How can you change the lower reference force in a forcecontrol application?

Swerdfish

Hello everybody

I have a question concerning the force control program provided by ABB.

I want to use the program in order to improve the accuracy of machining applications with an industrial robot. When the measured force is above a certain value the movement speed is decreased and when this force drops below a certain value the robot regains speed. The upper value can easily be set with the Reference Force in the FCSpdChgAct function. However, I did not find a way to adapt the value of the lower force level. It seems to be at 10% of the defined reference force, set by the value of “Decrease rule 2 fdb ratio”

 

Does anyone know how this parameter and the other decrease rules are defined? Unfortunately, they are not explained in the user manual.

Or is there maybe another way to change the lower reference force to trigger an increase of the movement speed earlier / at a higher measured force?

 

Because currently the measured force never drops below the lower reference force, so the robot never regains speed. This leads to the robot just finishing the task at a low speed instead of accelerating when the cluster of material has been removed.

 

I am working with an IRB 6660-205/1.9 and a 6axis force/torque sensor Omega160 IP65.

 

Thank you in advance