Optimal gliding guidance for a guided bomb unit in the vertical plane is studied based on nonlinear dynamics and kinematics.The guidance law is designed under minimum energy loss index.To avoid the complexity in solvi...Optimal gliding guidance for a guided bomb unit in the vertical plane is studied based on nonlinear dynamics and kinematics.The guidance law is designed under minimum energy loss index.To avoid the complexity in solving two-point-boundary-value problems,the steady-state solutions of the adjoint states in regular equations are suggested to be used.With these considerations,a quasi-closed,optimal gliding guidance law is obtained.The guidance law is described by the angle of attack in a simple nonlinear equation.An iterative computation method can be easily used to get the optimal angle of attack.The further simplified direct computation algorithm for the optimal angle of attack is also given.The guidance properties are compared with those of maximum lift-to-drag angle of attack control.The simulation results demonstrate that the quasi-closed,optimal gliding guidance law can improve the gliding phase terminal performance with significant increase in the altitude and much little decrease in the speed.展开更多
A spacecraft re-entry attitude control method using sliding mode control (SMC) theory is developed. The controller utilizes double-loop SMC scheme and provides the robust, de-coupled tracking of both the angular veloc...A spacecraft re-entry attitude control method using sliding mode control (SMC) theory is developed. The controller utilizes double-loop SMC scheme and provides the robust, de-coupled tracking of both the angular velocity and the shuttle orientation angles. In accordance with the hybrid-controlling characteristics of the aerodynamic surfaces and reaction control system of the spacecraft, the control torque commands are allocated into the actuators such as the aerodynamic surfaces and reaction control system by using the optimal control selection allocation algorithm. The simulation of the spacecraft re-entry attitude controlling demonstrates the robust, de-coupled tracking performance of the proposed method and its validity.展开更多
文摘Optimal gliding guidance for a guided bomb unit in the vertical plane is studied based on nonlinear dynamics and kinematics.The guidance law is designed under minimum energy loss index.To avoid the complexity in solving two-point-boundary-value problems,the steady-state solutions of the adjoint states in regular equations are suggested to be used.With these considerations,a quasi-closed,optimal gliding guidance law is obtained.The guidance law is described by the angle of attack in a simple nonlinear equation.An iterative computation method can be easily used to get the optimal angle of attack.The further simplified direct computation algorithm for the optimal angle of attack is also given.The guidance properties are compared with those of maximum lift-to-drag angle of attack control.The simulation results demonstrate that the quasi-closed,optimal gliding guidance law can improve the gliding phase terminal performance with significant increase in the altitude and much little decrease in the speed.
文摘A spacecraft re-entry attitude control method using sliding mode control (SMC) theory is developed. The controller utilizes double-loop SMC scheme and provides the robust, de-coupled tracking of both the angular velocity and the shuttle orientation angles. In accordance with the hybrid-controlling characteristics of the aerodynamic surfaces and reaction control system of the spacecraft, the control torque commands are allocated into the actuators such as the aerodynamic surfaces and reaction control system by using the optimal control selection allocation algorithm. The simulation of the spacecraft re-entry attitude controlling demonstrates the robust, de-coupled tracking performance of the proposed method and its validity.
