Hybrid force/velocity control of industrial manipulators with elastic transmissions

This paper deals with the experimental charactherization of an hybrid force/velocity controller for contour tracking tasks of objects with unknown shape performed by industrial robot manipulators. In particular, we address the problem of the presence of elasticities in joint transmissions, and we show that this can cause the occurrence of large force oscillations depending on the robot configuration. We also show that to compensate for them it is necessary to employ an additional normal velocity feedback loop. Experimental results have been obtained with a two degrees-of-freedom SCARA robot.