MoTeC Global Forum

Is it possible to add a Long G based compensation to the corrected speed for motorcycle use?

This would be the opposite of the Long G correction for wheel locks under braking in cars.

Anyone got any ideas how to do this?

IDP wrote:Anyone got any ideas how to do this?

Yes.

Most importantly...
Do you need to compute the speed post-facto (in i2), or in real-time for an ECU?
(Since this is posted in i2 - it looks like post-facto)

What will you be using for determining when the front wheel(s) are in the air?
I think that would need one of the following:
A pitch gyro
front and/or rear wheel sensors
GPS
Longitudinal G

Do you only need this for starting (drag bike) or in many places around track (road race)?

How often is the Long-G sampled (100Hz?)

Thanks for your reply.

In I2 is fine.

The easiest way to determine front wheel lift is from the front damper sensor topping out.

However I have a pitch gyro, front and rear speed sensors, GPS, and Long G

The use is Road racing Superbike so many times per lap on some circuits.

Long G is currently sampled at 50hz but can be sampled higher if neccesary.

Regards

Ian

Is the GPS to slow to use for speed?

Hi, I'm not clear on what you are trying to achieve here. Are you looking for a better method to calculate your "true" ground speed from the two wheel speed sensors? And also are you using a MoTeC dash? Cheers.

Hi Omar
You are correct, I am trying to find a better method of true ground speed that is 100% reliable.

I have GPS but on a motorcycle signals aren't always great.

My thinking is that a reverse of the wheel lock under braking function in i2 would achieve this.

I'm using ADL2's with Pro logging.

Sounds like you want to use front wheel speed, except for during wheelies, when you should use rear wheel speed less the wheel slip. Front wheel slip is not significant so you can probably disregard this to prevent your calculation becoming to complex.

I would use a combination of fork position and front wheel speed acceleration to determine when the wheel is in the air (fork position on its own is not enough in my experience so also check that the wheel is decelerating) ie fork < threshold and front accel < threshold.

The simplest way to achieve this would be to create your condition then use the 'Choose' function in maths based on 'front speed and 'rear speed - slip'.

Makes sense, Thank you.