Asked — Edited
Resolved Resolved by DJ Sures!

Initial Classes And Setting Up Servos - Last One (Grippers)

Working through the tutorials...the gripper one is confusing to me. The last tutorial on kinematic setup of the servos for the gripper...all others work as expected and are correct.

Gripper servos set to 90 degrees (as instructed) fully opens both my grippers to fully open position.

Instructions show fully closed and describe such.

I can obviously change that by moving the gears, but want to make sure what is correct.

Hope everyone had a great holiday, finally (after flu, etc) getting a chance to build JD.

Thanks for the help. I believe these tutorials should help newbies quite a bit...

  • Electroboticist


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You should adjust the grippers, and then use the configure setting under the project option in ARC to make the final adjustments. This will allow you to set the gripper to closed and will keep you from burning out the servo by having it pressing the gripper closed too hard. The gripper should be touching or barely open after the adjustment to the gear, and then with the configure settings, you can get it touching but not making any noise.


Can you be more specific on the issue? I would like to change/update the tutorial if you are having trouble to prevent others in the future from having the same misunderstanding


I was using the JD robot instructions through the learning series. (#6 of the calibration series). Last calibration is the grippers. When examining the grippers by plugging them into the controller which was set at 90 degrees (all servos), the grippers connected to eZ controller FULLY open the grippers. This is opposite of the instructions which show the grippers fully closed per inspection instructions. My confusion is that the instructions are showing fully closed, action is fully open. Now, my issue is :

  1. Are the instructions correct? Then the action is to simply recalibrate mechanically by resetting the gears.
  2. Instructions wrong - then skip instructions on gripper

Thanks for investigating. I can send video if necessary.

I am continuing with the series, and now I am in the software stage....

  • Electroboticist

Can the issue be summarized as "it wasn't clear that the tutorial was about calibrating the grippers to be closed when set for 90 degrees"?

The instructions in that tutorial are for you to calibrate the grippers. The calibration servo section is calibrating servos. The gripper uses servos, and the parts may need calibration.

  1. if the grippers were fully open when the ez-b was set to 90 degrees, that means they need adjusting. As the tutorial displays, the grippers should be closed when set to 90 degrees.

  2. I still do not fully understand what may have been written incorrectly. Reviewing the tutorial, it states that if the grippers should be closed. This is in Step #9. Does the picture not help you? Would a different picture be more useful?

I do not need a video - thank you. I understand what you are saying... You are saying that..

  1. You connected the gripper to the ez-b in calibration mode (90 degrees)

  2. When connecting the gripper, it opened all the way

The tutorial for Gripper Calibration is to help you realign the gripper. As of Step #9, if the gripper is not in the position as displayed, then following the rest of the steps will help you manually calibrate the gripper. The point to the tutorial is to help you calibrate the gripper so it does not open all the way.

Can you provide me some feedback of what was misleading about the tutorial so I can understand better on what would need to be changed?


Also, i added an extra paragraph to the intro section of that calibration tutorial for the gripper. It states that if you connect the gripper to the ez-b, and it does not look like the photo, that you will calibrate the gripper.

Is that more of what you were expecting for the tutorial intro to state? To prepare you for what to expect?


Looks like that will resolve the issues so far... I will continue with the classes (been pretty tied up this week). I really believe these will help a lot of folks just starting out. I am going through them as I want to insure I utilize all aspects of the new robots and don't miss anything.

Thanks for all the help and the input.




We will soon have our manufacturing assembly 100% so servo calibration will no longer be necessary. :)