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  Rather Elementary UJoint 508KB (Message 1 to 8 of 8)  
From: Michael McKnight
Subject: Rather Elementary UJoint 508KB
Date: 17 Dec 2001 16:50:49
Message: <3c1e68b9@news.povray.org>
Here is my first ever articulated joint.  I don't know if it qualifies as
inverse kinematics - I use a vector to define the orientation of the moving
axle.  Toughts?

Michael


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Attachments:
Download 'UJoint.MPG' (509 KB)

From: Christoph Hormann
Subject: Re: Rather Elementary UJoint 508KB
Date: 18 Dec 2001 08:00:38
Message: <3C1F3DF6.12EEB70A@gmx.de>
Michael McKnight wrote:
> 
> Here is my first ever articulated joint.  I don't know if it qualifies as
> inverse kinematics - I use a vector to define the orientation of the moving
> axle.  Toughts?
> 

I think this is a very good demonstration for the fact that this kind of
joint does not lead to constant angular velocities on both sides.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Michael McKnight
Subject: Re: Rather Elementary UJoint 508KB
Date: 18 Dec 2001 12:22:15
Message: <3c1f7b47@news.povray.org>
> I think this is a very good demonstration for the fact that this kind of
> joint does not lead to constant angular velocities on both sides.
>
> Christoph

You know, that's interesting - when i was testing the animation, i had
accidentally rotated the axle the wrong way, and when it hit about 90
degrees relative to the other, it pretty much stopped.  Looking at the one i
posted,  i can see how the angular velocity becomes more erratic as the
angle between the two axles gets farther away from 180 degrees.  This is
really interesting because the front wheels on my old jeep are connected to
the font axle by U joints, and it's an all wheel drive.  Maybe that explains
the funny wobbling motion it makes on really tight turns.  I wonder if CV
joints would have constant angular velocities on both sides, and that's why
they are used now?

michael


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From: Christoph Hormann
Subject: Re: Rather Elementary UJoint 508KB
Date: 18 Dec 2001 17:02:33
Message: <3C1FBCF3.EBB1FB5F@gmx.de>
Michael McKnight wrote:
> 
> You know, that's interesting - when i was testing the animation, i had
> accidentally rotated the axle the wrong way, and when it hit about 90
> degrees relative to the other, it pretty much stopped.  Looking at the one i
> posted,  i can see how the angular velocity becomes more erratic as the
> angle between the two axles gets farther away from 180 degrees.  This is
> really interesting because the front wheels on my old jeep are connected to
> the font axle by U joints, and it's an all wheel drive.  Maybe that explains
> the funny wobbling motion it makes on really tight turns.  I wonder if CV
> joints would have constant angular velocities on both sides, and that's why
> they are used now?

I don't know what 'CV joints' are, but these days you mostly use what is
called 'Gleichlaufgelenkwelle' in German.  The single joints look somewhat
similar to a ball bearing.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: John D  Gwinner
Subject: Re: Rather Elementary UJoint 508KB
Date: 19 Dec 2001 12:57:22
Message: <3c20d502$1@news.povray.org>
I used to have a CJ-7, pretty old and beat up.

The reason your jeep wobbles is because it doesn't have a differential in
the front.  The inside wheel should be moving less than the outside, but it
doesn't, so they fight.  When one tire slips a bit the jeep 'wobbles'.  It's
not the CV joint per se, it's the lack of the differential.  A CV joint
would have the same problem.  All wheel drive units have three
differentials.

For Christoph, 'CV' joint means "Constant Velocity Joint".

== John ==

"Michael McKnight" <nes### [at] hotmailcom> wrote in message
news:3c1f7b47@news.povray.org...
>
> > I think this is a very good demonstration for the fact that this kind of
> > joint does not lead to constant angular velocities on both sides.
> >
> > Christoph
>
> You know, that's interesting - when i was testing the animation, i had
> accidentally rotated the axle the wrong way, and when it hit about 90
> degrees relative to the other, it pretty much stopped.  Looking at the one
i
> posted,  i can see how the angular velocity becomes more erratic as the
> angle between the two axles gets farther away from 180 degrees.  This is
> really interesting because the front wheels on my old jeep are connected
to
> the font axle by U joints, and it's an all wheel drive.  Maybe that
explains
> the funny wobbling motion it makes on really tight turns.  I wonder if CV
> joints would have constant angular velocities on both sides, and that's
why
> they are used now?
>
> michael
>
>
>


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From: Michael McKnight
Subject: Re: Rather Elementary UJoint 508KB
Date: 19 Dec 2001 17:39:06
Message: <3c21170a@news.povray.org>
I have an old  and beat up jeep wagoneer...my insurance company thinks it's
a sport wagon, whatever that means :)  i'm pretty sure it's got a
differential on the front too...anywho, i think my next anim's going to have
to be a cv joint.  i found some good pictures on the net.  thanks for the
heads up on the definition.

Michael

"John D. Gwinner" <jgw### [at] dazsicom> wrote in message
news:3c20d502$1@news.povray.org...
> I used to have a CJ-7, pretty old and beat up.
>
> The reason your jeep wobbles is because it doesn't have a differential in
> the front.  The inside wheel should be moving less than the outside, but
it
> doesn't, so they fight.  When one tire slips a bit the jeep 'wobbles'.
It's
> not the CV joint per se, it's the lack of the differential.  A CV joint
> would have the same problem.  All wheel drive units have three
> differentials.
>
> For Christoph, 'CV' joint means "Constant Velocity Joint".
>
> == John ==


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From: Tony[B]
Subject: Re: Rather Elementary UJoint 508KB
Date: 21 Dec 2001 18:44:47
Message: <3c23c96f@news.povray.org>
What a peculiar joint. I've never seen one like that. It's pretty cool. :)


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From: Michael McKnight
Subject: Re: Rather Elementary UJoint 508KB
Date: 21 Dec 2001 23:45:40
Message: <3c240ff4@news.povray.org>
Why thank you!

"Tony[B]" <ben### [at] catholicorg> wrote in message
news:3c23c96f@news.povray.org...
> What a peculiar joint. I've never seen one like that. It's pretty cool. :)
>
>


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