tyre balancing

[JChec]

Hi,

I'm looking replace and existing tyre balancing machine. Keep the existing mechanical hardware and sensors, but replace the controller with NI equipment. So IE. do the analysis on say a CRIO and labView. Although my knowledge on tyre balancing is limited as I haven't worked with a similiar system before. Does anyone know of any information describing how the analysis works or maybe just a starting point? Has this been done with NI products before?

Thanks

[muks]

This has been tried here

[Hummer1]

I seem to remember that in vibration analysis, there is a weight substitution technique that is used.  You have to be able to measure the position of the rotary device with respect to some datum and then add some weight...there is a 90 degree offset from where the maximum travel is and where the maximum weight is...(I seem to recall that the CG of the rotating device is offset ahead of the center of rotation by that 90 degrees...) So if you add weight (a trial weight) to the point 90 degrees behind the maximum position point, that will move the CG in the right direction.  If the trial weight is too much, then the maximum position offset point will move in phase by 180 degrees.  If the weight is too little, then the magnitude of the position offset will just get smaller but the phase relationship with the previous maximum position offset will be the same...

Here is a good discussion...(far better than mine.)

http://www.precibalance.com/gfaq.pdf

Would be an interesting project.  What sensors are available on the machine, and what control over the placement of trial weights (or capability to adjust weights) does the machine have?  

Hummer1 

[JChec]

Thanks Hummer for that great input there. Given me a good starting point to work with. Done vibration stuff, but not balancing before. Going through that document, at the moment, which you suggested. Only going down to the factory at the beginning of next week, so will hopefully get the specs on the sensors, as well as the control of the trial weights then.

Thanks!

[JChec]

I have an lvdt sensor available, the only problem is that there's no model number or any marking on it so will have to replace it otherwise I'll know very little about the measurements acquired from it. 

ok, I've come a little stuck in my research here. I've not managed to find much information about the relationship between the amount of vibration (displacement in this case - lvdt) and the amount of unbalance (eg. in grams). Does anyone have any knowledge on that or any good links. My research seems to have always taken me to the principles of how the balancing works but never much detail into the mathematics.

Thanks... and hope that paragraph makes sense