An integrated self-energized brake system for aircrafts based on a switching valve control

The aircraft brake system has an important influence on the safety of aircrafts. The traditional hydraulic brake system needs long and complicated pipelines, from the aircraft central hydraulic pumps to the brake actuators, which could cause serious vibration and leakage problem. This paper proposes a new Integrated Self-energized Brake System (ISBS) for aircrafts based on a single switching valve control. The new system needs neither external hydraulic sources nor complicated pipelines. It recovers some kinetic energy of the landing aircraft through a hydraulic pump geared by the main wheel. The recovered energy will convert into hydraulic power used for brake actuators. Compared with the traditional hydraulic brake system, the new system has a higher level of safety, economy and reliability, and has better performance than the electric brake system. Moreover, its self-energized feature makes it possible to brake as usual even in an emergency situation, such as when the airborne power is lost. In this paper, an aircraft longitudinal motion model and a hydraulic ABS model with a single switching valve are formulated. Based on these models, a switched control strategy with delay compensation is developed, which describes a switching surface derived from back-stepping to direct switching actions. The feasibility of the new system is verified by simulations. Meanwhile, an experimental prototype is designed to carry out experiments on a ground brake testing bench, whose results indicate the new system has a favorable development and application prospect.