Lean-o-meter

[BigKid]

some of those suggestions have difficulties due to the lateral load (centrifical force) and gravity. The angle locater works for figuring out swing arm angles very well however. Think about it like this, hang a disco ball from your mirror in your car, if you go around a corner and the disco ball is at a 45 degree angle you are pulling exactly 1 G., BUT you have to subtract the roll angle of the cars suspension and fugure out the formula for the exponential rate at which radial angle is related to the g forces. Now aply all of this to a motorcycle that leans. What you will find is the lean-o-meter in a bike will tell you that you are not leaning over at all if your body position is poor and you are only leaning a little bit if you do get off the bike well. I think the moto GP stuff works with gyros and is probably the only logical way to read lean angle. Couple that with the Lean-O-Meter and we could calculate who does a better job of lowering the center of gravity. If you have read this far into this post...I feel sorry that you read this dribble...better investment, ask a CR and use your knees...spend the $999.00 on tires and track days. LOL

 

[motormech1]

:agree:^WORD!^ Nuff said.

 

[rk97]

only thing i have seen like this was on an old Jeep CJ-7. it would (supposedly) tell you when you were in danger of flipping over.

while the point about centripetal force is excellent, you're really only looking for the measurement to be relative to itself, right? In that case, the angle gauge and a video camera should still do the trick.

It wouldn't be perfect, but it would show you lap-by-lap and turn-by-turn where you were consistent, or when you were further over.

I'd actually be really curious to see how you or I stack up against a CR when comparing lean angle in X corner, and then total lap time.

 

[BigKid]

Actually, lean angle and speed are not realative to consistencey in different corners. How much you lean off the bike affects your lean angle. In the middle of B I can hang WAY off the bike and have almost no lean angle and at the same speed sit straight up on the bike and drag hard parts. The point of my above post was the angle meter only works when it is standing still. If you have less lean angle (ie better body position) one time and go fast it could give you the same reading with worse body position at a slower speed. The inclenometer sp? as I think they are called are designed to work only when they are not moving. The needle is held in position by the earths gravity. When moving, space shuttle, motogp, etc you need a gyro to give you a non moving plane of axis to measure off of.

 

[rk97]

^ right - and i'm sure there's an equation to "complify" (sic) things accordingly.

I'm not disagreeing - it wouldn't be a perfect system, but i'm curious to see what it might show.

If you get the angle and speedometer in the same video shot, it should demonstrate how much of a variable your body position is. Not a measurement of that variable, but you could reasonably infer "better" or "worse" based on the difference between 2 laps (that's my theory )

so 50 mph @ 45 degree lean angle vs. 50 mph @ 40 degree lean angle - presumably your body position is better in the 2nd scenario.

I'd love to see a few laps of varying speeds/angles in the same turn. might be able to calculate your 'personal ratio' of speed:lean angle for a given turn - changing the turn would obviously be another variable, and start the whole thing over. in that case though, you're assuming YOU are consistent, and the speed and angle the variables.

would it be solid math? not at all. but it'd be fun to try!

(this honestly has me thinking enough that I might consider trying it. i'll send an email out to my High School physics teacher - my little sister probably has him for class next year, lol)

great discussion

 

[BigKid]

Sound like you understand all the principals, the good and bad of this experiment. Put on a tank mount camera and try it, think the disco ball would be cool, LOL

 

[Todd Stinson]

Don't forget that your lean angle relative to the horizon will be dependent on the camber of the turn as well. You would need a perfectly flat corner to eliminate this variable.

 

[rk97]

true - i think the chance of gathering concrete data is all but impossible.

anything learned would be specific to the turn itself (the only true constant in the 'experiment').

it's enough to make a guy want to pay for more pictures and bust out the protractor

 

[Surfinglbi23]

Maybe I am too simple but I just use my knees!

 

[track4me]

Surfinglbi23;1888 wrote: Maybe I am too simple but I just use my knees!

:agree:

And if you start dragging elbow, I think you are pretty well maxed out.... or you may be headed for a :doh:

 

[physicistkev]

It goes like this, if I am dragging the following things this is what I think...

1.Knee - good lean angle

2.Toe - real good lean angle

3.Lower fairing - not much more you can do

If you have all three then you can pretty much assume that you are at the limit. One step further

4.Elbow - you have issues

If you are dragging 2 and not 1 then you have bad body position. If you are dragging 3 and not 1 or 2 then you have real bad body position. If you are dragging 4 and nothing else you have exceeded the tires traction and are now in Newton mode

 

[Quantum_Ape]

Just my 2 cents guys, but couldn't you use an Dual-axis Accelerometer. To put it simply it's a chip that heats a gas and reads the flow and circulation to tell acceleration and pull. You could mount one axis vertical with the bike, the other horizontal. Depending on the amount of G's you pull down into the bike combined with the effects of gravity still felt on the mounted horizontal axis, you should get a fairly reliable reading of lean angle. Just throw in a micro controller to compute the numbers and a you got the possibility of reading lean angle that is self adjusting and can also tell you how hard your hitting the turn over all, suspension bound and rebound rates, total G's, center of gravity relative to the bikes natural center of gravity, etc...

Though it might take some time to code and work out the kinks. You could cut production time short by using a packaged chip like the STAMP chips rather than the cheaper alternatives. The only reason this method would work is because while centrifugal force on the bike in the turn keeps the majority of the g's vertical with the bikes axis, you will always have an influence of gravity. This can be read a number of ways with a Gyrometer being the most accurate, but an Accelerometer can do it cheaper.

