Design Of Lightweight Landing Gear Based On Magnetorheological Damper And Damping Performance Research

As the American new kind of aerospace plane, X-37B Orbit Test Vehicle,successfully launched and landing, the value of economic and military is apparently tosee. Because of its smaller size and fast landing speed, the landing gear will enduregreat level force when landing on the ground. This is a special requirement to thelanding gear’s structure and the damping performance. Therefore study on the structureof lightweight landing gear and the damper’s damping performance used on theaerospace plane has significant theoretical meaning and engineering value. Themagnetorheological (MR) damper which can be achieved semi-active control hasperfect damping performance, and the structure of rock arm landing gear is muchsmaller, the level force can also make the damper compressed, so study on the compactrock arm landing gear based on magnetorheological shock absorber is quite necessary.Based on the analysis of the landing gear’s structure style, arrangement, the formof put up and put down, according to the landing gear’s application and the shockabsorption requirement, confirmed the design plan that using the rock arm structure,front tricycle landing gear, and the form of keeping its geometry invariability by usingzero structure of bar system. Calculated and analyzed the landing gear system and chosethe tire size, calculated the wheel hub’s vertical travel and the overloading ratio of thelanding gear.On the basis of the landing gear structure form and overloading ratio, designed theabsorber part of the landing gear based on the MR characteristic. Designed themaximum stroke and damping force, confirmed a mixed work mode and the structure ofdamper which is combined with a gas spring, analyzed and calculated out the pressureand volume value of the gas spring, and deduced the damping force of MR fluids andthe whole damping force of the absorber. Using the ANSYS software analyzed theelectromagnetism characteristics of different damper structures, then chose the finalstructure scheme, and got the relationship of the magnetic field intensity with thecurrent intensity between the piston head and outer cylinder of the damper, thendetermined the damper’s Bingham model and its parameters.Using the virtual prototyping technique built the landing gear’s virtual simulationmodel in ADAMS software, including defined the motion relationships betweendifferent parts and the forces of gas spring and MR fluids. Also defined the input andoutput variables which would be used in the control simulation, then obtained the fileused for co-simulation. Based on the fuzzy control theory, designed the fuzzy logicalcontroller which adapts to the MR damper by fuzzy logical toolbox inMATLAB/Simulink. Then generate the whole control strategy of the landing gear shock absorber system.Refers to the mechanics experiment policy of landing gear, carried out the drop teston the designed landing gear in different drop situation by using the co-simulation ofADAMS and MATLAB. According to the simulation results, analyzed the factors thataffect the damping performance of the MR damper, and got the absorber’sforce-distance relationship. The simulation results demonstrate this landing gear’sdamping performance meets the design requirements. Carried out the kinematicsanalysis of the landing gear putting up and putting down process, acquired the wheelhub’s motion trail and the rotate angle of the landing gear.