A Sliding Mode Observer Based ABS for Aircraft and Land Vehicles

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.