Automated Gantry Choices

DesertDog · Feb 24, 2006

I'm looking at posibly doing a project using an overhead gantry to move a piece of equipment to perform operations at several stationary areas in a large room. I definately need 2 axis movement but up and down would be a great feature if I can fit it in the limited overhead room. I'm thinking a rack & pinion system with either absolute encoder or position sensors at each place. I could really use some ideas on hardware providers for such equipment.

Thank you

mgvol · Feb 24, 2006

Have used these in a 4-axis configuration. Didn't much care for the Parker Compumotor servo system though.

PLucas · Feb 24, 2006

DD

Perhaps if you went into a bit more detail on what you want to acheive, I might be able to offer advice, after all I deal with automated rail mounted gantry cranes daily.

I can fill you in on how we achieve our positioning on the three movements, gantry (long travel), trolley (cross travel) and hoist (up and down). We position our gantry's to within 10mm, the trolley to 5mm and there is a bit more scope on the hoist, I will explain that if required, because the hoist can position to within 100mm, mainly because it is looking for another signal to stop it in the right position, it doesn't rely on the encoder.

Anyway, I won't go into too much detail now, I will wait to see if you want any more information.

Paul

DesertDog · Feb 24, 2006

Some Detail

PLucas said:
DD

Perhaps if you went into a bit more detail on what you want to acheive, I might be able to offer advice, after all I deal with automated rail mounted gantry cranes daily.

I can fill you in on how we achieve our positioning on the three movements, gantry (long travel), trolley (cross travel) and hoist (up and down). We position our gantry's to within 10mm, the trolley to 5mm and there is a bit more scope on the hoist, I will explain that if required, because the hoist can position to within 100mm, mainly because it is looking for another signal to stop it in the right position, it doesn't rely on the encoder.

Anyway, I won't go into too much detail now, I will wait to see if you want any more information.

Paul

I can't get into too many specifics at this point anyway but if I can move close to 1000 Lbs with an accuracy of 1/2 inch I'll be doing good.

I basically find one of several start positions and then make a simple sequence of moves, then move on to the next position.

elevmike · Feb 24, 2006

DesertDog said:
I can't get into too many specifics at this point anyway but if I can move close to 1000 Lbs with an accuracy of 1/2 inch I'll be doing good.

I basically find one of several start positions and then make a simple sequence of moves, then move on to the next position.

I would think that would be very acheable with 3 axis, front -back, side to side, and up and down. The question is what's the mechanics of the system? The vertical axis could be tricky if your using a roped hoist. (have to account for rope stretch and dampen swing).

In short X & Y are pretty streight forward, but Z depends on a lot of unknowns that havent been disclosed yet. If you can use some type of a stiff armed lifting device, it would be a lot easer to acheive the accuracy required. Given low overhead and a requirement for high lift, a telescopicing guide on the vertical axis might be an answer.

PLucas · Feb 24, 2006

DD

Our cranes lift 30ton, they long travel over a distance of 540 meters, cross travel over 24 meters and hoist over 15 meters, all within the accurancy previously stated.

I understand where Mike is coming from with his comment about hoist ropes, but all our cranes are roped, we have no problems, you just need to have them reeved to give some sort of anti-sway properties, or you employ other anti-sway means.

Just for your info, our encoders on the hoist are driven direct from the rope drum, then scaled in the logic to the diameter of the drum.

Paul

P.S In case you don't know I work in a fully automated container port

ndzied1 · Feb 24, 2006

If you are looking for sources for someone to design and build gantries, here are two possible companies:

http://www.fibroinc.com/

http://www.wes-tech.com/

jstolaruk · Feb 24, 2006

EWAB is a gantry mfg that we'll be using in a job this year; the application is load/unload of transmission cases at Daimler Chrysler.

http://www.ewab.net/

PLucas · Feb 24, 2006

DD

Can you clear something up for me please...

I am assuming that you already have the overhead cranes in place and you wish to automate them, is this correct or are you having a brand new crane installed that will be automated?

Paul

rsdoran · Feb 24, 2006

I think the request, as stated, is too ambiguous. You state automated overhead gantry, but you state

I definately need 2 axis movement but up and down would be a great feature if I can fit it in the limited overhead room.

An overhead gantry (crane) is for lifting, the travel may be X-Y or just X depending.

It is not necessary to state exactly what is being done but several factors would be helpful, an example;
Range of motion: If room is 20ft x 20ft does it need to be able to go to within 1/2 inch of any point in the room? Or is the path pre-determined...maybe a straight line?

For someone that usually states things in a very orderly fashion you are not being very orderly in this request

SD_Scott · Feb 24, 2006

I'm designing one now that's aprox 20' X 20'. It's Controllogix talking ethernet to two VFD's and the x,y position is measured by Sick laser gauges that send RS422/RS485 position data to AB Point I/O.

SAK-CO TECH · Feb 25, 2006

A large part of our business is the design and automation of hoisting systems and plating lines for the metal finishing industry and others.

We have come to like SSI or DeviceNet signals to our PLC's from Sick lasers. With 250 lb. to 4 ton capacity hoists with ranges varying from 15' to 800', we have had no problem with getting to 5mm and under accuracy.

If this is an existing system, this is a very good and inexpensive alternative.

Regards,
Chris

CroCop · Feb 26, 2006

The Sick DME 5000 with device net is really easy to use. Import the EDS file, give it a bus address, wire it in, divide a dint by 10, and you've got an absolute measurement expressed in millimeters.

I've quite liked them.

Automated Gantry Choices

DesertDog

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mgvol

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PLucas

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DesertDog

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elevmike

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PLucas

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ndzied1

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jstolaruk

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PLucas

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rsdoran

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SD_Scott

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SAK-CO TECH

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CroCop

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