基于参数化气动模型的机载导弹分离轨迹优化

Trajectory optimization for airborne missile separation based on parametric aerodynamic model

论述了机载导弹分离过程中导弹气动参数化建模的方法。该方法将导弹在分离过程中的气动力视为导弹在无载机干扰的自由流场中的气动力与载机对导弹干扰气动力的叠加,建立了变系数多项式模型来描述干扰气动力的变化规律,采用多元正交函数最小二乘法和混合优化算法求解出模型中的未知参数。通过与CFD计算数据和CTS风洞试验数据的对比,本文方法得到的模型预测值与实验值相吻合,验证了参数化建模及计算方法的可行性。在上述参数化气动模型基础上,为保证分离过程的安全性并且使分离终端时刻姿态稳定,构建了纵向平面内的分离轨迹优化问题,采用高斯伪谱法将其转化为非线性规划问题并通过序列二次规划算法求解。计算结果表明,优化得到的分离轨迹可以保证分离过程的安全平稳。

A parametric missile aerodynamic coefficient modeling method is discussed for separation from aircraft.In this method,the total aerodynamic coefficients of the missile during the separation process are treated as the superposition of the free flow part and the disturbance part due to the non-uniform flow field influenced by the aircraft.Variable coefficient polynomial model is established to describe the disturbance part at different distances from the aircraft.For a given distance,the unknown parameters in the polynomial model are computed by using a multivariate orthogonal function-lease square method;then a hybrid optimization algorithm is adopted to establish the relation between these parameters and the distances.By comparing the data resulting from the presented method with the computational fluid dynamics(CFD)simulation data and the captive trajectory simulation(CTS)wind tunnel data,it is shown that the presented aerodynamic modeling method is efficient and accurate.To improve the safety level of the separation,a separation trajectory optimization problem in the longitudinal plane is established based on the above-obtained parametric aerodynamic model.The trajectory optimization problem is transformed into a nonlinear programming problem by using Gauss pseudospectral method and then solved by using sequential quadratic programming(SQP)algorithm.The results show that the optimized separation trajectory is able to ensure a safe and smooth separation process.