On the control of redundant coarse-fine manipulators

The problem of controlling the end-point position of a redundant coarse-fine manipulator is investigated. For small motions for which a a linearized model of the coarse-fine dynamics is assumed, it is shown that, under mild assumptions, a good disturbance rejection over a wide frequency range of the fine manipulator is sufficient to insure stability and good performance of the coarse-fine redundant manipulator. The fine robot controller can be designed by H∞ norm minimization, while the coarse robot controller need not be changed.