Comprehensive System Identification of Ducted Fan UAVs - Cal Poly

Table 3.23 – Actuator Nonlinear Characteristic SummarySERVOVOLTSPOSITION(deg)RATE(deg/sec)MIN MAXDS8417JR94091DS368HS12MGCS10BB5 -437.2 437.1+/- 37.45716-524.5 534.95 -402.3 422.0+/- 38.53156-435.2 467.85 -219.8 220.5+/- 40.57446-264.6 265.75 -328.1 317.6+/- 41.43946-376.5 404.75 -474.7 442.1+/- 41.79926-567.2 536.4It is apparent from Table 3.23 that there are different rates for different directionson the actuators. The test stand was mounted horizontally, so gravity is was not the cause.The DS368 proved to have the best symmetry in its rates where the smaller and lighterCS-10BB showed to be more asymmetric. Many factors can contribute to thisasymmetry. Because there is a motor with an armature inside, the brushes on the motormay be conditioned to one direction.It should be noted that the square wave used for the first test was repeated at 50%maximum deflection. There were not enough data points at which the actuator rate wassaturated to fit a valid linear curve at this deflection. For this reason, all results used a full100% deflection command in the square wave to ensure saturation of the rate.The sampling rate of 50 Hz and nature of the square wave did not reveal anyidentifiable stiction or hysteresis. Although they undoubtedly exist, the methodsemployed here did not reveal any substantial findings. More accurate potentiometers,- 74 -