Recording max force value

abeachy_HG24

I am using the FT 300 on a UR 10 and we are trying to perform a quality check on our product. The UR will bias the part that needs to be checked all the way in one direction to ensure that we are actuating the part fully. Then the UR will bring the part back and while it is doing this I would like to record the max force that the FT sees during the actuation to a variable and then use an if-statement to decide if the part is good or bad. Right now I am actuating the part and after it reaches the waypoint where the part is fully actuated, I then will record the force value to a variable to compare in an if statement. I think this method works just fine but if possible I would like to use the max force during the actuation, is this possible?

matthewd92

@abeachy_HG24 that's pretty straightforward to do in a background thread. Use a flag variable to turn it on and off when you want to record max value. You might want to play around with some filtering but you can do something like this 

thread

if measureMax == True:
   If Fx > previousMax:
      maxValue = Fx
   end
    previousMax = Fx
end

else
  maxValue = 0
  previousMax=0
end
sync()
end thread

Let me know if that does what you're looking for. Depending on how much your signal is fluctuating you might want to do some signal filtering using time averaging. 
 

abeachy_HG24

This is how I set my thread up, is that correct?

matthewd92

Looks correct, is it working?  Just remember to set your flag to True before your move and False afterwards to clear the value once your done.  I'd use another variable in your main program to assign the max value to and then use that for your test. That way you can stop calculating the max as soon as your move is over. 

abeachy_HG24

Kind of. If I run it and watch the Fz value during the move, the Max_force variable seems to be correct. But if while the robot is making the move and checking the max force I press against the part with my hand, I can see the Fz value go up to 75 or 80 but the Max_force variable does not show that. If it does, it changes before I can see it.

louis_bergeron

@abeachy_HG24 you can see some example with this template.  There are UR program, explanations and other stuff.

http://blog.robotiq.com/measuring-insertion-force?_ga=2.167629758.1210040562.1495193479-73641461.1495193474-556149795

abeachy_HG24

I got it working now, thanks for your help!

matthewd92

You're welcome.