Simulators: from the racetrack to the sky
Simulators have long been in use for everything from pilot training to fairground pleasure rides. E&T talks to some of the brains behind the latest generation of simulators.
The technology used in simulators has been turned to reducing the cost and risk of training in aircraft, and even providing thrill-seekers with excitement in fairground rides.
So, which is the more complicated to build, a simulator for an aircraft or a simulator for a Formula 1 racing car?
'It is slightly more complex with the aircraft because of all of the avionics in the cockpit,' says Pim van den Dijssel, business manager Europe, for Moog. 'However, from the motion perspective and the feel then I think the car is more complicated. It has more to do with the dynamic behaviour of the vehicle.'
Van den Dijssel believes that an F1 simulator represents the ultimate challenge. 'Aircraft and car simulators are not designed totally differently from the start - the base is the same. However from the hardware and software perspective modifications are made, which have more to do with the stiffness and the dynamics of the system.'
One of the most advanced simulators to be built was recently delivered to Ferrari to enable the testing of new parts on its F1 racing cars as real-life testing is now severely limited by F1 regulations in an effort to reduce costs.
The new test simulator delivered to Scuderia Ferrari in the Gestione Sportiva at Maranello, Italy was two years in development and features a customised motion control solution with combined motion mechanism, control loading system, complete software package, cockpit and dedicated operator workstation. A crucial requirement was that the system needed to operate at a higher-frequency bandwidth compared with conventional systems.
The project development entailed a bilateral exchange of expertise to overcome technical challenges. In particular, addressing the latency and bandwidth requirements of the simulator led to advances in the use of carbon-fibre composite materials in the structure to create more stiffness and less weight.
'From the beginning [Ferrari] have been changing the specification, and every time they recognised that the technology could be pushed further by making use of different materials or slightly changing the design, these changes were requested,' says van den Dijssel.
'Obviously there is always a point where you have to say 'we have to freeze the design at this stage' because we were never going get to started on the project. That was really after they had pushed the technology to the limit. Both sides had the impression that not much more could be gained by changing materials or the design. We said 'lets freeze it and begin' and in the future if we get further insights or different materials become available we can still make these additional steps, but we need to use what is available today, as this is what is possible.'
Ferrari test-drivers are already using the new simulator, which offers a heightened sense of driving reality as well as highly responsive and immediate feedback on their actions. Marco Fainello, head of the Car Performance Department for Scuderia Ferrari, stated: 'The driving simulator is being used to test current and future car designs and train new drivers on multiple F1 circuits. In both these training scenarios we cut track time and can plan training with more certainty without wondering about weather forecasts.'
The driving simulator recreates real race track conditions and is used to test different aspects of the car such as wings and brake settings that affect performance. The high fidelity of the simulator allows the pilot to feel the difference that modifications to a part or component of the car can produce without the high acceleration of a real test drive. Moreover, driver training is no longer restricted, saving both time and money, while respecting new regulations.
Ferrari required the simulator to run at mechanical frequencies high enough to help drivers get the most accurate feel of the car's behaviour and create much higher velocity and acceleration than standard systems. This represented one of the most challenging aspects of the project and resulted in Moog designing new actuators in order to deliver the desired strength and stiffness at lower weight. The degree of difficulty of designing a simulator to fit Ferrari's needs, 'had more to do with the stiffness and the lower rate, which means different materials for the actuators, which in this case involves using is a carbon fibre composite,' says van den Dijssel. Low weight, stiffness and rigidity of the cockpit cabin were also important.
High bandwidth and less latency make braking and steering more responsive, creating the high fidelity test drivers need to correctly feel and assess the car's behaviour. 'The high bandwidth allows for fine control, explains van den Dijssel. 'If you can imagine the differences between a race car and an aircraft, the vibrations and the motions you feel in a race car are significantly different.'
The test pilot is seated in front of a screen providing a viewing angle of more than 180 degrees. Ten multiprocessor computers control the system with a total 60GB of RAM producing around 5GB of data per day. It features a 3,500W Dolby Surround 7.1 sound system.
'We are delighted with the success of this dynamic driving simulator for Ferrari. Engineering hardware and human-in-the-loop testing solutions in a driving simulator is an area in which we have over 20 years' experience, since Moog pioneered advanced cueing technology. Using Ferrari's software model, we can achieve enhanced fidelity through advanced platform kinematics and optimised motion cues,' he continues.
'We do have interest from some other F1 companies,' says van den Dijssel. 'We already have one other company which is using some of our controller technology, more for providing force feedback, and we are talking to some companies about the motion technology. We have other companies using it to shorten their development cycle and the number of prototypes that they need to produce, and there you can think of things like suspensions or tyres, in areas where you can build virtual models of that particular component.' This is both in the racing environment and normal road car developments.
'I definitely see an increase in demand for this type of equipment,' says van den Dijssel. 'It is relatively new and the fact that you can build virtual models - because that is basically what you do - is an interesting new technology and I see more and more R&D flowing in this direction. If you can really shorten the lead times and the number of prototypes you can save a lot of money and get a quick ROI as well.'
