A unified adaptive force control of underwater vehicle-manipulator systems (UVMS)

A unified adaptive force control approach for underwater vehicle manipulator systems (UVMS) is proposed in this paper. First, a direct adaptive impedance control scheme is introduced. This controller is further incorporated into the unified force control strategy, which combines adaptive impedance control with hybrid position/force control by means of fuzzy switching to perform autonomous underwater manipulation. This approach combines the advantages of impedance control with hybrid control without knowing the accurate dynamic model of the system and has the potential to be effective in underwater environment. Extensive computer simulations are performed to verify the efficacy of the proposed control scheme based on a UVMS model with 6 DOF autonomous underwater vehicle and a 3 DOF robot arm that is mounted on the vehicle.