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T800_412T800_412 Posts: 51 Apprentice
I am searching for examples for how to use the FORCE instruction correctly. The goal is to have the UR10 arm be compliant in all axis, X,Y,Z when the gripper is closing on the object to be picked up.

Using the Cam Locate function with the wrist camera. The part is a dark gray grinding wheel stacked in 4x3x8 array. The location is not always exact, but close enough for the robot to move and pickup a wheel. Sometimes, because it is slightly off center X,Y, or too high Z, the wheel is moved by the gripper fingers as they close. I want to use the force function set to a very low N in order to have the arm move if any force is detected. I think that will help ensure the wheel is properly centered so it will be easier to place on a spindle after it is picked up.

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  • David_GariepyDavid_Gariepy Beta Tester Beetle, Wrist Camera URCap 1.3.0, Vacuum Beta tester Posts: 186 Handy
    Hi @T800_412,
    I don't think the Force Mode can be use for such application. Do you have a FT Sensor installed on this robot? 
    I think the easiest solution would be to set the robot in free drive using the following function:
    freedrive_mode() 


    David Gariépy
    Integration Coach
  • T800_412T800_412 Posts: 51 Apprentice
    I will try this. When I tried the force command and set the axis as compliant, the gripper started to fall away from the wheel it was supposed to pickup due to the position of the shoulder and elbow.

    Is there any examples of the proper use of this function, or better explanation? I tried several experiments yesterday in the "test" mode and the results are confusing. For example, with compliant NOT checked, and force set <1, the arm would not move when force applied to the gripper, but when force set to 10, the arm began drifting X/Y axis but would stop when opposite force applied to the gripper.
  • David_GariepyDavid_Gariepy Beta Tester Beetle, Wrist Camera URCap 1.3.0, Vacuum Beta tester Posts: 186 Handy
    There is some explanation on the UR website.
    Force mode doesn't work very well with low force. I would say the minimum usable force is 10-20N
    The shift over the other axis is a known problem using force mode

    Using the freedrive will probably work better for your application.


    David Gariépy
    Integration Coach
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