Effect of waves and current on motion control of underwater gliders

This paper investigates the effect of waves and ocean currents on the dynamics and motion control of underwater gliders. Waves and ocean currents affect a glider's performance by deviating from its desired path and reducing its operational range. The influence of wave disturbances and ocean currents is estimated using mathematical models for sea state, potential flow theory and linear wave theory. The effect of waves at various heights, frequency and period were studied for a nonlinear dynamic model of the underwater glider. The wave characteristics have been simulated to investigate their effect on the depth, velocity and range of the glider. Subsequently, a line of sight algorithm in conjunction with controller was designed for the newly designed prototype of the Universiti Teknologi PETRONAS autonomous underwater glider to investigate the action of internal actuators in performing a saw tooth trajectory in the presence of waves and current disturbances. The glider was slightly perturbed due to the shallow and deep waves, with the more pronounced effect at increasing wave amplitude. However, the range of the vehicle remains relatively unchanged.