An evaluation of ultrasonic motors as driving technology in impedance controlled robots

The present paper address the analysis of Ultrasonic motors, UM, as driving technology in impedance controlled robotic manipulators. A focus is given on rehabilitation robotics as an emerging field in which impedance controlled approaches are more suited. The article gives some general remarks on impedance control, briefly introduces a UM driven miniature SCARA robot and describes a model of the manipulator and UM that serves the goal of gaining insight in the expected behavior of the controlled system. The experimental results and evaluation of UM as driving technology make use of a set of figures of merit previously defined. Eventually, some concluding remarks are given.