Adaptive backstepping sliding-mode controller with bound estimation for underwater robotics vehicles

Station keeping and trajectory tracking are necessary capabilities for underwater robotics vehicles (URVs), allowing them to maintain a reference position and orientation, or follow a reference path. Disturbances to the system are caused by wave-induced hydrodynamic forces acting on the vehicle, and sudden changes in parameters and operating variables. This can lead to degraded performance, accuracy, and stability. An adaptive backstepping sliding-mode controller with bound estimation is proposed to handle these parametric uncertainties and external disturbances. The validity of the algorithm is demonstrated via numerical simulation.