Kinematic modeling, analysis, and load distribution algorithm for a redundantly actuated 4-DOF parallel mechanism

This paper presents the kinematic modeling and analysis of a gravity balanced 3T1R parallel mechanism with actuation redundancy. The screw theory is employed for Jacobian derivation and singularity analysis. Actuation redundancy is introduced to eliminate forward kinematic singularities. Moreover, three load redistribution algorithms employing redundant actuation to avoid torque saturation are presented and the comparison analysis shows through simulation study that the newly suggested algorithm considering a relaxed form of torque limit has several advantageous features in comparison to other load distribution algorithms.