warship automation under servo control

Spineless Cougar

Hi-

I work at the USS Slater (www.ussslater.org) and am working on automating the Combat Information Center (CIC). This involves simulating radar displays, having various equipment light up and move.

I'd like to use servos to move an x-y positioning system, a speedometer and a gyro compass repeater. The positioning system can be run by a continuous rotation servo and the speedometer can be run by a standard servo.

The gyro repeater is the problem. It is a directional display to show direction like a compass but under control of a gyroscope. What I want to do is be able to rotate the display to indicate what direction the ship is going. A standard servo only rotates about 180 degrees, I need the ability to rotate in both directions possibly multiple rotations and settle on a specific compass position. I had hoped a continuous rotation servo would do it for me but, alas, it doesn't seem possible.

So, I'm looking for ideas on how to power a compass with a servo. Any ideas?

Attached is a picture of part of CIC with a yellow arrow point to the gyro repeater.

-Erik

Franklin

You could still use a continous rotation servo (CRS) and add some kind of encoder so you would know where the dial is set. One thing to remember in a setting like this where things are moving is that servos make noise. You will need to take that into account when the equipment was originally silent.

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- Stephen

TechnoRobbo

Looks like you need a rotary sensor that you can read with rctime.

http://www.mouser.com/catalog/630/1542.pdf

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Have Fun


TR

Post Edited (TechnoRobbo) : 5/20/2007 9:48:45 PM GMT

Lawson

Alternatively you could just directly drive the Gyro Compass repeater. Find out what the motor like thing that drives the pointer is called (should be written on the thing) and poke around Wikipedia and Google. Should be able to find a description of what kind of signal it expects fairly quickly. I seem to remember that similar devices use a referance AC input with a 3-phase AC signal setting the pointer's direction. I think that the basic magnetics will also work at DC.

Best of luck,
Marty

John Abshier

Here is a 360 degree servo kit
http://www.budgetrobotics.com/shop/?shop=1&cat=157

Spineless Cougar

A progress update:

I found that by entering the correct pulse duration I could get the continuous rotation servo to make very small steps. With a contact to to zero the position this method should work, it does pretty well in tests at home, I'm on vacation this week so I'll test it on the ship next week.

The rotary sensor looks like the way to go if the first method fails to live up to my hopes. The 360 degree servo would work in another application I'm looking at but I suspect it's just a standard servo with 180 degrees of rotation while what I need has to do multiple 360 rotations.

The servo will actually be hooked to a self synchronous motor that will then drive the synchro in the gyro compass repeater. Putting the servo directly in the repeater would be a major pain - there is vry little space to work with in there.