pydobot Pydobot Gripper Issue (Cannot Disable Gripper)

Hi,

Is there currently a way to disable the gripper attachment once it has been activated? Currently I am only able to open and close the gripper, but not able to fully release. Thanks!

Mar 02 '21 04:03 lukerbs

Do you mean disabling the suction to fully release pressure in the grip?

Mar 05 '21 04:03 luismesas

To release the pressure in the gripper you have to deactivate the suction device

device.suck(False)

Let me know if the trick works

Mar 05 '21 07:03 luismesas

Instead of fully releasing pressure, device.suck(False) appears to activate the grip. With device.suck(True) , the gripper is also still activated but in the reverse (it reverses the pressure to open the gripper).

The only way I am currently able to deactivate the pressure is by restarting the dobot via the physical on/off button.

Mar 05 '21 18:03 lukerbs

When you do device.suck(True) does the grip closes?

device.suck(False) should deactivate the vacuum.

I have ran some tests on my end and if I do the following if opens the grip and then releases pressure.

device.grip(False)
device.wait(100)
device.suck(False)

Mar 05 '21 18:03 luismesas

When I reset the dobot, the gripper arm is flaccid.

Running device.suck(True) causes the gripper attachment to open open up. (I can hear the air pump sucking). Running device.suck(False) reverses the air pump and causes the gripper attachment to grip. (air pump reverses and stays on).

So device.suck(False) causes the air pump to continuously blow air out (instead of simply turning off the vacuum pump).

Mar 05 '21 19:03 lukerbs

Ok looks like somehow your sucking device is working in a different way to mine.

Mar 05 '21 19:03 luismesas

can you confirm pydobot and firmware version?

Mar 05 '21 19:03 luismesas

Let's try one more thing, please execute this piece of code and reply with the log output

    device = pydobot.Dobot(port=port, verbose=True)

    device.wait(1000)
    device.grip(True)
    device.wait(1000)
    device.grip(False)
    device.wait(1000)
    device.suck(False)

    device.close()

Mar 05 '21 19:03 luismesas

Running the above code, the following occurs: 1. Gripper closes 2. Gripper opens 3. Gripper closes again and stays closed

I am using pydobot version 1.3.2 It may be worth noting that the Dobot model I am using is the Dobot Magician Lite.

Mar 05 '21 21:03 lukerbs

Can you copy-paste here the console output with all the serial messages going back and forward?

Mar 05 '21 22:03 luismesas

Here is the console output:

pydobot: /dev/ttyACM0 open pydobot: >> AA AA:2:240:1::15 pydobot: << AA AA:2:240:1::15 pydobot: >> AA AA:2:245:1::10 pydobot: << AA AA:2:245:1::10 pydobot: >> AA AA:34:80:3:00 00 48 43 00 00 48 43 00 00 48 43 00 00 48 43 00 00 48 43 00 00 48 43 00 00 48 43 00 00 48 43:85 pydobot: << AA AA:10:80:3:DB 00 00 00 00 00 00 00:210 pydobot: >> AA AA:18:81:3:00 00 48 43 00 00 48 43 00 00 48 43 00 00 48 43:128 pydobot: << AA AA:10:81:3:DC 00 00 00 00 00 00 00:208 pydobot: >> AA AA:10:82:3:00 00 20 41 00 00 48 43:191 pydobot: << AA AA:10:82:3:DD 00 00 00 00 00 00 00:206 pydobot: >> AA AA:10:83:3:00 00 C8 42 00 00 C8 42:150 pydobot: << AA AA:10:83:3:DE 00 00 00 00 00 00 00:204 pydobot: >> AA AA:2:10:0::246 pydobot: << AA AA:34:10:0:54 4D 49 43 EF 03 D4 C1 01 EF 85 41 00 00 F0 C0 00 00 F0 C0 7A E4 8B 41 3D F2 65 42 00 00 00 00:44 pydobot: x:201.3 y:-26.5 z:16.7 r:-7.5 j1:-7.5 j2:17.5 j3:57.5 j4:0.0 pydobot: >> AA AA:6:110:3:E8 03 00 00:164 pydobot: << AA AA:10:110:3:DF 00 00 00 00 00 00 00:176 pydobot: >> AA AA:4:63:3:01 01:188 pydobot: << AA AA:10:63:3:E0 00 00 00 00 00 00 00:222 pydobot: >> AA AA:6:110:3:E8 03 00 00:164 pydobot: << AA AA:10:110:3:E1 00 00 00 00 00 00 00:174 pydobot: >> AA AA:4:63:3:01 00:189 pydobot: << AA AA:10:63:3:E2 00 00 00 00 00 00 00:220 pydobot: >> AA AA:6:110:3:E8 03 00 00:164 pydobot: << AA AA:10:110:3:E3 00 00 00 00 00 00 00:172 pydobot: >> AA AA:4:62:3:01 00:190 pydobot: << AA AA:10:62:3:E4 00 00 00 00 00 00 00:219 pydobot: /dev/ttyACM0 closed

Mar 06 '21 03:03 lukerbs

@lukerbs I am also using a DOBOT Magician Lite and was able to fix the suction cup issue.

Problem: bot.suck(True) Would start sucking bot.suck(False) Would cause the suction cup to blow. This should cause it to turn off

Solution: in dobot.py: change from: ...def _set_end_effector_gripper(self, enable=False): ......msg = Message() ......msg.id = CommunicationProtocolIDs.SET_GET_END_EFFECTOR_GRIPPER ......msg.ctrl = ControlValues.THREE ......msg.params = bytearray([]) ......msg.params.extend(bytearray([0x01])) ......if enable is True: .........msg.params.extend(bytearray([0x01])) ......else: .........msg.params.extend(bytearray([0x00])) ......return self._send_command(msg) to: ...def _set_end_effector_gripper(self, enable=False): ......msg = Message() ......msg.id = CommunicationProtocolIDs.SET_GET_END_EFFECTOR_GRIPPER ......msg.ctrl = ControlValues.THREE ......msg.params = bytearray([]) ......if enable is True: .........msg.params.extend(bytearray([0x01])) .........msg.params.extend(bytearray([0x01])) ......else: .........msg.params.extend(bytearray([0x00])) .........msg.params.extend(bytearray([0x00])) ......return self._send_command(msg)

@luismesas I am not comfortable enough with git/pip to push this change myself but can you please update this?

I'll look into the gripper later tonight/tomorrow.

May 13 '21 21:05 jobo89

@jobo89 Thanks for looking into this.

I suggest 3 gripper options: gripper open, gripper close, and gripper off

May 14 '21 00:05 lukerbs

@lukerbs sorry, that code should be for suck not grip. Also, I think you are right, 3 states would be good. I used 0, 1, and 2 but is there a way to pass an ENUM? I'm just getting back into python from C so I'm fighting adding a semicolen at the end of each line :)

Here is my dobot.py and Testing.py

Changes: _set_end_effector_gripper now has 3 states _set_end_effector_suction_cup now changes both bytes Archive.zip

May 14 '21 01:05 jobo89

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Pydobot Gripper Issue (Cannot Disable Gripper)

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