倾转四旋翼飞行器直升机模式操稳特性分析

Analysis on controllability and stability of quad-tilt-rotor aircraft in helicopter mode

针对倾转旋翼飞行器直升机模式下的操纵性和稳定性进行了研究分析,为后续控制系统的设计提供一定的理论依据。在考虑旋翼-机翼干扰的情况下建立了倾转四旋翼飞行器飞行动力学模型并结合试验数据进行验证。提出了一种适用于直升机模式下的操纵策略并对飞行器进行了配平计算。以该操纵策略为基础,计算了相应的操纵功效和操纵耦合,并分析了主要稳定性导数和特征根的变化。结果表明:航向操纵功效相较于其他通道较小;垂向输入引起的纵向力和俯仰力矩的大小随速度的增加不断增大;横向输入下引起的偏航力矩随速度增大而增大;速度稳定性随速度的增加而变得不稳定;除螺旋模态外,其他模态随速度的增加稳定性增强。

The controllability and stability of quad-tilt-rotor aircraft in helicopter mode are modeled and analyzed,which will provide a theoretical guidance for the subsequent control system design.First of all,the flight dynamics model is established considering rotor-wing interference and verified with relevant experiments.Then,a control strategy for helicopter mode is proposed with trim characteristic analysis.Finally,corresponding control efficiency and cross coupling are calculated and analyzed along with characteristics of the stability derivatives and eigenvalues.The results show that the value of heading control efficiency is much smaller than that of other channels.The longitudinal force and pitch moment caused by vertical control input increase with the increase of the velocity.Yawing moment caused by lateral control input shows similar variations.The velocity stability becomes worse with the increase of the velocity.The stability of all other modes is augmented as velocity increases except the spiral mode.