Grasping Issue
Muhammad441 opened this issue · 3 comments
Hi,
I am trying to grasp small blocks in pybullet using the PR2 gripper. However, I notice that there are some artifacts that I encounter while actually grasping the objects. This leads to significant inconsistencies. I have attached a gif of one such artifact. Can someone confirm the source of this issue and possible solutions?
In the example below, the gripper is closed by position controlling to a pre-determined value. There are also cases, where the gripper does not properly grasp the object causing it to fall.
The PR2 model was taken from this repository.
This repository doesn't add any significant simulation functionality over https://github.com/bulletphysics/bullet3, so the issue/difficulty isn't within the scope of this repository. Realistically simulating grasping can be challenging. PyBullet's documentation and forums have some recommendations for improving reliability by, for example, changing the frictional properties of the block and gripper.
Sure, yes. I just wanted to verify the issue did not lie with the PR2 model. And confirm if the grasping functionality has been successfully implemented in this repository.
As per my perusal, I see that the objects are being attached to the arm/hand directly rather than actually simulating the grasp. If I am wrong could you please point me to the relevant files/functions. Thank you!
I typically doesn't use PyBullet's physics simulation capability during planning. Instead, I use attachments to maintain the current kinematic tree for visualization and collision-checking purposes. Again, simulating stable grasps is difficult, so I avoid it unless I'm treating the simulator as ground truth (rather than the real world). If you want to use the physics simulator without worrying about grasping, you can add constraints to further stabilize the grasping process.