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Course: Introduction to Dobot
Lesson 3: Gripper Attachment

  • 9-12 grade
  • Beginner

Lesson Description:

Objective:
Learn to use the gripper attachment for Dobot, and write code to control it.

image description

Lesson Modules


Teaching Tips:


Air Pump

The air pump is the mechanism that provides gripping and suction power to the gripper and suction cup attachments. These attachments will not function without the air pump.


Here are the instructions to complete the air pump installation:

#1  Connect power line labeled SW1 on the pump box with the interface on the Dobot labeled GP1.


#2  Tighten air pump kit onto the end of the Dobot with the butterfly nut.


#3  Connect GP3 of Joint4 servo line with forearm connector GP3.



Pneumatic Gripper

The gripper and suction cup attachments share the same air pump kit. So when switching between those two attachments it is faster to just remove the gripper or suction cup, rather than disassembling the whole air pump.

#1  If the suction cup is attached, unscrew it from the air pump with the smallest hex wrench.

(Be careful, the screws are very tiny. It might help to hold them in a water bottle cap if you are worried about misplacing them.)


#2  Install the gripper kit using the silver coupler.

#3  When you are done, it should look like this:

(It may help to wrap some tape around the handle of the wrench)


#4  Attach the air tube to the adapter. 

(It isn't always easy to attach the tube, don't worry, you won't break it.)





Teaching Tips:


Blockly

These two blocks control most of the Gripper functionality.

Choose Tool

Tell the program what attachment you are using for the Dobot.

This block should be placed at the beginning of each program.


Gripper On/Off

Open and release the gripper during the trun of the program.


They can be found here:


Here is an example of a responsive program using these blocks:



1. Tell the program what attachment you are using for the Dobot.

2. Repeat the inner blocks (steps 3-8) 10 times.

3. Move to a location you specify.

4. Close the Gripper.

5. Pause for 1 second (and do nothing during this time)

6. Move to a location you specify.

7. Open the Gripper.

8. Pause for 1 second (and do nothing during this time)



Challenge (see teacher tips for solution)

Write a program that:

  1. Picks up a block with the gripper
  2. Places it down in a location you specifty
  3. Picks up another block (from the same location from step 1)
  4. Places it on top of the first block

When your program is done running, you should have a stack of two blocks.


Script

Here is the same example program completed in the Script programming environment:

dType.SetEndEffectorParamsEx(api, 59.7, 0, 0, 1)
for count in range(10):
  current_pose = dType.GetPose(api)
  dType.SetPTPCmdEx(api, 2, 200,  0,  0, current_pose[3], 1)
  dType.SetEndEffectorGripperEx(api, 1, 1)
  dType.SetWAITCmdEx(api, 1, 1)
  current_pose = dType.GetPose(api)
  dType.SetPTPCmdEx(api, 2, 200,  0,  0, current_pose[3], 1)
  dType.SetEndEffectorGripperEx(api, 1, 0)
  dType.SetWAITCmdEx(api, 1, 1)

Teaching Tips:


General troubleshooting:

Ensure that your Dobot is:

  • Plugged into power
  • Powered on
  • Connected to your computer via USB
  • Connected via DobotStudio

Check the firmware in the Settings menu, and make sure it matches the task you are trying to complete.

If your Dobot is not moving as you expected, press the home button and allow it to recalibrate.


Gripper troubleshooting:

No specific troubleshooting information is available for this attachment. Please contact us at support.robotlab.com if you have any issues with this attachment. We will work with you to solve them and update this lesson with new troubleshooting information.