[Bug] FE Panda Python - Githubissues

KonradJuenger commented 11 months ago

Is there an existing issue for this?

[x] I have searched the existing issues

What Robots version are you using?

1.6.6

What Rhino version are you using?

Rhino 7 on Windows

Problems:

Hi,

I know that FEPanda support is still early -- but here are some bugs I found while testing it with a setup with frankx and an Ubuntu machine:

1. python version

the script is called via sudo -S python -u and on my machine this defaults to python 2.7, Frankx-Fork expects python 3.7 so I would assume the correct command should be sudo -S python3 -u. Python 2 does not find the frankx library

2. Incomplete Script definition

The python script robots generates references to the object dynamic_rel wich isn't defined. (see below)

3. Motions with more than one target fail

For some reason any motions with more than one cartesian target produce an error (see below)

Thank you for the continued development of the plugin!

Steps To Reproduce

2.

from argparse import ArgumentParser
from time import sleep
from frankx import Affine, Robot, JointMotion, PathMotion, WaypointMotion, Waypoint, MotionData, Reaction, Measure, StopMotion, LinearRelativeMotion

def program():
  parser = ArgumentParser()
  parser.add_argument('--host', default='172.16.0.2', help='FCI IP of the robot')
  args = parser.parse_args()
  robot = Robot(args.host)
  robot.set_default_behavior()
  robot.recover_from_errors()
  robot.velocity_rel = 1.0

  DefaultTool = Affine(0, 0, 0, 0, 0, 1, 0)
  DefaultZone = 0

  robot.acceleration_rel = **dynamic_rel**
  robot.jerk_rel = **dynamic_rel**
  data = MotionData(**dynamic_rel**)
  data.velocity_rel = 0.1
  motion = JointMotion([0.10451, -0.00774, 0.15871, -2.44068, 0.00188, 2.43304, 1.83259])

  robot.move(motion, data)

program()

3. panda_fails_with_multiple_tgt.zip

visose commented 11 months ago

Hi @KonradJuenger, thanks for testing this. I realize I left out some important info on the summary post, once this is a bit more stable I will make a proper entry into the wiki.

Python version You can change the default python version as shown here: https://linuxconfig.org/how-to-change-from-default-to-alternative-python-version-on-debian-linux Using python3, even though it narrows it down, it might still run the wrong python version if you have multiple python3 versions installed. The user still must make sure the correct python3 version with the Frankx package is set as default.
Currently it is expected that a custom component defining this variable is connected to the "Init commands" input of the CreateProgram comoponent. For example: dynamic_rel = 0.2. I'll try to better integrate this, maybe with the CreateSpeed component. I prefer to avoid adding any inputs/components that are specific to a single robot manufacturer.
Cartisian motions with the Motion input set to "Joint" are not supported, make sure that they are set to "Linear". I will add a meaninful error when this motion type is set. I think getting an error (or warning) is better than ignoring the Motion input altogether as a user might get confused on why the robot is moving in a straight line when it's set to Joint. Joint motions using joint values are also supported.

I'll also try to publish a wheel file of the modified Frankx package so it's easier to install.

I also forgot to mention, you can use the external axis input of the CreateTarget component with a single value to force the redudant axis to a particular value.

KonradJuenger commented 10 months ago

Thank you for your prompt response! I've tested the changes after Christmas, and it works! Thank you. Some further observations:

FrankX assumes a default TCP at the FE hand gripper, and the conversion to a joint target for the first target doesn't. This results in a jump at the beginning of the movement.
Speeds appear to be in mm/s for FE, but Robots generates m/s. (Edit: hm - unsure, something is off the the speeds)
The current installation of FrankX from source as root is quite complex; a wheel file would be very helpful. (Edit: are you aware of https://github.com/TimSchneider42/franky ? )

This isssue can be closed. If I can assist with any further testing of robots with FE Panda, just drop me a line.

visose commented 10 months ago

FrankX assumes a default TCP at the FE hand gripper

Not sure if the issue is that the robot controller has the TCP set to the hand gripper by default. You can use the desktop interface to change it to an identity matrix (all zeroes except a diagonal of ones).

something is off the the speeds

Not sure if this is it, but dynamic_rel will have an impact on speed, a low value might not allow the robot to accelereate to the set speed.

you aware of https://github.com/TimSchneider42/franky?

I did not know about it, I'll have a look and see if it's worth using this fork. Thanks!