Driverless Transport Systems Being Put to the Test

If you enter a modern warehouse today, you will encounter scenes that a few years ago might have been dismissed as science fiction or pipe dreams. Driverless transport systems zip back and forth between order pickers and warehouse workers; these are automated trucks that can, for example, perform pick and drop tasks independently, relieving the workload for people. The trucks, known as DTS (Driverless Transport Systems) or AGV (Automated Guided Vehicles), operate autonomously: Without an operator, without rails embedded in the floor—and without needing to take a break. Driverless transport systems from Dematic, for example, range from narrow fork AGVs such as the FLV 2012/NL to heavy-duty driverless transport vehicles such as the FLV 2032/SL, which is capable of handling loads of over three tons. Both AGVs navigate independently through the warehouse and can be integrated into existing warehouse structures.

The same applies to the AGVs from STILL: When STILL introduced the OPX-L 20 S iGo neo driving assistant, for example, the message was clear: Efficient picking is intelligent—the truck thinks for itself. The autonomous driving assistant relies on a hybrid tracking system that detects and responds to its surroundings. In a dynamic environment characterized by fast and sudden movements, the trouble-free functioning of such a system should not be taken for granted. On the contrary, the safety and reliability of AGVs are the result of a rigorous testing and validation process that subjects the software and all features to stringent checks. There is a KION Mobile Automation test center located in Antwerp, Belgium, not far from the Scheldt River. Seven hundred square meters provide the test engineers with ample space to ensure that the KION Group’s AGVs are ready for operation and series production. Fabrice Lemoine, a test engineer at the facility, explains: “It’s a huge challenge ensuring safe workflows in a dynamic environment, i.e., an environment where people and machines work alongside one another.” It requires a lengthy process involving numerous test loops. “We leave no stone unturned during the process,” adds Fabrice: “At the end of the day, it’s all about protecting the customer from any dangers and possible incidents. That’s why we spend countless hours looking for potential errors and bugs during our concept and validation phase.”

The AGV testing process is divided into several key phases. It begins with the concept phase—well before the prototype is ready for its first test drive. The first step is to provide a proof of concept: the design for a driverless transport system as well as the software to be used. This step entails examining whether the project is feasible in principle. The design engineer’s work is then handed over to test engineers, who proceed to run practical tests on processes and movements during the second development phase. We have not yet reached the stage where we can take a holistic view: The features that have been developed are first examined on an individual basis before the next validation stage focuses on system integration, bringing together software and hardware components.

“Now we turn the key,” says test engineer Lemoine while smiling. What he means is: The truck’s engine is started. At this point, the first practical test follows the theoretical analysis and the computer simulation. “This is always an exciting moment,” remarks Lemoine: “System integration is basically a reality check. This is when you start to see what actually works and what doesn’t.” Ideally, a holistic architecture combining both component levels (i.e., hardware and software) will result in a coherent and functional picture—but even if this is the case, many questions still need to be answered: Which software components work well together, and which do not? Can the functionality of the hardware be guaranteed in all conceivable circumstances? Take sensors as an example: Can they really detect everything, or are there blind spots? “This stage involves varying degrees of time and effort, depending on the level of maturity of the original design,” explains Lemoine. This is where the optimism of the developer is met with the pragmatism of the test engineer, who pushes every test device to its limits in their search for potential issues. After all, this is what it’s all about: Probing every possible aspect and scenario, and determining what still needs to be changed on the truck in order to avoid hazards and correct faults. In addition to safety, the test engineers are also thinking about reliability and service life. “After a certain number of hours, there will always be one component that starts to fail. This is the case with industrial trucks, just as it is with cars,” says Lemoine: “It is our job to figure out what component that is, identify the load limit, and determine how to do that in a calculable way.”

It is well known in the industry that the demands and expectations placed on the stability of all KION Group industrial truck components have always been very high. The KION brands Dematic, Linde Material Handling and STILL carry out rigorous, complex, and extensive testing procedures before each new product launch to ensure that the trucks are fit for practical use. In this process, conventional, physical test procedures are increasingly being supplemented by virtual tests.

In the case of AGVs, system integration is then followed by the next step at the Belgian test center, which is known as prevalidation: This step focuses on the relevant industry-specific safety requirements. It involves a major step towards bringing the device being tested closer to real-world applications: For example, pick and drop routes are now programmed in and run several times in succession in the test center. This is done while taking into account the relevant safety regulations at all times, because needless to say, all guidelines, specifications, and laws must be complied with in automated operation. In order to create conditions that are as close as possible to subsequent customer use, different warehouse layouts are set up, and various obstacles are positioned and retested each time: Does the AGV register them in time? Do the sensors detect all angles, does the stop mechanism work, does the truck avoid obstacles correctly?

Finally, the prevalidation phase transitions smoothly into the validation phase: The driverless transport system has to prove that it can navigate efficiently in a space and make optimal use of its speed. In practice, this involves the following: The layout contains several filled pallets that are to be picked up independently by the AGVs and brought to the target position according to a specific protocol. This is repeated numerous times, with continually changing spatial variables, until all possible application environments have been checked. When performing an error analysis, KION Mobile Automation’s test center relies on maximum data transparency—and on the Group’s own diagnostic tools, such as Linde Material Handling’s AGV Insights. This software collects process data and enables cloud monitoring, as the data from an AGV tells a story. Crucial KPIs such as response time, availability, and reliability can be viewed at any time via the tool, and the AGV’s entire movement history is completely transparent. This also means that the routes within the particular warehouse layout can be checked, retraced, and, of course, optimized at any time. All data is stored in the cloud and processed using trend analyses, so that the test engineers do not miss even the smallest of details.

During the course of this multi-stage and complex validation process, all types of errors or bugs can be identified and corrected until no further adjustments are necessary and the security requirements are met. This concludes the work of the test engineers at KION Mobile Automation for now. For now? For now. This is because after a new product has been produced in the factory, there is another test loop before an AGV is shipped out to the customer. “At KION, we prefer to play it safe,” explains test engineer Lemoine. There are only a few companies in the world that are able to develop, produce, and test an AGV completely in-house from the concept phase to the implementation phase. “I’m proud that the KION Group is one of the few companies that can do this,” remarks Lemoine.