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Operative word is "if".ubrben wrote:I'd be surprised. 2G maybe, 2.5G unlikely, 3G not a chance.olefud wrote:If a kart made such numbers, it could be a result of light weight and optimizing all parameters which, as JT points out, is not done in F-1. The light weight would allow ultra gumball tires that in conjunction with a smooth track with a high density of cogging openings could produce 3-D “keying” grip, i.e. into rather than on the track.
Ben
You are 'cleaning up' your acceleration signals by introducing aliasing in your data (when logging at 10Hz). Not a good idea for a dynamic signal like body acceleration, with freq content above 10Hz. Instead, log it at the highest rate you can afford (based on file size) and low-pass filter the data using AIM software. The logger will (should) also apply anti-aliasing filters based upon the logging rate you choose.jtc127 wrote:I looked at the sample data that comes with AIM and for the unknown kart it shows shock peaks of 2.9 in one direction at 3.3 in the other. I know these are not sustained, and the logger looks like the sample rate on the accelerometers is way too high. I used to use 50hz and 25hz on my car but it captured way too much noise, so I started using 10hz, which cleans up the signal noticeably.
When my brother and I get our karts out for the first time this spring I'll resurrect this thread with some actual data.
I used 10hz to knock down the peaks and give a better look at what is actually happening. I'll grab some data when I get home of what things look like at 50hz, almost unusable. Not sure how to apply a LPF in AiM, I do know they have a filter with 10 steps that isn't worth a ---, it just knocks down the peaks a little bit.GSpeedR wrote:You are 'cleaning up' your acceleration signals by introducing aliasing in your data (when logging at 10Hz). Not a good idea for a dynamic signal like body acceleration, with freq content above 10Hz. Instead, log it at the highest rate you can afford (based on file size) and low-pass filter the data using AIM software. The logger will (should) also apply anti-aliasing filters based upon the logging rate you choose.jtc127 wrote:I looked at the sample data that comes with AIM and for the unknown kart it shows shock peaks of 2.9 in one direction at 3.3 in the other. I know these are not sustained, and the logger looks like the sample rate on the accelerometers is way too high. I used to use 50hz and 25hz on my car but it captured way too much noise, so I started using 10hz, which cleans up the signal noticeably.
When my brother and I get our karts out for the first time this spring I'll resurrect this thread with some actual data.
I believe that a kart can hit 3+ G's peak, but not sustained as everyone has stated. Transient effects (roll/yaw accelerations) and orientation 'errors' (roll angle, track banking, etc) can all combine to greatly increase (or decrease) your lateral acceleration measurement. A skidpad would a good way to generate data.
The problem with our car is that it was severely underdamped (rules don't actually allow shocks, we had to use elastomeric spring material and derlin strips at our rockers to provide some friction/damping). Between being way underdamped and the parallel twin two stroke motor's vibrations, the G traces had massive oscillations.GSpeedR wrote:Surely there's at least moving average filter, if not then you could import into another program (MS Excel or Matlab) and perform it there. You can certainly log accel data at 10Hz if you like, just beware that it's not completely "what's actually happeneing". To get average accel values, it's probably fine.
Do you have any AiM experience? I'm racking my brain and I can't think of where I'd find an LPFJersey Tom wrote:Even 10 hz is way high. I'd take your logged data and put a 1 or 2 hz low pass on it if you want to get realistic numbers. Log at high rate and crush it down with a filter rather than sample at low rate.