Trajectory Tracking for Uncrewed Surface Vessels with Input Saturation and Dynamic Motion Constraints

Researchers from the Indian Institute of Technology Bombay have published a significant advancement in autonomous maritime control systems with their paper "Trajectory Tracking for Uncrewed Surface Vessels with Input Saturation and Dynamic Motion Constraints." The work addresses critical challenges in controlling uncrewed surface vessels (USVs) where physical limitations, mission requirements, and safety considerations impose strict constraints on vehicle states and inputs. The team developed a novel nonlinear feedback controller that uniquely handles both asymmetric constraints on position and heading alongside symmetric constraints on surge, sway, and yaw rates—a combination that existing controllers struggle to manage effectively.

The technical innovation centers on using log-type Barrier Lyapunov Functions to enforce static and dynamic motion constraints while incorporating a smooth input saturation model to guarantee stability under actuator bounds. This approach prevents the severe performance degradation and poor tracking that typically occurs when actuator limitations are unaccounted for. Rigorous Lyapunov stability analysis demonstrates that the closed-loop system remains stable with all state variables staying within prescribed bounds, provided initial conditions also satisfy those bounds. The 32-page paper includes numerical simulations showing the controller's effectiveness for surface vessels without violating motion or actuator constraints, representing a substantial step toward safer, more reliable autonomous maritime operations in complex environments.