[ODE] Patch to optimize the angles calculation of Universal joint

[LR]

Hi,

In fact i use a hinge 2 to have a suspention on axis 1 and wheel on axis2
(of course !).
On each axis a have to know angle to compute odometry (odometrics ?
Odometers ?).
Today, for the axis 2, i use AngleRate to compute wheel odometry but the
rate is not efficient, i must look at what happend every time step.

On the hinge joint, it's easy using GetAngle to compute the odometry, on
hinge2 it's not ...

In my precedents mails i confused axis 1 and axis2, sorry. But my real
problem is to know the two angles to compute a good odometry for each axis.
Then i think GetAxis2Angle (or GetHinge2Angles) should be a good feature.


Laurent.
 

-----Message d'origine-----
De : Jean de Largentaye [mailto:jlargentaye at gmail.com] 
Envoyé : vendredi 28 avril 2006 09:30
À : LR
Cc : ODE Mailing List (E-mail)
Objet : Re: [ODE] Patch to optimize the angles calculation of Universal
joint

Hi Laurent,

I remain surprised that you'd need the Hinge2 Angle2 value, especially for
changing the direction of the wheel. For that you should only need
Angle1

The point of hinge2 is that the object on Axis2 turns quickly, typically a
wheel. The angle of that object isn't really important, only its speed is
(Angle2Rate). Or maybe in your situation it's turning slowly, but in that
case you shouldn't be using Hinge2, but rather two hinges, I believe.

My understanding is that GetHinge2Angle2 was omitted purposefully, so that
people wouldn't want to use Hinge2 in a situation where they would need
Angle2.

But then, maybe I'm ignoring some blatant fact or specific case. Damn
fridays :)

Jean

On 4/27/06, LR <logreg at free.fr> wrote:
> Hi,
>
> Do you think you can code the dJointGetHinge2Angle2 function ? Or 
> Codeing the getHing2Angles ?
>
> Laurent.
>
>
> -----Message d'origine-----
> De : ode-bounces at q12.org [mailto:ode-bounces at q12.org] De la part de 
> Remi Ricard Envoyé : jeudi 27 avril 2006 19:44 À : ODE Mailing List 
> (E-mail) Objet : [ODE] Patch to optimize the angles calculation of 
> Universal joint
>
> Hi,
>
> This is patch optimize the way to get both angles for the Universal joint.
>
> Instead of calling getUniversalAngle1 and getUniversalAngle2 and doing 
> some redundant stuff I added the function getUniversalAngles(j, angle1,
angle2).
>
> I did some testing and the function universalGetInfo1 using the 
> getUniversalAngles to find both angles is 23% faster.
>
> The patch is done againts latest svn trunk (2006/04/27).
>
> I submitted the patch on the sourceforge website.
>
> I'm only posting this here to let the developer with svn acces know 
> that there is a new patch.
>
> The patch is produced with:
> svn diff >> ../add_getUniversalAngles.patch
>
> Description:
> Add a function optimizing the calculation of both angles of the 
> universal joint.
>
>
> Remi
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