Sliding regime of a nonlinear robust controller for robot manipulators

The paper examines the relationship of an outer-loop robust control approach for robot manipulators with sliding-mode control. The approach is based on the general problem of stabilising a linear system with bounded uncertainties; it involves controls across switching surfaces which, for the case of robots, are proved to be decoupled and global asymptotically attractive. The design methodology highlights different design aspects from those highlighted in typical sliding-mode control schemes, but the resulting controls are equivalent. Equivalence of this approach to the sliding-mode control is shown through simulation experiments for a planar two degrees-of-freedom manipulator