Robotiq 2F Adaptive Gripper Control with python

noam92 2021-10-05

Hello,
I want to control 2F-85 Adaptive Gripper using python with minimal modbus using RTU mode.
Im using pyRoboticGripper from the github repo https://github.com/castetsb/pyRobotiqGripper.
Using the GoTo function the gripper is reaching the desired location and move.
I want to receive the position feedback from the status register but it seems it does not change.
When the gripper is in motion I'm using the readAll function that receive the register data from the Input register (2000-2005)
Its look like the first 3 register are fine and data is received good while register 4 and 5 which is the postion and actual current is stay at 0 and doesnt change
even though the gripper is in motion and changing is position.
I didnt make any change in the code and i read all the user manual to see that the registers are matched to the code.
what can be the problem?
Thank you

bcastets 2021-10-05

@noam92
I will have a look at it. Please give me some time.

bcastets 2021-10-07

@noam92
Looking at the code, I found a confusion between register and byte. There are only 3 registers to read and not 6. I modified the code to fix this problem but don t have time and material to test it at the moment. Please try it and let me know if it works.

noam92 2021-10-07

should fix line 265 in github repo to

posRequestEchoReg3 = "0" * (16 - len(posRequestEchoReg3)) + posRequestEchoReg3

instead 8 need to change it to 16.
i see the confusing now, each register is consists of 2 bytes so
register 2000:
byte 0 - gOBJ gSTA gGTO Reserved gACT
byte 1 - Reserved
register 2001:
byte 0 - kFLT gFLT
byte 1 - gPR
register 2002:
byte 0 - gPO
byte 1 - gCU

there is another problem that i see in the feedback
variable gPO is suppose to return value between 0 - 255
when im using the GoTo function and set it the desired location to 255, the gripper is moving to its close position but the highest value i get from gPO or getPositionCurrent is 230, the lowest is 3 when i set the gripper to 0(Open position)
I can see it also in the RUI.

bcastets 2021-10-07

@noam92

Thank you for your feedback. I made the correction.

The value of gPO are correct. You can check this behaviour by connecting the gripper on your PC and control it via our PC User interface.

Minimum is 3.
Maximum can be 255 if the gripper surround the object. If it is a grip with finger parallel the maximum will be 230.