DIRECTIONAL CONTROL OF AN ADVANCED AIRSHIP

Directional control of a relaxed static stability airship is considere d by means of an active control law. The yaw control moments from rudd er deflection, differential thrust of two vectorable cruise/lift thrus ters and a bow thruster device are integrated to synthesize an active control law that can be implemented in a digital fly-by-wire/light fli ght control system configuration, It is shown that significant improve ment in airship directional control and maneuverability can be realize d, especially at low airspeeds below 20 kn, by using the proposed acti ve control law. Results are illustrated by considering an example 2.8- million-ft(3) vehicle.