Adaptive integral backstepping surge motion tracking control for an underwater vehicle

The nonlinear tracking and controlling problem of surge motion for underwater vehicle was proposed. Taking aim at generally existential uncertainty factors, such as unknown ocean current, unknown parameters in dynamic model and external constant disturbance, a novel adaptive nonlinear controller with integrator based on backstepping was designed by using adaptive mechanism to overcome the uncertain factors and adding integral item in feedback to improve the robust against the unmodeled dynamic character. The designed controller can make underwater vehicle track the instruction of the reference position globally and asymptotically. The functions of adaptive mechanism and integral item were analyzed by simulation method at different conditions. The simulated results show that the tracking system of closed loop has global and asymptotical stability.