An energy management ascent guidance algorithm for solid rocket-powered launch vehicles

This paper is concerned with the ascent guidance of solid rocket-powered launch vehicles subject to the terminal velocity, terminal local flight path angle, and terminal angle of attack constraints. To satisfy the three constraints, the energy management ascent guidance is introduced in the two-dimensional pitch plane. The basic idea of the energy management is to control the angle between thrust and velocity to exhaust excess energy. For this purpose, the velocity capability curve is shaped in the local horizontal-vertical velocity frame. Based on the alternate attitude control energy management (AEM) and the general energy management (GEM), the spline energy management (SEM) ascent guidance is proposed, whose velocity capability curve is a spline curve. The coefficients of the spline function are updated every 0.1 seconds, and the local pitch angle command is generated in the closed-loop. A three-stage launch vehicle example is presented. In the SEM simulation result for the 6000 m/s desired velocity, the three constraints are satisfied. The results for multiple desired velocities are presented, and the corresponding terminal constraint errors are analyzed. According to the comparison among AEM, GEM, and SEM, the SEM ascent guidance has a better performance on satisfying the three terminal constraints.