Quaternion-based Space Interceptor Attitude Control Design

With development of control science and technology, precision guided weaponshave played a very important role in modern warfare. The guidance and controlsystem design of precision-guided weapons is of great significance. In this paper,the attitude control method of a space interceptor can provide a theoretic foundationfor the precision guided weapon. While the space interceptor is transferred from amidcourse guidance phase into a terminal guidance phase, in order to search for andtrack the target, the interceptor’s attitude probably needs to do a large anglemaneuver and requires a fast tacking. In fact, a target seeker is fixed in theinterceptor’s body and its view angle is adjusted with the interceptor’s attitudemotion.In this paper, we consider an exoatmospheric interceptor with attitude controlengines and design its attitude control system. Considering large angle maneuvers,quaternion space has been used to establish interceptor kinematics equations. Adetailed stability analysis of the resulting closed-loop system is included later.(1) In order to alleviate three-channel coupling, we design the ignition logic forthe attitude control engines. Firstly, we give a configuration of the six attitudecontrol engines. The ignition logic design gives the number of opening and theopening direction of the engine.(2) Considering the nonlinear characteristics of the control system, we usesliding mode variable structure control theory to design the attitude control system.A sliding mode control law is designed and a stability analysis is given. Thensimulation results demonstrated the effectiveness of the designed control law. Spaceinterceptor will inevitably encounter the problems such as model uncertainty andexternal disturbances. Furthermore, an adaptive sliding mode control law isdesigned to alleviate external disturbances and system parameter perturbations.Simulation results show that with the designed adaptive control law the controlsystem has a fast convergence performance, higher robustness and anti-disturbanceperformance.(3) Space interceptor terminal guidance requires rapidity. Finite timeconvergence control law has fast convergence performance and has better robustness,so we utilize finite time convergence theory to design control law for the attitudetracking problem. Moreover, stability analysis is given. In practical applications, theinterceptor needs to actuate a rest-to-rest attitude maneuver. For such a maneuver wedesign a trajectory planning command for the attitude control system. It significantly improves the dynamic property of the attitude control system.