Investigation of the Behavior of Vibration-Damped Flexible Link Robots in End-Effector Contact: Simulation and Experiment

Lightweight robots with flexible links are perfect candidates for applications which require contact with the environment due to their inherited compliance. However, due to the lower stiffness compared to typical industrial robots it is imperative to handle occurring link vibrations. This can be done with different vibration damping control approaches. This paper focuses on a method based on analytical estimation of the joint torques using accelerometers. The joint torques are estimated by reconstruction of the link dynamics. This is valid as long as no external forces are present. Stability of a robot with active vibration damping control in a contact scenario is essential. In this regard the switching caused by unilateral contact must be investigated carefully. In this paper the stability of the control system is verified in simulation and moreover in an experiment.