Here is an example of the chip if your at all interested and anyone is still reading this post

http://www.parallax.com/Store/Sensors/AccelerationTilt/tabid/172/CategoryID/47/List/0/Level/a/ProductID/93/Default.aspx?SortField=ProductName%2cProductName

Oh, and yeah, you could use your knees too.

 

[Brian Laws]

I'd love to see someone build one of these. How would you store the data, and DL it for review?

 

[JGardy_781]

811Racer;3548 wrote: I'd love to see someone build one of these. How would you store the data, and DL it for review?

Probably be cheaper/easier for the laymen amongst us to buy a datalogging setup instead... starting from scratch with a sensor, you'd have to assemble hardware for some type of wee-sized computer to process the signals, then put together something to serve as a data storage device, then write software to run the on-board computer with its sensors, then develop some way to transfer data to a laptop for analysis in something like Excel or some custom made app...

Probably be easier to just buy something, but not near as adventurous - Maybe something like this: http://www.racepak.com/ (detail here: http://www.sportrider.com/features/146_0606_racepak_g2x_data_acquisition/index.html)

There's been lots of articles recently in the brit sportbike press detailing data acquisition how-tos, theroy, etc.

Course, I could be wrong: Quick search on the web turned up this: http://www.advantagemotorsports.com/

 

[physicistkev]

I think the easiest way would be to use a laser measuring tape like device to record the distance from your bike to the ground at a given angle when the bike is vertical.

As the bike leans over that distance will get shorter and you should be able to calculate the lean angle given the change in distance. You could record this over time as you circulate the track and see what your various lean angle is through the corners.

This just seems simpler than any type of gyroscopic effort. Not as accurate but simpler to execute.

 

[updated]

I added dimension lines to your angle, look at the picture.
Looks close to 42 degrees off vertical.
Do you have any other pics that show more ground for better reference?

 

[Quantum_Ape]

811racer, if someone were to build this, you can have the data store to a number of things, the microchip itself, an external storage which could be a flash drive. As for viewing, anyone that knows a bit of python coding could whip up a simple app in a day to show time vs data logged with a little scale to show lean angle.

JGardy, I definitely agree. In no way would i expect every race to be able to put together a data acquisition system. Just trying out ideas and even buying the parts retail, it still would be WAY cheaper than most of the data acquisition systems on the market. Might be a fun project too.

For a more complete system that solves most of the issues you described would be to do this.

Ever heard of the Zipit? It's an IM'ing handheald thingy. It runs Linux natively (YAY LINUX) so naturally someone wrote an OS for it that makes it a mini computer rather than a simple IM'ing tool. I actually reflashed one of these a while back and put a bi-directional serial port on it.

For $100 you can have your data acquisition computer and with about another $15 mod it to be able to interface to a microcomputer with the accelerometer. It can store the data to a flash card, and because it has a serial interface, you can plug it into a computer and directly transfer the data. Actually it has a wireless B/G card if i remember correctly so you could grab all the data wirelessly with a laptop in the pits

Unfortunately i have all the hardware and the microcontroller programing down, but i've yet to nail the software programming. Maybe one day i will finish up my other projects and get playing with this one. Sounds like fun.

physicistkev, I thought about a distance measuring system. Actually i think the so called laser systems are actually using ultra sonic with a laser pointer so we can see where its pointing. But thats neither here nor there. The problem i found was if the turn your on is banked in either camber, your reading will be off the exact amount the turn is banked. This can lead to inconstant readings but if your just comparing it to itself on each turn separately it's a very good way to do it. Just need to hook something up to capture the data.

Anyway, sorry for spewing out a bunch of giberish, i just love this stuff and enjoy talking about it.

 

[BarryD]

I use this Fowler electronic protractor at work all the time.

http://www.sjdiscounttools.com/fow74-422-450.html

It's very accurate and robust, gives constant readout, plus you can zero it in any position. Unfortunately, there is no memory function, so I guess you'd still need a camera to record...... or read it in the middle of the turn:notsure:

 

[JGardy_781]

Quantum_Ape;3652 wrote: JGardy, I definitely agree. In no way would i expect every race to be able to put together a data acquisition system. Just trying out ideas and even buying the parts retail, it still would be WAY cheaper than most of the data acquisition systems on the market. Might be a fun project too.

For a more complete system that solves most of the issues you described would be to do this.

Ever heard of the Zipit? It's an IM'ing handheald thingy. It runs Linux natively (YAY LINUX) so naturally someone wrote an OS for it that makes it a mini computer rather than a simple IM'ing tool. I actually reflashed one of these a while back and put a bi-directional serial port on it.

For $100 you can have your data acquisition computer and with about another $15 mod it to be able to interface to a microcomputer with the accelerometer. It can store the data to a flash card, and because it has a serial interface, you can plug it into a computer and directly transfer the data. Actually it has a wireless B/G card if i remember correctly so you could grab all the data wirelessly with a laptop in the pits

Unfortunately i have all the hardware and the microcontroller programing down, but i've yet to nail the software programming. Maybe one day i will finish up my other projects and get playing with this one. Sounds like fun.

Cool. Get to work... I'll buy one!

 

[Brian Laws]

Well, however you guys decide to do this, I just want to see some lean angle & accl/deccl windows on these trackday videos like we see occassionally on MotoGP. Owe, that reminds me - would like to see the occassional brake lever shot on these trackday videos as well. Ya'll are taking requests right?