The ongoing developments in intelligent and flexible material handling systems, which are basically robots, continue to fascinate me. For example, automatic guided vehicles (AGVs) used to be fairly dumb machines that moved from point to point by following a preset trail of magnets in the warehouse floor. Humans loaded them at one end of the warehouse and unloaded them at the other. But AGVs have gotten a whole lot smarter.
At the RedPrairie user conference a few weeks ago, Tom Grohalski, a project manager at the Kellogg Company, talked about how Kellogg’s is using AGVs with forks on them from Egemin. AGVs take pallets from the end of the production line and stack them in a bulk warehouse. Other AGVs then take product from the warehouse and stage them on the dock. As a result, this warehouse needs very few people. However, “chasers” and “super users” are still needed. Some AGVs stop due to small obstructions, such as shrink wrap dangling down from a pallet, or they go off course and chasers needed to put them back on track. The “super users” handle IT glitches and issues. Kellogg’s also has forklift drivers on the dock to load the truck, but these drivers are now almost three times more productive.
Here are some takeaways from Grohalski’s presentation:
- Kellogg’s conducted simulations to figure out how many AGVs it would need to handle peak production in conjunction with various fulfillment scenarios.
- The RedPrairie WMS tells the system where to put the product. The AGVs have a control system that contains a vision system (i.e., the AGVs could run without reading magnets in the floor), sensors, a digital map of the warehouse, and the move logic. The RedPrairie put-away configuration logic needs to make sure too much product isn’t being unloaded in the same zones; otherwise, the slow-moving AGVs (350 feet per minute) would have congestion problems. “AGVs are polite,” Grohalski commented, “they will patiently wait their turn.”
- The dimensional pallet and warehouse layout master data needs to be very, very accurate.
- Kellogg’s ran two pallets high from the production line and would stack pallets up to four high. Pulling from the warehouse to the staging area, AGVs might take one or two pallets. Consequently, there could be bays that would only have three high pallets. Thus, there was a tradeoff in using AGVs. Kellogg gained labor efficiencies but lost some ability to fully utilize all of its warehouse space.
- The pallets were scanned off the production line. After that the WMS knew their license plate and where they were to be stored and the pallets did not need to be rescanned in the warehouse.
- Kellogg’s experienced big reductions in damage and improved safety.
- Kellogg’s expects a three year payback period and it is on schedule to achieve that target.
In conclusion, AGVs are becoming more like forklifts, and some forklifts are becoming more like AGVs. If you add a vision control system and control software to forklifts, they begin to act a lot like AGVs (see our posting on “New in Flexible Warehouse Automation: Real-Time Location Forklift Automation”). Meanwhile, AGVs, which used to just tug pallets or move carts, are beginning to act more like forklifts because the latest generation of AGVs have forks on them that move up and down and can stack pallets.