OpenServo.com

[eric_lmi]

"Curve in velocity" and "Curve out velocity" reg are always the same?

for a hermite curve, p0 is the current position. how to define v0?

[ginge]

Hi Eric,

I started to document the curve features on the wiki here.

http://openservo.com/MotionProfile

It is not finished yet, and probably does not cover everything, but it is getting there.

The in and out values are the same because you presumable want the servo to move in a nice curve motion from one point to another. The OpenServo is based on keypoints are not the entire curve. The Tangent in values and the tangent out values are for the keypoint, and not the beginning and end of the curve. Each curve is comprised of two keypoints, making up one keyframe. Doing it this way gives us much more flexibility when it comes to creating differing motion profile shapes.

v0 will be the same as v1, which is the velocity of the servo movement. This is also defined as the tangent. v0 is the tangent in, and v1 is the tangent out.


http://www.cubic.org/docs/hermite.htm gives a good overview of how hermites work. In this example, the v0 and v1 values are defined by (T1x-P1x)/(P1y/T1y)

The wiki entry covers the tangent creation and conversion to OpenServo values.

I hope this all makes sense to you... It took me a while to get to grips with it.

Barry
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[eric_lmi]

thanks Barry
very useful information.