Control and Navigation of Autonomous Underwater Vehicles

This thesis presents an efficient attitude control design, which combined L1 adaptive control and backstepping control together. Based on this attitude controller, a design of autopilot is also proposed for the fixed-point navigation scenario. An advanced design of Autonomous Underwater Vehicles (AUV) driven by four water pumps is reviewed first. With different power distribution of these pumps, the AUV could provide the capability for propulsion and maneuver to achieve the desired motion. Based on this prototype, the modeling analysis, including rigid body dynamics, actuator dynamics, force and moment generation, is presented. In view of well study of the nonlinear AUV dynamic model, the design of the attitude control is proposed. In Euler-angle representation, kinematics and dynamics of the attitude are in the strict feedback form. The uncertainties only in dynamics are considered, which come from modeling uncertainties, actuator dynamics and external disturbance. By using backstepping as the baseline controller and bringing adaption for dynamics problem, this control strategy for attitude is developed. For uncontrollable channel, the self stability is also analyzed. Simulations are used to demonstrate the performance of this controller in comparison to a conventional backstepping controller in this thesis. Further, based on the fixed-point navigation, an autopilot design for this AUV is also presented. Conclusions and future work for AUV topics were presented at the end of this thesis