Aircraft anti-skid braking control with flow servo-valve

Pressure servo-valve is usually used for aircraft anti-skid braking system (ABS). It provides closed-loop pressure control via internal oil feedback. This structure complicates the manufacturing process and limits the adjustment of closed-loop parameters. It also increases the difficulty of system design and system test. In addition, local pressure closed-loop characteristic is coupled with long brake pipeline, which causes underdamped pressure closed-loop control. This paper builds aircraft hydraulic system model including pipeline model to analyze the reason why the output of pressure servo-valve is oscillating, and proposes an aircraft anti-skid braking control method with flow servo-valve. Then, the configuration of aircraft ABS using flow servo-valve is given. Simulations based on aircraft movement model are carried out to verify the anti-skid control performance of the system. This method needs pressure signal detected by pressure sensor. Using this method, better open loop features are achieved, and control algorithm is used easily. Software simulation comparisons between pressure servo-valve system and flow servo-valve system are also included to show advantages of using flow servo-valve. The results prove the feasibility and advantage of using flow servo-valve for anti-skid braking control.