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ROS 2 Driver for AR4 Now Available

Hi Annin Robotics Community,

I'm excited to share that I've recently developed and released a ROS 2 driver for the AR4 robot arm. It uses ros2_control framework for robot control, MoveIt 2 for motion planning, and Rviz2 for user interface and visualization. It's available to use at https://github.com/ycheng517/ar4_ros_driver and will be actively developed and maintained. Check it out if you wish to tap into the power of ROS 2 with the AR4, and contributions are welcome!

28 comments

28 Comments

duanemclemore

Sep 25

Any chance this works with the AR-3?

My use of it has gone in fits and starts, and I'm back to it now. I never got ROS Melodic fully implemented, and now it's so old it's starting to lose compatibility with new equipment like the depth and tracking cameras I'm trying to use...

ycheng517

Sep 28

Replying to

It should work with moderate effort. You just need to figure out the differences between AR3 and AR4, and update configs in both the Teensy sketch and the hardware interface. Then you should be able to run the AR3.

Jann H

Aug 14

I have tested this with the MK3, looks very promising and works. We are still working with @ycheng517 on calibration details, my joints are a little off.

Evan Wassmann

Jul 30

When using the driver I often have issues with path tolerance being violated, halting the robots movment and causing problems, this especially happens for joints 3 and 4, do you run into this problem? When the controllers.yaml file in ar_hardware_interface is updated it seems the new values are not used, and it continues to use a tolerance of .200.

ycheng517

Aug 03

Replying to

hey I'm not sure why that's not being updated but another way of tackling the problem is to reduce the max_velocity of those joints in ar_moveit_config/config/joint_limits.yaml

philippe

May 27

Great work ! Thanks a lot. My AR4 is now ROS2 controlled. Calibration works, path planning and execution using MoveIt works well. I'm stuck with the hand-eye validation. Intel camera is detected and I see the video in MoveIt. Hand-eye calibration is ok, I took 6 samples, aruco tag is detected. When I try to run the hand-eye validation procedure, the aruco tag is detected but planning fails. with the following message: "unable to sample any valid states for goal tree" Any idea why ??

ycheng517

May 29

Replying to

cool things look mostly good now. One thing I did notice is that you move the marker to different spots on the screen, but actually it's recommended by easy_handeye2 that the marker should stay at the same spot, and the only change you make is rotate it in all different axis. This is something to try

ycheng517

May 29

Replying to

see: https://github.com/marcoesposito1988/easy_handeye2?tab=readme-ov-file#tips-for-accuracy

for calibration accuracy tips

philippe

May 31

Replying to

You rock ! I didn't catch that part in the instructions, sorry about that. The result is well better now. There are still a few things I'm trying to understand: 1) in validation mode, in general, the robot finds the marker successfully and moves accordingly but sometimes it targets the center of the marker and sometimes it targets the borders (and not always the same side) 2) results are not so good when the marker to find is placed at a lower position. For example: calibration has been performed at Z = approx 25 cm. During validation, the marker is placed at z = approx 10 cm, the robot finds it but goes to low and hit the marker.

ycheng517

Apr 05

Update: AR4 servo gripper control has been added!

Jacob

Apr 06

Replying to

I’ll be testing this out this weekend! Get ready for some pull requests with OpenCV/Camera functionality in the coming weeks too :)

Chris Annin

Feb 17

I wanted to mention that Yifei Cheng has added files for the MK2 to this repo. I have not had time to test yet but I was hoping someone in the comunity would be able to test this out on the MK2 and give feedback. I also wanted to thank Yifei for taking the time to put this together and contributing to the project. This is a great development - Thank you.

ycheng517

Apr 02

Replying to

@Jacob it would be great if you can test it!

Jacob

Apr 02

Replying to

@ycheng517 So I've had a chance to get ros2 installed and try out the ar4_ros_driver repo on my AR4-MK2.

Good news! The initial calibration went without a hitch, and some route planning/execution tests also worked as expected.

If there's anything specific you'd like me to test further please let me know, otherwise I think we can say that the the ros driver works for the AR4-MK2!

Here's a brief video showing it in action.

ycheng517

Apr 05

Replying to

Thank you very much! Great to hear this result! I've updated the repo to say that MK2 is supported.

ycheng517

Feb 12

Yes it should work on the raspberry pi, you'll have to install Ubuntu for Raspberry Pi. I'm not supporting the nano/gripper yet but will be working on that in the medium future

Pierre-Alexandre Girard

Feb 08

That looks awesome, I'm not familiar with ROS/ROS2, would this run on a light client like a Pi ?

Also, does your driver also control the nano/gripper ?

ANNIN ROBOTICS

ROS 2 Driver for AR4 Now Available