Gravity Compensation of Articulated Robots Using Spring Four-Bar Mechanisms

This paper presents a design method for gravity compensation of articulated robots. The method is realized by installing spring four-bar mechanisms onto the robot to eliminate the gravity effect on its joints. This elimination allows reducing the actuation torque and energy consumption of the robot during operation. The design of the spring mechanisms is obtained by solving an optimization problem for minimizing the actuation torque of the robot. A numerical example is provided to demonstrate the proposed design method, by which a significant reduction in the actuation torque over the robot workspace is received. A simulation-based validation showed that the actuation torque of the robot could be reduced by approximately 90% when the design method is applied.