A design of a nose wheel steering control law based on fuzzy control

It is required that, during low-velocity taxi phase, neither nose gears nor main gears shall slide side when aircrafts are swerving^[1]. In practical application, the nose wheel turns at a constant rate, equal to the lower limit of the nose wheel allowable steering rate to meet above requirements. However, in this control method, aircraft ground maneuver control performance reduces significantly. Meanwhile, due to the degree of freedom of a multiple-bogie undercarriage system is high, it is too complicated to find the general solution of a nose wheel allowable steering rate. To solve above problems, a kinetic analysis model of a multiple-bogie undercarriage system was built and a control law was designed based on the fuzzy control theory. The calculations and simulations demonstrate that allowable nose wheel steering rate can be affected by aircraft velocity, nose wheel steering angle, and engine thrust; allowable nose wheel steering rate can be improved by reducing aircraft velocity and engine thrust on condition that aircraft configuration is identical and aircraft safety and performance not reduce. Fuzzy control theory can be implemented on nose wheel steering rate control design. Nose wheel steering rate control law based on the fuzzy control theory can fully make use of aircraft ground maneuver control capability and improve aircraft ground maneuver control performance.