Using 2f 85 gripper with Sawyer in gazebo

micahreich

Hello. I want to use the robotiq 2 finger 85 gripper in the gazebo simulator with ROS and the Sawyer robot. I can control sawyer in gazebo but I’m not sure how to control the gripper. Any starting points / tutorials for me to follow? I would like to do this all in simulation without the involvement of the actual (real-life) robot and gripper. I just need the gripper to open and close. Thank you. 

Guillaume_Charron

@micahreich

I believe that @jproberge would be able to help you with that, he is a ROS expert!

micahreich

@Guillaume_Charron ok! How can I get in contact?

jproberge

Hello @micahreich  ,

Thanks for reaching out to me! In a personal message you've written to me, you mentioned your end-goal is to do pick and place with the 2F-85 Gripper in simulation. In fact, you will see it unfortunately requires a bit of work. In fact, picking and placing objects in Gazebo is a bit tricky and you will need to tune many parameters (joint, and surface properties, controller among other things). I have worked on a project a few weeks ago where the goal was exactly to perform pick-and-place of a rod and we had a bit of a hard time...

So anyway, you can start by downloading our official ROS package stack on Github. There, you will find description files for the 2F-85 Gripper. Then to control it to pick and place objects, you will need a controller. A typical controller that can be used here is the ros_control plugin (libgazebo_ros_control.so) . Then you will need to configure and run the controller, which will probably requires you to read a little bit about it. 

There's no real tutorial for how to make a complete project with a robot + Robotiq Gripper to perform pick and place, but a good starting point would probably be to read the beginning of this post  . Also, even if it's three years old, this post is still relevant, especially this sentence: "In newer Gazebo versions (>2), the robot may not display strange behavior any more when grasping, but the object to be grasped may still slip off the robot hand. ". We have had this exact specific issue in the aforementioned project I was working on. You might want to consider using this plugin as well.

While it is a bit hard and trick, it can still be done with a bit of patience

All the best,

Jean-Philippe Roberge, 
ROS Package Developper / Maintainer 
[email protected]

micahreich

@jproberge

Thank you for your response. Currently, I have a combined URDF of my Sawyer robot and the robotiq 2f-85 gripper. So, I’ve concluded from your message and the posts that you have linked that I now need to write / use a controller to control the gripper. Is this correct? Are there any controllers for the gripper which already work / have been configured? 

After I have done this, i should install the gazebo plugins you mentioned to avoid the weird behavior which robots may experience. 

One question: am I able to control the Sawyer robot and the gripper within one script? Thank you 

jproberge

Hello @micahreich ,

-Yes, you are indeed right: you will need to configure and use a controller to control the gripper. Unfortunately, there are no controllers that I am aware of that would already be preconfigured for the gripper. Typically, one would consider to use the ros_control as a controller. There is a tutorial about how to use this controller to control a robot here. However, you would obviously need to adapt this tutorial to the gripper in your case. Also, while I'm personally not aware of any preconfigured controller that would be available out there for the 2F-85 Gripper, it doesn't mean there are none and maybe you would still be able to find one by browsing on the web. Maybe someone has shared his project involving this specific gripper on their Github for example, I think this is worth taking the time to look.

-About the plugin I pointed out, I'm not saying it is mandatory to install them, I was just pointing them out in case you experience any trouble. I just wanted to inform you that grasping / lifting / manipulating objects in gazebo is sometimes tricky. If you experience the kind of problems mentioned on the github I pointed out, then you could consider using the plugins.

-Yes sure, you could definitely control both from the same script. If you want to control them simultaneously though, using different scripts (if Python) or threads (C++) might help.

Don't hesitate to reach out to me, should you have any additional questions!

All the best,

Jean-Philippe Roberge, 
ROS Package Developper / Maintainer 
[email protected]

smortezapoor

Hi!
I have the same problem and need a 2f (2f 85 or Hand-E) working in Gazebo. Is there any already developed solution for it provided that this conversation has happened a long time ago?
Thank you
BR
Soroosh
TU Wien 

Stu

Hello @jproberge
I haven't been able to just find the 2finger urdf file in the repo. Could you point me in the right direction or anyonw on this post? I only need the urdf file for my application.