Abstract
Due to the short duration of impulsive impact of an aircraft during touchdown, a traditional landing gear can only achieve limited performance. In this study, a magnetorheological (MR) absorber is incorporated into a landing gear system; an intelligent control algorithm, a human simulated intelligent control (HSIC), is proposed to adaptively tune the MR absorber. First, a two degree-of-freedom (DOF) dynamic model of a landing gear system featuring an MR absorber is constructed. The control model of an MR damper is also developed. After analyzing the impact characteristic during touchdown, an HSIC is then formulated. A genetic algorithm is adopted to optimize the control parameters of HSIC. Finally, a numerical simulation is performed to validate the proposed damper and the controller considering the varieties of sink velocities and sprung masses. The simulations under different scenarios show that the landing gear system based on the MR absorber can greatly reduce the peak impact load of sprung mass within the stroke. The biggest improvement of the proposed controller is over 40% compared to that of skyhook controller. Furthermore, HSIC exhibits better adaptive ability and strong robustness than skyhook controller under various payloads and sink velocities.
Highlights
The very important design issue of landing gear systems with an adaptive ability of impact energy mitigation and simultaneous generation of minimal deceleration on the protected aircraft structure is an intensive research topic
To attenuate the landing impact transmitted to aircraft, some active or semiactive types of landing gear systems have been suggested in aircrafts
Where cs denotes the damping constant due to viscous damping, V is the relative velocity of MR absorber or piston rod relative to the absorber body, FMR represents the controllable coulomb damping force which is a function of external magnetic field or electric current and sgn() indicates the sign function
Summary
The very important design issue of landing gear systems with an adaptive ability of impact energy mitigation and simultaneous generation of minimal deceleration on the protected aircraft structure is an intensive research topic. To compass all impact scenarios (i.e., a wide range of flight parameters such as ground friction coefficient, aircraft overall weight, attitude, and sink velocity), a traditionally passive landing gear has to be employed to meet the requirement of the most heavy dynamic excitation or harsh environmental loading. As a result, it cannot avoid the highly redundant structure and trade-off performance. Many numerical and actual road tests show the effectiveness in reducing the vibration of vehicle suspension and improving the ride comfort To accomplish this goal, a two-DOF dynamic model of aircraft incorporated with an MRF-based landing gear is firstly constructed to simulate the course of touchdown. A great deal of numerical simulations considering variable masses and sink velocities are performed to evaluate the effectiveness of the proposed control algorithm
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