Getting joint angles for passive urdf model

asked 2016-07-05 15:18:20 -0600

klaatu
13 ●2 ●4 ●5

updated 2016-07-05 18:32:56 -0600

I'm a bit confused about how to get joint states.

I'm trying to set up an inverted pendulum on a two-wheeled cart. I've successfully attached differential drive, and also control of the revolute joint for the pendulum rod.

But, now I want to remove any actuators and simply access the state of the passive model. E.g., I want to view the angle of the rod as it collapses under gravity from vertical to about horizontal.

Do I nevertheless need a joint_state_controller, or even position controllers? I'm simulating in gazebo, of course.

The joint_states I see published are empty. --- header: seq: 105994 stamp: secs: 2120 nsecs: 302000000 frame_id: '' name: [] position: [] velocity: [] effort: [] ---

Here are links to the relevant files as they stand now...

URDF: http://pastebin.com/MTkTgZmH

YAML: http://pastebin.com/eD0jK7AZ

Launch: http://pastebin.com/Zwrrb

Screenshot in Gazebo

My setup...
ROS Indigo, Gazebo 2.2.6.
Linux Mint 17.3 (Rosa) 64-bit.
(3.19.0-32-generic #37~14.04.1-Ubuntu SMP Thu Oct 22 09:41:40 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux)

I'd love to get angular position and velocity for the three joints (turret_to_rod, motor_to_wheelleft, motor_to_wheellright).

Thanks!

edit retag flag offensive close merge delete

add a comment

 <plugin name="joint_state_publisher" filename="libgazebo_ros_joint_state_publisher.so"> <robotNamespace>your_robot_name</robotNamespace> <jointName> turret_to_rod, motor_to_wheelleft, motor_to_wheellright </jointName> <updateRate>100</updateRate> <alwaysOn>true</alwaysOn> </plugin>

Comments

OK, thanks, that worked after I removed controller references in my my launch file. (Actually I now recall I had tried that before, but was disappointed to find no velocity data -- nor effort data.)
name: ['turret_to_rod', 'motor_to_wheelleft', 'motor_to_wheelright'] position: [-1.6200029645491254, 0.9563870177604148, 0.9066213357244619] velocity: [] effort: []

I guess velocity and effort are not implemented?

klaatu ( 2016-07-06 10:31:38 -0600 )edit

Still no implementation in Kinetic on 16.04 or am I doing something wrong?

yossi.ovcharik ( 2018-01-13 09:44:27 -0600 )edit

add a comment

Getting joint angles for passive urdf model

1 Answer

Comments

Question Tools

Stats

Related questions

Getting joint angles for passive urdf model edit

1 Answer

Comments

Question Tools

Stats

Related questions

Getting joint angles for passive urdf model