Nullspace Adaptive Model-Based Trajectory-Tracking Control for a 6-DOF Underwater Vehicle with Unknown Plant and Actuator Parameters: Theory and Preliminary Simulation Evaluation

We report a novel model-based nullspace adaptive trajectory-tracking control (NS-ATTC) algorithm for fully- actuated 6-degree-of-freedom (DOF) underwater vehicles which estimates unknown plant and actuator model parameters simul- taneously. We provide a stability and convergence analysis with proof of asymptotically stable tracking error convergence, as well as a preliminary simulation study demonstrating 6-DOF trajectory tracking. The NS-ATTC algorithm does not require acceleration instrumentation and provides a stable online pa- rameter estimate, enabling robust model-based autonomy.