OFFSET-FREE TRACKING CONTROL FOR A MARINE AUTONOMOUS SURFACE SHIP

The importance of autonomous surface vessels is increasing day by day because of more and more missions and safety concerns. An offset-free control system is essential for a Marine Autonomous Surface Ship (MASS) to follow its desired trajectory. The position, yaw angles, and desired velocity are the main parameters that need to be controlled precisely to keep the ship on course in the presence of environmental disturbances. In this current research, we propose an advanced control system for surface vessels that is versatile and can achieve a broad range of operational objectives while obeying safety constraints. A Nonlinear Model Predictive Control (NMPC) is the heart of our proposed system. The NMPC solves a quadratic optimization problem and dynamically calculates the control actions considering the safety constraints of the vessel. The conventional way of calculating the yaw angle and the line-of-sight guidance method for the same are compared when the trajectory tracking results are simulated in the presence of disturbances to test the performance of the controller. Such controllers are expected to provide substantial benefits by providing less operational cost, enhanced safety, and efficiency.