Comprehensive System Identification of Ducted Fan UAVs - Cal Poly

It can be seen that the Aerovironment Proposal prototype OAV was successfullymodeled with a state-space model. The identified model shows good agreement for boththe time and frequency responses. The identified system showed an unstable periodicmode in the pitch and roll responses. Time delays were determined for all three channels.The ratio of the lateral to longitudinal moment terms Lv and Mu reflect the ratio of theinertias I yy to I xx . All of the modes dictated by the hovering cubic forms were identified,but because of a lack of acceleration data the speed damping force derivatives could notbe accurately identified. The identified transfer function modes closely match the modesof the identified state space dynamic model.After flight test was completed for the purposes of identification, the OAV designwas further analyzed in the wind tunnel. The vehicle was put into the Virginia TechStability Wind Tunnel by Techsburg, Inc. without the payload nacelles. A photograph ofthe setup is shown as Figure 3.7.Figure 3.7 - Techsburg Wind Tunnel Setup for OAV- 33 -