Study On Attitude Control Method Of Heavy Launch Vehicle Based On Adaptive H_∞Control

New generation of heavy launch vehicle has shown many newcharacteristics that significantly different from conventional large launch vehicle.Old methods of attitude control are no longer suitable in this situation. Itbecomes more and more important to find a new approach to solve this problemand obtain good control performance. This paper studied the application ofadaptive H_∞method in the attitude control of heavy launch vehicle.First, the history and current situation of the development of differentcountries’ heavy launch vehicle is surveyed. And their unique characteristics andtheir impacts on attitude control are analyzed. Then the merits and demerits ofdifferent control methods are compared. The vision of using adaptive H_∞controlin the attitude control of heavy launch vehicle is proposed.Secondly, the mathematical models of heavy launch vehicle as the object ofstudy are established in detail. The unique characteristics different fromconventional launch vehicle are discussed. This is the base of follow-up studies.Then, based on the fundamental theory of robust control, the approach tosolve standard robust H_∞control is discussed. And a robust H_∞controller isdesigned using mixed sensitivity method along with μ synthesis. Its responsesto step command and suppression to vibration are analyzed. Then, the simulationof whole ballistic trajectories was performed and the results are analyzed.Then, the basic theory and method of adaptive H_∞control are studied. Andthe approach of using direct parameters projection to solve the problem ofadaptive H_∞control is proposed and discussed thoroughly. Correspondingsimulation is performed and its performance is analyzed.At last, the comparison of two sets of results from different control methodsis studied.