Non-smooth H_∞-position control of mechanical manipulators with frictional joints

Non-smooth H_∞-control synthesis is developed and applied to a regulation problem for mechanical manipulators with friction. Due to the nature of the approach, the resulting regulator additionally yields the desired robustness properties against the discrepancy between the real friction and that described in the model. To facilitate exposition, the friction model chosen for treatment is confined to the Dahl model augmented with viscous friction. Performance issues of the nonsmooth H_∞-regulator are illustrated in an experimental study made for a three degrees-of-freedom robot manipulator.