Closed loop identification of a remotely operated flight vehicle

A closed loop identification (CLID) technique termed the two-stage method used to identify the dynamics of a remotely operated flight vehicle (ROFV) is presented in this paper. The vehicle operates underwater and is known as Subzero III. The closed loop identification tests were performed on the ROFV in an experimental tank. During the experiments, proportional, integral and derivative (PID) controllers were used for the control of the ROFV and pseudo-random binary sequence (PRBS) signals were used to excite the system. The advantage of the CLID approach is that the controlled variable in the system will not drift significantly from the nominal operating point whilst undergoing the identification procedure. CLID also provides the opportunity for possible on-line auto-tuning of the autopilot of the vehicle to take place.