Partial Potential Energy Shaping Control of Torque-Driven Robot Manipulators in Joint Space

The partial potential energy shaping control of fully actuated torque–driven robot manipulators in joint space is addressed in this paper. In contrast to the well-known potential energy shaping control of robot manipulators–which achieves global joint position regulation–here the term partial means to cancel out the natural potential energy at the joints selected by the user via the feedback control law. This formulation is useful when the robot joints are intended to track a desired time-varying trajectory that has joints with null potential energy. To the best of the authors’ knowledge, this is the first time that a formal analysis is presented on joint position tracking of robot manipulators by means of an adequate kinetic energy shaping plus total damping injection with partial potential energy shaping. The proposed controller is designed via an energy shaping plus damping injection approach, and the closed-loop system analysis is carried out via the Lyapunov’s theory and LaSalle’s theorem. Real-time experimental results on a manipulator arm model of two degrees of freedom illustrate the main results.