In the weeks leading up to Silverstone hosting both the F1 grand prix and the Formula Student final, I got the chance to get a sample of both these worlds. Although I didn’t get behind the wheel of a real F1 car, I got the closest you can get outside of an F1 Factory at the University of Hertfordshire’s Cruden Simulator.
F1 teams have been using simulators for a long time, initially these were closed loop with the vehicles dynamics modelled and run without any driver intervention. Now the technology has progressed to bring the driver into the loop. The driver is fed with realistic forces and feedback from the simulator to replicate the driving experience. Many teams are on their second generation of ‘driver in the loop’ simulator and this forms a day to day part of the development of their car.
Cruden provide simulators to several Motorsport customers, including: several F1 teams, Wirth Research, AST auto and Base performance. Able to link into several car modelling programmes, Cruden state that their system is “fully compatible with Matlab/Simulink and integrating with simulation models via dSpace, CarSim and VeDYNA”. This provides simulation of “chassis, wheelbase/track, tyres, suspension settings, drive train (engine, gearbox, differentials) aero loading, aero draft (slip streaming), steering, brakes and driver aids such as traction control, ABS, etc.”. With the driving platform mounted six legs, provides six degrees of freedom, the system can provide an aggressive and realistic sensation of the forces encountered while driving. Cruden say “The secret ingredient of the Cruden package is its highly developed motion-cueing algorithms – the complex and critical maths which translates driver input into motion and force feedback response via the simulator’s interactive motion platform and control loading.”
University of Hertfordshire
Cruden have recently installed their simulator system into the Universities engineering department, use of the simulator will form the part of the curriculum for the motorsport degree courses. Whereas F1 teams are restricted on the amount of testing they can do, so they use simulators to replace some of the testing. University are budgets restricted, so simulators are a good way to teach students the art & science of driving and race engineering, without having to resort to track testing.
With this very aim in mind the Cruden simulator set up replicates the loop of information and the environments the students would work in if they were trackside. The simulator takes it car model from Racer Pro, the simulator provides creates a realistic representation of the driving of a car and the results are displayed on a pit wall set up for the students to analyse the data using tools such as Pi Toolbox. The students use of the set up will change each year, as they progress through the course. First years students being the drivers, the second year students act as their race engineers and the third year students mentor both lower years. So the fresher’s will get more track time and are free to make on-track mistakes without the danger of injury or expensive repairs. Allied to the extensive facilities at the Hatfield campus and the breadth of the course itself, this is an excellent way to train young motorsport engineers.
Why a simulator?
As mentioned actual track testing is expensive, it requires the capital investment in the car and spares, as well as the running and repair costs. A driver making an error requiring repairs or a technical fault on the car, soon sees the car stuck in the garage and no track time being accrued. As result the students get less time learning about how the car is behaving. With the Simulator this can be run at any time, with little downtime and at low costs. Aside from the capital investment to buy the system, it only requires a moderate electrical power supply and can be run for around £12 a day.
Even if its economic in terms of costs and track time, the simulator must also deliver the technical experience the students need to learn about driving and race engineering. The software the Simulator links are well known in motorsport, it’s the simulator itself that brings the rewards.
An overview of the complete Cruden set up is, the simulator itself; complete with a three seat cockpit atop the six leg platform. Beneath the platform are the electrical systems to power the servo motors in the legs, which in turn is controlled by a small server rack and console. As already alluded to, the system is controlled by electric motors to extend the legs and not Hydraulics as perhaps I had expected. However these are able to accelerate and decelerate more than fast enough to give the driver a rough ride. As well a long stroke, as the clearance around the simulators attests. Indeed the violence of the F1 shift or hitting a barrier, provides enough of a jolt to make the LCD screen “white-out” slightly as the liquid crystal is thrown around inside the cells of the display! This is a near self-contained set up just requiring plugging into a commando socket for its electrical feed. The data that comes out of the system feeds the PCs and 14 screens on the ‘pit wall’.
Although other cockpit set ups are available the University uses the three seat set up, much like a McLaren F1 road car, the driver sits centrally and passengers can sit either side of them. With Sparco race seats and four point harnesses, the seating experience is correct. The driver then has a small suede Sparco wheel, with paddle shifts on the back, a Farringdon Dash and a Tilton two pedal (brake & accelerator, no clutch) set up, with suitably hard brake pedal pressure required to replicate a racecar set up. Three 42” LCDs form the panorama ahead of the driver, which once you’re concentrating on driving, is all you can see.
Within the software as it comes from the factory, there are several cars and track maps, each perfectly detailed within Racer Pro and visually represented on the screens. Although there is no foreground projected on screen, i.e. you don’t see the front wheels of the F1 car. Tracks provided are Kylami, Zandvoort and the Cruden-ring (an amalgam of classic corners). Cars provided are the BMW M3, Renault Megane trophy (a silhouette V6 mid engined car) and a generic F1 car. Other tracks and maps can be developed andor purchased, while some are available as open source code from other Racer Pro developers.
