AR in factory

Industry benefits from the digital baby boom

Image credit: Getty Images

Modelling of products and processes has been around for decades, but it is only in very recent years that the digital twin has come into the mainstream. It is in the industrial sector that it has its spiritual home.

While it so often struggles to move on from its tried and tested past, the manufacturing industry is nonetheless a driving force when it comes to the application of new technology. This digital age – the fourth industrial revolution – when looked at historically will seem like the blink of an eye, but such are the radical changes in technology involved that not everyone is immediately reaching for the digital switch.

Entering this digital age naturally involves change, and investment is required in making those changes. There is a strong argument that those who don’t make the investments will struggle to survive. The digitisation of industry is a wide-ranging topic and one that affects every aspect of a business, but it is the digital twin that lies at the heart of the engineering.

Mathematically modelling a process (or product) with a view to predicting the outcome of changes to that process was a technique used by forward-thinking manufacturers at the end of the last century. It wasn’t until 2002 that a team at the University of Michigan coined the term ‘digital twin’ when linking digital models with data from the real world. This change is transformational in the field of process and product lifecycle management.

The definition of a digital twin is open to interpretation – people like the term and use it to suit their needs. Rockwell Automation’s John Pritchard says: “I think the difficulty is that the digital twin can mean so many things to so many different people that it actually doesn’t mean anything at all. But the main thing is that there is some value in having it – you can do things in the digital world that can help you achieve more in the physical world.”

Most importantly, these twins will remain bonded from cradle to grave, starting with the conception and design of a product. Once the design has been completed, a real product is manufactured and the design, assuming it has been made in 3D CAD, can be used as the digital twin – a model that can accept real-life and real-time data from the real twin, and use simulation to ensure that the product delivers to maximum effect throughout its life. This may be to entertain, to transport, to assemble, to live in – anything applies and, of course, the parameters change depending on the product.

However, the digital twin is not just a CAD model, although that is a natural starting point. A CAD model may not even be available, as is the case in old factories – so can only new products and factories be blessed with digital siblings? Not at all, as Tony Hemmelgarn, CEO Siemens PLM Software, explains: “Say you want to introduce a new robotics system in a plant that has been around forever and there is no 3D data. We can do a point cloud scan of the whole plant and you would be amazed at how accurate a representation that can give. I could then drop in the 3D representation of the new robot that we have designed, and I can have it interact with the rest of the plant. So, I can check for interferences, rotation, movement, I can simulate the process flow. You have put a hybrid world together where I can work out what to do with my digital twin.”

Using a CAD model to simulate a process valve, for example, might show when and where it would fail and how fluids flow through it, but such CAE analysis of one part is a long way short of a digital twin. One way to view the digital twin is like a PLM (product lifecycle management) environment, which is fed by data from every aspect of that product’s life. Rather than just the (largely) dumb data that comes from a 3D CAD model, it absorbs information from such things as the bill of materials, electronics, control systems, manufacturing and process plants, even service manuals and, critically, the data from the real product when it is operational.

Marc Lind, senior VP for strategy at Aras, adds that having that vast pool of data alone is not enough. “You need traceability across the whole system,” he says. “You need connectivity and interrelationships between not just mechanical aspects but also the software and electronics, not just in the design but also in the build process.” Which is where the digital thread comes in.

Lind explains: “Everything is linked by this digital thread that goes through not just design but also the build process and the operating process. So, if you had an unintended acceleration problem, like Toyota had, then you have traceability back through the factory process to the original design. It seems to me that the accuracy of digital thread traceability from the digital twin product configuration back through the lifecycle will be a necessary foundation for deriving value from the IoT.”

Factory Planning

Virtual workstation

The automotive sector has been an early adopter of digital-twin technology, and BMW has followed the progression of using it for cars to using it for making cars.

Individual workstations have been laid out in a virtual environment that will replicate the production facilities for the new BMW 3 series. This includes cockpit preassembly, where the cockpit is put together before being installed in the vehicle. For the first time, building, systems, logistics and assembly planners, together with production employees, were able to assess the whole production area in virtual reality and test new procedures in 3D.

Matthias Schindler, responsible for virtual planning and implementation in production at BMW Group, says: “Virtual reality technology has enabled us to set up cockpit preassembly workstations quickly and efficiently. Time-consuming trial installations that replicate the workstation in its actual dimensions were no longer needed. And the fact that all the specialists involved – from logistics experts to systems planners to production employees – were easily able to exchange ideas in the early stages was an important added benefit for the team.”

Production of the existing cockpit continued during preparations, since planning only took up space in the virtual world. Being able to work with the same data and software also saved a lot of time.

What can you do with a digital twin? Firstly, it accelerates the design process. Production-ready designs that previously took months can be reduced to weeks. This aggregation of so many data sets means simulation at this design stage goes beyond just measuring physical stresses, but according to Paul Goossens, VP market development for Maplesoft, there are markets such as those for machine design that are proving very slow on the uptake. “The days of being able to build a machine and then tweak it because something doesn’t work, are over. They have to start doing virtual commissioning of their designs much earlier in the design process. Many machine-design companies are not doing that. They have to make sure they are looking much more analytically at their designs.”

