Using Virtual Reality to Model a Nuclear Components Factory in Four Dimensions
Chris Freeman and Rab Scott, head of Virtual Reality, inside the ActiveCube full immersion VR system
While researching a story about the University of Sheffield’s role in the anticipated nuclear power renaissance in the UK, we ran across another fascinating project featuring the use of cutting-edge immersive virtual reality and advanced visualization techniques to create a four-dimensional model of a nuclear component factory.
The visualization work was commissioned by Rolls-Royce to help in the decision-making stages of factory design, layout and assembly processes at its proposed plant located at the Advanced Manufacturing Park in South Yorkshire. Part of an initiative known as Project Power, the factory will be used to build reactor pressure vessels. The simulations are being carried out at the Nuclear Advanced Manufacturing Research Centre (Nuclear AMRC) at the University of Sheffield. They are being used to visualize work flow, process management, and health, safety & environmental (HS&E) issues.
Combining DES and VR
At the Joint Virtual Reality Conference coming to Madrid in October, Chris Freeman, virtual reality systems developer at the Nuclear AMRC, presented a paper entitled “Discrete Event Simulation Using Immersive Virtual Reality for Factory Simulation,” which summarized the visualization team’s research.
The team has developed a Discrete Event Simulation (DES) model depicting the interactions of large complex parts for nuclear reactors, which can weigh up to 40 or 50 tons. Moving these parts around can take a fifth of the total manufacturing lead time. Of this time, about 70 percent was predicted to be complex lifts, which can cause increased disruption within the plant and greater HS&E risks.
Although modeling these movements using DES helped create a statistically accurate simulation, it could only provide a limited amount of information and understanding of the process flow and scheduling. So the team developed an immersive 3D virtual reality (VR) model of the facility, linked it to the DES model, and then demonstrated the results in the full 4D virtual environment.
In a factory where there is no steady flow, such as the Rolls-Royce facility, each component has its own routing that often intersects the routes of other parts. The team programmed both the part movements and the assemble processes using a sequence of movements. The sequence recorded the state of all the components in the time line either frame by frame, or continuously. This information was fed into the model to set the Cartesian coordinates and orientation of the parts.
In the paper, Freeman reports, “The goal of the project was to prove that VR simulation of production sequences was possible, and could be of practical use to SME companies. The simulation allows the viewer to watch and record where parts are interacting and potentially causing delays; this is particularly useful in non-linear routed flow factories… Certain areas of the factory were very closely packed with often more than one vessel, undergoing a process like heat treatment or assembly in the same bay at the same time. This significantly reduced the amount of equipment and people that could be at work in the area at one time, and could also have caused problems with cross process pollution and safety concerns. Other areas were also identified where reduced areas also restricted vessel movement. These challenges have since been overcome through iterative review and reconfiguration within the VE (virtual environment).”
Simulation with color coding
The team modeled assemble sequences for each component part, then combined these to model the complete factory cycle over months. Each second of the model represented 12 hours in the life of the factory.
The report went on to describe other HS&E challenges that were uncovered by the VR simulation. For example, when a load was craned over another process within the factory, that process had to be suspended until the load transit was complete – the simulation demonstrated the full extent of the disruption.
It also highlighted many challenges in other areas of the factory that can cause congestion. For example, an air ventilation system significantly reduced available working space by restricting movements in the assembly bays and blocking movements into the furnace. Building support pillars housing gas extractors, electricity and gas lines prevented direct movement between the assembly bays and machining areas. For these, and in many other cases, the VR simulation was used to solve problems in virtual space before they were encountered in the real world of solid, intractable objects.
Total 3D Immersion
VR capabilities at Nuclear ARMC include a Virtalis ActiveCube system, a 3.2 meter cube that provides a cave-like environment with 3D images on three walls and floor. The fully immersive system is ideal for applications such as training and assembly design, including dealing with the complexities of creating an efficient and safe nuclear component factory. It can accommodate up to four people at the same time.
The Center also has a Virtalis ActiveWall, a 4.5 meter wide single-screen system that can be viewed by up to 25 people. The ActiveWall can be linked to the ActiveCube for collaborative efforts.
The research was completed as part of the Copernico project to help European companies – particularly small and medium-sized businesses – be more competitive in global markets by improving the technological base of manufacturing. Copernico’s primary objective is to develop a model of a virtual factory that includes integrated models of organizations, processes and systems in a virtual environment (see video below).
VR for SMEs
Although the Rolls-Royce project is massive in scale, Freeman points out that the technology isn’t just for large factories – it can be used by smaller manufacturers to optimize their own production systems.
“The goal of this project was to prove that VR simulation of production sequences was possible, and could be of practical use to SME companies,” he says. “The potential to save money, increase safety and visualize problems – before building and after – is limited only by the designers. We want the SMEs to embrace the technology and take part in its further development.”