On Energy-based Robust Passive Control of a Robot Manipulator

This research proposes a novel robust passive control approach for a robot manipulator with model uncertainties to interact with its dynamic environment by considering the robot's mechanic energy. Here, we analyze the robot's robust passivity as seen from its environment. By adjusting a scaling parameter of the robot's desired velocity with respect to the robot's mechanic energy, we propose our robust passive control approach. We also perform computer simulations to show the effectiveness of our approach. In the simulation, we studied three cases where the robot has no model error, or its model has errors. As the results, it is found that the previous robust position tracking control may loss passivity to the external force. However, by adjust the robot's desired velocity as in our approach, we can realize the robot's passivity even when the robot has mode errors. The applications of our control approach are expected be used in those robots that are required to make safe physical interaction with human.