Revolution Roli

Gripper Servo Calibration

Introduction

Servo Gripper EZ-Bits may need calibrating. This process should only need to be done once per servo. This is a physical process, in which you will require a screw driver to remove the EZ-Clip to realign it at 90 degrees. This process is very easy and is highly recommended before building your EZ-Robot.

When a gripper needs calibrating, it will not align into the position demonstrated in this document. A non-calibrated gripper will open very wide, or close too tightly when connected to the EZ-B in calibration mode (90 degree setting). If the gripper is open wide, or closed tightly, that means you will use a screw driver to manually realign the gripper. The instructions to realign the gripper are included in this document.

What You Will Need

  • No. 1 Philips Screw Driver
  • Flat Head Screw Driver
  • Your Robot Body (JD, SIX, Roli) or the Power Base from the developers kit
  • Freshly Charged Batteries
  • An EZ-B v4
  • A PC with EZ-Builder Installed
  • EZ-Bit Gripper to be calibrated



Step 1

Insert the EZ-B v4 into the robot body or powerbase



Step 2

Turn the power switch to the ON or 1 position. Early Revolution robots have a power switch labelled ON/OFF, while the newer robots are labelled with a 0/1.



Step 3

When the power switch is turned to the ON position, the EZ-B will be flashing Blue. This means it is ready for a Wi-Fi connection.



Step 4

Locate the EZ-B Wi-Fi Access Point in your Wi-Fi Networks List. This is accessed by pressing the Wi-Fi button on your system tray.



Step 5

Load EZ-Builder and press the Web Configuration Access button on the Connection Control.



Step 6

Your default web browser will open to the EZ-B v4 Wi-Fi Web Server home page. Press the Diagnostic button from the left side menu.



Step 7

The Diagnostic page will now be displayed. Press the button labelled "All Ports Servos 90 Degrees". This will set all 24 of the digital ports on the EZ-B v4 to 90 degrees. Any servos that are connected to any digital port will now move to what it has been calibrated as 90 degrees. In the next steps, you will see how to calibrate the servo to be aligned at 90 degrees. You will repeat the next steps one at a time per servo.



Step 8

Connect the servo gripper to the EZ-B v4 to view it's calibration position.



Step 9

Once the servo gripper is connected to the EZ-B v4, it will move to what it thinks is 90 degrees. Consult the image above to see what 90 degrees should look like. The gripper should be closed but not tightly closed. If the servo is humming or making a noise then it is too tight and must be calibrated.

If the gripper must be calibrated because it makes a BUZZING sound (due to being too tight), or it is wide open, then continue with this tutorial to calibrate the gripper. If the gripper does not need to be calibrated, then you may skip to the rest of this section and continue with the next gripper to test for calibration.



Step 10

After viewing the gripper alignment in the previous step, the servo may need calibrating, If the servo needs calibrating, use a Phillips screw driver to remove the screw that holds the gripper onto the servo gear.



Step 11

Now that the screw is removed, you can separate the edges of the lever from the servo to remove it from the servo with the flat head screw driver.

*Note: Do not disconnect the servo from the EZ-B v4 until instructed to do so.



Step 12

Slide the gripper on the flat surface toward the servo to reconnect. The gripper should now be flat (as it can be) with the servo. There are teeth that hold the lever on the servo gear, do not force the lever to be perfectly flat if the teeth do not line up. It is okay if the lever is a little angled by one gear tooth. Count the teeth according to the above photo so your gripper aligns correctly.



Step 13

Insert the screw back into the servo gear which holds the lever and tighten it snug. Do not overly tighten, you do not want the screw to dig into the plastic. The strength of the lever from slipping is dependent on the teeth of the gears and not the tightness of the screw.



Step 14

Now that you have calibrated the gripper, it will be closed at 90 degrees. Consult the image above to see what 90 degrees should look like now that you have calibrated the gripper. The gripper should be closed but not tightly closed. If the servo is humming or making a noise then it is too tight and must be re-calibrated.



Gripping and Holding Objects

*NOTE: The grippers are not just aesthetic, they may also be used for holding objects. However, the tightness of the servo around the object can damage the servo. That's right! If the servo is set to close entirely and the object forces the gripper open, the servo will overheat and burn out. If you burn out a servo, they can be easily replaced with this micro servo from our store. So, how do you use a gripper to hold an object? You will need to modify the Auto Position Control of your robot and adjust the "Closed" position. Adjusting the position to lightly grip the object.



Repeat and Complete

You have now calibrated your gripper. Disconnect the servo from the EZ-B v4 and place it with other calibrated servos. You may now repeat this process and calibrate another servo by returning to Step 8.




Continue to Next lesson

Last updated 2/19/2015

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