[QUESTION] How should one import the VrepInterface?

[marcos-pereira]

Hello,

I found a similar problem to issue #14 when trying to import the VrepInterface in python. I am currently trying to run the example vrep_interface_move_kuka.py.

When the VrepInterface is imported with

from dqrobotics.interfaces import VrepInterface

a similar error to issue #14 occurs:

Traceback (most recent call last):
  File "vrep_interface_move_kuka.py", line 2, in <module>
    from dqrobotics.interfaces import VrepInterface
ImportError: cannot import name 'VrepInterface'

I tried the same approach from issue #14 but it didn't work.

The DQ Robotics version is the dqrobotics-19.10.0.53. I have also installed the V-REP Interface package .

Any hints on how to solve this one?

[mmmarinho]

Hello, @marcos-pereira,

The correct class name is DQ_VrepInterface and the submodule is vrep.

from dqrobotics.interfaces.vrep import DQ_VrepInterface

Let me know if it doesn't work well.

[marcos-pereira]

Hi @mmmarinho ,

The DQ_VrepInterface was found, but it seems that the method get_object_handles() is not being found. I am probably missing some tiny detail.

I tried the following approach within the example vrep_interface_move_kuka.py

from dqrobotics.interfaces.vrep import DQ_VrepInterface
...
## Creates a VrepInterface object
vi = DQ_VrepInterface()
...
## Connects to the localhost in port 19997 with timeout 100ms and 10 retries for each method call
vi.connect(19997,100,10)

## Starts simulation in V-REP
print("Starting V-REP simulation...")
vi.start_simulation()

## Store joint names
joint_names = ("LBR_iiwa_14_R820_joint1","LBR_iiwa_14_R820_joint2","LBR_iiwa_14_R820_joint3","LBR_iiwa_14_R820_joint4","LBR_iiwa_14_R820_joint5","LBR_iiwa_14_R820_joint6","LBR_iiwa_14_R820_joint7")
## Get joint handles
joint_handles = vi.get_object_handles(joint_names)

which has the following behavior

###############################################################
In order for this example to run correctly, you have to
open a scene in V-REP and drag a drop a "LBR_iiwa_14_R820" robot
and remove or disable its child script
before running this example.
###############################################################
Starting V-REP simulation...
'dqrobotics._dqrobotics._interfaces._vrep.DQ_VrepIn' object has no attribute 'get_object_handles'
There was an error connecting to V-REP, please check that it is open and that the Kuka Robot is in the scene.

I tested it with the newest CoppeliaSim version 4.0.0.

[mmmarinho]

Hello! Thanks for trying to fix it.

That method does not exist anymore because it was superseded by better methods. In general, you should not use get_object_handles, hence why it was removed in the Python version. You can directly call most methods using the object's name, as a string.

See DQ_VrepInterface.m for the MATLAB class. It is well documented.

The following example might also be helpful vrep_interface_move_kuka_and_youbot.py