Allowing free movement in Y while moving in Z (CB3)

General Application Help: How do I?
1

Hi, I am looking for a method for allowing free motion in the Y direction while the robot moves the tool down in the Z axis. The aim is for the robot to insert a tool into a hole, however the alignment can sometimes be slightly out in the Y direction. To avoid damage I am trying to write code for the insertion to continue in the Z axis, but the presence of the hole wall will direct the tool into correct alignment, it will not try to resist motion in the Y direction.

Currently the tool head will moveL in Z and if it experiences too much force will abort the operation and move away.

Any help would be greatly appreciated!

2

I’d reccomend a hardware change here. Since your looking to use force on a CB3 (no force torque sensor) you should consider buying one. I can reccoment the Robotiq force torque sensor, it’s pricy but does a great job.

Trusting the CB3 and force is not reccomended

1 Like
3

Hi, thank you for the response!

I do have a robotiq force torque sensor on the CB3. Currently I am telling the robot to record the force in the X and Y as it inserts, if it then aborts due to an excessive force in Z it will record the X and Y forces and using these it can almost determine which direction it needs to move to complete a successful second insertion.

I am trying to see if there is a way for it to “freedrive” in X and Y as it descends in Z, or if I will just have to code this via lots of little translations.

4

Without using RTDE I guess you can’t supply the built in Force template with an external force sensor data.

For a script version I guess you can look at the Z position as the end goal, trigger a slight upwards movement if the Z stops to early then mode sideways a little in a little outward spiral pattern or something every time it doesn’t reach the desired Z position.
Depending on the shape of the hole you’re trying to hit you can also detirmine if you need to move in X or Y by looking at the force in your sensor.

5

Magnus - As far as I remember, the Robotiq URCap for the FT300 does overwrite the Force template sensor data (or you can enable it as an option?). Or are you completely sure that isn’t the case? :slight_smile:

6

I’d have to wire up one and test, it’s been a while since I’ve had to use force on a CB3 so you could be right.
I’ll see if I can get around to doing so.

7

It’s been a while for me, too. :slight_smile:

I think he should give it a try with the built-in Force template.