As the authors reported, the optimal steering for the ascending vehicles like a spaceplane, which has the air breathing engines and the large wings, shows oscillatory behavior in contrast to a conventional law for rockets. In the case of more complicated and proper equations of motion, it is difficult to solve two-point boundary value problem on the on-board computer. This paper firstly shows the analytical description of this periodic behavior emerged from the optimal steering. It concludes that a conventional linear tangent law is applicable only to non-lift vehicles. Then the numerical analysis of the optimal control law with the state constraint is achieved by DCNLP method. Next, the paper proposes two kind of the new guidance schemes to compensate the flight path error aroused by the disturbance. The first one is the way to approximate the optimal steering using the trigonometric function form and the second one is the newly proposed guidance scheme in this paper using the approximate expression of the dynamics derived from the result of the optimal steering. Adopting this method, the guidance scheme with only a few parameters is easily obtained by substituting the approximate expression of the dynamics into the equation of motion and can keep maximizing the terminal horizontal speed by the consumption of a few percentage fuel margins.
|Number of pages||15|
|Journal||Advances in the Astronautical Sciences|
|Publication status||Published - 2005|
ASJC Scopus subject areas
- Aerospace Engineering
- Space and Planetary Science