Force sensitivity analysis and scale design of Stewart parallel manipulator

Abstract

There are many indices for evaluating the operational performance of parallel robots, but most of them start from kinematics and rarely pay special attention to the force transmission process. After studying the relationship and characteristics of the forward and reverse force transmission of the Stewart parallel manipulator under quasi-static conditions, three new indices are proposed in this paper, which are forward force sensitivity, reverse force sensitivity, and overall force sensitivity. Subsequently, the influences of six parameters on the overall force sensitivity index are analyzed. Furthermore, this paper propose three new structural optimization design schemes based on the three newly proposed indices. Finally, it is verified experimentally that the unit reverse force sensitivity of a single joint is consistent with the theory and the error between the theoretical and experimental values is obtained.

Improving machining accuracy for a robotic arm with hybrid kinematic chains based on deformation characteristics

“…The local sensitivity index is defined based on the projection theory of spatial vector to evaluate the contribution of an error component in a definite pose, and the results show that the pose accuracy can be increased greatly by improving very few error components [19]. Wang et al [20] pay attention to the force transmission process of the robot, three indices are proposed which are forward force sensitivity, reverse force sensitivity, and overall force sensitivity. Also, the structural optimization design schemes are presented based on the above indices.…”