Singularity-Free 3-Leg 6-DOF Spatial Parallel Robot with Actuation Redundancy

Parallel robots with closed -loop kinematic chains have been used in industrial applications. They exhibit superior precision, stiffness, and operating speed than serial robots owing to their mechanical architecture. However, parallel robots demonstrate static singularity unique to parallel mechanisms, which further impede their application. Static singularity is caused by passive joints included in the mechanism. In this study, a 3 -leg 6-DOF spatial parallel robot with actuation redundancy and its statics are analyzed. The analysis indicates that static singularity does not occur if actuation redundancy is properly introduced. This analysis is based on the decomposition of force transmission in the robot. Experimental results show that precise trajectory tracking and stable contact are achieved by virtue of the actuation redundancy. This study opens new avenues for the application of parallel robots.