A contrastive study on the force analysis of the active and passive overconstrained parallel mechanisms

Abstract

This paper reveals that the distinction between the statically indeterminate force problem of the active overconstrained parallel mechanisms (PMs), i.e., the redundantly actuated PMs, and that of the passive overconstrained PMs is the displacement coordination condition. For the redundantly actuated PMs, the displacement consists of the input displacements of the actuators and the elastic deformations of the system. While for the passive overconstrained PMs, it just refers to the elastic deformations of the system. Besides, taking the typical 2RPR+P redundantly actuated mechanism as an example, the relationship between the input displacement and the driving force/torque of an actuator under the position and torque control modes are discussed. The results will provide an important theoretical guidance for the control of the redundantly actuated mechanisms.