Development of a Morphing AUV for Path and Station Keeping in Complex Current Environments

A general formulation for a morphing AUV operating in complex current environment was developed. Two sets of morphing X-canard rudders at the stern and aft of the vehicle were used. Morphing is introduced with Shape Memory Alloy (SMA) to deflect the rudders' trailing edge and therefore enhance lift and reduce drag. A numerical simulation using Simulink was performed for the AUV motion in a horizontal plane. A proportional-integral-derivative (PID) controller delivers forces and moment to maintain the vehicle on course or remain stationary while operating in moving current in a surf zone. A force allocation function allows the rudders to move independently to overcome the vehicle's underactuation. With morphing rudders and fixed thruster, it was shown that path keeping and station keeping could be achieved for a given unsteady current.