Adaptive feedforward control for crosswind landing with variable step size

In this article, a modified Steiglitz–McBride (SM) structure with variable step size is proposed for aircraft feedforward control to reduce lateral landing deviation in the presence of crosswind disturbance. Currently, most of the aircraft landing studies focus on the trajectory tracking problems in the longitudinal plane and seldom focus on lateral disturbances. This article develops a modified SM structure–based feedforward control system to online estimate both the primary path and the control path (secondary path), where a fuzzy logic–based variable step size strategy is implemented to ensure fast convergence rate and strong robustness under complex crosswind scenarios. As a consequence, the lateral deviation during crosswind landing could be largely reduced as fast as possible while the stability of the flight control system is maintained. A Boeing 747 model is used as a test bed, and the simulations are carried out on two different crosswind conditions to demonstrate the feasibility and effectiveness of the proposed method.

Influence of Control Coupling Effect on Landing Performance of Flying Wing Aircraft

As flying wing aircraft has no tail and adopts blended-wing-body design, most of flying wing aircrafts are directional unstable. Pitching moment couples seriously with rolling and yawing moment when control surfaces are deflected, bringing insecurity to landing stage. Numerical simulation method and semi-empirical equation estimate method were combined to obtain a high aspect ratio flying wing aircraft’s aerodynamic coefficients. Modeling and simulation of landing stage were established by MATLAB/Simulink. The control coupling effect on lift and drag characteristics and anti-crosswind landing capability was studied. The calculation results show that when the high aspect ratio flying wing aircraft was falling into the deceleration phase, appropriate to increase the opening angle of split drag rudder can reduce the trimming pitching moment deflection of pitch flap, thereby reduce the loss of lift caused by the deflection of pitch flaps. Flying wing aircraft can be rounded out successfully by using the pitch flap gently and steady. Both side-slip method and crabbed method can be applied to the landing of high aspect ratio flying wing aircraft in crosswind, the flying wing aircraft’s anti-crosswind landing capability was weakened by the control coupling effect of split drag rudder and elevon. Sideslip method was recommended in the crosswind landing of flying wing aircraft after calculation and analysis.

Analysis and Structure Optimization of the Wind Distribution of Nozzle in the Gravure Printing Drying System

The drying system plays an important role in printing speed and energy consumption of gravure printing machine. Nozzle is a factor which decides heated air distribution in drying system finally. This research makes a model for the structure of nozzle and takes a numerical simulation analysis of heated air field with hydrodynamic theory. The defect of structure is found through the distribution of velocity, temperature and trajectories. A crosswind landing area is added around outlet area of nozzle. In this study, it is evaluated that the distribution of the wind field. It is found that the velocity and pressure of heated air in the vortex area between substrate and nozzle by the cross-wind board can be improved from the simulation results. The study has significance on optimizing the structure of nozzle and improving efficiency of drying system.