At-sea testing of an unmanned underwater vehicle flight control system

The design and testing of an advanced unmanned underwater vehicle (UUV) flight control system (FCS) using a nonlinear control technique known as sliding mode control (SMC) are described. SMC provides a theoretical framework for the design of controllers that are robust to uncertain or unmodeled dynamics, disturbances or bandwidth restrictions, and are able to account for varying payloads. The FCS was tested aboard MUST, a UUV testbed built to test and evaluate critical technologies such as this. The FCS has demonstrated significant advantages for SMC in comparison to traditional linear control. The SMC controller has demonstrated robust stability to large uncertainty in the controller model and payload variation. Inwater testing was performed to both check the control design and critique the nonlinear hydrodynamic model. Testing demonstrated that SMC is a viable method of meeting aggressive UUV control requirements