## 5 Discussion
Many manufacturing plants have their operations in confined spaces where they want to automate their logistics processes. It is not only the width, length, load capacity, and guidance system of the AGV that are limiting factors, but also the towed loads of trolleys, crates and boxes that the AGV pulls behind it. Because the AGV sees an obstacle and stops, but if it does not see the obstacle and pulls a load that is, e.g., wider (see our case study), the AGV can collide with other goods, other handling equipment, racks.... The result is a delay in delivery and a logistical breakdown in production. It is therefore necessary and urgent to address this issue in the production facilities of each manufacturing company. Again, AGVs can be used in a factory, but only in one where they have a job to do, to handle, not to stand on a rack and load as if for no reason [24]. Production logistics in terms of the use of AGVs can be approached from two perspectives, either by developing new production halls with AGVs or by adding AGVs to existing production halls. The first solution, the use of AGVs in production, is very simple, as it allows you to optimise the logistics and set up the production system. In the latter case, we need to adapt to the production capacity of the machines and equipment, so as not to reduce it, and use AGVs. In production halls where there is already more handling equipment, more production workers, and more suppliers to the production line, it is not possible to install the latest guidance systems [42]. They require additional space and could cause signal interference, so a simple solution such as installing magnetic tapes or electric wires, as in our case study, is beneficial. AGVs in manufacturing are just the beginning of the automation system within the elements of Logistics 4.0. Other expectations are the interconnection of AGVs with robots, with extendable arms, with conveyors, whether belt or roller, in mass production. Another constraint that we have addressed in our case study, in addition to the aforementioned width of the handling aisle, is the load capacity of the AGV, the collision points of the AGVs in the production hall, but also the possibility of the loading stationing of the AGVs in production. Even for this activity, it is necessary to allocate space in the existing premises. In most cases, AGVs with 8-12 h batteries are used. It is possible to change them (requiring a human operator), automatically recharge along the route, or employ an automatic battery change. This is one of the most modern and latest ways of recharging/replacing the battery [43]. The basic questions an automation manager should be asking on any production floor are the following:  
If we are going to use AGVs, do we have enough space for them? What loads will the AGV carry? What is the economic payback of the AGV? AGVs are worth using for repetitive material handling over long distances, regular deliveries of non-changing loads, medium production volumes where on-time delivery is critical and delays in logistics cause production inefficiencies, operations with at least two shifts, and production where tracking of material movement is important. Last but not least, the human factor is a big problem. With COVID-19, many companies have learned that you cannot succeed without the human factor, so any kind of automation on the factory floor is welcome and extremely cost-effective compared to losing a customer, compared to having a company in the market [44]. It is harsh, but firms are trying to eliminate humans from manufacturing. Common operational issues such as sick days, PTO, or employee holidays in 24/7 production are undesirable. However, robots can completely replace some logistics processes. Humans will always be needed in manufacturing, but in a slightly different way. For repairs, machine control, setting up production lines, etc. The safety of the human factor in production is also important.