Grasp issue

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radnaskela
Posts: 7
Joined: 02 Feb 2021, 15:04

Grasp issue

Post by radnaskela »

Hello,

I have a problem with the RG2 gripper. The gripper needs to grasp an object & it's programmed as recommended: the object is attached to the gripper attach point, and the gripper force and velocity are set for the grasping to appear realistic. However, the 'fingers' of the gripper do not align nicely with the object. They fall through the surface of the object a little bit. Is there any way it could be fixed? I need that object in an assembly task, so it's really important for me that the gripper fingers remain on the surface.

Cheers
Alex

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

Re: Grasp issue

Post by coppelia »

Hello Alex,

what type of object does it try to grasp? Is it a pure primitive shape, a convex shape, a non-convex shape, or even an open shape?

A physics engine can easily compute contact points and forces between primitive shapes (i.e. cuboids, spheres, etc.), handles it still ok with convex shapes, but has really a hard time with the two last categories.

Also try switching to another engine to see if the problem persists there too

Cheers

radnaskela
Posts: 7
Joined: 02 Feb 2021, 15:04

Re: Grasp issue

Post by radnaskela »

Hello,

The object I'm trying to grasp is a pure compound shape. It's a group of small cuboids that make up something like a 3D puzzle piece. The problem is that because of the shape of the object, the gripper finger is partly on the surface and partly in the air, and so it falls through the surface a little bit. It's better with Bullet 2.83, but the object and the gripper are shakier than with 2.78.

Thanks in any case
Cheers

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