Control Optimization of Small-Scale Thrust-Vectoring Vertical/Short Take-Off and Landing Vehicles in Transition Phase

Abstract

The core of the short takeoff and landing problem in thrust-vectoring V/STOL vehicles is the tilt angle control of the thrust vector nozzles. This work resolves it by figuring out the optimal tilt angle time history with optimization methods. Since the optimization process is constrained by the transition corridor of the vehicle and the mission requirements, the transition corridor is firstly established by the AES theory with the longitudinal model of the V/STOL protype, where the jet-induced effect of the 3BSD nozzle and the lift fan are especially considered. In addition, the control redundancy caused by the multiple physical control actuators is addressed by a suitable control allocation and flight-mode-based control strategy, which ensures a smooth conversion. By establishing appropriate mission references and optimization constraints, the optimal control strategy and the corresponding transition process are obtained, based on the direct inverse and SQP algorithms.