Hovering Control Based on Buoyancy Control Approach for Under-Actuated AUVs

Abstract

A buoyancy control system was presented to realize the powerless descent/ascent motion for an under-actuated AUV like REMUS. The sea water was injected into or drained out of the pressure water tanks to tunes the residual buoyancy of the vehicle, and the buoyancy control was realized. An engineering hovering control law based on buoyancy control approach was proposed to keep the vehicle hovering at the programmed depth. The injection and drainage instructs were worked out only based on depth data and its difference, so the hovering control system need not additional sensors. The simple and reliable hovering control system was applied to a type of huge under-actuated AUV, and the experiment results show that it is feasible.