanism with Multi-Motion Mode

A mobile parallel mechanism with multiple motion modes is proposed which is to adapt to unstructured terrain environment. Firstly, the degree of freedom is analyzed based on screw theory. Secondly, kinematic analysis is conducted for the varied-width straight-line mode to obtain the velocity Jacobian matrix. Stiffness analysis is conducted based on the velocity Jacobian matrix to obtain the stiffness performance under different widths of straight-line mode. Finally, the ratio of the instantaneous motion power at the output of the mechanism to the instantaneous input power at the input is used as the evaluation index of the mechanism motion/force transmission efficiency. The motion/force transmission efficiency is analyzed in the variable width mode, and the transmission efficiency in the straight line mode with different widths is obtained.By comparing the stiffness performance and the motion/force transfer efficiency of the straight mode with different widths, it can be concluded that the mechanism has the best performance in mode d, with high bearing capacity and moving capacity.