- By Jeff Graupmann
- July 23, 2021
- SICK, Inc.
Increasing efficiency using real-time, tag-based localization solutions. This article comes from the IIoT & Industry 4.0 eBook.
Logistic processes within distribution and fulfillment centers must be efficient. The goal is to lower costs and increase the quality of sequential processes to ensure maximum throughput and productivity. Entirely in keeping with the smart manufacturing approach, the data collected in this area forms the basis for commercial decisions and indicates possible opportunities for optimization. Being able to localize goods during transport, in particular, constantly poses new challenges for companies. Only if you know where each object is at any given time is it possible to analyze the material flow chains, optimize transport processes, and increase the quality of supply.
This article from SICK shows why reliability and transparency in the material flow are decisive factors in production logistics and intralogistics, and how you can achieve them with the help of localization solutions. It explains the concept of tag-based localization, and describes possible applications of such a real-time locating system, as well as the benefits that full object traceability brings to production and logistics companies.
What are real-time localization solutions?
Real-time localization systems (RTLS) provide information about the exact location of an object being traced at any given time. These systems offer valuable information about where exactly a certain item currently is in a production facility. To do so, the item must be equipped with a sender or tag that the appropriate system infrastructure can detect.
Different localization scenarios generally require different localization technologies. In fully automated applications, it is possible to perform the object identification and localization using scanning systems. Other technologies that may also be suitable include radio frequency identification (RFID), Global Positioning System (GPS), LiDAR, and Bluetooth Low Energy (BLE).
Ultra-wideband (UWB) technology is a common solution for realtime localization. Similar to BLE, UWB is a short-range wireless communication protocol that operates through radio waves. However, it operates at very high frequencies and can be used to capture very precise spatial and directional data useful for localization of assets.
When compared to other solutions intended for identification and object tracking in automated applications, a real-time UWB tag-based localization system has enhanced accuracy, positioning, and radio frequency security. It can also be used in conjunction with other technologies, such as code readers, 2D and 3D cameras, 2D and 3D LiDAR sensors, and RFID read/write devices.
Real-time UWB tag-based localization solution for partially or nonautomated applications
A real-time UWB tag-based localization solution comprises UWB tags and receiver antennas. The tags send very brief UWB signals (“blinks”) at regular intervals, received by the surrounding antennas. The antennas in turn send the time stamp of the received UWB signals to the localization platform via the Ethernet infrastructure. The localization platform then calculates the position of the tags by precisely measuring the difference between the times at which this signal arrived at different antennas.
Since only the differences in the arrival times are used to calculate the tag locations, the principle of operation is referred to as the time difference of arrival (TDoA). A real-time UWB tag-based localization solution ensures that the location information about tracked goods or assets is also available in partially and nonautomated applications. A connected localization software, for example Asset Analytics from SICK, calculates the corresponding location of the tag based on the data obtained. Besides visualization functions, the localization software also offers intelligent standard functions or user-specific services for further utilizing the obtained information.
Transparency and data acquisition in process chains and value chains
Intelligent networking of machines and processes using various information and communication technologies plays an important role in modern production and logistics companies. It serves a key purpose: to collect data along the process and value chain for evaluation and implementation.
Absolute reliability of the processes and data is essential for this because the knowledge gained is the basis for various kinds of commercial decisions. The objective, therefore, must be to avoid system discontinuities, as these can result in delayed and noncongruent information both in the field and at the IT level and, thereby, have a negative impact on transparency. In intralogistics, system discontinuities occur, for example, when objects (assets) or materials at sources leave a rigid production, assembly line, or stationary conveying technology to be transported by mobile transport equipment like forklifts, industrial trucks, tugger trains, or mobile robots.
In contrast to fixed transport systems, no identification or localization of the assets or materials occurs during transport through the facility. This is like a blind spot for the control level. The assets or materials are not tracked and, in the worst-case scenario, may even be lost without anyone knowing. Process efficiency suffers significantly due to this lack of transparency, which can lead to shrinkage, delays, deliveries to the wrong location, and numerous other errors.
Real-time UWB-based localization solutions can prevent this because they ensure full transparency throughout the material flow. A system that automatically tracks assets with the help of UWB tags and provides insights into the status of the company makes it possible to focus on business decisions and optimization. Companies that spend less time on data collection can devote more time to reducing investment expenses, increasing revenue, and improving work processes.
