An Optimal Depth Control Technique for Underwater Vehicles

摘要

This report develops a general control technique, based on modern control theory, which maintains an underwater vehicle such as a torpedo at a constant depth. A state variable mathematical model of an underwater vehicle in conjunction with a quadratic cost functional were used to determine the optimal control technique. Included in the model are the effects of a non-neutrally buoyant vehicle with different centers of gravity and buoyancy, and the effects of ocean currents when the vehicle is operating near the surface in high sea state conditions. Three of the state variables are directly observable, but the fourth state must be estimated using a reduced-order Luenberger observer. Once all the states become available, the optimal control problem is formulated as an output regulator with a constant reference input vector. The results of torpedo simulations illustrating the feasibility of the closed-loop control scheme are presented and discussed. (Author)