Hi all,
I am currently using the until tool-contact function. Does anybody know how much force the robot uses on the surface he touches in this application? We are using the function to touch a display and I have to make sure the force is low enough to not damage it.
I didnt find any information about it in the manual.
Thank you for helping me out.
Felix
I don’t think there’s any specific number assigned to that function. It looks at the sensor and abrubt changes. The faster you move, the more force is applied (stopping time).
You should test it on something other than a screen to begin with. 
Depends on how fast the robot is moving. I used once a UR3e on a testbench a linear movement on the Z axis downwards, and the movement was linear, speed 10mm/s and it could detect a small plastic object with a value of 3~5 N.
This is something I have wondered as well. It would be really nice if you could set the force limit, but unfortunately that doesn’t seem to be possible. You might try doing a “force move”. This is a trick UR showed me once. You can try a simple program like this. Observe the you get real-time force updates. Add a “move until” and you can terminate a movement early when a force threshold is reached.
When using this approach, you should do call a zero_ftsensor() in your program beforehand to get the most accurate result.
Also, put a Wait 0,2 seconds before the zeroing to make sure the robot is completely still.
Interesting, I didn’t know this. So I should add wait(0.2) and zero_ftsensor() in the BeforeStart section? Or before each move that depends on the force reading?
zero_ftsensor() then wait then make the move that depends on force.
I disagree with that. Wait, then zero (and then some people have a wait afterwards as well).
Ideally, you must do it before each Force motion/measurement. And make sure the tool is not touching anything stationary.
The wait is to make sure the tool is completely still when you do the zeroing, as vibrations etc can cause the zero values to be off.
