A Novel Approach to Kinematic Characteristics Analysis of Parallel Manipulators with Fewer Than Six DOF

In this paper, a novel approach to the identification of instantaneous and continuous motions of a constrained rigid body is proposed by employing the concept of constraining-power rate. With the investigation into the constraining-power rate of a general constrained rigid body, the sufficient and necessary conditions of continuous motion of a general constrained rigid body are firstly presented. The conditions are then applied to distinguish continuous rotating axes of 3-RPS platform mechanism and 3-RPS pyramid mechanism. The corresponding physical and mathematical criteria are obtained, which gives a valid mathematic method for analyzing kinematic characteristics of parallel manipulators with fewer than six DOF. The presented approach is significant for the path planning of parallel manipulators