This is #newtk: Automation of the last mile
Automotive-sector | Digitalisation and industry 4.0 | future of production | All over the world, our colleagues at thyssenkrupp are working to safeguard the future of our company by making it more flexible, more efficient and more high-performance. In our new strategy #newtk, we are putting performance center stage. One concrete example of this are the autonomous transport vehicles at our Fameck and Terre Haute sites. These vehicles control the flow of goods between Production and the high-bay warehouses fully automatically. The result: greater efficiency, improved safety, lower costs and higher productivity.
Everything flows. At the thyssenkrupp plant in Fameck/France, people assemble steering systems from a large number of individual parts in what appears to be an endless cycle. Crates and boxes containing pre-assembled assembly groups, ball bearings, metal tubes and other components roll to the production line on forklifts; semifinished parts leave the line heading for the warehouse; finished steering columns and steering gears are transported automatically to the outgoing goods department. Driverless, electrically powered forklifts glide back and forth between machines and racks almost silently, as if controlled by a magic wand. Everything flows, and the employees at their workplaces are supplied with components and materials with the utmost precision.
Driverless forklifts: for better flow over the “last mile”
There’s a system behind the continuous flow of goods – and it’s called ONE Flow AGV. AGV stands for “automated guided vehicle,” which in Fameck’s case refers to two types of vehicle: driverless forklift vehicles (FLVs), which transport goods to and from the high-bay warehouse, and driverless turret trucks, aka very narrow aisle trucks (VNAs), which lift the pallets into the local high-bay racks. All to achieve one big goal: to automate the flow of goods over what’s called the “last mile”, i.e. the stretch between the materials store and the assembly point on the production line.
“The last mile is an extraordinary logistical challenge,” explains Fabian Liebetrau, Head of CC Lean Services at thyssenkrupp’s automotive steering specialists. “On the one hand, the number of components and the volume of packaging in the plant are enormous. On the other hand, our production flows in Fameck intersect, as we have to respond flexibly to our customers’ requests. In addition, automated production facilities, automated forklifts and human colleagues work closely together on site – which is why safety takes top priority.”
One Flow AGV: autonomous transportation of goods and materials for greater efficiency
In practice, human forklift drivers first bring the delivered goods to the conveyor, which measures each load carrier, checks the integrity of the goods and then makes them available to the FLV. The driverless forklift then takes the goods to the transfer point of the high-bay warehouse, where a VNA finally sorts and slides them into one of the approximately 7,000 slots in the high-bay warehouse, which is more than eight meters high.
As soon as a colleague in Production requires specific materials for their work, they request the components via one of the 60 touchscreens installed around the factory. The narrow aisle trucks immediately start to move, pick up the required components from the high-bay racks and hand them over to an FLV that is free. This then delivers the package and empties to one of the numerous drop points at the production lines. Of course, this process also works in the opposite direction – from production back to the high-bay warehouse or shipping.
The company also relies on One Flow AGV at its Terre Haute plant in the USA, but in this case only on driverless FLVs – there are no high-bay warehouses in Terre Haute. For this reason, the load carriers received by the incoming goods department there are moved to a transfer rack by human colleagues. To store these goods, driverless forklifts then remove them from the opposite side of this rack.
Highly efficient transport via laser localization
The autonomous robots can transport goods weighing up to one metric ton at speeds of up to six kilometers per hour. The working environments and processes have been adapted to the specific requirements of the AGVs so that these rapid-moving, heavy loads are always transported effectively and above all without endangering the human workforce. “We have completely changed our processes and standardized interfaces at which, for example, goods reach the production lines,” says Olivier Martinelle, Supply Chain Manager responsible for thyssenkrupp’s French plants in Fameck, Florange North and Florange South sites. The drop points at the production machines now all have the same dimensions. “Automating shop floor logistics means much more than just deploying AGVs,” adds Martinelle.
The FLVs and VNAs being used rely on laser scanners to navigate around the production shed. Comparable to GPS localization used to navigate the road network, the beams emitted by rotating lasers installed at the top of the autonomous vehicles hit reflectors distributed around the walls of the shed. Whereas a normal GPS module uses just three satellites to identify the position of a vehicle, the system in Fameck uses between five and ten reflectors. “Movement of the robots is accurate down to plus-minus 5 millimeters,” enthuses Martinelle.
Based on this information, warehouse management software then controls which points are to be approached, which goods and finished parts are to be transported and where they are to be stored – and how they get there as quickly as possible. The transport software determines the ideal route automatically and guides the vehicles precisely to their destination. The two programs communicate with each other to ensure that the AGV most readily available is always used. Finally, the contacts at the production line transmit the information about the goods and their destination to the FLV. “The system always knows the inventory levels and the exact storage locations of all components in the plant,” explains Liebetrau. “The transport orders are initiated by our machine operators. There are practically no waiting times at the production machines, because once they have completed their training and familiarized themselves with the system, the operators know exactly how far in advance they need to place their orders.”
One Flow AGV project: highly complex and interdisciplinary
The different operational departments at the plants worked hand in hand to implement the project. In total, more than 30 employees were involved, with a cross-functional team of colleagues drawn from Logistics, Production and Quality Assurance taking charge of actual implementation. At the same time, the staff in Fameck and Terre Haute – more than 700 employees in all – were put through rigorous training to prepare them for this automation of the last mile.
It took a little more than two years to develop ONE Flow. In a complex simulation, the planners determined how many vehicles were required – 25 FLVs and 6 VNAs in France and 10 FLVs in the US. “The ratio is perfect,” says Liebetrau, summing up. “Since One Flow AGV was launched in September 2016, the flow of goods has been perfectly smooth and, most importantly, totally accident-free.”
Successful conclusion, comprehensive increase in efficiency
Martinelle and Liebetrau are highly satisfied with the outcome of the project after two years of service. “We were able to optimize space utilization to such a degree that we can now store 50 percent more goods and materials,” says a happy Martinelle. What’s more, the automated aids have significantly reduced costs at the sites, among other things by shortening the length of time the colleagues in Production have to wait for the materials they need. Productivity has increased overall.
The number of times racks and the materials themselves have suffered damage has also declined sharply since the introduction of One Flow AGV: Previously, on average, one forklift load per week was dropped and smashed at the three sites. Since the autonomous system went on stream, this figure has remained constant at zero. “FLVs and VNAs are equipped with sensors that are so sensitive that they can identify a collision risk super-fast and come to a stop,” explains Liebetrau. “Thanks to the many improvements made to the process, the project has paid for itself after just 3 years. That said, automating the last mile was by no means an end in itself – we have always focused on improving performance and efficiency at our plant.”
Workforce in the digital age: formerly a forklift driver – now a supervisor
Today, you don’t see forklift operators around the factory as often as you used to. But they are still needed to load and unload trucks, for example. AGVs are not (yet) able to do this. Nevertheless, the team of forklift drivers in Fameck has been cut from 40 to 6. Many of them have been retrained and have now taken on other tasks, such as supervising the automated process. “Together with our workers, we have all acquired new skills,” says Martinelle. So that everything keeps flowing smoothly.