Prismatic joints aren't supported

[AndyZe]

You can tell by searching for prismatic here: https://github.com/ros/joint_state_publisher/blob/ros2/joint_state_publisher/joint_state_publisher/joint_state_publisher.py

It's not a big deal but I wanted to raise the issue so others don't waste their time.

[clalancette]

Did joint_state_publisher support prismatic joints in ROS 1? I also looked for prismatic in https://github.com/ros/joint_state_publisher/blob/noetic-devel/joint_state_publisher/src/joint_state_publisher/__init__.py , and I didn't find anything.

[DLu]

So prismatic isn't explicitly called out, but the joint types are handled in this block:

joint_state_publisher/joint_state_publisher/joint_state_publisher/joint_state_publisher.py

Lines 95 to 109 in 0a765c0

	if jtype in ['fixed', 'floating', 'planar']:
	continue
	name = child.getAttribute('name')
	self.joint_list.append(name)
	if jtype == 'continuous':
	minval = -math.pi
	maxval = math.pi
	else:
	try:
	limit = child.getElementsByTagName('limit')[0]
	minval = float(limit.getAttribute('lower'))
	maxval = float(limit.getAttribute('upper'))
	except:
	self.get_logger().warn('%s is not fixed, nor continuous, but limits are not specified!' % name)
	continue

floating and planar are excluded (because they would require multiple sliders).

continuous joints are handled with a special case because their limits don't exist.

prismatic and revolute joints are handled implicitly by the else block.

Can you given an example of how it doesn't work? If you launch the URDF tutorial that uses joint_state_publisher_gui, you should be able to extend/retract the arm using the prismatic joint gripper_extension