Study on the kinematic characteristics of 3 DOF in-parallel actuated platform mechanisms

This paper presents a simple method based on the screw theory for determination of the possible motion characteristics for constrained 3 degree-of-freedom (DOF) parallel mechanisms when the linear displacements of the platform are restricted. The theory is significant for understanding novel constrained multi-DOF mechanisms, their inverse kinematics and robot path planning. The paper firstly discusses theoretically the relationship between the reciprocal screws and the motions of the mechanisms, then presents the analysis of the kinematic characteristics of several 3 DOF in-parallel actuated mechanisms.