A Guide to Landing Gear System Integration

10.4271/air5451 ◽

2016 ◽

Author(s):

Keyword(s):

System Integration ◽

Landing Gear ◽

Gear System

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Robust force and displacement control of an active landing gear for vibration reduction at touchdown and during taxiing

SN Applied Sciences ◽

10.1007/s42452-021-04320-1 ◽

2021 ◽

Vol 3 (4) ◽

Author(s):

Mehran Pirooz ◽

Seyed Hossein Mirmahdi ◽

Ahmad Reza Khoogar

Keyword(s):

Control System ◽

Force Control ◽

Direct Method ◽

Landing Gear ◽

Gear System ◽

Displacement Control ◽

Robust Nonlinear Control ◽

Control Loops ◽

Tire Force ◽

The Mathematical Model

AbstractIn this paper, a new approach is proposed to control the dynamic response of a landing gear system subjected to runway force, both on heavy landing conditions and at the taxiing process. The mathematical model of the system is used in a way that covers nonlinear dynamics characteristics of landing gear and nonlinear/nonaffine property of the external actuator. The operation of the landing gear system and its components are described briefly. The desired control system includes two different interior loops for displacement and force control. The inner loop determines the actuator force and the outer loop performs the displacement control. A lumped uncertainty is considered in both displacement and force control loops that represent uncertainties including parametric errors, measurement noises, unmodeled dynamics, disturbance due to runway excitation, and other disturbances. The direct method of Lyapunov is utilized for asymptotic stability analysis of the robust nonlinear control system (RNCS). This system is simulated in MATLAB software and the performance of the proposed controller is analyzed exactly. Besides, the results are compared with a passive system and conventional PID control. The comparison indicates that RNCS works better and more precisely. This method can reduce vibrations at touchdown and taxiing and effectively overcome uncertainty and provide well aircraft handling by decreasing the changes in tire force.

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Design and dynamic analysis of landing gear system in vertical takeoff and vertical landing reusable launch vehicle

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410018804093 ◽

2018 ◽

Vol 233 (10) ◽

pp. 3700-3713

Author(s):

Ming Zhang ◽

Dafu Xu ◽

Shuai Yue ◽

Haifeng Tao

Keyword(s):

General Scheme ◽

Surface Friction ◽

Launch Vehicle ◽

Landing Gear ◽

Gear System ◽

Extreme Condition ◽

Response Characteristics ◽

Reusable Launch Vehicle ◽

Vertical Landing ◽

Vertical Takeoff

Landing gear system is a key part of the implementation of reusable vertical takeoff and vertical landing launch vehicle, where its buffing performance is directly related to the vehicle whether it can land safely or stably. According to the reusable launch vehicle general scheme, outrigger landing legs are designed, and the hydraulic absorber is used for the landing gear system. Meanwhile, a scaling principle prototype of landing gear system is developed, and the landing impact test is carried out. A dynamic simulation model of the landing vehicle has been set up, researching the influence of parameters, such as the horizontal velocity, initial inclination, surface friction coefficient, and pitch angular velocity on the landing performance. Four kinds of extreme conditions are identified, and dynamic response characteristics of landing system under each extreme condition are conducted. The simulation results are in good agreement with the experimental data. The buffing performance of the vehicle meets the design requirements, which provides a reference for the design of landing gear system of the vehicle.

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