How to upgrade the detection of little object with a gripper?

Context

When trying to detect very small objects, your gripper might close without detecting anything. This is often due to the limits of detection resolution. This article shows how to improve the accuracy of the gripper so it can better detect small items.

Information

• Understand Gripper Resolution
  Each Robotiq gripper has a maximum stroke, which is divided into discrete steps (command bits).
  Example with a 2F-85 gripper:

  • Max stroke: 85 mm

  • Resolution: 255 bits

  • 85 mm / 255 ≈ 0.333 mm per step

  If the object is smaller than 0.333 mm, the gripper may close fully without detecting it.

• How to Increase Detection Accuracy
  If you don’t need the full stroke, you can limit the gripper’s range, effectively increasing resolution.

  Procedure:

  1. Prepare a fixed object (e.g., a 40 mm jar) with an internal diameter smaller than the gripper’s max stroke.

  2. Close the gripper and place it inside the object. Here is a 40mm diameter jar :

     
     

  3. Activate the gripper while it’s still inside the object. This will set a reduced stroke (e.g., 40 mm).

     

  4. From now on, the gripper will operate within this shorter stroke.

  Example:

  • New stroke: 40 mm

  • Resolution: 40 mm / 255 ≈ 0.156 mm per step
    → This doubles your detection resolution.

Conclusion

You can improve the gripper’s ability to detect small objects by reducing its stroke and increasing positional resolution. Just remember to repeat the limited activation at every startup.
Need help setting this up? Contact support@robotiq.com