gyroscopic stabilizer

[blary]

we are students in naval architecture in an engineering school. We must study a means to stabilize a sort of buoy.
We have been proposed to study a gyroscope to stabilize this buoy, which is 800 ton-weighted and measures 37 meters high. Have you any idea how to design such a system?
Moreover, the center of gravity is 7 meters below the center of the caren?
thanks for answers

[zcg0085]

blary
see current issue of professional boatbuildes there is a short treaties on such

[Sander Rave]

There has been een earlier thread on gyroscopes on floating bodies. pretty interresting! I think you could find it with the search engine.
Good luck

[cyclops]

My age will show. But it always came down to unsatisfactory power to weights ratios to hold steady? in sustained sea conditions. 800 tons is not a buoy. It is someone trying to get lucky on a cheap revoultionary way to stabilize a ship by tapping into a brilliant young mind for no money. Good exercise for the talented mind.

[hateka]

Originally Posted by blary

we are students in naval architecture in an engineering school. We must study a means to stabilize a sort of buoy.
We have been proposed to study a gyroscope to stabilize this buoy, which is 800 ton-weighted and measures 37 meters high. Have you any idea how to design such a system?
Moreover, the center of gravity is 7 meters below the center of the caren?
thanks for answers

Such gyroscopic stabilisers were used in the battleships late 1800 early 1900.

[cyclops]

Would it not be a lot easier to just stabilize the light or horn or transmitter of the buoy? Let the other 799 and 1/2 tons swing as it wants. Answers like that can embaress professors and others.

[yokebutt]

Blary, putting the bulk of the bouy well under water should help. There is a very strange looking research vessel that works on that exact principle, forget the name, though.

Yoke.

[JPC]

I think that submarines use, or have used, gyroscopic stabilization. Obviously difficult to get data on current designs (and to put a reactor on your bouy to power the thing), but a discussion of principles should be available with a little looking.

[hateka]

I think there is some similarity with the spar-buoy of Shell where Greenpeace made a lot of fuss about. That huge vertical drum was ballasted with iron-ore, and had holes in the bottom of the vertical oiltanks, to have always the same amount of liquid on board giving it a 'fixed' freeboard. The upper part could be conical with the point down, weight in the point, and that conical part hanging in gimbles. Hateka.

Only recently - I saw a guy with a revolutionary new vessel stabilising gyroscope device - and I'm trying to think where?

It was one of two places.

1. Aussie ABC TV (Channel 2) http://www.abc.net.au/newinventors/txt/s1415189.htm

www.webace.com.au/~sea_gyro/
sea_gyro@webace.com.au

or

2. At the recent Perth boatshow.

I'm sure it was on the TV show - and for what it was (my memorys sketchy) I didn't think it got a very good review from the judges, commensurate with how well it worked - even on smallish boats. I think some clever water saving device won that week - go figure! (ours is a desert country!).

Anyway - I'm sure the same dude was at the boatshow also - and tried to convince me I needed one for my 25 ft charter boat. Sadlly for you - I wasn't much interested at the time, so didn't grab one of his brochures...(sorry I had other gadgets on my shopping list and limited time).

Hope the above details give you something to go on...theres some good info on the web sites.

Cheers!

[cyclops]

His post was in 2-15-02! He has a full time position by now. --------I am old. What are your excuses?

Didn't need one - I figured that the info / links - might help anyone with an interest in gyroscopic stabilisation, when they turn up this thread in a search on the subject.

Thats the great thing bout the internet, - you never know - who you will help or when - it's like leaving a legacy behind, for the benefit of future generations...

I like helpin people - what can I say!

Cheers!

[tspeer]

I think you need to make a distinction between gyroscopic stabilizers, like the Sea Gyro, that use gyroscopic moments directly to resist disturbances by brute force; and feedback control systems that use gyroscopes to measure the disturbances and then use some other control effector to counter the disturbance. A good example of the latter would be active stabilizing fins.

The latter is more typical of the modern approach. Computation is no longer a limiting factor, so you can use quite sophisticated algorithms for control Today you can buy solid state inertial measurement units that have solid state devices for measuring linear acceleration and angular rate. Even though the sensors themselves may not be all that accurate, they are adequate for stabilization purposes and when combined with GPS signals in a Kalman filter, can provide a highly accurate source of motion information.

The problem with stabilizing a buoy is finding a means of applying the forces. You don't have the dynamic pressure from a boat's speed to use in hydrofoils. You may want to consider something like a spar buoy with a raft surrounding it. With actuators between the spar and raft, you can exert forces on the spar to cancel out the effect of waves. Or you can use something like a robotic arm with the payload on the end. The payload can be kept stationary, even considering vertical motion, for waves less than the range of articulation of the arm.

I recommend Thor Fossen's book, "Guidance and Control of Ocean Vehicles," John Wiley & Sons, 1994.