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uniform travel over a oval shape

puppet

Moderator
i have a datam curve in the form of a oval and a object that needs to follow this curve.



how can i get my object to do laps of the oval at constant speed .

in mechanism.
 

kvision

Moderator
This is done with a slot connection inmechanism.

the moving part will have a point that follows the curve.

Set the velocity of the servo to be the constant you want.
 

puppet

Moderator
i tried this,

but it needs a plane of reference of a point of refernce from teh curve.

what happens is that the part follows the curve 1/2 way but once its starts to loop back it fails.
 

slashct

New member
When you select the curve Query select the entire curve, not the one half at a time. If its a solid surface that you are traveling on you can use a cam.
 

puppet

Moderator
hmm i must be doing somthing wrong can someone help me out with a small demo or tell me what i am doing wrong



i have



part - a

which is a datum curve in a oval shape, which was generateed from a rectangle and then 2 circles on either end.



part - b

which is a block with a point on it. this



the assembly

simply they are assembled via a slot connection



the driver

View attachment 435



again as the part attempts to go around it causes a error 1/2 way around, once it 's reverse its direction
 

Israr

Active member
Puppet,



I think you need cam folllower connection. Can you attach your files so that I fix it for you?



Israr
 

puppet

Moderator
hey israr,

sorry not allowed to send out models :(



its really simply to construct.



i just need uniform speeds :( and no idea why it doesnt work.



i will try a cam follower connection

:)

and keep u posted
 

Luis Aguirre

New member
Puppet,



The tricky part is to make sure that your contact vertors are normal through the motion and that any extra degrees of freedom are eliminated (i.e. rotation) by adding a zero driver. Also are you using WF 1.0 ro WF 2.0?





Luis
 

WMF01

New member
I had made something like this case, so I think the errorwas made by the velocityof motorand the curvature of the curve.
 

xcad

Member
hmm





i think that you need MDO licence to do this.


i will look for it and post you a reply for sure, but i know for sure that you cannot archive this with a cam follower connection or a slot connection





karavasilis
Edited by: xcad
 

Israr

Active member
xcad,


I was sure you , only you, can reply this difficult question. Please put your reply (solution) here in this posting so that we all could benefit.


Israr
 

IceFai

New member
puppet:


try dynamic analysis but not kinematic analysis.


so you can define a tangentia slot velocity to a constant value(for example 60mm/sec) for you slot connection . and then use initial condition you defined to run a dynamic analysis .


View attachment 462
 

IceFai

New member
the slot connection can make the block run with constant velocity in trajectory,but the orientation of block keep no change in running.


to adjustthe orientationof the block correctlyin running,i have to define a more cam connection.now the block can drag freely an correctly.but when i run the dynamic analysis ,the compute time is so long......no patient as me ,i have to manual stop it before all done.


here is my wildfire2.0 assembly .


2004-10-15_002205_track.rar
Edited by: IceFai
 

Israr

Active member
iceFai,


You are genious. I thought xcad will solve it but you did it before him.


Congratulation!


Israr
 

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