Basic example project of a gripper holding an object in Gazebo

Question

I am searching for a working example of a gripper that can hold an object in Gazebo / Gazebo Classic. The example should ideally:

• use a 1-DOF gripper with two fingers where one is mimicked
• use Python for controlling
• use only minimal number of libraries

I tried:

• using ros2_control, however the Humble version has problems with effort-based control and mimicked fingers.
• following Gazebo Tutorial: Make a Simple Gripper, however I could not hold the object, it slips.

Slipping objects from the gripper in Gazebo seem to be a popular problem and I found some workarounds that basically attach the object/s to the gripper (vacuum or two fingers):

• IFRA Link Attacher
• Gazebo Grasp Fix — here is a ROS1 video tutorial that uses it
• Code from a competition named ARIAC

There is also an alternative approach that periodically sets the position of the object to make the object seem fixed.

I don't want to overcomplicate the project using extra Gazebo workaround code.

Finally Moveit2 contains a pick and place example, however this is based on C++.

Do you know a minimal basic example project of a gripper holding an object that meets my expectations?

Answer 1

I believe the current state-of-the-art attaches the object to the gripper via Gazebo when the object is in proximity, so the ideal solution that I am looking for does not seem to exist. I will use the workarounds that I listed in my question.

I hope other solutions will be posted here in future. According to Jennifer Buehler in the Gazebo grasp fix plugin wiki solutions without workarounds may exist:

... It may be possible to get the robot to grasp the object still, by adjusting the material properties of object and gripper. ...