LONGITUDINAL STABILITY AUGMENTATION SYSTEM

摘要

The control system includes a schedule (54) which plots airspeed versus stabilizer angle for a trim condition. Following a pilot adjustment of the stabilizer angle to establish trim, the schedule (54) plots the trim airspeed to obtain a stabilizer angle value. A change in airspeed from trim is sensed by a sensor (52) and the schedule (54) plots the new airspeed on the same graph to obtain a new stabilizer angle value. The schedule (54) determines a change in stabilizer angle signal in the form of increments of movement of the stabilizer control actuator (28) to return the stabilizer (18) to a trim condition. A schedule (40) in the system also senses any change in the rate of change of altitude from trim and computes from this change a second signal in the form of increments of actuator movement. There is an algebraic summation of these two signals and a stabilizer angle feedback signal to produce a command signal. The system includes cutoff schedules (66, 68) which transmits the command signal on to the actuator (28) only during the high thrust, aft center of gravity region of the flight envelope. The change in rate of change of altitude feedback path senses an impending change in speed and in response thereto starts a change in direction of stabilizer movement, so that the stabilizer will be moving in the right direction when the change in speed signal becomes operative.