The kinematics of a class of 3-DOF, 4-legged parallel manipulators

In this paper a class of 3-DOF 4-legged parallel manipulators are enumerated. The general architecture of such manipulators consists of a moving platform, a fixed base, and four supporting legs that meet the fixed base at four distinct points and the moving platform at four distinct points. One of the four legs is passive whereas each of the remaining three legs is driven by a linear actuator. To gain a better understanding of the mechanisms, a methodology for analyzing the kinematics of such manipulators is presented. The Tricept manipulator is used as an example to illustrate the methodology.