Active Control Of The Aircraft Landing Gear Buffer Technology And Research

During aircraft take-off and landing phases, the dynamic loads and vibrations caused by landing impact and the unevenness of runway will result in airframe fatigue , discomfort of passenger and the reduction of the pilot's ability to control the aircraft. Therefore, the dynamic loads should be considered and limited in designing landing gear. The traditional landing gear is a passive system and the parameters changes may produce an unsatisfactory performance. This paper mainly researches the application of the active control technology to the landing gear system. The aim is using different control methods to design the active controller to improve the performance of the system, according to the characteristic of the parameters' variations. The main work of this thesis:1 . The mathematical model describing the landing gear active control system is established. An available mechanical model with two degree of freedom that consists of a mass, a spring and two dampers is given. By the use of this model, motion equation and formulas are deduced. Then the mathematical model and the transport functions are established.2. The influence of the parameters on the system performance is studied. Severalparameters will change during aircraft take-off and landing phases. This papergives the fields of the parameters' variations and analysis the influence ofparameters' variations on the system performance.3. Active controller, such as PID type , feed-forward type , fuzzy type and adaptivetype are designed and used in the system.4. Simulations are formed for the passive control system and active control system with different controller. Then the performance of the active and passive control system is compared. The results show that active control system has superior performance over the passive control system.