A Sliding Mode Observer Based ABS for Aircraft and Land Vehicles (2003-01-0252)

Control of an antilock brake system for aircraft and land vehicles is based upon estimates of the torque applied to braking wheels by means of a sliding mode observer. The observer yields a highly accurate estimate of torque that is robust for the entire operating range of the brakes, and provides an input to a relatively simple control system that regulates applied torque from either an electro-hydraulic or electromechanical actuator. Excellent braking performance for a regional jet transport is demonstrated in this paper via hardware-in-the-loop simulation. A simple scheme for suppressing gear walk (aircraft application) is presented.