Material flow round table: AGVs - autonomous free-flyers in 2D

The automotive industry was once the big driver. The "rolling workbenches" soon conquered other industries too. AGVs have long since left the guide wire behind and score highly as autonomous transport systems with 24/7 performance.

Modern computer technology and sensors have accelerated this development. What can automated guided vehicles do today and where is the industry heading? The experts had exciting answers in store.

At the Bader Hotel in Parsdorf near Munich, Martin Schrüfer, Managing Editor-in-Chief of Material Flow and LT-manager, editor Susanne Frank and Walter Dorsch (freelancer) welcomed five experts from Germany, Austria and the Netherlands:

What are we talking about when we talk about AGVs?

Peter Ossendorf gets the ball rolling from the panel discussion. The Head of Marketing and Sales at MLR Systems distinguishes between automated guided vehicles (AGVs) and automated guided vehicles (AGVs). "When we talk about a driverless transport system, we should be talking about at least three components. The first is the moving device, the second is the corresponding stationary control system and the third is the radio component, which performs the tasks as part of the device. AGV is just a single component of the AGV."

Ossendorf does not consider AGV systems to be the group of service robots, which are currently very much in vogue. He justifies his distinction by saying that the term "AGV" already includes the term "transportation", whereas the term "service robotics" is more about goods handling. However, Ossendorf concedes that it is no longer possible to differentiate so precisely between the classic areas of application. Today, there are driverless transport vehicles in every industry that fulfill their tasks.

"The AGV is safe and will stop if a person stands in front of it." Jan Jongbloets, Director Business Development at Oceaneering, Utrecht (Netherlands)

Jan Jongbloets, Director Business Development at Oceaneering, points out that people often focus too much on the vehicles. Ultimately, it's about the logistics AGV solution, supported by AGVs. For Dr. Markus Aichinger from the Innovation & Logistics team at Knapp, it's also about delivering a solution for the customer. "Starting with devices that can transport 15 kilos up to several tons, it's about creating an overall concept. For us, this is usually a combination of transportation and picking processes. This is because we came from the field of distribution warehouses and have only developed in the direction of manufacturing companies in recent years," says the Austrian. Dr. Andreas Richtsfeld from DS Automation sees a trend towards mobile robotics becoming more and more popular with AGV manufacturers. However, the product developer believes that industrial transportation in logistics is still the main area of interest.

This is also the view of Elmar Issing, Vice President Robotics & Innovations at SSI Schaefer Noell. "The material flow does not stop at transport systems. Attempts are being made to generate even more from transportation. I think that further development is necessary today in order to do justice to the changing processes not only in warehouse logistics, but also in assembly processes and manufacturing processes." In his view, we need to move away from rigid interlinking and towards sensible networking of the various process areas.

Will the AGV replace the forklift truck?

"When we talk about a driverless transport system, we should be talking about at least three components. Dipl.-Ing. (TH) Peter Ossendorf, Head of Sales/Marketing at MLR System, Alsdorf

Ossendorf does not see the AGV as a pure substitute. "If the customer wants to replace a forklift truck with an AGV, that would be the wrong approach. You first have to analyze the task at hand and then bring the appropriate device onto the scene. There are hundreds of different types of driverless transport vehicles and the forklift truck is only one small area. However, today AGVs perform tasks that a human can no longer perform." This is the case when it comes to heavy loads. In coil handling, for example, we are talking about 30 tons and even over 60 tons for tools used in pressing plants. There are now very good solutions that can replace humans in this area. The depth of advice demanded by customers today has naturally become correspondingly intensive, reveals the sales manager.

Markus Aichinger can only agree: "It's always very exciting when customers come and want a process solution, but then want to have several options to choose from in the concept development process." The Austrian recalls an order where the customer had no option to install conveyor technology and only aisles that were also used by people were available. "A combination of people and traffic - how can you do that cleverly, depending on the scaling? We then came up with interesting approaches that had never been seen before in this form. In addition, the customer wanted to start with a simple solution because they didn't know how their business would develop. Tasks like this are predestined for flexible solutions that require little infrastructure and are exactly right for this customer."

For which companies is it worth considering AGVs?

"24/7 and multi-shift operations for sure," says Jan Jongbloets. Elmar Issing adds: "24/7 - three numbers, a dash in between, it's often just written there. But what's behind it? 24/7 means round-the-clock operation, year in, year out. That's quite extreme! We have a customer in Belgium who moves 360 pallets per hour with AGVs in 24/7 operation, day and night, Sundays and public holidays. Everyone knows what it means if you have to provide staff for this. Nobody can be absent, it always has to run. Driverless transport systems can also be considered in deep-freeze warehouses," says Issing.

According to Ossendorf, the return on investment is still an important criterion for an investment. "You really have to look at it from an industry-specific perspective. If you are working in two-shift operation, then customers in the automated goods movement sector have to operate with an ROI of 2.2 to 2.4 years. However, if you go into specific areas such as heavy-duty AGVs, you can definitely earn money with them in single-shift operation. People are then prepared to accept an ROI of 5 or 6 years."

"The ROI cannot be generalized," Issing points out. "In 24/7 operation, it can be within a year. Elsewhere, it can take five to six years and still make sense." In this context, Ossendorf refers to the VDI guideline "Economic efficiency of driverless transport systems", which shows that other factors play a role in addition to personnel savings, such as avoiding damage to the building structure caused by manual industrial trucks.