One of the technologies that made the Ferrari simulator possible is the adoption of electric actuators. 'In flight simulation there are hardly any hydraulic systems any more,' explains van den Dijssel. 'The market has switched to electric. What we traditionally supply to the aircraft industry for flight simulation are the six degrees of freedom electrical motion bases, which we introduced several years ago. We do not normally supply the visual system, or the cabin structure on top of the motion base. There are just a few exceptions, such as the Ferrari case where we supplied the dome and the visual and sound systems and the force feedback system for the steering wheel.'
Thales has historically built full mission simulators using hydraulic actuators but has moved over to what it calls a 'RealitySeven' (R7) system. When asked whether this was customer-driven or seen by the company as the way forward for the future Mark Gasson, director, Civil Simulation for Thales says: 'It was a combination of the two, we are always looking to do to build a greener simulator.
'There is a pure electric system which is very quiet and has absolutely no hydraulics but you have a series of cabinets, which replace your HDU, or you have a small reservoir. In the Thales system the oil is only in the jacks, which results in a significant reduction in hydraulic oil we were using before, and we are also using biodegradable oil. Our system is an electric hydraulic system with a small reservoir and electric motor-driven pumps situated on each jack, so you get the movement only on demand. Other systems out there are a pure electrical system with a worm and mechanical nut type construction. They both work, it is just two different ways of looking at the same problem.
'We developed the C2000X system in the mid 1990s and it has proved to be a very successful product and extremely reliable with over 99 per cent reliability from our worst fault figures that we are getting,' says Gasson. 'However, we needed to be more competitive in the market and one of the problems with C200X was the cost to build it, and also that each aircraft type was unique for that particular simulator.'
The R7 full-flight simulator is based on a modular design, with a common core element (a docking station that incorporates a proven electric motion system) independent of the aircraft type. Different aircraft modules can effectively be 'swapped' out, as a customer's fleet or training business needs change, without the entire simulator needing to be replaced and without the need for further investment.
R7 uses key technologies including digital electrical control loading and electric motion systems to drive down operational costs through greatly reduced power consumption while continuing to deliver increased reliability and availability above 99 per cent. The design also encompasses the latest environmental directives and manufacturing processes to reduce carbon footprint. 'We have taken away the uniqueness of the rest of the simulator, which gives us several opportunities,' says Gasson.
'We are still building them here [in Crawley] so we are only at final assembly and test here and we have outsourced everything else. In the long term, which is phase 2 and 3, the cockpit module will be the only part that comes to Crawley with the rest of it delivered by our suppliers, direct to our customer's site at a given date. It is just to cut down the delivery time, and to cut down the cost of testing everything twice.
'We have delivered four R7s so far, three to airbus (two in Toulouse and one in Miami); the second one in Miami is being installed now. The Turkish Airlines A320 went into service also this month and the Tunis Air A320 is currently also being installed.'
The cockpit module is slightly different from the old one in that the whole section is what comes out and it contains any electronics which are specific to the aircraft type. We haven't yet had the requirements from a training centre where they want multiple fits on the same aircraft. We have done A330s, 340s now, that is easy, and 737s, 800s and 900s we have done before. We have the Eurocopter training centre which is a roll-on roll-off and it takes three hours to make the change. But that is a big beast and not necessarily effective for an airline.'
When it comes down to what airlines want, Gasson explains: 'Each airline trains slightly differently, so we took a lot of their inputs and filtered them down to what we have today, which we hope is the best mix.'
'The most controversial part of the simulator is always the instructor station because everyone wants to design their own for left-handed instructors, pilots and so on,' says Nick Bendall, head of projects. 'The key to the whole concept is the back end of the simulator - the motion is absolutely the same for every aircraft type. The only thing we have to change is the aircraft module (the front bit), the computing and the IO that go with that aircraft module. So for our supply chain we can set it up to build 10 docking stations and then we just select which aircraft type we need to apply to that docking station.
When it comes down to just how realistic the experience is Bendall says; 'it is difficult because this is their job, so the instant they sit on a flight deck they are immersed in their world. So even with the technology from 15-20 years ago we still get pilots coming out of the simulator sweating because it is as if they are flying the aircraft.
'Technology these days is a lot better and particularly with the out the window scenes and with the introduction of satellite imagery and gaming technology, the visual system improvements have been staggering over the last five years. With the out the window scenes and the environmental conditions we are able to tax the pilots and put them in a scenario which appears even more real. However, they did see it as being real before.'
When it comes to improving the details even further, Gasson says, 'We have had this conversation with a visual supplier recently but military and civil applications are very different. With the civil applications, if you are landing in San Francisco over the water, splashing waves are great but they have zero training value. The surrounding area around an airport and it being in the right place is a necessity. With military applications, when it comes to a fighting scene in a valley - that has a training value for a pilot to know that everything is proportionately in the right place and a house would be there. For guys flying at 36,000ft they don't need to know where there is a house, but the terrain is still the same. You need to look at the training value on the visual system. If you took the aircraft down then the terrain would be there but you wouldn't have the detail you would have in a military application.'
Bendall agrees saying: 'Civil simulation is really about systems management, crew interface and how they handle conditions in the simulator. Military is far more grassroots flying, and by its very nature you do have to fly low terrain and use your instruments to track low level flight. For us [in civil] on a visual scene if when they are approaching the airport everything looks right, that is what they need. On the ground it will be about managing traffic conflicts at various airports, so you have moving traffic, air traffic control and it is all about managing the resources around you - a different training style.'
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