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Slipstream-Based Dual-Rotor Tail-Sitter?

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Slipstream-Based Dual-Rotor Tail-Sitter?

Postby lum-supakorn » Mon Jun 15, 2020 5:54 am



Hi, all.

I'm developing a slipstream-based dual-rotor tail-sitter UAV similar to the Phoenix Drone (https://github.com/utiasSTARS/PhoenixDrone), and I need a simulator to make control algorithm development and testing easier.

The available solution is to test the model through the Gazebo simulator; however, its aerodynamics simulation is very limited (http://gazebosim.org/tutorials?tut=aerodynamics&cat=physics). For instance, the current Gazebo aerodynamics plugin makes great (and possibly incorrect) simplification to the lift and drag polar and does not support aerodynamic moment at all.

It seems to me that FlightGear handles aerodynamics and flight dynamics in a much more sophisticated and accurate manner and might be a better solution to simulating the vehicle. Also, the flow over the target vehicle involves complex slipstream dynamics that might not be supported in FlightGear, so I might need to develop some extension to make that possible.

As I'm very new to this software package and don't have a full understanding of its capacity, may I ask if creating such a flight vehicle simulator is viable and practical?
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Re: Slipstream-Based Dual-Rotor Tail-Sitter?

Postby erik » Mon Jun 15, 2020 7:39 am

JSBSim could model this if you got the math to simulate it.
I quick search found a book that covers the math:

https://books.google.nl/books?id=hr4vDw ... AV&f=false
Intelligent Robotics and Applications
10th International Conference, ICIRA 2017
Wuhan, China, August 16-18, 2017
Proceedings, Part III

YongAn Huang, Hao Wu
Honghai Liu, Zhouphing Yin (Eds.)
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Re: Slipstream-Based Dual-Rotor Tail-Sitter?

Postby lum-supakorn » Tue Jun 16, 2020 2:09 am

erik wrote in Mon Jun 15, 2020 7:39 am:JSBSim could model this if you got the math to simulate it.
I quick search found a book that covers the math:

https://books.google.nl/books?id=hr4vDw ... AV&f=false
Intelligent Robotics and Applications
10th International Conference, ICIRA 2017
Wuhan, China, August 16-18, 2017
Proceedings, Part III

YongAn Huang, Hao Wu
Honghai Liu, Zhouphing Yin (Eds.)


Thank you. I'll give it a read.

So JSBSim is definitely capable of modeling rotor dynamics also (I just need force as a function of rotor angular velocity squared)?
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Re: Slipstream-Based Dual-Rotor Tail-Sitter?

Postby abassign » Tue Jun 16, 2020 7:45 am

I hope I understand your question correctly...
Yes, JSBSim can easily be programmed to simulate this drone and be used, for example with a Raspberry, as a near real-time control program.
The problem is building a good physical model of the object, for example giving the right aerodynamic coefficients on the wing-flap system, it is not simple as it is necessary to simulate the flow of air that has the X axis of the aircraft as its direction, instead the movement in the space (y and z axis), leads to compose a force vector that acts on the surfaces. The value of this vector is difficult to determine, however you can try to consider surfaces as plane surfaces subjected to an aerodynamic flow, there are experimental tables that should allow for a good approximation.
Obviously it would be even more exciting to try the transaction phase from vertical flight to horizontal flight, this phase should take place when the flight takes place with a decisive movement on the z axis, which should rotate the aircraft on the y axis and take it to a flight similar to that of a flying wing,
with the flaps in a negative position.

I hope you are not discouraged, but it would be really exciting to see an aircraft made in this way fly in FGFS.
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Re: Slipstream-Based Dual-Rotor Tail-Sitter?

Postby lum-supakorn » Tue Jun 16, 2020 8:15 am

Thank you! Will give it a try. Right now I'm working on extending the current Gazebo sim plugin to handle aerodynamics in a more accurate manner.
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