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ACM vs Luffy Vibration Test


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:thumbup: Rehab1's got guns too!  It looked like the Luffy didn't climb enough which led to your toe getting hooked on the edge of the pavement.  I wonder whether an angled approach might have been better, but maybe not if the edge is too high?

Edited by Hunka Hunka Burning Love
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Don't know if I'm interpreting the data correctly...but based on your vibration data graphs, it appears the ACM ride produced more vibration than the Luffy?  That seems counter intuitive since the larger wheel is supposed to produce a smoother ride.  Is there a big difference in your Velcro attachment method on both wheels?

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6 hours ago, Rehab1 said:

I purchased an app for my IPhone 7 that is a 3 channel vibration spectrum analyzer. It uses the internal accelerometer and gyroscope of the phone to analyze vibratory and rotational motions.

36612477176_67c60bdb41_b.jpg

You simply place the IPhone so it is firmly attached to the object you want to analyze, hit the sample button and the vibratory readings begin. I only used one channel to measure the vertical (+Y) coordinates during my initial test run. I attached the phone to both my Luffy and ACM 1600 using Velcro but a more stable mounting platform is in the works. Below are 2 sample graphs depicting what data can be produced when using all 3 channels of the app.

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So I went for a little ride on the ACM and Luffy around a bumpy piece of property next to my facility to see if I could obtain any quantifiable data. The data may be skewed a bit due to the Velcro method I used to attach the phone to both wheels but it was a fun experiment and only cost $4.99.

Below are 2 more graphs depicting the Y coordinate data I obtained from each ride. Combining X, Y and Z data will be performed in future tests. You can see the very small vibration levels at the beginning and end of each graph ( Luffy had an issue) representing the smooth parking lot where I entered and exited the course. Unfortunately Luffy could not make it over the parking lot bump ( also might be my skill level) at the end of the course and I fell off which created an interesting peak. In the middle of the graph there is a good representation of the various bumps I encountered throughout the simple course. 

acm graphluffy graph

 

Now for a good laugh!

 

 

That was great. Nothing like a fun crash :D  Somehow I don't think the Mten will suffer such humiliation with it's beefed up motor.

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4 hours ago, Clovis said:

Don't know if I'm interpreting the data correctly...but based on your vibration data graphs, it appears the ACM ride produced more vibration than the Luffy?  That seems counter intuitive since the larger wheel is supposed to produce a smoother ride.  Is there a big difference in your Velcro attachment method on both wheels?

The scale on both graphs is different! So the vibration accelerations could be around the same for both...

as the phone was velcroed at the front the "y acceleration" does not only measure the up/down accelerations from all the bumps one rides over, but also the pitch changes - and since at the acm the phone is further away from the center of rotation it gets higher acceleration values. (If this pitch "vibrations" are in a range as the normal vibrations from driving over rough ground at all...)

@Rehab1: the frequency spectrum of the acm vibration looks interesting - thus was from a short ride on the flat parking lot? The maxima at 5, 10 and 21-22 Hz are very distinct. 5 Hz would mean a repeating occurance at a speed of ~3,5 km/h at the circumference of a 16 inch wheel. 10 Hz ~7 km/h and the ~21Hz ~15 km/h. Could be from an not balanced tire ore just repeating patterns on the parking lot (small bumps, etc,...)?

i've just seen that these maxima are for all 3 axes - so bumps on the parking lot seem the explanation? An unbalanced tire should not give a "distortion" on all 3 axes?

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6 hours ago, Hunka Hunka Burning Love said:

:thumbup: Rehab1's got guns too!  It looked like the Luffy didn't climb enough which led to your toe getting hooked on the edge of the pavement.  I wonder whether an angled approach might have been better, but maybe not if the edge is too high?

I should not have worn that shirt! :facepalm: Luffy's pedal scraped slightly when I first dropped off of the parking lot onto the grass course so I should have repositioned the cones to the left side of the dumpster where the transition is smoother. This was my first attempt on this makeshit (shift) course.  I should have reshot the video before posting it but wiping out is part of the fun. I  think my boobs may have also impeded my balance.:confused1:  

 

6 hours ago, Clovis said:

Don't know if I'm interpreting the data correctly...but based on your vibration data graphs, it appears the ACM ride produced more vibration than the Luffy?  That seems counter intuitive since the larger wheel is supposed to produce a smoother ride.  Is there a big difference in your Velcro attachment method on both wheels?

Your correct on both counts. After further research the best placement may be mounting the phone to my belt or chest.  The Velcro mount was not the best. Interestingly the ACM did have a wider base to support the phone compared to Luffy. 

 

 

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2 hours ago, Marty Backe said:

That was great. Nothing like a fun crash :D  Somehow I don't think the Mten will suffer such humiliation with it's beefed up motor.

I love watching crashes but mine was peanuts compared to your's and so many other members! Any crash you can :laughbounce2: about is a good crash!

