Reserch On Direct Force/Aerodynamic Compound Control Method Of Low Speed Spinning Missile

Response time constant of the missile is one of the key parameters whichdetermine the miss distance in the antimissile interception. Generally speaking, thefaster the interceptor’s maneuver response, the less miss distance can be achieved atthe interception point in regard to the same guidance law. As for the traditionalaerodynamic missile, the available load and the available control force and momentof the missile will decrease enormously due to the lower air density when intercepta target at medium-altitude or high altitude, and as a result, the response timeconstant will increase. The control force and moment of the missile can beincreased at the same time. And with the result that the response time constant ofthe missile can be decreased and the interception precision can be improved. So,this method has been widely used in the new generation air defense missile.As for the missile studied in this thesis, the lateral thrust is produced byAttitude Control Section(ACS) which contains an array of radially installedAttitude Control Motors(ACMs) with solid propellant grain that thrustperpendicular to the centerline of the missile. The ACS is located near the nose ofthe missile to provide pitch and yaw control moment. The lateral thrust is a series ofdiscrete impulse because of the solid propellant. In addition, ACMs are spacedevenly around the centerline of the missile. So the missile must roll at somevelocity to make use of all of the motors. And this make it more difficult to thedesign of autopilot.The dynamic model of the missile with six degree of freedom and the modelsof the forces act on the missile are made at first in this thesis. It become hybridsystem due to the impulsive characteristic of the lateral thrust and the modelmethod for hybrid system must be used. For the hybrid system, the thrust is suitedto be modeled as finite state machine. On this basis, the method based on thedecompose of the command is discussed.When designing the compound controller ACMs and the aerodynamic controlsystem can be treated as the same in a sense of generator of control moment. Thecontrol moment command to steer the missile can be gained through dynamicinverse method. And then the command is allocated to ACMs’ controller and the command allocated to ACMs. Finally, the command of aerodynamic control systemis determined according to the fired motors.