Abstract: A system for automatically controlling the braking of an aircraft to a desired setting upon landing or during a rejected takeoff. The inputs to the control system are airplane acceleration and airplane pitch. The output from the control system is an electric current which is sent to a hydraulic servo valve. This valve meters hydraulic pressure to the brakes.

Abstract: An aircraft autobrake system utilizes a hydraulic fluid pressure sensor to provide a signal proportional to brake hydraulic fluid pressure magnitude to a control system. The control system uses closed loop feedback of this pressure signal to control autobrake application. Such control avoids pressure or deceleration overshoot or undershoot caused by not achieving brake stack closure when deceleration control is applied. Upon landing, if autobrake control command plus the change in autobrake control command necessary to eliminate deceleration error is less than a specified minimum, then brake stack closure needs to be maintained. In that case, the control system determines hydraulic fluid pressure error and adjusts hydraulic fluid pressure to eliminate such pressure error, using closed loop feedback. Upon elimination of pressure error, indicating brake stack closure, deceleration control then applies autobraking to slow the aircraft without pressure or deceleration overshoot or undershoot.