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Bumpers or shift+bumpers?


Recently our Newton gripper suddenly stopped working. We followed all the troubleshooting suggestions (trying with an Arduino to generate the PWM signal, measure the signal from the PIxhawk with an oscilloscope, etc). We conclude that the problem was with the gripper. We did not want to open it because of the guarantee. We sent it back to the distributor (Nido Robotics Spain) and they sent us a new one. This new one works fine so far.

They advice us that the servo_min_momentary and servo_max_momentary commands should be assigned to the SHIFT function of the Xbox controller bumpers and not to the bumpers function directly (as stated in the documentation provided by Bluerobotics) and they said that failing to do this may result in a unexpected behavior that can cause a malfunction in the gripper and that this was likely the problem with the gripper we sent back. How true is this?

I am asking because we don’t want to break another gripper, but we would prefer to use the Xbox controller bumpers directly to command the gripper rather than the bumpers+shift.

Thanks in advance! :slight_smile:

We have routinely assigned the gripper functions to the bumpers as outlined in the Gripper: Setup in QGC section. It shouldn’t cause any damage.

@roy Would you like to elaborate on the recommendation from Nido?

Hm, not sure where that came from, let me check with our support team. I’ll get back ASAP.

Sorry Alex, I might not have expressed myself properly in the email.
What we found out is that if servo_min_momentary and servo_max_momentary are selected in several SHIFT fields at the same time, the gripper will have an anomalous behavior, not being able to stop at the desired point. But as long as the commands are not used twice, it should be no problem to set it somewhere else in the joystick.
I hope this helps.

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Thanks for clarifying Arturo!

Is it possible to know what was the problem with the gripper we returned?

If it was a mistake on our side we would like to know what was the problem so it won’t happen again.

I finally didn’t have the chance to look at it personally, but my colleagues from the factory told me that the gripper didn’t react at all. It was clearly a return case, so they didn’t spend the time finding out the faulty part.
As long as you follow Blue Robotics procedures for installing and operating the gripper, you should have no problem at all.

Do you recall the stall behavior before it died? When it reached max open/close, did it beep once and then stop trying to open/close?

We did not notice any malfunction symptoms. One day we want to operate the gripper as usual and it did not work. The gripper was in “closed” position when it stopped working. We did not hear any noise or feel any movement when trying to make it work, as Arturo said the gripper was unresponsive.