LAUSR

Abstract The payload capacity of robotic manipulators is often considered to be the same throughout their workspace. However, the actual capacity largely depends on posture, velocity, acceleration and actuator limits. This work studies a method to increase the payload capacity of manipulators through trajectory optimization. This optimization is performed on a task basis and therefore, the load-carrying capacity varies from one task to another. Although the studied method is general and is not limited to specific robot architectures, an analysis of the method is conducted based on its application to a planar RR serial manipulator in a vertical plane. This manipulator is the most appropriate as a simple test case because most manipulators are built in such a way that most of the vertical motion of the manipulator is done by two parallel revolute joints: planar RR mechanism. Simulation and experimental results show that the payload capacity can be greatly increased compared to nominal values. It is also shown that, although the trajectories produced are not time optimal, the method is much more versatile and much simpler to implement than some other optimal control methods. The accompanying video provides a summary of the method and the results.