Composite Control Strategy of Stratospheric Airships with Moving Masses

In general, an airship is equipped with hybrid-heterogeneous actuators, aerodynamic control surfaces, the vectored thrusts, and buoyant ballonets; however, moving-mass control is still introduced to a stratospheric airship for its special working condition of low atmospheric density and low airspeed...

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Bibliographic Details
Published in:Journal of aircraft 2012-05, Vol.49 (3), p.794-801
Main Authors: CHEN, L, ZHOU, G, YAN, X. J, DUAN, D. P
Format: Article
Language:English
Subjects:
Actuators
Aerodynamics
Airships
Control surfaces
Control systems
Design engineering
Exact sciences and technology
Fundamental areas of phenomenology (including applications)
Mathematical analysis
Movements
Physics
Solid dynamics (ballistics, collision, multibody system, stabilization...)
Solid mechanics
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Summary:In general, an airship is equipped with hybrid-heterogeneous actuators, aerodynamic control surfaces, the vectored thrusts, and buoyant ballonets; however, moving-mass control is still introduced to a stratospheric airship for its special working condition of low atmospheric density and low airspeed. Thus, the composite control of hybrid-heterogeneous actuators is the primary object in controller design for stratospheric airship. The dynamic equation of airship is derived using the Newton-Euler method, and the mechanism of moving-mass control is investigated. The control capabilities between the moving mass and the aerodynamic control surface are compared. The weighted generalized inverse (WGI) is used to design the nonlinear composite controller, where the authority of every actuator can be decided by setting the corresponding value of the control efficiency weighted matrix; thus, the control law is unchanged under different actuator configurations. Using the stratospheric airship as an example, the aerodynamic control surfaces, moving mass, and vectored thrust are combined into the composite control system, and the simulation of altitude tracking is provided. The results of the analysis show that the movements of the moving mass change the pitch and roll angles of the airship such that the passive gliding movement can be realized in the same manner as a glider in water. The moving-mass ratio and the displacement of the moving masses are the primary factors affecting the moving-mass attitude control. The moving-mass attitude motion is unaffected by airspeed; hence, it has a strong adaptability. The WGI achieves a good distribution and reconfiguration among these heterogeneous actuators and maintains the minimum control energy, thereby enhancing the reliability of the control system.
ISSN:0021-8669
1533-3868
DOI:10.2514/1.C031364