Semi-active control of shimmy in aircraft landing gears using magneto-rheological dampers

• Grant number: 20/15787-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2021
• End date: October 31, 2021
• Field of knowledge: Engineering - Mechanical Engineering
• Principal Investigator: Flávio Donizeti Marques
• Grantee: Luis Eduardo Prado Pereira
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Shimmy is an aeromechanical phenomenon characterized by a potential for instability in aircraft landing gears, even when they are in contact with the ground. The appearance of this phenomenon reveals a self-excitation mechanism. High levels of vibrations are observed in the aircraft's landing gear, which can cause fatigue and structural limb failures, and therefore are undesirable and must be suppressed. In this work, a new semi-active control strategy is proposed to ensure the aircraft's shimmy envelope, based on the polytopic description of its instability boundaries. The actuation in the system will be done by applying a rotary magneto-rheological damper, with dynamics modeled according to the Dahl model. Linear and non-linear models of shimmy will be studied in this research. The nonlinearities present in the system will be modeled according to Takagi Sugeno's fuzzy theory. Lyapunov's theory will be used for the design of controllers, and the control gains will be calculated using linear matrix inequalities. Computer simulations will be performed in order to show the capacity of the proposed strategy to suppress linear and non-linear shimmy.