issue about a lift mechanism (prismatic joint)

[ferrariqi]

Hey, guys. I have a issue about prismatic joint. I am trying to build a lift mechanism which simply includes a cylinder(cylinder link), prismatic joint and a shaft (cylinder link). However, when I set the joint to dynamic mode an start simulation, the shaft keeps moving up and down in a high speed.

details:
bullet engine
both cylinder and shaft are dynamic and responsible
prismatic joint is controlled by torque or velocity

what I have done to fix the issue:
change the local and global responsible mask of the cylinder and the shaft
change the mass of the cylinder and the shaft
but still cant fix the issue

Could you please tell me how to build a lift mechanism or how to fix the problem?

(this is the link of my scene https://drive.google.com/file/d/1aGAtH1 ... sp=sharing)

[coppelia]

Hello,

there are several things that are not correct in your scene:

• The spherical free_joint is in kinematic mode, not in Dynamic mode
• There are several collisions occuring within the model: in the simulation dialog, turn on Display contact points to visualize them
• When switching to other physics engines, the joint won't wobble anymore. This usually indicates that the problem is directly linked to the engine in some way: it could be something linked to inertia or mass dimensioning, but in your case, you can alleviate the problem by adjusting the prismatic joint's Bullet stopErp value down to e.g. 0.02

Cheers

[ferrariqi]

thank you so much. I think I have fixed the issue!
cheers