ELECTRORHEOLOGY FOR SMART LANDING GEAR

Electrorheological (ER) technology was explored for its suitability to the continuous control of force and motion in aircraft landing gear. Although the state of knowledge on all types of active suspensions was examined, the analytical and experimental portions of the study focused upon the control of damping, alone. A specific class of ER damper designs was selected by means of a generalized analysis that modeled the ER fluid as a "bingham" plastic material. This analysis reveals the advantage of ER damping devices that minimize shear rates such that static shear stresses tend to dominate the damper's response. A prototype damping device in this class was constructed and simplified response parameters of the device were measured. Alternative formulations of the ER fluid are discussed and the employed test fluid is described. An analysis of the landing transient for an example military aircraft was performed so that the nominal performance of an ER-based damping controller could be estimated. The study observes that although ER technology offers promise over the long term, current limitations in fluid performance severely constrain the application to aircraft landing gear.