Closed loop identification of a remotely operated flight vehicle

A closed loop identification (CLID) technique termed the two-stage method which was 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 motivation to use CLID for this ROFV is analyzed. The two-stage method is then described in detail. The closed loop identification tests were performed on the ROFV in an experimental tank. During the experiments, proportional and integral (PI) controllers were used for the control of the ROFV and 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. CLID also provides the opportunity for possible on-line auto-tuning of the autopilot of the vehicle to take place.