Driving the simulator feels totally natural. Not being an experienced track driver, I completed short 5 minute stints, which were enough to sense the realism of the simulator and get a feel for the cars themselves. Not to mention improving my driving technique along the way. I first sampled the Renault Megane trophy around Kylami. A clutchless start see’s you accelerate down the straight, with the gear paddles providing a rapid jolt as you upshift into the next gear. Under acceleration the car moves around and the steering feel to keep the car straight feels natural. Braking requires a hard push to get the deceleration started, with the pedal not moving in classic racecar style. As you decelerate the platform pitches, when you turn the steering loads up and the platform tiltsyaws. The feeling is immersive, as you are focussed on the screens you don’t notice the amount of movement you’re experiencing and it feels like the G-loads you’d experience on track. All the dynamics of the car come through; understeer sees the steering wheel force reduce, power oversteer is provided with yaw, locked brakes lighten the steering feedback and make the car slew into the turn. Amongst several high speed ‘offs’ the changes in steering feel and yaw sensation help you guide the car out of a spin. Even running on kerbs and the grass provide the vibration and feedback you’d expect. Soon the handling merits of the car can be felt, although this was at first confused with the roll induced by the platform to provide a sensation of lateral G. This feature is known as G-roll, is to provide you with the lateral loading, but the tilt does also feel somewhat like the body-roll of the car. Some drivers get on with this feature, others turn it off. With it turned off the car felt stiffer in roll, although the actual car model hadn’t changed. I found it better with G-roll switched off. After a few sessions around Kylami I drove Spa in the Megane. The gradient and road camber changes around the track are dealt with realistically by the platform.
Then it is on to the Cruden F1 car. This is accurately mapped in Racer Pro; engineers from within F1 have affirmed its accuracy, especially its power delivery. Despite driving in the same position on the same rig, the F1 car feels so different to the Megane car on the simulator. This shows the Cruden set up does fully replicate the vehicle dynamics and driving experience. You’re not simply driving a faster version of the lower formula car model.
Acceleration off the start sees the car moving about the track as the rear tyres struggle for grip, the car darts about on the straight far more than the Megane. Braking is the first surprise, not least because the replication of the efficiency of the carbon brakes is accurate. Hauling you up long before the turn, until you push your braking point further on towards the corner. But also because you need to mentally decrease braking effort as the braking event continues. In an F1 car downforce is rapidly lost with decreasing speed, so the tyres have less and less potential for grip. Keeping a constant force on the brake pedal will see the front wheels lock and spin the car. Under braking you have to decrease pedal pressure. For road car drivers braking with their right foot, this skill comes naturally as you learn to drive. Learning to left foot brake means you need to relearn this skill and driving an F1 means you have to further learn to feather the brakes. Luckily I am comfortable left foot braking, which eases the considerable mental load of driving the F1 car. Locking a brake will see the F1 car rapidly snap out of line, but you can catch these moments as the feedback from the simulator is so immediate and accurate.
The next thing I learnt in the F1 car was the breadth of power, as I’ve mentioned the power curve is truly representative of a modern F1 car and you can accelerate from 5,000 RPM all the way to the 18,000 RPM red line. Of course the power really comes in at the last 1,500 RPM, but strong acceleration makes it relatively easy to drive an F1 car a revs below this. But once you do go over 16,500RPM, the acceleration causes instability in turns and on the straight, the shift lights on the (projected) steering wheel display only light up at these revs and rarely did I find it possible to match the gear shift to the last shift light. Often either hitting the limiter or shifting early. I’ve much respect for an F1 driver’s ability to time shifts manually for lap after lap.
When the gear shift is made the jolt that goes through the car is immense and will unsettle the car is some turns. Downshifts can be made rapidly, but perhaps a demonstration of my poor braking, was the downshifts could be left for some time after I started braking.
In slower turn’s power oversteer or corner entry understeer is evident, but the downforce soon makes itself felt in the higher gears. The laps of Spa made Eau Rouge and Pouhon easier than you’d expect, but I’d doubt I’d be brave enough to attempt these turns in 6th gear in a real F1 car. In fact the biggest problem of Eau Rouge was lining up the car coming down from La source, with a grass kerb to the left of the track and no visibility of the front wheels on the Simulator. Placing the car was a problem, and although most likely still a problem in a real f1 car, was mainly a downside I’d associate with the simulator. My bad line into Eau Rouge (once I’d stopped trying to take it in top gear in the Megane) was the reason and place for my most spectacular spins. Indeed with the simulator you really don’t want to be hitting the barriers, the hard jolt the platform delivers reminds the driver they have crashed, this is no soft ride.
My fastest lap of Spa was still one minute of pole in 2010 and I’ve proved I’m no racecar driver, but the simulator provide enough of an experience to get some feel for real F1 car.
For the teams and the students at the university the ability to run these cars, make set up changes and then feel the effect physically and in the data, make this realistic solution. Going forwards the simulators can be linked to other systems, a four post rig so you have both the real car and driver in the loop. Even linking the simulator over the internet to other Cruden systems or even racing several cars, it’s all technically possible. For now the students can start to learn the basic skill sin driving and engineering with this powerful tool.
I have to extend very large thank you to both Cruden and University of Hertfordshire, for providing me with access to their simulators. Especially to Jeff Peters (Principle Lecturer in Motorsport Engineering and Head of Simulation and Modeling at the University of Hertfordshire), who provided me with his time and expertise, out of hours to test the simulator. He also provided me a with tour of the extensive facilities at the University and the progress on their Formula Student car. They will be competing at the Formula Student event at Silverstone this weekend (good luck).
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