Blurring the boundaries between design and automation
How virtual commissioning and digital twins reduce time to market and minimize risk
By Noam Ribon and Colm Gavin
Machine, station, line, and system development is usually sequential: Mechanical design, electrical design, and automation are performed one after the other. If a mistake is made anywhere in the development process and is not detected, the error costs grow substantially over the phase of development. Undetected errors can be expensive during commissioning.
Virtual commissioning is essential to minimize, if not eliminate, those costs. Though virtual commissioning is not a new concept, the now ubiquitous digital twin that is sufficiently accurate, combined with vendor multidisciplined expertise, is allowing leading-edge companies to use it. For these companies, virtual commissioning is another added benefit of their investment in simulation, or digital twins, extending value in the manufacturing of lines, production cells, machines, and even systems. For example, in bids for delivery of turnkey production cells and lines, some automotive companies require an accompanying simulation that confirms the performance of the proposed solution.
This demand is causing machine builders, for example, to modernize and transition traditional systems for the benefit of their customers and the longevity of their brand and services.
What is driving the success of virtual commissioning? Let’s explore this technology in more detail and discover the properties catapulting its popularity.
Figure 1. Robotic ultrasonic inspection of a composite wing, driven by PLC code, emulates the system’s behavior.
Figure 2. Virtual commissioning based on simulation is used to understand operations and, when linked to the actual PLC counterpart, makes validating the entire automation system possible.
Definition, benefits, differentiators
Virtual commissioning allows developers to debug automation control logic and programmable logic controller (PLC) code in a virtual environment before downloading it to physical equipment. Simulating and validating the automation equipment virtually confirms it will work as expected, thus substantially reducing system installation cost and startup time.
An overall driver in virtual commissioning is the widespread availability of the digital twin, which is a virtual representation of a physical product, process, or system used to understand and predict the physical counterpart’s performance characteristics. Using digital twins can lead to:
- Compressing time: Customers are continually changing their tastes, very quickly, driving a reciprocal need to respond quickly.
- Saving costs: Less time is required to physically debug design and its associated controls. Costs eliminated are travel and time and material costs associated with the physical presence of a team on site, and in some cases, rebuilding the physical twin that was damaged by running incorrect controls logic. In this case, delays from waiting for a new prototype may prove to be the costliest. Customers with long startup times due to machine issues are affected financially.
- Minimizing risk: All testing can be done virtually, so transitions result in only minimal issues, with no PLC program problems. Knowing that issues will be ironed out virtually increases the confidence of an on-time, on-budget delivery, for example, when shipping a machine and starting it at a new facility. This process that once took a week is now complete in a weekend—two work shifts.
When the virtual commissioning or digital twin is linked to the actual PLC program of its physical counterpart, it makes validation of the overall automation system possible. On one end, the PLC program is tested by observing how the physical system would behave, and on the other, with an actual controls program running the operation of the physical system so it can be better anticipated. Siemens provides a virtual PLC for some of its hardware PLCs, making virtual commissioning completely virtual, sometimes referred to as software in the loop (SIL).
All insights obtained and errors discovered can be used for optimization purposes before real production begins. Virtual commissioning significantly empowers a company to move toward availability, accuracy, and vendor multidiscipline expertise.
Two all-encompassing benefits of virtual commissioning are parallel work and improved communication between the designer and automation engineer. These aspects bring effective results, including:
- Verifying sequence of operations: A virtual human-machine interface (HMI) and PLC allow you to debug your code. Very early in the design process, design engineers can experience the intent of the automation engineers. Automation engineers can better relate to what their design engineer counterparts had in mind, arriving at an all-around better multidisciplinary outcome.
- Training: With a virtual HMI and model running, you can provide comprehensive training for operators to become familiar with the machine before interacting physically, reducing the operator turnover rate.
- Promotion: With simulation, you demonstrate how the machine will work for a customer in its unique environment and validate precisely what the machine does before using it.
