Whi is my Ik model shaking when I use undamped IK model

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efirvida
Posts: 2
Joined: 17 Jan 2018, 21:02

Whi is my Ik model shaking when I use undamped IK model

Post by efirvida »

Hi I follow the tutorials:
  • Building a clean model tutorial.
  • Inverse kinematics tutorial.
And I also saw the 7Dof Manipulation model to compare with mine. But I can't figure out why my model begins shaking when I'm using undamping model.

What I want for the moment is to create a simple model to draw something using api with python, so my Idea is change the dummy with the api. For this reason I need to use the undamping model to get rigid the pen when draws.

here is mi model:

https://mega.nz/#!rMxzxCZR!byrGqH68U50T ... ZIKHClOS-M

coppelia
Site Admin
Posts: 10339
Joined: 14 Dec 2012, 00:25

Re: Whi is my Ik model shaking when I use undamped IK model

Post by coppelia »

Hello,

you have two IK groups active: an undamped one, followed by a damped one. The undamped IK group will make the manipulator go crazy, since you have specific 6 constraints (x/y/z and orientation), but your mechanism has only 4 DoFs.
And your undamped has a too high damping to correct for the large positional/orientational error caused by the first IK group.

You can also enable following for the first IK group, in the conditional parameters:

Restore if Linear precision requirements were not fullfilled

At the same time, since you have an overconstrained system, the undamped IK will never succeed, and you can just remove it completely.

Cheers

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