Abstract
This paper presents new theoretical and experimental results on control of flexible robot arms using direct strain feedback method. First, a class of perturbation operators satisfying some assumptions is defined, then the properties of the perturbation operators themselves and the issues such as the existence, uniqueness, and stability of a second order evolution equation involving the perturbation operator are investigated. It is found that the direct strain feedback defines a differential perturbation operator and introduces damping in the dynamic model of the flexible arms.
To verify these theoretical views, experiments such as direct strain feedback, direct strain-integration feedback were conducted. It is seen that the direct strain feedback can damp out vibrations quite satisfactorily, and that the direct strain-integration feedback increases the vibration frequencies of every modes of the flexible arms. For the case where the flexible arm carries a rigid tip body, it is shown that the coupled bending and torsional vibrations of the flexible arm can be suppressed simultaneously by direct feedback of both the bending and torsional strain signals.
