Adaptive integral backstepping control for vertical pitch motion of underwater gliders

The pitch motion tracking and controlling problems of buoyancy-driven underwater glider were studied for the uncertainty of its dynamic model and parameters. The relationship between pitch angle and moving mass displacement was determined, a adaptive nonlinear tracking controller based on Lyapunov theory and backstepping was designed, the uncertainty of model parameters was solved using an adaptive mechanism, and the integral items were synthesized to reduce steady error. And then The backstepping method was used to design a moving mass servo controller by taking the moving mass displacement as a reference input. The controller can enable the underwater glider to tack a pitch angle reference command globally and asymptotically. The stability and error convergence of the system were proved based on Lyapunov theory. Simulation results show that the method can verify the global asymptotical stability of the controller and its adaptability to the uncertain parameters of model.