Vibration control of flexible-link manipulators using generalized output redefinition

This paper presents a generalized nonlinear control scheme for achieving small tip-position tracking errors while suppressing vibrations of flexible modes in flexible-link manipulators. The control strategy is based on partial feedback linearization, where a desired output vector corresponding to a subset of the system states is controlled by using a tracking controller. The remaining states correspond to the internal dynamics of the system that can be either marginally stable or unstable, corresponding to a weakly or strongly nonminimum phase system. We address how to obtain an appropriate output vector in the general case and also present a scheme for obtaining matrices corresponding to the feedforward damping terms in the control law.