Automotive manufacturers seem to be at the forefront of implementing Industry 4.0 and ‘Industrial Internet of Things’-initiatives. The aim is to track and measure goods throughout the whole manufacturing process from goods inwards through to final dispatch. This makes the complete production process more visible, efficient, and ultimately more profitable. In many manufacturing plants, the development of making the workflow more visible is already implemented or in progress.
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There are, however, some areas in the process where assets, materials and even completed vehicles are not visible in the digital world. This applies especially to the production process of vehicles, where assets do not follow a predetermined path. For example, once a vehicle leaves the manufacturing line and enters the finishing area, it can be moved freely around the production site. The challenge is to know the location of each vehicle at any given time and subsequently avoid production delays. This situation also applies to manufacturing processes, where raw or semi-finished materials are moved freely throughout the facility on trolleys.
Even with the best manual processes, trolleys can end up in the wrong place, resulting in massive time and productivity losses. To meet these challenges, Real-Time Location Systems can help you make unguided processes highly visible and integrate them into the digital landscape.
Integrating an RTLS into your manufacturing landscape can be highly complex, and an investment in this area should be thoroughly researched. To simplify the implementation and choice of the right system, several questions need to be answered, which will support your decision-making process.
In many cases, when considering an RTLS implementation, clients focus on the question: “How accurate is the system?” But, since the answer to this question depends on your specific needs, companies need to be aware of their starting point. Before selecting the ideal RTLS solution for your situation, you should closely investigate your manufacturing processes and clearly define the problem and the situation to be improved. To facilitate selection, specific documentation, including sketches, layouts, drawings, and a clear picture of the desired result, is required.
This also enables everyone involved in the process to be up-to-date and well-informed. Once completed, the clarity of your current situation will allow you to select the best RTLS solution for your company, often resulting in the insight that the question of accuracy is all about process-based requirements.
Most RTLS transponders require a clear line of sight to satellites mounted around the facility. At least three satellites must be in range to calculate a location via trilateration/multilateration. However, sometimes this is impossible, for example, in the production of tyres.
Consider an application where material trolleys are tracked on the shop floor and then moved into a production machine. The instant the material carrier enters the machine, the system will not be able to locate it anymore via RTLS, at least not precisely enough. Using a system that combines RTLS with a close-range identification system, also known as active RFID, this problem can be solved. Close- range identification does not only enable the precise location of a production carrier inside the machine but also confirms that the right material and batch is being used, taking for example the expiration date into consideration (learn more about the pick by light system).
Another benefit of using a system that incorporates both technologies is the cost-effectiveness, especially for vehicle manufacturers. In cases where vehicles must be temporarily relocated to another parking area, it can be sufficient to install a gate with close-range identification at an entry or exit point instead of having the whole area equipped with an RTLS infrastructure (see also: RTLS chip).
Depending on your needs and the level of accuracy required, different RTLS technologies are available, most commonly 2.4 Ghz, Ultra-Wide Band (UWB), Bluetooth LE or Wi-Fi-based systems. Choosing the ideal system is crucial, especially in a production environment (1).
All technologies have their own individual advantages and disadvantages. A shop floor with a high quantity of metal surfaces, for instance, will reflect some signals and distort positional accuracy.
Some systems require a digital shop floor footprint to serve as a reference. If the footprint changes by moving machines or other reference points, reliability drops. To avoid downfalls, mishaps
and high maintenance costs for the system, the right choice of RTLS for your specific environment is essential to achieve the best possible performance.
Independent of the different RTLS solutions available in the market, the integral part of every software is the conversion of trilateration/multilatera- tion location data into specific positions. The chosen software obviously needs to seamlessly fit into your current IT landscape, but as mentioned before, also here the starting point is the definition of the core problem you are trying to solve.
Traditionally, an RTLS tracks the position of transponders. Operators, however, want to track assets, such as vehicles. Only a few of the software packages available allow you to associate a transponder with an asset or vehicle number. This feature alone brings huge advantages; hence, your company should make sure that such a feature is included.
The required RTLS software should be designed to seamlessly integrate into third-party application software and will, therefore, be compatible with your current IT landscape, databases, production management, and ERP systems.
Some RTLS solutions are based on frequencies that are only suitable for indoor use. It is also important to know that a simple projecting roof is technically “indoor” used for an RTLS solution, whereas it is “outdoor” from a legal perspective.
Therefore, it is necessary to consider whether the application is indoors only or if the system must also operate in an outdoor environment. While an indoor solution may satisfy your current needs (e.g. for your brownfield operations), possible future outdoor extensions should be considered. Failing to do so may make an outdoor extension impossible.
How to attach a transponder to an asset is a critical and sometimes underestimated part of the installation. Consider heavy reels of cables on steel drums that are rolled in and out of machines.
