Grasp ball but always fall down

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wozxfdha
Posts: 51
Joined: 10 Jun 2021, 09:40

Grasp ball but always fall down

Post by wozxfdha »

Hi,

I use RG2 to grasp balls, but it always falls because of gravity. How should I set the firction or is there any other solution besides attach?

Thanks

coppelia
Site Admin
Posts: 10312
Joined: 14 Dec 2012, 00:25

Re: Grasp ball but always fall down

Post by coppelia »

Hello,

grasping is not an easy task. Make sure to have high friction parameters for the ball and the various gripper elements. Additionally, try to adjust some of the gripper parameters (e.g. max. force of the open/close joint openCloseJoint, or the target velocity).
The problematic aspect of a ball is also that theoretically, there would be only 2 contact points, one on each side of the ball. You can try to mitigate this by adjusting the material properties (e.g. restitution, custom collision margin, Soft CFM, etc.). You can also try to adjust the fingers of the gripper, e.g. so that each finger has 4 smaller cuboids that could better hold a sphere.

Cheers

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