Conceptual Design of a Two-Stage Variable Gravity Compensated Mechanism

Abstract

Conceptual design of a two-stage, gravity-balanced, single articulated system carrying variable payload is presented. Aim of the work is to develop a general energy-free methodology to achieve the equilibrium of the system as the payload mass is changed. Two stages are required in this self-adaptive method: In the constant-mass stage, the system performs as a normal gravity compensated mechanism (GCM) where equilibrium of the system can be achieved at all configurations; while in the variable-mass stage, position of the ground pivot is set free such that the pivot would be automatically moved to a new position as a result of the force balance due to the addition/removal of the mass. Right after the self-adaptive relocation of the pivot, position of the pivot is locked and then a perfect, gravity-balancing system with the new mass prop-erty is regained.