# An Action Classification Method for Forklift Monitoring in Industry 4.0 Scenarios
## 3 Materials and Methods  
### The I-READ4.0 System Architecture  
The I-READ 4.0 system was conceived by considering large-area warehouses with a high pallet-handling per day. The demonstrator was designed to operate in the _Tassignano_ warehouse of the Sofidel paper industry with headquarters in Porcari, Lucca ([[https://www.sofidel.com/](https://www.sofidel.com/)]([https://www.sofidel.com/](https://www.sofidel.com/)), accessed on 26 May 2021). It has an area of around 20,000 m\({}^{2}\) (Figure 1) with an average handling of 2000-3000 pallets per day. Figure 2 illustrates the I-READ 4.0 framework, which comprises two main technological elements: the UHF-RFID Smart Gate (studied in this paper) and the UHF-RFID Smart Forklift. Figure 1: _Tassignano_ warehouse plan. The general architecture of the system is briefly described here. The proposed solution uses the passive UHF-RFID technology and particularly an integrated network of RFID readers, some fixed (UHF-RFID Smart Gates) and other mobile (UHF-RFID Smart Forklifts), capable of identifying individual pallets, their status (loaded by a forklift or unloaded), and their location (Figure 2). The tagged objects are pallets containing the final product, e.g., tissue paper. The pallets exit from the end of the production line and are brought into the storage warehouse carried by forklifts. Again, when the product must be shipped, a forklift lifts the pallet and brings it to the loading area (pallet preparation area). Then, each single pallet is loaded onto the truck manually handled by a pallet truck. For the correct management of the warehouse, it is essential to trace all these steps. Both the warehouse entrance at the end of the production line and the exit are equipped with a UHF-RFID Smart Gate, described later in this manuscript, which is capable of monitoring all the access/departure of products and forklifts to/from the warehouse. When the UHF-RFID Smart Forklift moves inside the warehouse, it is localized with a tracking system to allow the real-time pallet localization. In fact, the pallet location is associated to the forklift location at the time of the unloading event. In this context, the presence of the UHF-RFID Smart Gates can be fruitfully exploited to set the initial position of the forklift when developing tracking systems. Through the Wi-Fi network, the Smart Gate and the Smart Forklift send the data regarding position and status of each pallet to the warehouse central server. The knowledge of the position of pallets and forklifts allows to produce a real-time map of warehouse occupation and therefore enables to implement an optimization algorithm to improve the management of good flows and the occupation of warehouse areas. Furthermore, the information on the forklift position, combined with the data of the collision detection system installed on each forklift, allows to carry out a statistical analysis about the areas with the highest risk of collision. The detection of these potential collisions (near miss) will be shown to the forklift drivers and the Warehouse Management System (WMS) through the Event Server. For the aim of this paper, the design, development and testing of the UHF-RFID Smart Gate are relevant. That is, we are going to focus on that component of the global system architecture. Items coming out from the production lines are assembled in pallets. Each pallet is around 80 \(\times\) 120 cm wide, and it has to be equipped with an identification label of size 148 \(\times\) 105 mm according to the Global Standard GS1 (Figure 3). The label is printed at the end of the production line and shows the Serial Shipping Container Code (SSCC). Behind  
Figure 2: The I-READ 4.0 framework.