Research Of Unpowered Emergency Landing Control Technologies For UAV

Unpowered landing is the most complicated and risk link of UAV in flight course, while thetechnique is the most weak, which is also the critical stage affects the flight safety. The research of theability to return to the airport, energy management mechanism, landing guide strategy for unpoweredUAV become the key issues to guarantee the emergency landing, which flight control must considered.Based on this, this essay takes a sample UAV as object and studies energy management strategy andcontrol scheme of unpowered emergency landing for UAV.First, the six DOF unpowered mathematical model is built by applying the Newton rigid bodydynamics in inertial space while mobility, maneuverability and modal characteristics mode are analyzed,and this provides the basis for the formulation of the control strategies and the design of the control lawof unpowered landing.Second, the emergency landing process is divided into course adjustment stage, energymanagement stage and landing stage based on the energy status of the sample UAV, the landingboundary of unpowered emergency landing is determined and the landing trajectory is designed,meanwhile, the energy management and control scheme is given which take trajectory angle as controltarget, through the rational allocation of energy, these provide indemnity for stable flight and safelanding of unpowered UAV.Then, the modern robust servo LQR method and classical root locus method are adopted by theintegration of the robust performance and control quality, and the control law of longitudinal and lateralmode are designed which takes the angular rate as the control loop and height and trajectory as theguiding loop, this solves the control augmentation and track of three dimension trajectory in courseadjustment stage, energy management stage and landing stage.Finally, control law for emergency landing is simulated and tested for the whole landing processaiming at uncertainties of different initial status, wind disturbance, aerodynamic and control parameters,the results show the robust performance and control quality of energy management strategy and controlscheme satisfy the control demand of emergency landing for sample UAV.