[burpg] Measuring Servo Spline
- From: Armor Harris <armorharris@xxxxxxxxx>
- To: "burpg@xxxxxxxxxxxxx" <burpg@xxxxxxxxxxxxx>
- Date: Sat, 16 Aug 2014 22:24:15 -0700
Hey guys,
We need someone back at the lab to measure the old e-regulator servo
spline. Looks something like this
http://www.servocity.com/html/hitec_servo_splines.html#.U_A6QvldV8E
I think the best procedure here is to use a high resolution camera (read:
not an iphone) to take a perfectly 2D picture of the servo spline with a
pair of micrometers set to a known distance on the same plane as the servo
spline (calipers probably aren't accurate enough unless they're really nice
ones).
Then, someone can use imageJ to measure the length in pixels of each spline
tooth and use the distance between the micrometers in the same plane as a
pixel to length ratio. ImageJ makes it really easy.
I've done this before on another application, I used an SLR with a stock
lens and a tripod and it worked pretty well. The setup was in a difficult
environment but I was still able to get accuracy of less than .001" You can
probably do better since it's in a well lit lab environment and you can
control the photo a lot better. I would suggest is setting up the camera
for maximum contrast so that when you zoom in, you can still see sharp
lines.
Once we get that measured, we want to try using wire EDM to machine our own
attachments for high precision valves like the thrust vector control and
the throttle valve. This could potentially make our servo driven valves a
lot more reliable and rugged, so it's a really big deal if we're able to do
this.
Anyone up for it?
Armor
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