The analysis of contradiction and solution for stability of launch vehicle

The control parameter can not be traded off against the upper limit, the lower limit and normal states in the design of launch vehicle attitude control system. That is, the attitude control system can meet the demand in the states of upper limit and lower limit but can´t in the normal state and vice versa. The cause of the problem is presented in this paper that the parameter deviation of the launch vehicle is large and the frequency of rigid body in upper limit state is close to the first-order elastic vibration frequency. Therefore, the contradiction exists in the motion stability performance of the rigid body, sloshing and elastic vibration. Then the detailed solution to deal with this phenomenon is described and the feasibility of each solution is analyzed as well. With the design of the launch vehicle´s entire body and the control subsystem, the problem proposed in this paper provides an important reference for improving the control system performance of the launch vehicle.