Active Damping in a Three-Axis Robotic Manipulator

This paper explores several methods to eliminate residual vibration of a robot arm at the end of a move, using open-loop control. The robot structure is modeled as lumped masses and springs with negligible damping, representative of a three-axis Cartesian manipulator. Vibration control is achieved using two different types of forcing functions: (1) a “bang-bang” control function for time-optimal response, and (2) a function constructed to avoid exciting resonance throughout the move. These functions are then compared in their ability to attenuate residual vibration in practice and the response time using (2) is compared with the optimal time using (1).