CASCADED ADAPTIVE-CONTROL OF OCEAN VEHICLES WITH SIGNIFICANT ACTUATORDYNAMICS

This paper presents a cascade adaptive control scheme for marine vehic les where the non-linear equations of motion include a model of the ac tuator dynamics. The adaptive controller does not require the paramete rs of the vehicle dynamics and the actuator time constants to be known a priori. Both the velocity and position tracking errors are shown to converge to zero by applying Barbalat's lemma. Global asymptotic stab ility is proven for the velocity scheme while the position/attitude co ntroller is only proven to be convergent. Furthermore, all parameter e stimates are shown to be bounded. Computer simulations of an ROV speed control system and an autopilot for automatic ship steering are used to illustrate the design methodology.