Advantages of a real-time UWB tag-based localization system
Localization data enables agile planning of production and logistical processes, thereby ensuring better delivery quality and greater reliability. Knowledge of the precise location of assets or materials in real time brings crucial transparency to the material flow. The real-time UWB tag-based localization system therefore contributes to savings in time and money, as it allows for the analysis of asset movements and the identification and elimination of workflow bottlenecks. This type of localization system can be used both indoors and outdoors, taking into consideration country-specific regulations.
The advantages of a real-time UWB tag-based localization system at a glance are:
- Continuously tracking all physical movements with no “blind spots” improves real-time transparency.
- Improved planning and control of material flows and reduced search times lead to a minimization of idle times and a higher capacity utilization.
- By monitoring the movement of goods through automated transfers of transported materials and information triggers as they enter or exit certain configurable zones, it is possible to achieve a higher level of process automation.
- Transparency and a better overview in large plants or on large premises increase productivity, as does the automated management of storage spaces with no manual posting processes.
- Minimal downtimes, flexibly prepared or scheduled setup times, and dynamic, optimizable, and adjustable routes lead to higher overall equipment effectiveness.
- The availability of specific production equipment or goods can be checked in real time.
- The system allows flexible navigation within logistics and production processes.
Implementing a real-time UWB tag-based localization system
The following components play a decisive role when implementing a real-time UWB tag-based localization system:
- Physical devices: SICK offers a complete UWB technology-based localization system comprising tags, antennas, and the Asset Analytics platform.
- Localization area: The physical space in which localization services are required. It must be covered by a set of antennas.
- Localization cell: The localization area is divided into localization cells. Each of these is covered by at least four antennas that are located within line of sight of a master antenna. The localization area is also divided into virtual zones based on the signal quality. The signal strength depends primarily on the distance and any physical obstacles in and around the signal path.
- Master antenna: Each localization cell must have a master antenna in order to synchronize the antennas within that cell. When using the localization system from SICK, each antenna can be adjusted to the master antenna mode. No radio connection between the master antennas and neighboring cells is required.
- Absolute position: This is calculated based on the TDoA, which is calculated to an accuracy in the submeter range (± 30 cm) using at least three antennas.
- Presence information: The antennas are used to trace the entry and exit of assets in the respective localization cells. Localization is performed based on the nearest antenna.
The experts at SICK advise customers on how best to design the antenna infrastructure in their localization area from an optimization perspective. They ensure that the client’s performance requirements on the localization are met using the minimum number of devices, which maximizes the return on investment.
The prerequisite for successfully applying the TDoA principle of operation is that the antennas used to calculate the tag location are very precisely synchronized. On the other hand, the tags require less precise synchronization, which makes it easier to operate them using less power. The antennas are synchronized with a selected master antenna at regular intervals. Because one master antenna generally does not provide sufficient radio coverage to synchronize the entire localization area, the area is divided into localization cells, each of which is synchronized by its own master antenna.
The Asset Analytics visualization and analysis platform from SICK
Asset Analytics is a technology-independent and highly flexible platform for visualizing and evaluating location and sensor data.
A large number of modules for extending Asset Analytics are available. They make it possible to display, combine, and even merge data from different types of sensors, for example UWB, LiDAR, RFID, or bar code sensors. Asset Analytics does not require any installation or special configuration on the end user devices. The data for all objects being traced can be viewed in real time in a web browser running on any computer, tablet, or cell phone after logging in with a username and password.
A flexible role-based user management feature allows different access rights to be assigned. This enables numerous different users, depending on the type and size of the company, to obtain a transparent view of their own data and minimize the time they spend searching.
Core functions of Asset Analytics
- Data visualization: Clear presentation, e.g., of current objection locations, location, and status information, as well as additional sensor information in real time
- Data analysis: Processing the collected data, e.g., to analyze routings, transport times, and downtimes, as well as identify opportunities for optimization
- Event management: Automatic triggering of user-defined actions such as SMS or email notifications, e.g., when entering or exiting predefined geozones
- Integration and API: Asset Analytics can be integrated into your application via the API using the REST, WebSocket, or MQTT interfaces. SICK can also create custom connectors for the customer’s enterprise resource planning (ERP) system, manufacturing execution system (MES), or other systems
- Protection against manipulation: All actions in Asset Analytics are logged with time, user ID, and action details, so that unintentional or deliberate manipulation of the system can be recognized and undone
Application examples for tag-based localization solutions
When implementing tag-based localization solutions, first it is necessary to clearly define the application goals. The requirements on the data to be collected play a decisive role here. In addition, the value and characteristics of the assets being tracked and the application conditions are important.
Application example 1: Tracking industrial vehicles and high-value assets
The ability to determine absolute locations is particularly useful for tracing large and high-value assets in open areas (i.e., conveyors and other material handling machinery, industrial mobile robots, or stationary robots).
