Inverse Kinematic with Sawyer

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mari
Posts: 3
Joined: 02 Oct 2018, 13:27

Inverse Kinematic with Sawyer

Post by mari » 04 Oct 2018, 14:51

Hi everyone!
I'm a university student and my professor gave me the task to learn this program to simulate the robots in the laboratory. The professor doesn't know this program, so I'm trying to learn it by myself.
I'm trying to apply the inverse kinematic tutorial on a Sawer, but the robot and the target are unstable and constantly tremble.
Searching on this forum I've found other topics over this posible problem and putting suggestions into practice the situation has improved, but the system remains unstable.
So the questions are:
- I have some links of the robot that are respondables and dynamics, but if I uncheck these options the situation get worse, so is correct that some links have to stay in this way?
- If the target doesn't follow correctly the mouse, is that a problem connected with the instability of the robot? I noticed that if the translation of the mouse is only along Y and Z the system is more stable, can you tell me why?
-The basement (link0_visible) moves with the robot, it follow the direction of link3_visible, but it don't have to move, what can cause this? Maibe is because the joint1 is in IK mode?

Thanks to anyone who can help me.

coppelia
Site Admin
Posts: 6864
Joined: 14 Dec 2012, 00:25

Re: Inverse Kinematic with Sawyer

Post by coppelia » 10 Oct 2018, 07:18

Hello,

you can have many things that go wrong. Typically:
  • your adjacent robot links are colliding with each other
  • your robot links have a bad mass and/or inertia. The Vortex engine handles these problems much better, try with Vortex to see if that might be the reason
  • your joint position controller had bad parameters (e.g. torque, P, I, or D parameters)
  • your IK element is overconstrained or has bad settings
Cheers

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