Although automotive and aerospace industries have embraced this technology, the machine-design sector is more typical of the engineering world in ignoring the benefits of virtual commissioning as part of the design process. Goossens continues: “A lot of our packaging machine manufacturing customers are doing weird things with cardboard folding to put the packaging together; all of that is driven by motors. All these mechanisms have weird inertial loads that are cited, but very few packaging manufacturers have an insight into what those loads look like. They have plenty of instinct and after a few bloody noses they know what to avoid. But that it not scaleable.”

That instinct and knowledge is not easily transferrable. It comes under the ‘black arts’ category that makes an individual engineer indispensable but makes consistency, particularly when there is a changing of the guard, very difficult. “Having tools like this – and the digital twins – can help capture that knowledge and reuse it in the design process so that you avoid the pitfalls that they went through,” adds Goossens.

Virtual prototyping, which strictly speaking occurs before the digital twin is created, is part of the overall PLM methodology and uses every bit of relevant data to create both a better design – given that it has been optimised in simulation rather than tweaked in reality – and much quicker results, having effectively removed a chunk of prototyping time. It also means a product starts its life with a perfectly matched digital twin, a valuable partner to have.

One area of value is in the ability to simulate the operation of a product or plant. Software to predict factory bottlenecks, the effect of product changes or altering line configuration – adding a new machine into a line, perhaps – is not new. What is new is both the depth of data and, more importantly, the tie back, often in real time, to the real world. In this digital twin, everything from the forces acting at the business end of an assembly machine to the code used by a PLC to control a conveyor come into this complex equation, resulting in a reliably accurate simulation of the real process.

While useful in mass production plants, it will prove to be invaluable in mass customisation plants – providing the agility to adapt to a world where customer demands are constantly changing. Rockwell Automation UK’s CTO Mike Loughran says: “Changing design of a can or packaging needs to be done quickly. By the time they have introduced a new machine the consumer has already bought something else. So, they need to be able to model and see what they can do with what they have already got and get to market quicker. That’s what we are seeing in the manufacturing space – they need to be more agile, and modelling is the way to achieve that.”

What is getting the industrial sector most excited about digital twins is in predictive maintenance. Plant downtime can bring crippling costs, particularly when it has not been planned. Having that simulation fed by real-time data allows constant re-evaluation of what is going to go wrong and when. Fixing things before they break is obviously the most efficient way to run a factory, and balancing the mode of operation of equipment with the consequent wear and tear can be simulated as part of an informed argument. As outlined in the box ‘The killer app’, the combination of AR technology with the digital twin appears to be the perfect dovetailing of technologies to provide new methods of working.

With nearly two decades behind it, why are digital twins attracting so much attention now? Loughran says: “What is new is that it has been democratised. People can get on board without being uber mathematical modellers or uber design engineers. The barriers are coming down. In the past, you would need to build a model for each machine or each bit of a machine. Now vendors are building in some of these features, so it is much more about linking them together. That, I think, is what has brought about the digital twin as people are talking about now. It’s about the interoperability.”

Standards have emerged to make this possible. For example, OPC allows Windows programs to talk to industrial hardware devices, JT allows the import of design information without compromising intellectual property, and functional mock-up interface (FMI) allows simulation models to work with each other.

“It’s bringing down the barriers,” concludes Loughran. “And I think you will see more and more that the vendors will make it easy to digital-twin.”

Augmented Reality

The killer app

Virtual (VR) and augmented reality (AR) technology has captured the imagination for many years but, with the exception of the gaming market, has struggled to find the killer app that elevates it into a useful mainstream technology. The emergence of digital twins could, says Rob Patterson, VP production marketing IoT at PTC, be about to change that.

“It becomes extremely powerful in the service market when you can merge it with data from the Industrial IoT platform,” claims Patterson. “Being able to take that specific object you are looking at as a service technician and populate the AR experience with actual data that is coming off the device in real time, allows you to know what to fix, what’s broken, what’s the current performance of that object in real time. We think the killer use-case is for service using AR, because it’s not just instructions on how to fix something, it is instructions plus data that is coming off the machine. There is also the ability to exercise control from within the AR experience.”

Training and expanding employee versatility also become important benefits. While products become more complex with more configurations, demands on productivity mean not everyone can leave their workplaces to get the necessary training. Patterson continues: “AR can provide the information when you actually need it, so it is a big performance boost not actually taking the people out of the job.”

While there is an uptake in use of the AR in tandem with digital-​twin technology, Patterson feels that the hardware is not as advanced as the software, but he believes this will be rectified when the HoloLens 2 headset hits the market. He says: “I think there is going to be a powerful processor in there, better power consumption and, most importantly, the graphics and field of vision will be increased significantly. I think HoloLens will do to the AR market what the iPhone did to the smartphone market.”

Release for the HoloLens 2 has been like a virtual date – apparently within touching distance yet not solidifying itself in the calendar. It seems Microsoft is confident in being sufficiently far ahead of the competition with first-generation HoloLens that it has time to get the product right rather than rush it onto the market.

Nonetheless, HoloLens 2 may make an appearance in the first half of 2019 and even Q1. This lighter and more functional unit should further accelerate uptake of AR in this application.

Now in its third year, the annual collaboration between the IET, the High Value Manufacturing Catapult and Immerse UK focuses on the cross-sector adoption of immersive technologies, with digital twins set to be one of the major talking points this year. Registration is now open.

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