Based on classical terrain following (TF) algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from Digital Elevation Map (...Based on classical terrain following (TF) algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from Digital Elevation Map (DEM) for TF control is discussed in order to save store space. The block control model, which is suitable for backstepping design, is given for nonlinear model of aircraft. Making full use of the characteristics of the system and combining block control principle, backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors converge to the neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the aircraft model are presented to demonstrate the effectiveness of the proposed control law.展开更多
Based on the optimal control theory, a 3-dimensionnal direct generation algorithm is proposed for anti-ground low altitude penetration tasks under complex terrain. By optimizing the terrain following(TF) objective fun...Based on the optimal control theory, a 3-dimensionnal direct generation algorithm is proposed for anti-ground low altitude penetration tasks under complex terrain. By optimizing the terrain following(TF) objective function,terrain coordinate system, missile dynamic model and control vector, the TF issue is turning into the improved optimal control problem whose mathmatical model is simple and need not solve the second order terrain derivative. Simulation results prove that this method is reasonable and feasible. The TF precision is in the scope from 0.3 m to 3.0 m,and the planning time is less than 30 min. This method have the strongpionts such as rapidness, precision and has great application value.展开更多
An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integra...An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integrating the general optimal servo system with a preview feedforward compensation that feeds forward future command and future disturbance produces an optimal preview servo system. In the terrain following system, the flight altitude of the cruise missile is a command signal, and its future information can be known apriori. Hence, we have designed a terrain following controller with a basic state feedback and a feedforward compensation for future altitude information. Simulation results show that the performance of the terrain following system with such an optimal preview controller has been improved dramatically.展开更多
In the terrain following coordinate,Gal-Chen and Somerville[1]and other proposed a vertical coordinate z∝(z−z_(bottom))/(ztop−z_(bottom))and constant spatial intervals ofδx andδy along the other directions.Because ...In the terrain following coordinate,Gal-Chen and Somerville[1]and other proposed a vertical coordinate z∝(z−z_(bottom))/(ztop−z_(bottom))and constant spatial intervals ofδx andδy along the other directions.Because the variation ofδx andδy was ignored,their coordinate does not really follow the terrain.It fails to reproduce the divergence and curl over a complex terrain.Aligning the coordinate with real terrain,the divergence and curl we obtained from the curvilinear coordinate are consistent with the Cartesian coordinate.With a modification,the simulated total mass,energy,and momentum from the Navier-Stokes equations are conserved and in agreement with those calculated from Cartesian coordinate.展开更多
文摘Based on classical terrain following (TF) algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from Digital Elevation Map (DEM) for TF control is discussed in order to save store space. The block control model, which is suitable for backstepping design, is given for nonlinear model of aircraft. Making full use of the characteristics of the system and combining block control principle, backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors converge to the neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the aircraft model are presented to demonstrate the effectiveness of the proposed control law.
文摘Based on the optimal control theory, a 3-dimensionnal direct generation algorithm is proposed for anti-ground low altitude penetration tasks under complex terrain. By optimizing the terrain following(TF) objective function,terrain coordinate system, missile dynamic model and control vector, the TF issue is turning into the improved optimal control problem whose mathmatical model is simple and need not solve the second order terrain derivative. Simulation results prove that this method is reasonable and feasible. The TF precision is in the scope from 0.3 m to 3.0 m,and the planning time is less than 30 min. This method have the strongpionts such as rapidness, precision and has great application value.
文摘An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integrating the general optimal servo system with a preview feedforward compensation that feeds forward future command and future disturbance produces an optimal preview servo system. In the terrain following system, the flight altitude of the cruise missile is a command signal, and its future information can be known apriori. Hence, we have designed a terrain following controller with a basic state feedback and a feedforward compensation for future altitude information. Simulation results show that the performance of the terrain following system with such an optimal preview controller has been improved dramatically.
文摘In the terrain following coordinate,Gal-Chen and Somerville[1]and other proposed a vertical coordinate z∝(z−z_(bottom))/(ztop−z_(bottom))and constant spatial intervals ofδx andδy along the other directions.Because the variation ofδx andδy was ignored,their coordinate does not really follow the terrain.It fails to reproduce the divergence and curl over a complex terrain.Aligning the coordinate with real terrain,the divergence and curl we obtained from the curvilinear coordinate are consistent with the Cartesian coordinate.With a modification,the simulated total mass,energy,and momentum from the Navier-Stokes equations are conserved and in agreement with those calculated from Cartesian coordinate.