"Ultimately, however, the customer wants to optimize their processes. That is always a question of cost." Dipl.-Ing. Dr. Andreas Richtsfeld, Technology & Product Development at DS Automotion GmbH, Linz (Austria)

"Ultimately, however, the customer wants to optimize their processes," says Richtsfeld. "This is always a question of cost. What's more, customers today expect more from automation than they used to. The fear of losing flexibility has been reversed. The customer believes in the technology and knows that AGVs make sense. You no longer have to do much convincing. The customer assumes that the technology is available today to solve all tasks. But it's not just about moving the goods from A to B. Process reliability must be guaranteed. Today, we are seeing more and more integration of different technologies. The influence of robotics is very great. Work is being done to get even more out of the technology."

Jan Jongbloets describes process safety as a critical case where expectations of products and technology need to be curbed. "This applies to applications where you combine chaotic transportation with AGVs. The AGV is safe and will stop if a person is standing in front of it. However, if the disturbances are too high, then the performance goes down. You have to be honest about that. But in most cases, manual transportation can be automated if the environmental disturbances are not too high."

Change of topic in the discussion round. It's about technology trends such as navigation and positioning systems. Richtsfeld mentions the keyword "virtual game", in which the vehicle moves along a virtual guideline. "We plan the routes and intersections, but the virtual guideline is not a planned lane. With free-moving vehicles, we enter the realm of mobile robotics, i.e. the vehicles could decide for themselves which routes to take. However, free driving also brings problems with people in the vicinity. In my opinion, there is currently no broad solution that solves all the problems with truly free-moving AGVs," says Richtsfeld.

"The material flow does not stop at the transport systems." Elmar Issing, Vice President Robotics & Innovations at SSI Schäfer Noell, Giebelstadt

Issing brings the swarm-intelligent organization into play, although he is not entirely convinced whether it actually works like in the animal world. "It's not about vehicles that I push through the area one after the other, but about vehicles that can navigate freely in space. The topic really gets going when vehicles communicate with each other and assign jobs to each other. Then it goes on to having a central control system to control and organize an entire fleet. The decentralized "intelligence" on the machine has of course been programmed beforehand."

Ossendorf has his own definition when it comes to navigation. "I always call the track-guided systems 1D navigation, i.e. one-dimensional navigation, in order to find a terminology. 1D navigation is cheaper than free navigation due to its simple technology. I call free navigation 2D navigation because it offers the possibility of freely navigating xy coordinates. In 2D navigation, there are three models and I differentiate between artificial placemarks and natural placemarks. The latter are referred to as building navigation. For example, it can be a pillar, a machine or a door panel. Artificial placemarks are the reflectors in laser navigation or the magnets in the floor in magnetic navigation, but these also only serve as references."

Free navigation is often misunderstood, says the MLR sales manager, because customers often think that the artificial placemarks are there for them to follow. However, they are only references that the vehicle uses to check whether it is on the right track. If it is not on the right track, it corrects itself.

Richtsfeld defines swarm intelligence as the sum of intelligent agents that are networked with each other and can jointly solve a task that a single vehicle cannot solve. The individual vehicle would then be the agent. He considers it an exaggeration to speak of the intelligence of individual agents.

Ossendorf rejects swarm intelligence of any kind: "For me, intelligence means abstract thinking with the corresponding triggering of actions. I don't currently attribute that to any machine in the world. I'm a bit more tolerant of artificial intelligence, because that means it's not human intelligence. In the case of swarm intelligence, one could certainly speak of a master-slave system, because it is actually the case that one person leads the way and the others arrange themselves around it and try to fulfill the overall performance through the multitude of interactions. Is that intelligent then...?"

"Starting with devices that can transport 15 kilograms up to several tons, the aim is to create an overall concept. Dipl.-Ing. Dr. Markus Aichinger, Innovation & Logistics at Knapp Systemintegration, Leoben (Austria)

Aichinger reports on a trade fair exhibit where the problem of freely navigating AGVs was demonstrated. "We deliberately created a conflict via the transport route so that the vehicle could never take the direct route, simply to show what can be achieved algorithmically. When developing our system, we always had the traffic problems in cities in mind, where one lane is jammed in the morning and the other in the evening. We try to reproduce this situation with our fully automated systems and a clever guidance system."

Richtsfeld is of the opinion that you can't put it so bluntly. "The guidance system is at the heart of this complexity. If we take the example of the road and replace all cars with self-driving vehicles, you would still be stuck in a traffic jam without a guidance system. I can try to turn around on the road, but not with an AGV! If there's a blockage, that's the end."

When it comes to energy systems, Ossendorf speaks of a trend towards lithium-ion batteries, which would replace nickel-cadmium systems. Li-ion technology scores particularly highly in terms of fast charging, cost-effectiveness and, above all, maintenance quality. "If you add up the follow-up costs, then a customer is better off using Li-ion batteries as an initial investment rather than systems that have to be replaced every two years. If you talk about total cost of ownership (TCO), then Li-ion batteries are absolutely competitive. It would be nice if they had even more capacity and an even higher energy density than is currently available."

Issing also reports on the effects of using Li-ion batteries at FTS. "We drive 24/7 with a fleet of 15 vehicles and only need three charging stations. There are no special charging rooms and no more battery changes. The vehicles take turns at the charging stations. We drive for two hours and charge for exactly eight minutes - with high amperages, of course. With new capacities, we will be able to drive for three hours in future and only have a charging time of eight to ten minutes."