April 14th, 2010 by Mike Dempsey
Dymola modelling and simulation tools are changing the fortunes of west-midlands based aerospace control systems and test rig company RTC Electronics as part of a scheme called the Knowledge Transfer Partnership (KTP) run by the Technology Strategy Board (TSB), a partnership between business and academic institutions. RTC is saving time on site commissioning its test rigs by a factor of five, has gained flexibility in workforce by reducing the need for experienced engineers to go to site and allows test rigs to be sent to site fully tested through simulation and with its software completely debugged. The result is that the company is now, for the first time in its 30 year history, able to grow its business and start expanding into new markets.
The business benefits RTC is getting from Dymola summarised by RTC managing director, Nick French
It’s not often that a business makes a fundamental life-changing decision. But it’s the reality of a decision recently taken by Nick French to choose Dymola modelling and simulation software and transform his business.
RTC Electronics managing director explained the issues: “Every test rig we design is different. We have tight deadlines which in the aerospace industry are often first flight dates which are set in stone. The work we do is at the sharp end of the project timeline which means that if any other company in the project supply line experiences delays the impact is pushed onto our time on site.
And it’s this that has been our company’s limiting factor in offering us the chance to grow. Before Dymola we always had to rely on the experience of our engineers on site to make the necessary changes to the rig. It’s very difficult work as our arrival on site is the first time we have been able run any tests and it’s therefore only at this point that we are able to see the effects of hydraulic, mechanical and electronic control systems all interacting together. When on site we also can’t test the rig for peak loads on components and the systems in case you break the rig itself – so you can’t under or over test the components. So we have tight deadlines, we need experienced staff which is a limited resource, we get limited time on site once the rig is handed over to the customer and we only have experience to fall back on to know how the test rig will operate with all systems working for the first time together”
The need for experienced engineers on site has previously limited RTC’s flexibility to take on more work and has by default led to an inflexible staff which in turn makes the business hard to grow and leads to feast and famine business model.
Another key problem that RTC faced was how to simulate more than one system on a rig.
Nick French continued: “We could only see one system at a time. We spend time on site trying to commission hydraulic, electronic control and mechanical systems. We had to look at problems ourselves without knowing up-front how the rig would behave and react before getting on site.
Every rig is peculiar and it has always been a nightmare – and it’s often the control systems that get the blame for a complete solution not performing as expected.“
RTC is expecting overall time savings on site of a factor of five, which for any business offers almost life-changing results. The company has adopted Dymola multi-domain engineering modelling and simulation tools. The result is real business benefits.
RTC started exploring the potential of using new skills and knowledge to create commercial advantage back in 2009 through a scheme called the Knowledge Transfer Partnership (KTP) which is run by the Technology Strategy Board (TSB). The KTP programme helps create partnerships between business and academic institutions such as universities, enabling access to skills and expertise to help the business develop. Working with the KTP, it identified the potential of modelling, simulation and the use of real-time hardware-in-the loop technologies as the way forward and Dymola was selected as the tool of choice for modelling and simulation.
Tom Horsfall, KTP associate, is a University of Warwick employee although through the KTP scheme is now a key member of the RTC team. Also registered for the degree of Master of Science by research at the university as part of the Knowledge Transfer Partnership, Horsfall has been leading the company’s adoption of the Dymola software. Tom Horsfall explained: “We recently had a client contact us who wanted to model drive trains. With Dymola we did it within three hours, not only fast, but we’d never been able to do it before. The same is true with our test rigs. We can see the effects across all systems; hydro-mechanical and electronics and controls.”
The move to modelling and simulation across multiple systems has had many effects. All systems are modelled at the same time so engineers pick up issues earlier. The company can test all components to their limits before the rigs are even built at physical component and system level. This not only saves time on site up to a factor of five times according to Nick French, but also means that they can de-skill the commissioning process which previously always required experienced engineers with 20 years experience to be on site.
Nick French continued: “Any problems we can sort out and solve before even getting to site whereas before we would have to wait until we arrived on site before we could find out any problems, which introduces another delay. Smoothing out the commissioning process we can now take on more work and grow the business with more flexibility in the staff.
“In a controlled environment it is easier to modify parameters, easy to make changes. You can do anything with the model that you can’t do on the rig without the fear of breaking it. We can prove the full functionality of the rig before we go on site with all the software debugged and the hardware tested in the simulated model. Also we can put the extremes into the model with different fault conditions in to see how the rig would perform.”
The aerospace industry is naturally risk averse. The Dymola simulation and modelling system helps remove the risk factor and RTC can model aircraft hardware systems before the physical test rig is even built and can get feedback on for example, position loading without being connected to test rig.
They have reduced development times, modification times and, with the extensive use of HIL (Hardware in the loop) and SIL (software in the loop), has reduced on site times for commissioning.
And Nick French is also delighted about the visibility that modelling offers: “Often we would be blamed for anything going wrong on site because people invariably try and blame the control system. With modelling problems can be pre-empted across systems so we can see any problems before even arriving on site.
Selecting the right tool for the job
Before choosing Dymola, the project team at Warwick University and RTC staff looked at Simulink but, in the words of Tom Horsfall: “We found Dymola easier to use and more graphically pleasing to work as a graphical user interface. With Dymola we can easily look at every component and understand its influence and effect. We can add in other elements like loading, carriage, bearings and testing as we go.”
The first step in evaluation was to run the tests in Dymola and then match to the results of Simulink which is being used by RTC’s aerospace client to ensure first that they get the same results. Dymola gives the team the chance to see all systems working together – hydraulics, mechanical, electrical and control systems.
Tom Horsfall is one year into his MSc at Warwick University and is running his MSc as part of the University of Warwick’s MSc Knowledge Transfer Programme working as an education-commercial partnership. Tom is pioneering modelling with Dymola in the aerospace industry on a variety of test rigs and is modelling the plant side of aircraft test equipment. Tom Horsfall was trained by the tools’ distributor Claytex.
Dymola is part of the Dassault Systemes software family and is distributed in the UK and Europe by Claytex (www.claytex.com).
The multi-engineering capabilities of Dymola makes it possible to simulate the dynamic behaviour and complex interactions between systems of many engineering systems, such as mechanical, electrical, thermodynamic, hydraulic, pneumatic, thermal and control systems. This means that users of Dymola can build more integrated models and have simulations results that better depict reality.
The Dymola environment uses the open Modelica® modelling language which means that users are free to create their own model libraries or modify ready-made model libraries to better match users’ unique modelling and simulation needs. The flexibility of Dymola makes it a versatile tool which is perfect for modelling and simulation of new alternative designs and technologies.
RTC electronics (www.rtcelectronics.co.uk) has over 20 years experience in complete turnkey solutions in the design and development of bespoke industrial control systems and test rigs – supplying equipment to the aerospace, military, semiconductor, automotive and general industrial markets. All work comes to the company via recommendation and RTC boasts a one hundred percent customer satisfaction rating.
Recent projects for RTC include Thrust Reverser Test Rig control systems for the Airbus A350 and Boeing 787 aircraft. Potential new work includes Test Rig control systems for new aircraft, including further thrust reverser systems plus Flap and Slat systems.