Session: 08-03-01: Design and Control of Robots, Mechanisms and Structures I

Paper Number: 165457

Landing Gears Using Six-Bar Linkages 

Landing gears (also known as alighting gears or undercarriages) are the critical components of airplanes for their operation. They are located beneath airplanes and used for parking, taxing, taking off, or landing of airplanes. The most common landing gears are the wheeled ones that are mainly for ground use. When airplanes such as seaplanes or floatplanes operate on water, snow or ice, their landing gears need to take the form of floats or skis. Landing gears are commonly retractable. They are folded into wings or fuselage during flight to reduce drag and noise, increase airplane speed and improve fuel efficiency. Although non-retractable or fixed land gears have their advantages of structural simplicity, lower maintenance and cost, their extended structures during flight result in higher drag, lower speed and efficiency. The overall performance of an airplane is enhanced by its suitable retractable landing gear. There are several arrangements of the wheeled landing gears for airplanes, which include tricycle, tailwheel, bicycle, quadricycle and others for different applications. When an airplane is taking off, landing or parking, its landing gear is fully extended and holds in its down locked state. On the other hand, the landing gear of an airplane is fully retracted during flight and stays securely in its place (wing or fuselage) with an up locked state. To switch the state of a retractable landing gear between up locked and down locked and securely hold each of the two states, a mechanism must be properly synthesized to generate the smooth motion for the state transition and hold the locked state. Four-bar linkages are well known for their simple structure, high stability, low cost and easy maintenance, which lead to their numerous applications. Due to the limited number of design parameters and the available output motion scope, a single four-bar linkage is often difficult to meet the requirements for a landing gear. Nevertheless, a four-bar linkage can be taken as a base part and extended to become a six-bar linkage with an added dyad such as 3R or 2R1P. Six-bar linkages with both Watt and Stephenson kinematic chains have been employed for landing gears. The current landing gears usually have fixed output motion ranges because the linkage dimensions are not adjustable. A landing gear with a fixed motion range is usually deficient of operation flexibility that restricts its applications. This research aims at broadening operation flexibility for landing gears through incorporating adjustable linkages into them. Six-bar landing gear mechanisms without and with adjustability are analyzed, simulated and evaluated. The research results are aimed at improving the motion performance of the existing landing gears.

Presenting Author: Hong Zhou Texas A&m University-kingsville

Presenting Author Biography: Professor, ASME Fellow, Mechanical Engineering, Texas A&M University-Kingsville, Kingsville, TX 78363

Authors:

Nishanth Bangla Votarikari Texas A&M University-Kingsville
Hong Zhou Texas A&m University-kingsville