Natural Feature Navigation Guides Autonomous Vehicles to Success

Summary

Automated Guided Vehicles (AGVs) have become a hot topic during the current COVID-19 pandemic with factories and warehouses struggling to continue their usual operations with reduced staff and social distancing. However, the value in automating internal logistic flows was well understood before the current crisis and the solutions are equally valid across manufacturing facilities and warehouses.
 
One company that has recently optimised its material flows is US-based GECOM Corp. There are more than 630 workers at the 400,000 sq ft facility where the company manufactures high-quality door locking mechanisms for the automotive industry with operations that include assembly, metal stamping, injection moulding, and warehousing. In 2018 the continuous improvement team at the site was challenged to undertake human resource optimisation without reducing the efficiency of the firm’s operation.

Looking to autonomous operations

The focus was on the key material handling processes that involved moving empty tubs and raw materials from the warehouse to the plant’s assembly lines, and the returning full tubs of finished products. “We had material handlers with pallet jacks walking around trying to figure out what they needed, when they needed it, but we never had a good time study to tell us if we had the right number of people or not,” Steven Lockhart, the team’s head industrial engineer says. “We knew we had some good opportunities to optimise our processes.”

Based on earlier experience at another of the company’s facilities, Lockhart decided to assess the potential of AGVs to automate the site’s tub-moving processes. The initial efforts focussed on small motorised trucks (tuggers) that material handlers would drive, pulling carts full of tub skids behind. These vehicles were used to bring raw components and skids full of empty tubs for finished product to the assembly lines and taking full skids of finished goods back to the warehouse.

"Our thought was that we could implement the tuggers and then transition from the tuggers to the AGVs," Lockhart explained. "Implementing the tuggers first would allow us to establish the routes and the pick and drop points, which would be one less challenge once we started with the AGVs. We were already able to achieve some headcount optimization by running one tugger, pulling five carts at a time."
 

When size matters

Lack of available space proved to be the biggest challenge in this approach. The height of the cart and tubs totalled 68 inches meaning that the top tub was physically too high for the workers to stack. Another drawback was the size of the tuggers themselves. “There is not a lot of free room on our assembly floor,” Lockhart added. “In theory the tugger driver could have done it but we knew that would not be possible if we were using AGVs.”
 
That forced Lockhart to investigate smaller AGVs. “I was immediately able to narrow down a lot of AGVs because our aisles are only 96 inches wide,” he says. “That proved to be the biggest challenge—finding an AGV that can operate in an eight-foot aisle.” After testing several variations, including a well-known brand of autonomous mobile robot (AMR), the team selected the Nipper AGV as a clear winner. In addition to being compact and agile, the Nipper also offered attractive battery life of almost five hours on a 30-minute charge, had an impressive maximum load of up to 2,200 lbs and was guided by natural feature navigation, specifically ANT by BlueBotics. This navigation system meant that minimal infrastructure changes were required on site. The installation could be completed by just adding a few adhesive reflectors.
 
“I knew I didn’t want a system that follows magnetic tape, as I have heard horror stories about trying to keep up the maintenance on that,” Lockhart explains. “The Nipper just runs off data from a 360-degree navigation scanner and uses Wi-Fi to communicate.” Two of the AGVs were purchased and the team set about calculating timings and routes. “We wanted to verify how the AGVs interacted with each other, at intersections for example and in the systems’ software,” Lockhart adds. “One of the things that really helped was using the ANT lab software to run a simulation before we had the AGVs on site. We managed a lot of work before the AGVs showed up. We had our spots on the floor, our pick and drop points, all done.”
 
A second software package, ANT server, was used to manage the fleet of two, and later more, AGVs. However, Lockhart’s team also added an additional, more expansive interface, a SCADA programme called Inductive Automation, to be built on top of the ANT server to make life even simpler for team leaders.  “We have 13 team leaders on first shift,” he continues. “They call the missions for the AGVs. They know what tubs they need to run that day and they know when their finished goods are done. So, we implemented tablets for these team leaders, instead of their desktop computers, partly to make them more mobile. We can also use the tablets to do other things on the line that team leaders need to do, like running lot control, scanning parts when these come onto the line, so we know what batch of parts were used on what day. There are different things like that, which help the team leaders become more efficient.”

 
Quick and easy installation

Commissioning the first two AGVs was completed inside three weeks, with two further AGVs added five months later in September 2019 and a fifth in March of this year. “With AGVs three to five, we knew what we wanted to set up beforehand, and we were able to make all of our lines for the AGVs interact with the API. So, we did a lot of that set up before AGVs three to five got here. This made for a much smoother transition.”
 
From GECOM’s perspective, the project and investment has been a huge success. The five AGVs run 24 hours a day, five day a week covering 65 assembly lines. “We have been able to meet our target headcount reduction of approximately 73 per cent, and it has also led the way for us to explore other AGV possibilities,” Lockhart says. The goal is usually to return the investment inside a year but because of the complex nature of this project, that was extended to 24 months. “We were okay with that, as we knew that no matter what customer it was or what assembly line we had running, this AGV deployment was more a general project that would cover pretty much anything we put on the production floor,” Lockhart concludes.
 
The next step for Lockhart and his team? Widening their AGV programme. This could mean procuring a high reach truck, also based on BlueBotics’ ANT navigation technology, to run in a fleet alongside the Nippers. And Lockhart is considering replacing the manual tuggers used to bring raw components to the assembly lines with AGVs too.