MoTeC Global Forum

what is considerd best for the traction control aim compesation table
throttle posistion or lean angle?

I found this sensor which can be used for lean angle
http://www.pennyandgiles.com/Sealed-Tilt-Sensor-pd-37,3,,.php

sphilips wrote:what is considerd best for the traction control aim compensation table
throttle posistion or lean angle?

I found this sensor which can be used for lean angle
http://www.pennyandgiles.com/Sealed-Tilt-Sensor-pd-37,3,,.php

Always throttle position - as throttle position is the causal mechanism for traction loss.

But I do not think that I understand your question.

But from a theoretical perspective...
If you know the traction that the surface offers then you know the total G-force available.
If you know the lean angle, then you have a pretty decent idea of how much traction is left for longitudinal G-force.
You would still need to know engine torque and gear, to know available wheel force. This means that you would also need to know the torque versus TP and RPM.
But then you could determine wheel torque open loop.
It is all pretty easy.

Then... later... about the time the track camber changes, and the surface goes from consistent to variable the easiness can diminish.

You could use lateral and longitudinal slip angle ,or just longitudinal slip.
I think the last one is vehicle speed related to wheel speed.
I doubt that a lean sensor alone would be of a great deal of use, but probably worthwhile along with other sensors.

i have found that the bmw s1000rr has a lean angle sensor. So traction controle doesn't work unless you have xx degrees of lean angle.

It is for motorcycle's that I want it.

is it possible to use a gyroscope with the m800?

sphilips wrote:i have found that the bmw s1000rr has a lean angle sensor. So traction controle doesn't work unless you have xx degrees of lean angle.

It is for motorcycle's that I want it.

is it possible to use a gyroscope with the m800?

At least 2 IMUs have been used.
Here is one example.

I have used the e-lean sensor and it performed well. The benefit of the E-lean sensor over the Bosch unit used in the S1000rr (the LAS-1) is that the E-lean outputs the actual lean angle (i.e. the calculation is internal). The Bosch LAS-1 sensor does not output a lean angle, only some measurements of the rate of change of lean and the acceleration forces. That means, you must calculate the lean angle outside the LAS-1. Unfortunately, the M880 is not capable of the more advanced math needed to calculate the lean angle from those measurements with a lot of accuracy. I believe Motec USA now sells the e-lean sensor, so they may have some additional feedback for you.

Also, you need to be aware that some IMUs output a floating point value, which the M880 and dashes cannot currently use, at least to the best of my knowledge.

we have tried IMU's on our racebikes last year in AMA superbike and could never get them to work properly.

the interference from the close proximity to the ignition caused the problems.

I also was told that the e-lean was a very reliable and cheap ($800 i think?) and sold by motec usa.

if you are just starting out, I think maybe it would be a good idea to just used a slip percentage differential in your table and get a feel for it and understand how much wheel spin you (or your rider) is comfortable with percentage wise. then after some significant testing, switch to lean angle, and then when looking at the data you'll know how much slip percentage is really accpetable and you won't be chasing insignificant "slips" and wasting your time.

FoxPerformance wrote:we have tried IMU's on our racebikes last year in AMA superbike and could never get them to work properly.

the interference from the close proximity to the ignition caused the problems.
...

Where was it mounted?
I know that magnetic interference from high current devices cause noise.

It would be interesting to know if that noise was correlated with engine speed, and what the frequency spectrum of the noise was??
i.e. Was it low frequency drift or high frequency (spikes).
It would probably be easy with the bike stationary and revving the engine to see it in the data.
When they are moving the spikes are always there!

The problem with some generic IMU is they use 3D magnetometers to get additional input for the sensor fusion algorithm. They measure earth magnetic field, that's why alternator magnets or high current cables (coil charge current is high) could cause problems. On other solutions, they use GPS speed and heading.

On a bike, the fusion algorithm need to know speed, to compensate for centripetal forces acting on accelerometers.
So if your unit doesn't need speed from external device, nor uses GPS, it probably uses magnetometers, which is not enough. That's why these units didn't perform well on bikes.

Angelo