The localisation accuracy can be affected if the transponder is mounted in a position that changes height when being rolled. Furthermore, no metal shielding can be placed between the transponder and the satellite. For instance, if two reels are placed side by side, the signal could be shielded by the neighbouring reel, making it impossible to calculate the asset's position.
In many cases, assets are clustered in the same area and knowing the location might not be enough to find it immediately. For these instances, some systems offer transponders that are equipped with visual signals to immediately identify assets instead of having to search for them.
Of course, such an option requires LED-equipped transponders and specific software so that shop floor personnel can easily activate the visual signals using a mobile application. Some solutions even offer transponders with multicolour LEDs, which can be utilized for other operational needs, such as asset status, material confirmation, etc.
All RTLS transponders require a battery unless the vehicle or asset can provide power. The battery's life span depends on the frequency and type of use. A qualified integrator can give you an estimate of the battery’s life expectancy. Unfortunately, many RTLS solutions offer transponders with built-in batteries that cannot be changed.
Once the battery is empty, the entire device must be replaced. Good RTLS solutions offer transponders with replaceable batteries. Although the initial investment per transponder may be higher, replacing the batteries is more cost-effective than buying an entirely new device.
Many production processes require scanners to acknowledge that a specific task was carried out. Some RTLS transponders offer a push button that can be used for this purpose. Since the RTLS knows the exact position when the push button is activated, the event that the push button triggers in the production management system gets tied to the location of the vehicle or asset.
A push button feature on the RTLS transponder can make other means of user feedback to your ERP system obsolete and may save you a lot of unnecessary investment.
The best way to implement an RTLS into your environment is to start on a small scale. Perhaps start with the most pressing area, where you gain the most payback. Once this has been established and is working, you can extend the system to further areas within the facility.
This, of course, requires a system that can be scaled easily. Some of the systems available on the market will only allow a maximum number of transponders. Make sure you consider future extensions to avoid limitations of your solution..
Some systems require extensive efforts during the installation of the satellites, which serve as counterparts to the transponders during the trilateration/ multilateration process. There are systems that require each satellite to be equipped with an ethernet and power supply. Considering that there may be hundreds of these satellites around a large facility, these installation efforts can be very costly. Other RTLS solutions do not need a data cable at all, as they solely work from a simple low-voltage power supply.
Another element to consider is what mounting options you have for the transponder. Many production facilities would need thousands of transponders to fulfil their needs, and if the transponder is not mounted properly to the asset, it will result in a lot of unnecessary effort.
As with all other capital investments, choosing a reputable integrator is essential. During the analysis process, a good partner will help answer previously unthought-of questions, which can greatly affect the solution you choose. It is very important that the integrator is not only capable of designing and installing the system but also offers full aftersales service capabilities.
Investing in an annual system health check is always profitable. Furthermore, choose an integrator who offers remote and onsite support and has a 24/7 helpdesk, as you would for any other production-relevant system.
Choose a company with reliable references and many years of experience in the market. Clarify who provides hardware, software, power installation, LAN connections and services before investing. This will save valuable time and money.
In many cases an RTLS is not a standalone system, it needs to be integrated into the existing infrastructure and IT landscape. If your application only requires a standalone system, where positions of assets need to be displayed on terminals around the facility, the installation is relatively straightforward.
Should you, however, plan the integration of RTLS into your current ERP and production management system, the process becomes considerably more complex; however, you now start to gain the real benefits of your investment. If you want to create bookings in your ERP system based on the location of assets, the position must be correct; otherwise, assets will be booked in the wrong place.
The accuracy of the RTLS becomes even more important than usual, yet clever business logic in the software provides a decisive difference.
Despite the fact that most companies' manufacturing field is highly digitalized and connected, it still lacks transparency in various areas. This can result in monetary loss, production downfalls and security issues. The information and functionality of an RTLS provide great value to a company. As the benefits are far-reaching, below is a list of some of the advantages:
A correctly specified RTLS will offer you operational, decision-making, service and monetary benefits, resulting in an overall quality improvement of the finished product.
Implementing an RTLS into a manufacturing environment raises many questions. The aforementioned list is by no means comprehensive, but it will offer a great start to choosing the right system.
Continue reading the complete overview about real time location systems in manufacturing and indoor logistics
Sources:
(1) Sebastian Thiede, Brendan Sullivan, Roy Damgrave, Eric Lutters: Real-time locating systems (RTLS) in future factories: technology review, morphology and application potentials; Procedia CIRP, Volume 104, 2021, Pages 671-676, ISSN 2212-8271,
https://doi.org/10.1016/j.procir.2021.11.113.
Note: This article was updated on the 4th of July 2024