Quote:
Originally Posted by JAJ
Getting the "clean" signal wasn't easy - it's very prone to small offset errors and to noise, so a full second of sensible results takes an hour or so to process by hand.
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Is the process by hand the elimination of errors or more? Did your integration involve some smoothing or data(n+1) = data(n) + d data(n) / dt * delta t?
Quote:
Originally Posted by JAJ
The run out of travel events are the flattening of the top of the suspension compression curve. I didn't go over the speed bump very quickly and it only just touches, so the "impact" is only really visible in the processed output - in the raw data it's buried in the noise and rumble. I don't recall a "thump", but then it was a year ago.
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Looking at it more closely, I see what you mean now: the top of the wheel/suspension curve is flatter than expected from a harmonic signal. From the technical drawings I recon that bump stops nowadays have their own additional spring and damping characteristics, rather then being hard stops but I still would expect a more significant deviation (acceleration spike) from the harmonic line. It could also be related to the shape of the bump (~flat top?) and/or a dry friction effect? Once I have time I wouldn't mind looking into deriving the shocks damping coefficient [Ns/m] and dry friction force from your curves. The mass (or weight), front-rear balance and spring rate of the measured setup would be useful for that (and if willing to share, the measurement data). My goal here is mainly to get a feel for the damping coefficients used in M3 shocks and in the end to quantify the difference in EDC damping settings vs their drive signal.
I started diving into old Matlab stuff and found that it lets you record directly from the PC's line-in, but I would need an accelerometer with the right output signal. Did you consider accelerometers with analog output?