Handling Qualitiy and PIO Analyses with State Space Predictor considering Time Delay of UAV

Abstract

Modern digital flight control systems have the time delay due to various sources including the data-link transport time delay between a vehicle and a ground pilot. Time delay not only degrades HQ (Handling Quality) but can also induce PIO (Pilot-Induced Oscillation), which may cause mission failure or critical accident during performing complicated missions such as precision approach, air refuel, and combat maneuver. This study analyzes HQ and PIO considering time delay of the UAS (Unmanned Aircraft Systems). Predictive pitch compensation is applied to improve the HQ degraded by the time delay. Even though the autonomous level of UAS becomes higher, a ground pilot is still required for safety and mission control. Therefore, UAS should be able to satisfy military requirements of HQ. In this study, the state space predictor is applied to the UAS to compensate for the effect of time delay. Neal-Smith, Bandwidth, and Ralph-smith criteria are used to evaluate the HQ and PIO. Numerical simulation is performed to demonstrate the performance of the time-delay compensation

the state space predictor improves the HQ of the UAS and reduces the PIO tendency compared to the lead compensator.