Experimental Investigation on an Improved Speed Control Law with Airbrake Usage

Abstract

Airspeed control is one major influence on the pilot's overall workload when manually flying. This is especially relevant during high precision tasks such as air-to-air-refueling maneuvers. This thesis is taking two approaches to mitigate the influence of airspeed control on the cognitive capacity of the pilot. The first one, the so called Load Factor Augmentation, is a feed forward control concept that utilizes the speed brake to reduce the lag between a throttle input and the aircraft's reaction. This is supposed to decrease the necessary pilot compensation and thereby allow the pilot to focus more on other subtasks. The second concept is an airspeed controller. To ensure a fast tracking behavior this controller uses the speed brake as its control variable. Within this thesis, both concepts are tests in a simulator by test pilots. These tests allow to evaluate them regarding their efficiency and practicability for airspeed control and their influence on the overall task performance during air-to-air-refueling as one example for high precision maneuvers. Both concepts show beneficial effects when being utilizes for tasks in which airspeed control is the primary task. In more complex air-to-air-refueling tests the latter mentioned controller improves measurable objectives while the former mentioned feed forward control is only perceived to be helpful by the pilots without resulting in measurable improvements of task objectives.