为优化设计多约束条件下高超声速再入轨迹,研究了一种基于微分平坦理论的数值方法。引入独立伪控制输入及其始终为零的附加约束,扩展系统的微分平坦属性,将初始优化问题转换到平坦输出空间中,避免积分运算的同时降低了设计维度;采用样条插值参数化平坦输出,将平坦输出优化问题转化为非线性规划问题求解。仿真表明:该方法能够较快的设计出满足约束的再入轨迹,具有一定的工程参考价值。

Concentrating on trajectory optimization problem of hypersonic reentry under multi-constraints, a differential flatness based numerical approach was studied. By introducing the concept of pseudo input and its additional zero value constraint, flatness of the reentry model was extended. Thus, the original optimization problem was mapped into flat output space, avoiding integral computation and reducing design dimension. The flat output optimization problem was ultimately transformed into a nonlinear programming problem by parameterizing the flat outputs with cubic spline functions. Numerical simulations indicate that the approach presented can generate trajectories that observe multi-constraints rapidly, and have some illumination for engineering application.