To get better tracking performance of attitude command over the reentry phase of vehicles, the use of state-dependent Riccati equation (SDRE) method for attitude controller design of reentry vehicles was investigated....To get better tracking performance of attitude command over the reentry phase of vehicles, the use of state-dependent Riccati equation (SDRE) method for attitude controller design of reentry vehicles was investigated. Guidance commands are generated based on optimal guidance law. SDRE control method employs factorization of the nonlinear dynamics into a state vector and state dependent matrix valued function. State-dependent coefficients are derived based on reentry motion equations in pitch and yaw channels. Unlike constant weighting matrix Q, elements of Q are set as the functions of state error so as to get satisfactory feedback and eliminate state error rapidly, then formulation of SDRE is realized. Riccati equation is solved real-timely with Schur algorithm. State feedback control law u(x) is derived with linear quadratic regulator (LQR) method. Simulation results show that SDRE controller steadily tracks attitude command, and impact point error of reentry vehicle is acceptable. Compared with PID controller, tracking performance of attitude command using SDRE controller is better with smaller control surface deflection. The attitude tracking error with SDRE controller is within 5°, and the control deflection is within 30°.展开更多
This paper makes researches on multiple independently reentry vehicle （MIRV） ballistic missile interception. It breaks through traditional intercepting methods of missiles and combines comba- ting time characteristi...This paper makes researches on multiple independently reentry vehicle （MIRV） ballistic missile interception. It breaks through traditional intercepting methods of missiles and combines comba- ting time characteristics of MIRV missiles with the principle of computer process schedule. In this paper, a way of firstly intercepting the target missile with higher threaten grade is proposed. This method determines the threaten grade of the attacking target according to computer process schedu- ling algorithms, then appljed a proportional navigation guidance law to intercept target missiles in priority so that it achieves the effect of less damage. The simulation results indicate that it is effective to use the proportional navigation guidance law based on the process scheduling to intercept target missile. It possesses referential value in modem weapon combats.展开更多
The concept of using an externally applied magnetic field to add the drag force of a hypersonic reentry vehicle during the blackout was proposed by Bush in 1958.The increased drag force is caused by electromagnetic fo...The concept of using an externally applied magnetic field to add the drag force of a hypersonic reentry vehicle during the blackout was proposed by Bush in 1958.The increased drag force is caused by electromagnetic force that is introduced by interaction between the applied magnetic field and the weakly ionized airflow around the reentry vehicle.We investigated the influences of magnetic field intensities on the drag forces of a reentry vehicle by three dimensional(3-D)magnetohydrodynamics(MHD)simulation.The results showed that the drag fore exerted on the vehicle reached 25 kN when the magnetic field was 0.4 T.The drag force increased with the enhanced intial magnetic field.The bow shock was also pushed far away from the vehicle when the magnetic field was strengthened.展开更多
基金Project(51105287)supported by the National Natural Science Foundation of China
文摘To get better tracking performance of attitude command over the reentry phase of vehicles, the use of state-dependent Riccati equation (SDRE) method for attitude controller design of reentry vehicles was investigated. Guidance commands are generated based on optimal guidance law. SDRE control method employs factorization of the nonlinear dynamics into a state vector and state dependent matrix valued function. State-dependent coefficients are derived based on reentry motion equations in pitch and yaw channels. Unlike constant weighting matrix Q, elements of Q are set as the functions of state error so as to get satisfactory feedback and eliminate state error rapidly, then formulation of SDRE is realized. Riccati equation is solved real-timely with Schur algorithm. State feedback control law u(x) is derived with linear quadratic regulator (LQR) method. Simulation results show that SDRE controller steadily tracks attitude command, and impact point error of reentry vehicle is acceptable. Compared with PID controller, tracking performance of attitude command using SDRE controller is better with smaller control surface deflection. The attitude tracking error with SDRE controller is within 5°, and the control deflection is within 30°.
文摘This paper makes researches on multiple independently reentry vehicle （MIRV） ballistic missile interception. It breaks through traditional intercepting methods of missiles and combines comba- ting time characteristics of MIRV missiles with the principle of computer process schedule. In this paper, a way of firstly intercepting the target missile with higher threaten grade is proposed. This method determines the threaten grade of the attacking target according to computer process schedu- ling algorithms, then appljed a proportional navigation guidance law to intercept target missiles in priority so that it achieves the effect of less damage. The simulation results indicate that it is effective to use the proportional navigation guidance law based on the process scheduling to intercept target missile. It possesses referential value in modem weapon combats.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41204105,41104093,41174122)the Chinese Academy of Sciences (Grant No. KZZD-EW-01-3)
文摘The concept of using an externally applied magnetic field to add the drag force of a hypersonic reentry vehicle during the blackout was proposed by Bush in 1958.The increased drag force is caused by electromagnetic force that is introduced by interaction between the applied magnetic field and the weakly ionized airflow around the reentry vehicle.We investigated the influences of magnetic field intensities on the drag forces of a reentry vehicle by three dimensional(3-D)magnetohydrodynamics(MHD)simulation.The results showed that the drag fore exerted on the vehicle reached 25 kN when the magnetic field was 0.4 T.The drag force increased with the enhanced intial magnetic field.The bow shock was also pushed far away from the vehicle when the magnetic field was strengthened.
