Sorry Tom, my bad. I uploaded the wrong pic, now I corrected.Jersey Tom wrote:Those don't look like histograms.. and somethin doesn't look right about em as a X/Y plot..
Still.. doesn't look right. If it's over the course of a lap it should cross back over itself many times over.Belatti wrote:The other 4 X/Y plots are the 4 wheels damper position, from 150 to 210 kp, at a 200Hz sample rate. You can plot either points or lines, I prefer lines because you can see better.
mm of damper displacementgambler wrote:What is the left hand vertical column representing.
its a matter of screen space... just to see the graph bettergambler wrote:and
why are the number scales different on side by side comparisons?
I have said its from 150 to 210 kph, its a straight, not a complete lap.Jersey Tom wrote: Still.. doesn't look right. If it's over the course of a lap it should cross back over itself many times over.
How can you say that? Do you know the car enough?Jersey Tom wrote: And that's an incredibly small range of damper travel.
All the graphs are "full" lap graphs. This a problem when looking for shock trends and aero trends.Belatti wrote:Hi,
I have been using linear damper sensors in a PI data acquisition system for a while.
The main purspose of this was to gather some data our consultant needed to perform a 4 post rig test (car with low aero downforce).
The rig test went very good, the laptimes decreased and the topics discussed here helped a lot.
I have used the PI Toolbox to plot histograms:
And tried to figure out downforce levels:
Taking into account the different motion ratio front and rear, I wonder how much can I trust these polynomials.
I have also processed the data in matlab, using FFT and some results were these:
You can see a peak at x:2,737 wich gets pretty close to the natural frequency of the car that I calculated using corner weight + spring rate at the wheel (2.75Hz)
Now I would like to know what are the other possible uses I can give to them.
Sorry, when I said that I had calibration issues I was referring to the track vs. post rig tests. What I question now its those graphs practical usefulness.Jersey Tom wrote:Looking at it again.. that your dampers are working almost entirely at less than 2 in/s seems really odd.
The FFT graph is for a braking + curve + beginning of acceleration (arround 8 seconds) for a single wheel.speedsense wrote: All the graphs are "full" lap graphs. This a problem when looking for shock trends and aero trends.
Right.speedsense wrote: With Aero downforce, the same technique can be applied, with perticular speeds chosen for gates. It is best to analyze, with the car straight (no lateral, or braking long g) and keep the range within a few KM's for each target speed.
Without a pitot tube however, you could be spitting into the wind... (pun intended)
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