2 hours ago, Chriull said:

as the phone was velcroed at the front the "y acceleration" does not only measure the up/down accelerations from all the bumps one rides over, but also the pitch changes - and since at the acm the phone is further away from the center of rotation it gets higher acceleration values. (If this pitch "vibrations" are in a range as the normal vibrations from driving over rough ground at all...)

Great analysis! A stable mounting base located on my body will be the answer to produce more accurate evidence based vibration data. Then I can begin measuring all 3 axis planes. 

2 hours ago, Chriull said:

Rehab1: the frequency spectrum of the acm vibration looks interesting - thus was from a short ride on the flat parking lot? The maxima at 5, 10 and 21-22 Hz are very distinct. 5 Hz would mean a repeating occurance at a speed of ~3,5 km/h at the circumference of a 16 inch wheel. 10 Hz ~7 km/h and the ~21Hz ~15 km/h. Could be from an not balanced tire ore just repeating patterns on the parking lot (small bumps, etc,...)?

I am at the very beginning stages of researching vibratory frequencies so any input from you and other members will be valuable. The IPhone 7 includes a MEM accelerometer and a MEM gyroscope. Apple provides an software interface to these devices allowing programmers to access the data at sample rates up to 100Hz. A 100Hz sample rate allows measurement of motion up to frequencies of 50Hz. 

The 3-channel accelerometer has a sensitivity of approximately 0.02g and a range of +/-2g making the iPhone sensitive enough to analyze the vibration of most moving machinery. The built in gyroscope is so sensitive that the compnay has not been able to determine its lower limit.

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23 minutes ago, meepmeepmayer said:

Not sure what the point of a EUC vibration test is, but I certainly appreciate your enthusiasm:thumbup: You seem to be a guy who always needs some kind of project, very productive!

I do love to experiment.  :)

There has been various discussions on the forum about how a larger diameter wheel is much smoother going over rough terrain than smaller wheels, which makes perfect sense. But when it comes down to the actual facts it becomes subjective based on the rider's personal impressions.  Auto manufacturers perform these type of tests all of the time to distinguish how much smoother their model's ride is compare to other vehicles in the same class. 

Eventually I want gather vibration data on the ACM, Mten, KS16, V5F+ and V8 on this course if I can even navigate it.

36493309846_ff315d2238.jpg

 

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52 minutes ago, Rehab1 said:

...

A stable mounting base located on my body will be the answer to produce more accurate evidence based vibration data. Then I can begin measuring all 3 axis planes. 

I am at the very beginning stages of researching vibratory frequencies so any input from you and other members will be valuable.

...

 

Maybe some tests on a perfectly straight and flat surface (gym, running track, volleyball court, etc..) with some different mounting locations and wheels could give some "base calibration" of the "vibration" data? So one could see what vibrations is coming from the EUC itself (tire, not perfect continous motor commutation, balancing, etc...).

Edit: Ps.: Mabye also mounting the phone on one side exactly at the center of the tire could be a good position? then everything but the z-axis should be valid vibration data? Mounting the phone on your body already gives quite some dampening of the vibrations...but on the other side it gets the real vibrations that inflict ones body...

Edited by Chriull
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15 hours ago, Chriull said:

Maybe some tests on a perfectly straight and flat surface (gym, running track, volleyball court, etc..) with some different mounting locations and wheels could give some "base calibration" of the "vibration" data? So one could see what vibrations is coming from the EUC itself (tire, not perfect continous motor commutation, balancing, etc...).

I really like your suggestion! Unfortunately I  cannot think of a perfectly straight flat surface in my community where a EUC would be welcomed. 

 

15 hours ago, Chriull said:

Mabye also mounting the phone on one side exactly at the center of the tire could be a good position? then everything but the z-axis should be valid vibration data? Mounting the phone on your body already gives quite some dampening of the vibrations...but on the other side it gets the real vibrations that inflict ones body...

Researchers are currently studying the effects of vibration on the human body while riding in vehicles. Whole Body Vibration (WBV)  testing is being studied to evaluate the health risks of long term vibrations induced on seated persons with vibration levels from 0.5 Hz to 80 Hz. Standing while riding EUCs over long stretches of roads might produce similar vibration levels. 

Granted most of us are not riding our EUCs for hours on end that would cause any detrimental effect on our health. I just find it interesting that researchers have determined that vibration levels in that particular bandwidth can cause disruptions to the functioning of the spinal column and associated nervous system, as well as potentially disrupting the digestive system. 

OMG I can already hear the skeptics pounding on my door. Please save the criticism. I'm just participating in some fun weird science stuff .:P

Edited by Rehab1
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5 hours ago, The Fat Unicyclist said:

If you're after some fun, might I suggest...

The short term effect of alcohol on EUC riding abilities, and how it enhances (or possibly compromises) your normal skill level.

If it helps, I am prepared to assist you with your testing?

:) Would that imply you are providing the alcohol?:cheers: 

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