MotoGP electronics: 'Doping' the IMU

In an ideal world, MotoGP Director of Technology Corrado Cecchinelli would like to see an RPM limit and reduction in corner speed for the premier-class.

But a more 'practical and relevant' rule change would be a control IMU (Inertial Measurement Unit), to further close the technical gap between machines and end the possibility of manipulated lean-angle data, for example, being sent to the ECU.

When MotoGP finally reached an agreement with the manufacturers for a mandatory single ECU (hardware and software) from 2016, the IMU escaped their grasp.

This would not matter if the IMU was just another sensor. But it is far cleverer than that. The IMU has its own programmable 'brain' and therefore the potential to pass on 'doped' figures that influence the unified ECU software.

"The IMU is a box full for sensors and there is firmware in it that applies maths. So there are calculations made and there is the chance of cheating with it," Cecchinelli told Crash.net.

"People believe the IMU measures lean angle. This is not true. The IMU measures the lean rate and then by mathematical integration it calculates the lean angle. But if, in this calculation, you don't just perform mathematical integration of the signal but also make an 'elaboration'...

"Imagine if I take the lean rate and I take the tyre temperature. I put them together and so I output a 'doped' lean angle to the ECU, which is not the 'real' lean angle and changes depending on if the tyre is hot or cold.

"Now I have a traction control that works differently to yours."

That would be illegal, since the MotoGP technical rules state: "The use of the Official MotoGP ECU software for engine and chassis control is mandatory for all machines, and no other engine and chassis control software strategies may be used on the machine at race events."

The part shown in italics, Cecchinelli confirmed, would be infringed by embedding strategies inside the IMU. However, it is virtually impossible to police without moving to a single system for all.

"It is unavoidable that you programme the IMU to do its legal job. So I cannot stop you connecting to your IMU with your PC. Because this must be done to make it work," Cecchinelli added. "But then I don't know what you actually do. There is room for cheating there.

"The IMU is actually a computer and as it is connected by a CAN line it could, in theory and out of our control - this is clearly forbidden - receive a number of inputs that it's not supposed to and so 'dope' the output.

"The IMU is upstream of the unified software in the ECU. So if you dope the IMU outputs you are actually altering the logic of the unified software. Only by a marginal amount, but still.

"Conceptionally, the IMU is a part of the ECU and so to me it should be unified."

Last year's MotoGP World Championship saw nine different race winners, an all-time record, with five riders already claiming a victory by the midway stage of 2017. If the IMU was standardised, Cecchinelli feels the racing would be even closer.

"Moving to a single IMU is a practical step that can be done now," he said.

"It would introduce a cost difference for sure. Even if only because the production numbers would be higher. This would be one benefit, but to me the main benefit is that it's another factor to close the technical gap.

"Because I think at the moment the reason some manufacturers are resisting to unify the IMU is because they have a better one. And if they believe so, it's true!"

The full explanation by Cecchinelli can be seen below...

Crash.net:
The racing in MotoGP has been very competitive again this year, are you happy with the technical rules?

Corrado Cecchinelli:
"Yes. For me I would do something else, but we are very happy and to be honest, being unlucky with the weather makes us lucky with the show! So for sure, last year and this year, MotoGP has made a big step in how good the show is but I want to be honest and say that not everything is based on what we did, which is tyres and ECU. Things like the weather and number of riders that are so good has nothing to do with us!"

Crash.net:
You said you would do something else, is there a next step?

Corrado Cecchinelli:
"I'm not thinking of this as a next step, because this is something that is already forgotten. But for me, we should work on things like an RPM limiter and reducing corner speed by smaller wheels for instance, things like that.

"But these are not next steps, these are things that have already been proposed in the past and not accepted. So in this sense, I'm not exactly where I would like to be. But these are not things we are considering for now."

Crash.net:
Is MotoGP still a long way from getting agreement on a rev-limit among the manufacturers?

Corrado Cecchinelli:
"It's not under discussion.

"But one thing that maybe in the present scenario is not as crazy to do, is go to a single IMU. Inertial Measurement Unit. Which contains the gyroscopes etc. This is something more practical and relevant to the present situation.

"Introducing an RPM limit now is another world at the moment. But moving to a single, which means compulsory, IMU is a practical step that can be done now."

Crash.net:
How would it help the sport?

Corrado Cecchinelli:
"It would introduce a cost difference for sure. Even only because the production numbers would be higher. This would be one benefit, but to me the main benefits is that it's another factor to close the technical gap. Because I think at the moment the reason some manufacturers are resisting to unify the IMU is because they have a better one. And if they believe so, it's true!

"Another thing is that the IMU is actually not a sensor, but a box full for sensors and there is firmware in it that applies maths. So there are calculations made and there is the chance of cheating with it. "

Crash.net:
In what sense?

Corrado Cecchinelli:
"To me the IMU should be considered a remote part of the ECU.

"In fact the ECU has an inbuilt IMU which is not used because it's not accurate enough. This is the only reason why we have an outboard IMU, but conceptionally to me the IMU is a part of the ECU and so to me it should be unified, like the ECU.

"Because there is a 'brain' inside it. It is not just a sensor, if you see what I mean."

Crash.net:
So teams programme the IMU?

Corrado Cecchinelli:
"They do, yes.

"Very basic example: People believe the IMU is a package of sensors that measure the lean angle. This is not true. The IMU measures the lean rate and then by mathematical integration it calculates the lean angle, which is not what it directly measures.

"But if, in this calculation, you don't just perform mathematical integration of the signal but also make an 'elaboration'... Imagine if I take the lean rate and I take the tyre temperature. I put them together and so I output a 'doped' lean angle to the ECU, which is not the real lean angle and changes differently depending on if the tyre is hot or cold. Now I have a traction control that works differently to yours."

Crash.net:
So you could manipulate the IMU to send a different output to the ECU for performance reasons...

Corrado Cecchinelli:
"Yes, because it is unavoidable that you programme the IMU to do its legal job. So I cannot stop you connecting to your IMU with your PC and doing something. Because this must be done to make it work. But then I don't know what you actually do. There is room for cheating there.

"The IMU is actually a computer and as it is connected by a CAN line to all the rest it could, in theory and out of our control - this is clearly forbidden - receive a number of inputs that it's not supposed to and so 'dope' the output.

"Just imagine, you think that we made a mistake in how the lean angle is considered in the traction control with the unified software. So you programme your IMU to set a fixed lean angle for instance. This is not a sensor, it's a computer.

"The IMU is upstream of the unified software in the ECU. So if you dope the IMU outputs you are actually altering the logic of the unified software. Only by a marginal amount, but still."

Crash.net:
Are you a long way from getting an agreement on a unified IMU?

Corrado Cecchinelli:
"Yes. I don't think we'll get an agreement. It is in theory an 'open' item, that is never discussed. When I spoke about an RPM limit, this is not even an open item. There are manufacturers that would be happy if we have the power to enforce the single IMU and others that would threaten to leave."