Ducted Fan Effect on the Elevation of a Concept Helicopter When the Ducted Faintail Is Located in a Ground Effect Region

In order to solve the existing deficiencies of the unmanned WIG ship, a new type of unmanned WIG ship with the optimized propulsion unit was designed, where the lift-type water-air amphibious double-ducted-fan propulsion unit increased the drainage and navigation speed of the unmanned WIG ship by a large margin, and the load at the junction between the propulsion unit and ship body was reduced to a great extent. Through simulation and theoretical analysis, it is verified that the unmanned WIG ship with the optimized propulsion mode can further accelerate the drainage and navigation speed of the unmanned WIG ship and reduce the load at the junction between the propulsion unit and ship body during the navigation in water, so its operating performance and safety are both strengthened. Therefore, this newly developed unmanned WIG ship can deliver good social and economic benefits.

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Aerodynamic analysis and control for a novel coaxial ducted fan aerial robot in ground effect

International Journal of Advanced Robotic Systems ◽

10.1177/1729881420953026 ◽

2020 ◽

Vol 17 (4) ◽

pp. 172988142095302

Author(s):

Tianfu Ai ◽

Bin Xu ◽

Changle Xiang ◽

Wei Fan ◽

Yibo Zhang

Keyword(s):

Disturbance Observer ◽

Ground Effect ◽

System Stability ◽

Bench Test ◽

Nonlinear Disturbance Observer ◽

Modeling And Control ◽

Ducted Fan ◽

Aerial Robot ◽

Nonlinear Disturbance ◽

And Control

Modeling and control for a novel coaxial ducted fan aerial robot in-ground-effect is presented in this article. Based on experiments using the ducted fan bench test, the fitting curve of the ground effect thrust of the ducted fan aerial robot at different heights is obtained. In addition, the flow field simulation results of the prototype with ground effect at different heights can be obtained using computational fluid dynamics software. A simplified model of the prototype for control can be designed based on several reasonable hypotheses that are established using blade element and momentum theory. To compensate for the disturbance associated with ground effect, a nonlinear disturbance observer is designed to estimate the disturbance, and control structure of the closed-loop system is composed of a nonlinear disturbance observer combined with a double-loop proportion–integration–differentiation controller. The results of several numerical simulations and experiments demonstrate the effectiveness of this controller structure. The performances of tracking trajectory and system stability are improved significantly, compared to the situation that the ground effect is not compensated for.

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