- #1
dragilla
- 15
- 0
Hello,
First of all - I love this forum - so many interesting topics!
My question is quite complicated - at least for me. My high level goal is to measure lean angle based on the difference of speeds between the front wheel of the bike vs the 'real speed' (let's just assume I have the accurate speed). I want the lean angle in relation to the tarmac not the ground - that's why I don't want to use accelerometer/gyroscope. I don't care about the sign of the angle - if the lean is to the left or to the right - I just need to know the value - how much is the bike leaned.
The next goal is to make this possible with as simple measurements of the tire as possible. In my application the tires will be changed frequently and possibly different tires will be used so I need to be able to perform quick measurements (like width, height when off the ground, then width height when under load of the bike + maybe some measurement of the profile shape),
I found this document that describes some basics of my problem:
2004_02 A Motorcycle Tire Model for Dynamic Simulations MECCANICA.pdf
But I think it's still too little for me.
The main problem here is to determine a formula for the tire profile shape, as it varies from tire to tire. I tried with a parabolic shape, but that does not match all the tire shapes, some are rounder, some maybe a combination of these two.
The other problem is to determine how the tire flattens under load (consider acceleration/braking forces - I have accelerometer/gyroscope on board, so I know the acceleration and the right direction of it) and how that affects the circumference.
As for the speed measurement I have magnetic sensors on the wheel and a counter, so I just count the pulses in a time period and knowing the circumference I know the traveled distance and thus the speed.
I know this is a complex problem, but I would really appreciate some help as I'm not an expert in the matter of physics and my math skills are 'overdue' (studied math over 10 years ago) - although it comes back to me slowly :)
regards,
--
Luke
First of all - I love this forum - so many interesting topics!
My question is quite complicated - at least for me. My high level goal is to measure lean angle based on the difference of speeds between the front wheel of the bike vs the 'real speed' (let's just assume I have the accurate speed). I want the lean angle in relation to the tarmac not the ground - that's why I don't want to use accelerometer/gyroscope. I don't care about the sign of the angle - if the lean is to the left or to the right - I just need to know the value - how much is the bike leaned.
The next goal is to make this possible with as simple measurements of the tire as possible. In my application the tires will be changed frequently and possibly different tires will be used so I need to be able to perform quick measurements (like width, height when off the ground, then width height when under load of the bike + maybe some measurement of the profile shape),
I found this document that describes some basics of my problem:
2004_02 A Motorcycle Tire Model for Dynamic Simulations MECCANICA.pdf
But I think it's still too little for me.
The main problem here is to determine a formula for the tire profile shape, as it varies from tire to tire. I tried with a parabolic shape, but that does not match all the tire shapes, some are rounder, some maybe a combination of these two.
The other problem is to determine how the tire flattens under load (consider acceleration/braking forces - I have accelerometer/gyroscope on board, so I know the acceleration and the right direction of it) and how that affects the circumference.
As for the speed measurement I have magnetic sensors on the wheel and a counter, so I just count the pulses in a time period and knowing the circumference I know the traveled distance and thus the speed.
I know this is a complex problem, but I would really appreciate some help as I'm not an expert in the matter of physics and my math skills are 'overdue' (studied math over 10 years ago) - although it comes back to me slowly :)
regards,
--
Luke