Design and Fabrication of an Active Gravity Balanced Planar Mechanism Using Auxiliary Parallelograms

This paper describes the design of an active gravity balanced planar mechanism, where auxiliary parallelograms are used to physically locate the center of mass of the mechanism. A sliding carriage positions a counterweight directly above the center of mass of the mechanism in order to make the system gravity balanced. The sliding carriage uses joint encoder data from the mechanism to compute the location of the center of mass. Experiment results demonstrate the effectiveness of the approach.