Research On Flight Envelope Of Ground And Air Vehicles

The objective in this paper is the ground and air vehicle,which has many functions such as air patrol,rescue and communication and transportation,and can be widely used in the military and civil fields,is a kind of multipurpose-combat platform and integrated transport which is able to run on the land and fly in the air.In this paper,the ground and air vehicle is taken as the research objective and the flight envelope is studied.The research contents include: flight dynamics modeling of the ground and air vehicle,modal analysis of the system,the study of the flight envelope of the ground and air vehicle,the design and implementation of the flight controller based on μ-synthesis and PID and the study of the close-loop flight envelope of the ground and air vehicle,the design and implementation of the controller switching in the scope of large flight envelope of the ground and air vehicle.Firstly,the structural characteristics of the ground and air vehicle is studied,the characteristics of modeling of the ground and air vehicles analyzed,and the structure of flight dynamics model of the ground and air vehicle is confirmed and the flight dynamics model of the ground and air vehicle via aerodynamics and rigid body dynamics is built.Secondly,the trim calculation of the model of the ground and air vehicle is carried out via genetic algorithm and sequential quadratic programming,the linear model with the hypothesis of small disturbance via central difference is gained.Thus the range of the flight envelope is preliminarily obtained.Then the characteristics of the ground and air vehicle based on linear model are deeply analyzed;the stability of the ground and air vehicle is analyzed via pole location,sensibility matrix and singular value.Thus the open-loop flight envelope of the ground and air vehicle is obtained.Thirdly,to the open-loop flight envelope of the ground and air vehicle,μ-synthesis control technology is used to design the attitude controller of the inner loop of the ground and air vehicle,which can effectively relieve the coupling of each channel of the system,suppress wind disturbance,measure noise and has good robustness.PID control technology is used to control the outer-loop speed and height.The performance of the inner-loop and outer-loop controller of the flight envelope of the climbing flight and the coordinated turn flight is simulated and assessed respectively in the chapter,and it turned out that the flight control system designed has strong anti-jamming capability and good robustness,which can meet the requirements of the controller in the range of the flight envelope.At last,to the controllers designed in the flight envelope of the ground and air vehicle,a new soft switching method for robust controllers is proposed and the control law switching is simulated and evaluated.It turned out that the designed soft switching method between different flight states in the flight envelope of the ground and air vehicle tracks quite exactly and quickly.