Path following controllers make the output of a control system approach and traverse a prespecified path with noa prioritime-parametrization. In this paper, we present a method for path following control design applicable to framed curves generated by splines in the workspace of kinematically redundant mechanical systems. The class of admissible paths includes self-intersecting curves. Kinematic redundancies are resolved by designing controllers that solve a suitably defined constrained quadratic optimization problem. By employing partial feedback linearization, the proposed path following controllers have a clear physical meaning. The approach is experimentally verified on a four-degree-of-freedom (four-DOF) manipulator with a combination of revolute and linear actuated links and significant model uncertainty.

Path following controllers make the output of a control system approach and traverse a pre-specified path with no a priori time-parametrization. This paper implements a path following controller, based on transverse feedback linearization (TFL), which guarantees invariance of the path to be followed. The coordinate and feedback transformation employed allows one to easily design control laws to generate arbitrary desired motions on the path for the closed-loop system. The approach is applied to an uncertain and simplified model of a robot manipulator for which none of the dynamic parameters are measured. The controller is made robust to modelling uncertainties using Lyapunov redesign. The robustified controller is tested on a 4-degree-of-freedom (4-DOF) manipulator with a combination of revolute and linear actuated links. The experimental results show a substantial improvement when using the robust controller for path following versus standard state feedback.