topic Re: Robot Gamma Angle in Robot Structural Analysis Forum

Robot Gamma Angle

Anonymous — Tue, 05 Jul 2016 10:00:35 GMT

Hello,

I still have problems with gamma angle : could you explain why a bar almost vertical (from x=0.01,y=0,z=-5 to x=-0.01,y=0.01,z=-3) is well positionned according to robot explanations (local xz plane is vertical) so I adjust the gamma to the angle between this vertical plane and the X axis in WCS and the bar is perfectly positionned.

A second bar starting from the second node above to a third node x=-0.1,y=0.1,z=1 is also well positionned (xz in the vertical plane) but in this case the gamma angle must remain to 0 !!. If I correct the gamma angle with the value = angle between vertical plane and X axis, the bar is no more well positionned.

So why and when do I have to correct the gamma angle ? For almost vertical bars, the correction is valid and for almost horizontal bars, the correction has not to be done...

Thanks for your tips

Re: Robot Gamma Angle

Rafal.Gaweda — Wed, 06 Jul 2016 07:58:31 GMT

You wrote the crucial word in your post: "...almost..."

Re: Robot Gamma Angle

Anonymous — Thu, 07 Jul 2016 07:11:42 GMT

Hi, Rafal

You are wright: the problem is almost...
I have found out a way to well position the bars, according to the gamma
angle I want.

I have still a difficulty : for a non symetrical profile such a U or L,
what is the direction for the profile for the y axis : I know that is
the strong inertia axis, but for a U, is it like ] or [ ?

Regards

Re: Robot Gamma Angle

Rafal.Gaweda — Thu, 07 Jul 2016 07:21:39 GMT

Tools \ Section Database:

Keep in mind that angle sections are available with properties in main axes or principal axes. Use the correct one

Re: Robot Gamma Angle

Anonymous — Thu, 07 Jul 2016 08:23:42 GMT

Where do I have access to this specific property ? I have seen
excentricity of the section in main or prinipal axes, but not the choice
for the section itself ?

Re: Robot Gamma Angle

Rafal.Gaweda — Thu, 07 Jul 2016 08:27:29 GMT

I am afraid I do not understand you.
All angle families names with P letter at the end mean that they are in Principal axes

Re: Robot Gamma Angle

Anonymous — Thu, 07 Jul 2016 08:38:42 GMT

Whooops . Sorry for this silly question. "Angle" is a false friend for me.