PCH-based L₂ disturbance attenuation and control of autonomous underwater vehicle

In this paper, we present a control design approach for systems in Port Controlled Hamiltonian (PCH) form. The controller design proceeds with different stages exploiting the benefit of having a preserved PCH structure of the system while in closed loop. An extension of L₂ disturbance attenuation control design under the assumption that the exogenous disturbance has a different input gain is also presented. Necessary and sufficient conditions to guaranty stability are stated. Robustness of the controller to parameter uncertainties is studied by assuming uncertain inertia and damping matrices. The design approach is applied to develop a PCH-based path tracking and L ₂ disturbance attenuation controllers for Autonomous Underwater Vehicle (AUV). The simulation results demonstrate the performance of the designed controller in tracking both an horizontal plane path and a vertical plane path that passes through the singularity points. The simulation results indicate that the designed controller is robust enough to uncertainties in inertia and damping matrices. In addition, the extension of L₂ disturbance attenuation controller is able to attenuate the exogenous disturbance effect on AUV path tracking.