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Author Topic: Can WinPLC be used on AGV/LGV systems?  (Read 5571 times)

Tywen

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Can WinPLC be used on AGV/LGV systems?
« on: February 21, 2011, 10:30:28 AM »
We are designing a very specialized AGV/LGV system.

The short of the long of it..
To make a long story short: the original development team went the old fashion route of using standard PLCs but have run into one snag after another. The integration of disparate vendor systems in conjunction with the projects logic requirements appear to be beyond a typical PLCs scope. Through the school of hard knocks I have had to learn PLC ladder logic and have come to the conclusion that a PLC is a finite task handler - not really a logic thinker. PLCs appear to handle a "task" very well but if you require it to solve problems or store significant data then a PLC fails dismally.

I am an experienced PC developer and stumbled onto the WinPLC site. I know PC's and currently program in C/C++ and .NET so I am somewhat excited at the prospect of possibly deploying a more robust logic control system. However, before I put my neck on the line I have several questions. I welcome any comments - especially from those who have used WinPLC in any similar scenario.

My team has been tasked to design the logic control for a specialized AGV. Mind you that I have never programmed for an AGV project. The logic control seems simple in my head but I keep going back to the last project team that was just fired for not getting the job done. So, I'm being cautious.

The AGV is to be guided by lasers. No guide wires in the floor due to environmental conditions. The AGV works in a warehouse that is mostly square. The AGV is to utilize four lasers that shoot from it's center of axis in four directions (X, -X, Y, -Y). In other words, the lasers shoot four walls to get distance to get an X,Y (2D) position within the warehouse. Based on a logical map that has "logical guide lines" the AGV can move about the warehouse. Does anyone know if this type of AGV navigation currently exist?

The original concept
The AGV is to have a task based PLC to navigate and perform the work. A PC server is to perform the logic and data storage and will communicate high-level commands to the AGV(s). A Simplistic Example:
PC Server to on board PLC: GET 56,34 PUT 11,22

The AGV should know how to navigate from where it currently is to position 56,34 and get the pallet and then navigate to 11,22 and place (put) the pallet and then wait for the next instruction. The AGV doesn't need to worry if a pallet is blocked by another pallet, etc. The PC Server program will ensure that any blocking pallet is moved first. The AGV just needs to more-or-less blindly perform the operation with some basic checks and balances. The on-board PLC will acknowledge the commands and provide real-time status updates to the PC server.

More over, the powers that be have permitted us to replace any and all the electronic equipment necessary. Therefore, I am asking this community:

A) Can the WinPLC perform the AGV task?
B) What about communicating with the WinPLC wirelessly (Like Wireless networking - WiFi)? Ok?
C) Is there a recommended drive train (system, motor, motor controller, etc) that works best with WinPLC?
D) Is there a laser measuring equipment that works with WinPLC?
E) Is there any radio positioning equipment that could replace the lasers and would work with WinPLC?

Of coarse I would really appreciated any advice from anyone with AGV development experience.

Thank you
« Last Edit: February 21, 2011, 11:12:03 AM by Tywen »

b_carlton

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Re: Can WinPLC be used on AGV/LGV systems?
« Reply #1 on: February 21, 2011, 10:39:52 AM »
This is not a comment on the usability of the WinPLC but on the laser location system. Is there really an assured perpindicular line-of-sight to 4 walls from anywhere in the warehouse? No blocking by any structures?
An output is a PLC's way of getting its inputs to change.

Tywen

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Re: Can WinPLC be used on AGV/LGV systems?
« Reply #2 on: February 21, 2011, 10:59:34 AM »
This is not a comment on the usability of the WinPLC but on the laser location system. Is there really an assured perpindicular line-of-sight to 4 walls from anywhere in the warehouse? No blocking by any structures?

No there isn't. That is why four lasers are being required. We only need two (one from each axis) to provide a location. In the schema there should always be at least two lasers (one from each axis) hitting a valid target. If the location is properly mapped the AGV would "know" (because of a map) that a particular distance value may abruptly change because the laser is crossing a column. That's the theory anyway. I know from a PC programmers point of view we could program this pretty easily however I have no experience with real-world AGV deployment and what the electronic equipment is really capable of doing. I'm open to suggestions.

MikeS

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Re: Can WinPLC be used on AGV/LGV systems?
« Reply #3 on: February 21, 2011, 04:02:00 PM »
I have no experience in AGV/LGV applications either, but I just wanted to throw out one point about the WinPLC into the discussion: that is, it is still using Windows CE v2.12, which does NOT support COM/DCOM.
Good design costs a lot. Bad design costs even more.