Motion Damping

I am presently in my final year at Southampton University in the UK and am doing a group project on motion control in multi hulled vessels.

Can anyone give me some pointers to start, or tell me where I can find some information on ultra-light flywheels and gyroscopes?

Many thanks,

Stuart Paterson Part IV Mechanical Engineering University of Southampton

Reply to
Stuart Paterson
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motion control multi hulled vessels

gave me loads of hits...

Reply to
simon

Well that's an obvious solution, and I've looked into that. I was hoping for something slightly more specific from and engineering newsgroup.....

Reply to
Stuart Paterson

Ahhh...Without wishing to start a flame war.... you, see, you said in your last post "I was hoping for something slightly more specific"

You'll get more response from people if YOU approach, with a more specific question, along the lines of:

...I used (google / the library / asked someone) and found out (insert in here what you found out) , but didn't totally understand (insert here what you didn't understand) about it. Can anyone tell me about (insert here specific parts about the bit you found out but didn't understand).

What exactly did you find out using Google...and what didn't you understand / what do you want to know more about the bits you found....?

regards SS

Reply to
simon

My mistake......

Myself and my colleagues have been forwarded information from within the university, however there are several aspects with which, being but a mechhie, I'm not familiar with.

There's ship/wave interations, energy transfer between waves and the ship, and building regulations on ship design, and the only papers online that I've found are still way above my level of understanding. There doesn't seem to be a "Ship interactions for dummies" site. Funny...

Slightly more specifically, being the only member of the group with any control systems experience, I've been delegated to design and build the sensing and control systems for the finished product. At the moment, I'm looking along the lines of accelerometers for the sensing side, which will feed information into a controller (possibly PD, but I'm open to suggestions) that will actuate a response from the system. It will have to be a closed loop system with some form of negative feedback, but given the ever changing input signal, I'm not sure how this might respond.

At the moment, fast ferries use T-foils to stabilise their motion, but these cause drag at slow speeds. If anyone has any data regarding their use I'd also be appreciative. We've only been able to come up with data for 18kts and 40kts - hardly enough to establish a working relationship....

Thanks for the advice Simon, I'll try to be more specific in my questions from now on....

Stuart

Reply to
Stuart Paterson

Dear Stuart Paterson:

What are you attempting to control? With what are you going to control it? Acceleration and time can yield displacement (with periodic re-zeroing)... ... now displacement of what?

David A. Smith

Reply to
N:dlzc D:aol T:com (dlzc)

Stuart.

you might also consider posting to sci.engr.control

regards SS

Reply to
simon

as a result of wave interactions.

actuators, the whole lot from scratch.

would be my best guess at the moment. That and roll and pitch angles.

Does that help at all?

Reply to
Stuart Paterson

Dear Stuart Paterson:

Sure. If you are using accelerometers, then you will be controlling the ship's *shape* based on its inertia.

You indicated multi-hulled... how many water-displacing surfaces touch the water when you are controlling pitch and roll?

You indicated you wanted to control pitch... do you have separate supporting bodies fore and aft?

David A. Smith

Reply to
N:dlzc D:aol T:com (dlzc)

I still find it surprising that people expect to find everything online.

First why should someone put "ship interactions for dummies online". The only people interested in ship motions, are people working on ship motions, but they don't need this dummy thing. Except maybe one group: students in ship design. So the most likely place to find your introduction are as lecture notes to the lecture series: "introduction to ship hydrodynamics", something which must surely be taught at your university.

When you need to go further the likely search would be for textbooks on the same subject, available from your university library, or scientific journals like "Journal of ship research" also available in your university library.

Timo

"N:dlzc D:aol T:com (dlzc)" schreef in bericht news:Gljbd.103$SW3.16@fed1read01...

Reply to
Timo de Beer

By the way: when you are in your library you could check out some titles from someone called Faltinsen. Don't be afraid to read publications from 30 years ago, the theory has not changed too much since then, only the computer power.

Timo

"Timo de Beer" schreef in bericht news:41703e32$0$62020$ snipped-for-privacy@news.wanadoo.nl...

hydrodynamics",

Reply to
Timo de Beer

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