One example is the design of a new machine. Design software and automation unite to provide value for simulating the kinematics, behavioral physics (gravity, friction, and torque), electrical architecture, and even hydraulics via a digital model. Knowing how a machine, for example, will perform in conjunction with the automation code saves time, allowing automation personnel to collaborate sooner with the mechanical engineer. Thus, the physical machine can be fabricated on the factory floor before finishing the code.
Figure 3. Tronrod Engineering used virtual images of the machine and digital twin to develop an innovative machine that could pack 300 pillow bags per minute into boxes.
Virtual commissioning eliminates errors early in the development process. The Six Sigma model describes the importance of detecting possible errors at an early stage. It helps calculate the error quotas that occur during a business process: The rule of tens says that error-related costs for an unidentified error increase by a factor of 10 from one value-added level to the next. The earlier an error is identified and corrected, the cheaper this is for the organization.
Error identification early in the product life cycle results in a quality engineering project. Therefore, finding errors in the planning phase versus the development lab (reworking parts), startup (machine on the factory floor), or operation (the machine is shipped to end customer) is ideal and economical.
Tronrud Engineering, a Norwegian machine builder, developed an innovative machine prototype that could pack 300 pillow bags per minute into boxes while maintaining the same footprint—twice the speed of traditional machines. During development, the project team created three-dimensional models of the machine and its parts to simulate its behavior. This virtual image of the machine—the digital twin—enabled parallel work on design, mechanics, and programming.
As a result, Tronrud reduced the design phase by 10 percent and commissioning time by 25 percent, significantly reducing the time to market. Reducing time on the shop floor makes it possible to produce more machines.
“Digitalization is a huge opportunity. It’s a matter of not being afraid of the challenges but rather take the benefit that helps us to create more value,” said Olav Tronrud, CEO, Forecasting.
End customers of systems, lines, production cells, or machine vendors are starting to demand virtual factory acceptance testing. A digital twin is essential to performing this task. Companies that use a digital twin put themselves at a competitive advantage to addressing these demands and winning that business. We can already see discussions and predict a new trend in the automation industry. As described above, companies are already significantly reducing their time to market, but also the time to commission systems once delivered. Commissioning time used to be nonelastic. It takes what it takes, and surprises are addressed by pouring more resources in, at significant costs. Using the digital twin for virtual commissioning, vendors can now offer their customers a share of those savings, otherwise accounted for as profits. With virtual commissioning it is now a win-win situation, that in turn has the potential to drive more business to the vendor.
Eisenmann builds facilities for surface finishing technology, material flow automation, environmental technology and ceramics firing lines, as well as special facilities for energy recovery, coating, thermal processing, and recycling.
As a future hub of international air traffic, the New Doha International Airport (NDIA) in Qatar set out to create a smoothly functioning, reliable logistics system. NDIA selected Eisenmann to install an electric monorail system.
Eisenmann started with the two-dimensional layout of the catering building and built a simulation model that runs an animated simulation of this layout. For the quotation phase, peak scenarios were simulated. In this project, Eisenmann practiced for the first time with a virtual commissioning concept, by connecting the material flow computer to the simulation model, and thus could identify and resolve most of the problems in the program.
“You can actually visualize any improper material flow in the virtual simulation model. I worked on this side by side with a control programmer, who developed and debugged the control programs” said Dr. Monika Schneider, simulation expert for Eisenmann.
Ralf Weiland, senior vice president of conveyor systems for Eisenmann added, “With our virtual commissioning capability, supported by creating realistic validations in a virtual environment . . . we believe we can shorten delivery time on every project.”
Figure 4. Working with a digital twin, automation engineers can better relate to what their design engineer counterparts had in mind.
Transitioning to virtual commissioning is an easy one. Start ramping up by learning the tools, and go from there. Once the mechanical engineers learn the tools, they become quicker and more adept for future projects. Commissioning a new production machine, station, line, or system is a crucial phase of a project. It demonstrates whether the overall system—consisting of mechanics, electrical systems, and automation—will operate as planned. Unplanned behavior can quickly lead to delays and high costs. Virtual commissioning can greatly reduce this risk.