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how to objectively define 'controllability' of underwater robots


I'm looking for ideas to this research problem I'm working on . . .

Let's say I have a list of 50 different underwater robots. They are all different. Some have many thrusters, some just one. Some have rudders, some have fish tails, some have side fins. Some are like mantarays, some are like fish, some are torpedo shaped and some are box shaped. And some mix/match those attributes.

I know the mass, velocity, and dimensions of most of them, and have a picture of all of them. I do not know their acceleration rates, drag coefficients, nor their control algorithms. I cannot run any tests on any of them.

Given this information, how could I objectively rank them in order of controllability?

Controllability, meaning how easy can it maneuver and to remain stable despite external environmental influences. I can think of a few ways, but they have have caveats and looking for other ideas . . .


--- Quote from: Admin on November 28, 2012, 12:57:17 PM ---I cannot run any tests on any of them.

Given this information, how could I objectively rank them in order of controllability?

--- End quote ---
Assuming some of them are quite similar, I don't think it's possible, as you have no real measure of drag for instance.

Some decades ago, scientists were quite surprised, when tests revealed that the coarse skin of a shark, is actually allowing it to move with less drag, as compared to a perfectly smooth surface and they predicted that ships would be painted with "artificial shark skin" (in an undefined future) to save fuel.

With that, the "no test" and the "objectively rank" in mind, it sounds like you have you work cut out.

And besides... That a subject should be capable of objectivity is an illusion and an oxymoron ;D

I could show you pics of super aerodynamic solar cars, and you'd really have no idea of their handling... The car comparison might be poor though... their ratio of interior importance to exterior importance is probably higher than submersibles, if that makes sense.

In other words, I agree with Soeren. But I'm probably just not imaginative enough.

The two ideas I currently have are the turning radius, and counting the degrees of freedom.

Mr. Ninja:
I think (even coming at this as someone with limited experience), that maybe you should factor in depth and water pressure (if you can?). Including the pressure exerted on the sides at their appropriate speeds, factoring in the surface area, radius, and DOF?

I'm thinking that might work but as I said before, I'm not experienced with this sort of stuff.


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