Setting up a gripper properly , with moveit configuration wizard

asked 2020-07-06 06:39:21 -0500

updated 2020-07-06 06:45:26 -0500

Hi there ,

I am using moveit under ros melodic. I have a very simple gripper which is consist of 2 prismatic joints. It’s supposed to be used manipulate cylindrical objects.

I have set up the URDF file for this gripper. I visually test this URDF file by attaching it to end link of my robot. When I launch the robot everything seem normal and in place.

In next step I proceed with moveit tutorial to create a moveit config, I don’t create it from scratch, just edit the existing moveit config , so that I can include my new gripper in the config. Note that this package has been tested and works as expected with only robot arm.

I have followed exact same configuration of panda in moveits tutorial and the generated files are also seem fine.

I test the results of this new moveit config package with Gazebo utilizing auto generated URDF file. Though the robot wobbles and acts weird, this is related to incorrect ineratias and this can be solved.

I face two things/problems that I have hard time figuring out ;

1- in the moveit configuration, I create two groups one for manipulator the other for hand. Now this two groups are consisted of different joints. When I launch a demo gazebo with gripper attached , it publishes to /joint_states topic , with 8 joints in total(2 for hand remaining for manipulator). Why are joints of different groups published to the same topic?

2- when I use real robot with industrial core package, the moveit rightfully complains that the complete states of robot are not known because the finger joints are not being included in /joint_states topic. I have the the states for joint of fingers from robot IO, but what is proper way to include this joints values into system so that moveit can have full information of every joint in robot?

Sorry if this is too long or incomherensive. Please let me know if further information is needed, much appreciate your help.

Thank you very much for your time !

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