Research On Safe Control Strategies For Aircrafts’ AutoLand In Low-altitude Wind Shear

Low-altitude wind shear threatens flight safety seriously during aircrafts’ take-off and landing.With the development of the aircrafts’ system reliability, the proportion of flight accident or unsafeevents which are caused by pilot’s error manipulation induced directly or indirectly by theatmospheric disturbances such as low-altitude wind shear increases greatly. In order to improve thesafety for aircrafts’ approach and landing under low-altitude wind shear, this paper designs severalcontrol law such as glide path tracking, autoland, etc by dynamic modeling and simulation.Furthermore, this paper does further research on safe control strategies for escaping wind shear. Themain research contents are as follows:(1)The typical wind shear model and flight dynamics model were built. Microburst wind shearmodel which shows the characteristics of wind field was built. Based on B747modeling data, theflight dynamics model was built. Furthermore, trim and model validation were studied.(2)Several basic flight control laws were designed and implemented. Pitch control, autolandcontrol as well as the coordinated turn control law were designed one after another. All the control lawhad been designed and validated repeatedly by adding into the dynamics model.(3)Several wind shear escape strategies are studied. The specific energy, F factor and flight safetyenvelope were used as safety index. Based on the basic flight control law, flight simulation was usedto study wind shear escape. The safety of three kinds of the longitudinal escape strategies as well aslateral escape strategies from weak wind side was analyzed successively.(4)In order to improve the glide path tracking ability under wind shear during approach, thispaper realized the optimal control glide path tracking. The simulation shows that, aircrafts’ glide pathtracking and holding ability can be greatly strengthened by optimal control.