Design and analysis of a redundantly actuated parallel mechanism for rapidmachining

This paper describes the design, construction, and performance analysis of the Eclipse, a redundantly actuated six-degree-of-freedom parallel mechanis m intended for rapid machining. The Eclipse is a compact mechanism capable of performing five-face machining in a single setup while retaining the adv antages of high stiffness and high accuracy characteristic of parallel mech anisms. We compare numerical and algebraic algorithms for the forward and i nverse kinematics of a class of the Eclipse and formalize the notion of mac hine tool workspace. We also develop a simple method for the first-order el asto-kinematic analysis of parallel mechanisms that is amenable to design i terations. A complete characterization of the singularities of the Eclipse is given, and redundant actuation is proposed as a solution. The Eclipse ca se study demonstrates how diverse analytical tools originally developed in a robotics context can be synthesized into a practical design methodology f or parallel mechanisms.