The Menken Van Grieken company decided to implement an ambitious project to automate its factory in Wassenaar, Netherlands, where various types of dairy products are produced.

The goal was to serve both large-scale retailers and local dairies, through orders placed via a web portal.

This is a warehouse-free system; goods leave the production facility, are accumulated in temporary buffers, and are immediately shipped in a fully automated manner.

This system consists of a higher-level supervisory system and various subsystems, such as:

• Warehouse management software, in this case implemented using accumulation buffers
• AGV system management, consisting of 11 magnetically guided carts with infrared communication
• Management of 5 ABB robots systems, each one with a 5-axis arm, that insert product boxes into the containers loaded by the AGVs
• Customer order management
• Supplier procurement
• Shipping management

Each subsystem has its own communication drivers, developed in-house.

The most significant work involved a completely rewriting the communication driver between the central computer and the AGVs, establishing a new standard that was subsequently adopted in other projects.

15 people from different countries, where having issues in continuing the commissioning because AGVs could not communicate correctly with the central computer so that the flow was not flowing.

We got incolved in the project the 26th of December 1996. We went onsite the 28th. It took 2 weeks to rewrite completely the AGV communication protocol driver, but then AGVs there driving without any stop. We completed the whole commissioning in april 1997.

Description of the flow:

1. products are coming out from production in boxes stacked in crates
2. each crate, according to which product is containing, is lined in a specific buffer line on a first floor
3. crates are taken down to the ground floor and goes on the lined buffer to the end where an operator pick it
4. on a side there is a line of positions where the operator should place crates taken from the buffers
5. buffers and positions have color codes, so operator take a crate from a certain buffer that has a certain color lamp on, and place it on the lined position with the same color turned on
6. On the other side of this lined up positions, there are 3 ABB robots that run on a rail. They pick boxes from crates and place it on AGVs that are stopped, with empty crates, on three stop positions in front of those 3 ABB robots
7. On the AGV chassis, there are markers painted. A camera on the top of the AGV see the stop position of the AGV and sends the X and Y offset to the AGV robot so it can drop the box on the AGV very fast with no error
8. Normally single product boxes are required for big orders for retail shops, while boxes with different products are required by single user that ordered via the web
9. Some crates are going from the top buffers, up over the AGV layout, then down to a picking area where operators are taking boxes and place them in some small shelves
10. AGVs, after to be loaded by the first 3 ABB robots, they go, if necessary to other 2 stop positions where operators prepared those mixed product boxes, having done picking from the shelves, and then the other 2 ABB robots place those mixed product boxes on the AGVs
11. The AGV then cotinue to drive in a loop to another position (eventually), where an operator load manually some “last moments” boxes
12. When the AGV has its crates fully loaded for that order, then it goes to the shipping bay where drops the crates.
13. The sequence of the AGVs to the same shipping bay is in reverse order of the shipping route that the truck is doing
14. The AGV goes then to the pick position for the empty crates and start the loop again
15. When the truck is full, it is leaving the factory and start the shipping route

This is one of the most automated system we have been participating to.

AGV navigation type: magnetic wire guidance.

System controller: IBM RS6000 in maxed configuration and hot backup. Oracle database is used with many store procedures and triggers.

AGV system controller: same IBM RS6000 but with Informix database, AGVs are communicating via infrared transreceivers.

Charging concept: charging stations with contacts on top of the AGV, when batteries are low, the vehicle is sent there to stay and charge, the flow is continous, so that AGVs will stand still only when the system goes in shutdown mode.

This AGV system is working over three shifts.

Number of AGVs: 11

AGV manufacturer: Digitron.

Function: AGV system controller development.

Year: 1997