Shimmy vibration control using robust model predictive control
Shimmy vibration is a very important common phenomenon in the landing gear system during either the take-off or landing of an aircraft. Shimmy vibration is the lateral and torsional vibrations in the wheel of the aircraft that is self-excited and causes instability in high speed performances which can damage the landing gear of the aircraft, its fuselage and even may result in hurting the passengers. In this paper, the aircraft landing gear shimmy dynamics model is studied with the following variable parameters; caster length, taxiing velocity and spring stiffness. The considered linearized landing gear system is a typical Linear Parameter Varying system, whose state-space matrices are functions of those varying parameters. The control objective is to steer the yaw angle to zero in order to suppress the shimmy when the landing gear system is subjected to uncertainties, which are varying taxiing velocity, and wheel caster length during landing; also, to rsional spring stiffness is considered as the probabilistic uncertain parameter. Therefore, both time-varying and probabilistic uncertain parameters are considered. Compared with two current robust model predictive controls, the proposed shimmy controller can effectively suppress the shimmy with more efficient computation. To verify the efficiency of the proposed algorithm, the simulation results are simulated by MATLAB software and its performance and efficiency are verified and discussed using comparative analysis.