基于参数化气动模型的机载导弹分离轨迹优化

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.