Research of multi-restriction energy management of solid rocket
In order to implement depleted shutdown and improve guidance precision in launching process of a solid rocket, the trajectory energy management approaches should be studied. First, the rocket inserting trajectory problem is described. The real velocity and the required velocity calculating model are given. Second, under the multi-restriction conditions, the spline energy management model is given. Third, required velocity is parameterized by a B-spline function. Take required velocity function to initial conditions, terminal conditions and process conditions, the energy management problem can be solved by an optimum approach. The optimum trajectory can be followed up with trajectory tracking control approach, and make the velocity vector track the required velocity vector. The simulation results show that the terminal and process restrictions are met.
Instantaneous Impact Point Guidance with Coast Arcs for Solid Rockets
This paper proposed an analytical iterative guidance method with the desired instantaneous impact point constraint for solid rockets in “burn-coast-burn” trajectory mode. Solid rocket motors expect to remove the thrust termination mechanism to increase the structural strength and launch reliability, which induce new difficulties and challenges to the guidance problems. In terms of the “Hohmann transfer” principle, a pointing algorithm is deduced in depth to establish the theoretical relations among the ignition time, the required velocity vector, and the orbital element constraints and provides the analytical expression of the ignition time. Then, an analytic solution of the required velocity vector is derived based on orthogonal and nonorthogonal velocity vectors, and a complete guidance logic is used to solve the target orbit elements satisfying the desired instantaneous impact point. Finally, the application of the developed theoretical algorithm in this paper is conducted using a two-stage solid rocket. The proposed guidance method is verified by Monte Carlo simulations, and the testing results demonstrate the adaptability, strong robustness, and excellent performance for different desired impact point missions.
PASSIVE AND LOW-ENERGY RESEARCH AND PRACTICES-DEHUMIDIFICATION
Methods of achieving acceptable indoor conditions in overheated, temperate, and underheated humid climates are discussed and compared. Desiccants and desiccant systems utilizing solid and liquid sorbents and various low-energy mechanical systems are described and evaluated.