Research On Large Angle Attitude Maneuver And Attitude Stabilization For Agile Satellite

The high performance and flexibility are emphasized when developing the control system of the agile satellites.To address such an issue,the following topics are conducted: 1.Near-optimal large angle attitude maneuver.2.Control Moment Gyros(CMG)based attitude maneuver and stabilization.3.On-line identification of the inertial properties of the agile satellite.4.Attitude stabilization against the strong disturbance caused by the orbital maneuver engine.5.Attitude maneuver control based on command filter.As a solution of the rapid large angle attitude maneuver,a global linearization based near optimal controller is designed.To apply the linear system theorem based optimization,the tensor product(TP)transformation and the LMI techniques are introduced,and a simplified 2nd order model is specifically derived from the attitude control system,which is raised for the decreasing of the design conservatism and real-time computation.As a result,the final control law is provided in a combination form of the near optimal control and the adaptive attitude tracking control,which is characterized by its rapid response,simple computation,and the adaptivity against the model uncertainty.Furthermore,the specific CMG actuator is concerned.To address the CMG based attitude control issue,a novel steering law is proposed,characterized by the approximate dynamics used in the control allocation to replace the statically calculated traditional allocations,which may improve the executed accuracy of the CMG driver.The analysis is conducted according to the steering law performance and singularity robustness.As a result,a new singularity avoidance strategy is proposed.Besides,a CMG based attitude tracking control law is investigated,which is characterized by the comprehensive consideration of the attitude control and singularity avoidance.When the singularity occurs,the proposed attitude control law can maintain the attitude stabilization as well as help the CMG apply the singularity escape.Otherwise,the used of the CMG momentum is free from any restriction.To decrease the impact of the model uncertainty when a rapid attitude maneuver is applied,an on-line inertial parameter identification issue is concerned.As an improvement,the new algorithm generally considers the effect of the momentum actuators and solves the multi-objects identification issue.Meanwhile,the attitude stabilization problem is investigated with the consideration of the strong influence of the orbital engine disturbance.As a preparation,an adjustment strategy of the thrust vector of the engine is proposed,in which a novel resolving method is utilized to obtain the effective component of the mass center in real time.Such strategy is practicable to the agile satellite even with a time-varying mass center caused by the structural deformation,attached flexibility,and the liquid sloshing.Besides,in order to specifically suppress the disturbance,a hybrid control strategy based on the CMG and the thrusters is proposed,which not only provides a better precision than the conventional thruster or CMG based control,but also guarantees the CMG against the momentum saturation issues.With the specific concerns of the rapid attitude control issues of the agile satellite,a Model Reference Command Filter(MRCF)technique is proposed,which may contribute to both of the rapidity,robustness,and anti-windup properties,and simultaneously simplify the designing process.As a practice,a cascade type nonlinear controller is accordingly designed to control a specific class of cascade systems,and further used in constructing the feedback control based MRCF application.As a result,a cascade control strategy based attitude control system is designed,which can guarantees the saturation restriction against the cascade states and control,and performs a rapid closed-loop response without the off-line optimization.At last,an integrated simulation with both of the universal runtime platform environment,the resource management mechanism,and the aerospace oriented model software framework is proposed in the paper.The design of the simulation system is implemented based on the high performance hardware and software platform,and is consequently used in performing the realistic task based verifications of several proposed control laws of the thesis.