Tiltrotor aircraft possesses redundant actuators in take-off phase and its flight control is more complicated than ordinary aircraft because the structural and dynamic characteristics keep changing due to tilting rotors. One of the fundamental bases for flight control is trim, which provides steady flight states under various conditions and then constructs the reference trajectory. Tiltrotor aircraft trim models are described by multivariate nonlinear equations whose initial values are difficult to determine and bad initials could lead to incorrect solution for flight control. Therefore, an innovative trim method is proposed to solve this issue. Firstly, genetic algorithm (GA), which possesses strong capability in searching global optimum, is adopted to identify a coarse solution. Secondly, the coarse solution is further refined by the Levenberg-Marquardt (LM) method for precise local optimum. The innovative trim method combines the advantages of these two algorithms and is applied to a tiltrotor aircraft’s flight control in the transition process of incline take-off. The limitation of trajectory is discussed, and tilt corridor is constructed. Finally, the incline take-off simulations are conducted and the effectiveness of the proposed trim method is verified through good match with the designed reference trajectory.

中文翻译：

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基于遗传算法的旋翼​​飞机起降架创新修剪方法研究

倾转旋翼飞机在起飞阶段具有冗余执行器，并且其飞行控制比普通飞机更为复杂，因为结构和动力特性会因旋翼倾斜而不断变化。飞行控制的基本基础之一是修剪，它可以在各种条件下提供稳定的飞行状态，然后构造参考轨迹。用多元非线性方程式描述倾转旋翼飞机的配平模型，这些方程的初始值难以确定，不良的初始名可能会导致飞行控制的解决方案不正确。因此，提出了一种创新的修整方法来解决这个问题。首先，采用具有较强全局寻优能力的遗传算法（GA）来识别粗略解。其次，Levenberg-Marquardt（LM）方法进一步改进了粗解，以实现精确的局部最优。创新的修剪方法结合了这两种算法的优点，并在倾斜起飞过渡过程中应用于倾转旋翼飞机的飞行控制中。讨论了轨迹的局限性，并构造了倾斜走廊。最后，进行了倾斜起飞模拟，并通过与设计参考轨迹的良好匹配来验证了所提出的修整方法的有效性。