Sliding mode control of a PR manipulator at physical constraint boundaries

In this paper we investigate the control of a PR manipulator to targets that lie on the boundary of its workspace within finite time. This is achieved by introducing a boundary avoidance parameter, /spl epsi/, into potential functions defined by constraint boundaries that are incorporated into a Liapunov function. We report and compare on the speed of convergence in two simulations that utilise the unique nature of the sliding mode surfaces in both Cartesian and polar formulations.