Frequency-response characteristics of a single-link flexible joint manipulator and possible trajectory tracking

A single-link manipulator consisting of servomotor, elastic shaft and rigid link is chosen to represent an elastic control system. Equations of the torsional elastic system are derived including the servomotor control system parameters. The transfer function of the elastic control system is obtained including not only control system parameters but also the natural frequency and the damping ratio of the torsional vibratory system. Non-dimensional parameters such as the ratio of the structural natural frequency to the substructural natural frequency and the ratio of the substructural natural frequency to the control system frequency are defined. The effects of these parameters on the frequency response of the system are investigated. A simple and effective method using the frequency-response characteristics is proposed to track a cycloidal trajectory precisely. (C) 2000 Academic Press.