Industry 4.0 comes out of its Shell

27 September 2021

Steve Sands explains the role of the Asset Administration Shell in delivering the Industry 4.0 vision.

Behind the scenes there is a lot of work required to turn the theory of Industry 4.0 into reality. The name ‘Asset Administration Shell’ (AAS) may not be instantly memorable, but every engineer does need to know what it is. 

The AAS is the 'digital shell' that wraps around each smart element of a machine, enabling it to explain to the complete machine architecture its function, identity and a whole host of additional information. While the cloud, networking and automation devices with Internet access can deliver a form of connectivity, the AAS is truly universal. It enables information to be exchanged between value chain partners, and uses neutral and common standards for communication, services and semantics across companies and across sectors.

The digitalisation process encompassed by the AAS is evolving quickly. The vision and the benefits are so compelling that many potentially rival organisations have collaborated to create a working, albeit evolving, solution. This multi-organisational collaboration has achieved a lot already. Examples of incorporated standards include OPC-UA for the communication of data. Automation ML is evolving to be a global standard for transferring the description of a physical item containing the information usually found in 2D or 3D CAD drawings and complete electrical circuit diagrams, programming information, kinematics and behavioural description.

Design time
The AAS is a crucial enabler in speeding up the design of complex machines and enhancing their whole life operating effectiveness. This can be demonstrated by taking a situation where a designer is looking for a particular component – say an electro-mechanical axis that can move a part of their machine with a defined mass, at the required velocity and acceleration.  

Picking the component from an intuitive, online selection and configuration package, the designer needs to match the axis to a motor and gearbox combination to deliver the required torque and performance characteristics. The matching servo drive is then selected.  As each selected part is configured in the virtual world, its digital descriptor is created in parallel, providing its identification (what it is), technical data (how it works) and documentation.  

As the design process progresses from a single asset to a sub-system, the digital descriptor grows and integrates the sum of all the parts. The virtual model is accessed throughout the machine lifecycle – for example for CAD design, CAE simulation, virtual programming, documentation – from the machine inception through build, operation, maintenance and even re-purposing.  It upscales in a modular way as the solution grows. The AAS includes a further digital model that captures the operation data. Under each of these headline modules are submodels that semantically enable the transfer of data – independent of the supplier or manufacturer. Common standards allow the seamless transfer of machine-readable data.  

As one of the collaborating companies, Festo already offers a simple to use, free of charge software tool called Quick Search Plus – a powerful extension to its digital catalogue. This tool eliminates the manual transfer and re-entering of data to reduce time and the possibility of errors. All product data within the bill of materials is captured and seamlessly transferable.  A designer can then pick a part from the BoM, such as a pneumatic cylinder, and immediately use it within the Festo 3D CAD design tool. The correctly matched accessories – such as piston rod and rear mounting clevis – are added to the drawing in seconds. Identifying perhaps six additional components in the past could have taken an experienced designer many minutes: but now the task is completed, right-first-time, in seconds.  The complete assembly can be offered up in the machine general assembly drawing and simply dropped into place.  

Engineering benefits
The AAS contains a complete description of the properties and capabilities of the system. In other words, it is the means by which Digital Twins become possible.  Having a Digital Twin allows a machine to be built, programmed, commissioned and operated from virtually anywhere in the world, saving time and cost. This principle can be extended to trouble-shooting. For example, once a machine is built and shipped to the customer, it is very costly (if not impossible under current restrictions) to conduct maintenance or investigate a problem. A Digital Twin can replicate its physical counterpart, enabling corrective actions to be tested without the costs or delays of long-distance support visits.

The AAS also supports predictive maintenance by enabling machine learning. An Edge or Cloud-based processor running a combination of algorithms is tuned to an application (such as the Festo AX Scraitec package), monitoring vast data tranches.  The system observes and identifies patterns within the data lake. During the set-up period, a human-in-the-loop trains the system by categorising the anomalies it detects.  The human operator teaches the system; rewarding and labelling predictions of failures and 'punishing' unhelpful observations.  In this way, the system is trained and improves its useful predictions whilst tuning out unhelpful noise.

Festo has several use cases – one of which comes from the automotive industry, where a body-in-white assembly line is equipped with hundreds of pneumatic clamps. While these are relatively low-cost products, if one fails, it can cost £100,000s in lost production: or, even worse, undetected, poor-quality welds. The ability to foresee pneumatic clamp failure, identify the individual clamp and categorise the failure (solenoid valve, pneumatic seals or clamp pivot bearings) enables planned maintenance interventions up to 14 days before a breakdown situation.

End-users rightfully need to see the evidence of improved lifetime efficiency and payback before specifying Industry 4.0 technologies to their line and machine builders. The Industrie 4.0 workgroup developing the AAS has done a fantastic job within a short space of time and use cases are emerging that will make the argument for automation digitalisation irresistible. The importance of the AAS in the implementation of Industry 4.0 cannot be underestimated.

A free webinar on the Asset Administration Shell within the concept of Industry 4.0 is available at

Steve Sands is head of product management at Festo in the UK.

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