Problem with Ik configuration

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Bellinsbauer
Posts: 6
Joined: 22 Apr 2018, 07:44

Problem with Ik configuration

Post by Bellinsbauer » 14 Jul 2018, 12:04

Hello!
I post here my scene. Inside, I created a Scara robot and a producer of pure shapes to simulate random pieces that flow on a conveyor belt. My purpose is to follow these random pieces once they pass through a proximity sensor that gives me the handle of the current piece. After some time I would like to grab the piece and to move it to the other conveyor. I hope the main idea is clear. My questions are:
- When the piece passes through the proximity sensor the Scara robot makes a sort of "jump" and I read that to avoid this issue, I should place the target dummy at the tip dummy position. I did it in the function to enable the ik mode but it seems that something is wrong.
- The suction pad doesn't grab the objects but I think there is something wrong with the high where I place the target.
- When I move my robot in the other conveyor belt It doesn't reach it but it moves in the position (0,0,0) and I am wondering why.

This is my scene:
https://www.dropbox.com/s/68ft9h3ffuja5 ... a.ttt?dl=0

If you could help me with some advices , they would be really appreciated.
Thank you in advance,
Leonardo.

coppelia
Site Admin
Posts: 6675
Joined: 14 Dec 2012, 00:25

Re: Problem with Ik configuration

Post by coppelia » 16 Jul 2018, 06:26

Hello,

you are trying to solve several problems at once, you should focus on one problem at a time.
First, with your scara robot, I am not sure it is the right approach to move the end-effector in Euclidean space, since you'll have to deal with the singular configurations of your robot (typically at simulation start). I'd run the robot in configuration space.
In any case, you can't simply have the target IK dummy jump into a position instantaneously: you should gradually guide and move that dummy to where you want to be with your end-effector. You'll have to use the sim.rmlMoveToPosition for instance.

Also, if you want your sucction cup to work, it should come closer to the part (the sucction cup works with a proximity sensor that will first have to detect the part).

Cheers

Bellinsbauer
Posts: 6
Joined: 22 Apr 2018, 07:44

Re: Problem with Ik configuration

Post by Bellinsbauer » 16 Jul 2018, 09:43

Thank you for your reply.
For what concern the suction pad, I supposed the problem was the distance between the pad and the object and I will solve it later. But my main issue is the other one. When a piece is created, I want to follow it with my end-effector. Why? Because I want to record the time that my scara robot takes to reach the object. After that, I would like to compare my Scara with a redundant Scara robot, always in terms of time took to reach several objects. For this reason, I thought to make my target child of the object and then, using the sim.rmlMoveToPosition, bring the end effector closed to the object with the max velocity and the max acceleration. But when I use sim.setObjectParent to put the IK target in the wanted position, the end effector jumps immediactely there, without using the sim.rmlMovetoPosition. And I'm wondering why.
Thank you.

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