Aircraft landing gear simulation and control

The focus of this work is the development of a Multi-degree Of Freedom (MOF) model for simulation and control of the landing performances of the SAE Heavy Lift Airplane model built by the Aerodynamics design team of RIT. From dynamic considerations, the landing gear performance has two areas of interest: a) behavior during touchdown impact, and b) response to excitation induced by track roughness during taxi, take-off and later part of the landing runs. As the problem at hand is highly nonlinear and complex, initially a simplified 1-dof model of the same aircraft is derived and analyzed using Lagrange\u27s equations and energy methods. After understanding the basic dynamics of the system, a more complex 3-dof model is derived considering the dynamics of the wheels of the landing gear. Analyses with and without the runway profile are carried out to study the effects of the input signals on the derived model. In order to achieve a controlled landing behavior of the aircraft, a linear damper or shock absorber is incorporated into the analysis and simulation, even though it is not available in the original prototype. The nonlinear models are linearized in Simulink and control system designs are performed on the linearized models using Root Locus techniques, Pole Placement methods, LQR approach, and Error Space approach. The designed controllers are then applied on the original nonlinear 3-dof model of the landing gear and a study of the effects of changing landing gear parameters is performed. Open loop and Closed loop simulations are carried out to come up with an effective controller type, which will ensure optimum landing performance in a normal landing situation