Optimal Robust Control of an Unmanned Underwater Vehicle Independent of Hydrodynamic Forces Using Firefly Optimization Algorithm

In this study, the nonlinear dynamic equation of unmanned underwater vehicle (UUV) with new propulsion arrangement is derived using robotics and dynamics techniques. Then, an optimal robust controller is designed to control the UUV. The uncertainty of extracted model is a problem dealing with model based controllers usually. The extracted hydrodynamic model of the UUV, which is included some errors and assumption, obtaining through some experimental study and computational fluid dynamic (CFD) software. In this research, the UUV s system is modeled regardless of hydrodynamic forces, then, nonlinear system error imitating a preset linear system error behavior, using feedback linearization method. By assuming hydrodynamic forces in an uncertain interval, feedback linearization controller gains are obtained using Firefly optimization algorithm in such a way that desired conditions are satisfied and a robustness of controller is supplied against hydrodynamic forces effect. Finally, by applying various hydrodynamic forces to the UUV system, the performances of designed controller are represented in simulation results.