Localization is performed using a UWB tag applied to the asset. The antennas installed on the walls or the ceiling of the localization area and operated using Power over Ethernet (PoE) receive the signals from the tags and transmit the time stamp to a localization platform. This stores the information together with the metadata in a database. All of this data can be accessed via the API of localization software, for example Asset Analytics from SICK. This can then be used to export raw data or processed data.
Application example 2: Tracking pallets and containers
It is also helpful to track assets deemed low value and high volume. These include, for example, consumables such as boxes of screws in the manufacturing industry, toolboxes in the automotive industry, or pallets/ containers of goods.
This form of tag-based localization solution employs the principles of summarizing assets and linking different technologies. Small objects are identified, for example, based on their bar code and stacked on a pallet that has been equipped with a low-cost RFID tag. The identified objects are associated with the pallet details.
The pallets are then transported using manned forklift trucks. The manned forklift trucks are equipped with an RFID read/write device, a UWB tag, and further sensors. When a manned forklift truck picks up a pallet, the RFID read/write device automatically identifies the pallet. The identification data stored in the RFID tag of the pallet is forwarded to the localization software via TDC-E gateway systems from SICK.
The localization software then links this data to the manned forklift truck, and thereby indirectly to its location, because this can be determined in real time by means of the UWB tag. When the sensors detect that the manned forklift truck has put the pallet down again, the current location of the forklift is stored as the last known location of the pallet.
Since this application does not require each of the small objects and assets to be equipped with the higher-priced UWB tags, companies can achieve considerable cost savings.
Using localization data to create geozones
On its own, the data from UWB localization systems, such as LOCU1xx and LOCU2xx, and IIoT gateway systems, such as TDC-E from SICK, as well as any supporting sensor technologies, does not create a greater benefit for logistics processes. The data can, however, be further processed using software and thereby generate added value.
To do so, the localization and time data from all localization systems used must be merged with suitable software algorithms and powerful middleware and interpreted as information. For example, the localization data obtained could be used to automate posting processes (i.e., item postings in an ERP system via middleware) without the need for manual intervention.
This is done using geozones, which allow users to track high-value components and know exactly when the items have been dropped off in a particular zone. Once that action is completed, it can be tied into the ERP system, showing exactly how many parts are used and how many more may be needed.
It is also possible to perform a completeness check in a picking process using the localization data obtained. In addition to its own visualization and analysis functions, Asset Analytics also offers open interfaces that enable raw data and pre-processed data to be used in companywide supply chain and asset management systems as well as in cloud applications.
This connectivity enables the localization data to also be used at the level of the ERP system or MES in order to obtain a better understanding of the material flows. It is thereby possible, for example, to evaluate the running and transport times between sources and sinks and intervene in the supply chain to optimize it.
Savings potential through the use of tag-based localization solutions
The savings achieved through the use of UWB tag-based localization solutions are apparent at several locations in the material flow.
Thanks to the higher data transparency and real-time localization of assets, the time spent each day on searching and the associated legwork are significantly reduced. The number of truck trips between the warehouse and production facilities can also be reduced as a result of the optimized material flow. Furthermore, the automated posting of items based on the localization data obtained (e.g., for goods receipts in production areas) eliminates the need for manual posting processes. With these potential savings, the total cost of ownership of a real-time UWB tag-based localization is amortized within just a few years.
The SICK localization system: Complete solution from a single source
The localization of assets and the gained transparency in the material flow offer clear added value for production and logistics companies. The localization data obtained with a real-time localization system enables the agile planning and optimization of production and logistical processes, thereby ensuring better delivery quality and greater reliability.
SICK offers complete localization solutions that include all the necessary components tailored to the specific requirements of the customer. The solutions include not only high-performance hardware and software, but also comprehensive service offerings that are available to customers both online and on site and provide comprehensive support.
The complete solutions from SICK ensure that all requirements on reliability and performance for the precise traceability of objects in indoor areas are met when implementing a real-time localization system. Every system meets the highest quality standards and offers industry-specific functionality.
This is possible thanks to SICK’s longstanding experience in the area of identification and localization technologies, top down expertise from the network technology right to the associated protocols and certification, as well as comprehensive experience gained from digitalization projects in real-life companies. Competent advice, best possible support, training offerings, and comprehensive but easy to understand documentation round off these technological solutions. SICK also pays particular attention to the time to value of every digitalization project as well as the acceptance of all involved parties and users, because these often neglected but important aspects can frequently make or break a project.
This article comes from the IIoT & Industry 4.0 eBook.
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