Comprehensive System Identification of Ducted Fan UAVs - Cal Poly

The time histories of the actuator command signals were computer generatedusing the frequency sweep code that was described for the flight test frequency sweepmaneuvers. The inputs to this code specify the various parameters of the frequencysweep. These parameters are shown in Table 3.18 for the sweeps used in the tests.Table 3.18 – Frequency Sweep Used for all ActuatorsDescription: Units: Value:Control axis - 1Total duration of sine sweep sec 30Duration of zero signal sec 2Time for signal fade-in sec 3Time for signal fade-out sec 1Signal sample rate Hz 50Minimum frequency of sweep Hz 0.1Maximum frequency of sweep Hz 10.0Filter cut-off frequency Hz -1Amplitude of control input % 10, 50, (80),100Maximum allowable amplitude % 100Noise random flag - -1The signal amplitudes used to drive the actuators during the frequency sweep testswere 10, 50 and 100% of the maximum pulse width amplitude and was generated withcomputer code. In the case of some of the smaller actuators (DS368 & HS512MG), the100% input was brought down to 80% because of clevis interference at higherdeflections. White noise is not required in the command signals for actuator testing. Acut-off filter could be included to ensure that the frequency content of the commandsignal does not go beyond a maximum frequency. This is not required for bench testingand no filter cut-off frequency was set, indicating that the signal should not be filtered.- 62 -