A Path-following Controller for the Delfimx Autonomous Surface Craft

This paper addresses the problem of guidance and control for an Autonomous Surface Craft (ASC). A path following approach is used for steering the vehicle along a predefined path. The presented solution is based on the definition of an error vector that should be driven to zero by the path-following controller. The proposed methodology for controller design assumes a polytopic Linear Parameter Varying (LPV) representation with piecewise affine dependence on the chosen parameters to accurately describe the error dynamics. The controller synthesis problem is formulated as a discrete-time H2 control problem for LPV systems and solved using Linear Matrix Inequalities (LMIs). In order to increase the path-following performance, a preview controller design technique is used. The resultant nonlinear controller is implemented with the D-Methodology under the scope of gain-scheduling control theory. The final control system is tested in simulation with a full nonlinear model of the DELFIMx catamaran.