倾转旋翼机动态倾转过渡过程的操纵策略优化

Control strategy optimization of dynamic conversion procedure of tilt-rotor aircraft

利用最优控制方法研究倾转旋翼机的最优动态倾转过渡过程,并得到最优操纵策略,使得由时间、姿态角变化以及驾驶员工作负荷等组成的性能指标达到最小。首先,在基本纵向刚体飞行动力学模型的基础上引入混合操纵方程,并使用杆量位移的一阶导数作为控制量,形成适用于计算倾转旋翼机动态倾转过渡过程的飞行动力学模型,从而能在动态倾转操纵策略优化过程中考虑到操纵系统特性对操纵量变化速度的限制,以及避免操纵量在优化过程中出现跳跃不连续。然后,将倾转旋翼机的最优动态倾转过渡过程转化为非线性动态最优控制问题,建立合理的性能指标,并采用直接转换法和序列二次规划算法进行求解。最后,以XV-15倾转旋翼机为样机,分别计算正向和逆向最优动态倾转过渡过程,并与驾驶员飞行仿真数据进行对比。结果表明:飞行状态量的时间历程与文献吻合地较好,且俯仰姿态角和杆量位移变化更加柔和。最优控制方法可以用于研究倾转旋翼机的最优动态倾转过渡过程。

The optimal control theory is applied to investigate the optimal dynamic conversion procedure of tilt-rotor aircraft to minimize the performance index described as the weighted sum of time consumed,variation of flight attitude and pilot workload.A flight dynamic model is built to extend the basic longitudinal rigid-body flight dynamic model with mixed control equations.The rates of pilot control sticks are set as the control variables to avoid jump discontinuities of controls in control strategy optimization.The dynamic conversion procedure is transformed into a dynamic optimal control problem with an appropriate performance index.The optimal control problem is formulated into a nonlinear programming problem and solved by a sparse sequential quadratic programming.XV-15tilt-rotor aircraft is taken as the sample for the demonstration of conversion and reconversion.The results indicate that the variations of state variables are in good agreement with the data from flight simulation,and the variations of pitch attitude and pilot controls are relatively more gentle.The optimal control theory can be applied to investigate the optimal dynamic conversion procedure.