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brics_actuator.msg only works with rostopic

asked 2014-05-08 21:04:23 -0600

cobhc999 gravatar image

updated 2014-05-08 21:05:27 -0600


I'm fairly new to ROS and the youBot. I'm trying to move Joint 1 of the arm. A notebook is connected via ssh to the youBot. When I use rostopic everything works as expected and the arm moves.

rostopic pub -1 /arm_1/arm_controller/position_command brics_actuator/JointPositions '{positions:[{joint_uri: arm_joint_1, unit: rad, value: 2}]}

ros_graph looks like this:

/rostopic_3016_lotofnumbers -> /arm_1/arm_controller/position_command -> /youbot_driver

Now I tried my own program "ArmVorlage".py, but it isn't moving:

class Goto_Searchposition():
def __init__(self):
    # Give the node a name
    self.node_name = "goto_searchposition"
    # Set rospy to execute a shutdown function when exiting       
    rospy.on_shutdown(self.shutdown) = rospy.Publisher("/arm_1/arm_controller/position_command", brics_actuator.msg.JointPositions)
    joint_positions = brics_actuator.msg.JointPositions()
    JointValue = brics_actuator.msg.JointValue()
    JointValue.unit = 'rad'
    JointValue.value = 2
def shutdown(self):
    # Always stop the robot when shutting down the node.
    rospy.loginfo("Stopping the robot...")

if __name__ == '__main__':

ros_graph looks like this:

/goto_searchposition -> /arm_1/arm_controller/position_command -> /youbot_driver

The debugging in /youbot_driver looks similiar except the ports are different and these logs are missing when running my own program:

[DEBUG] [1399616158.709991323]: Command for arm1 received

[DEBUG] [1399616158.710137675]: Arm ID is: youbot-manipulator

I would be very grateful if you could help me.


Timo (I'm sorry i cant post pictures or links cause as a new user i have too little karma)

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I have a similar doubt. Though I am getting a different error. Will just "from brics_actuator import JointPosition" work? I just made a python script and get this: youbot@youbot-desktop:~$ rosrun youbot_leap Traceback (most recent call last): File "/home/youbot/catkin_ws/src/youbotleap/scripts/", line 96, in <module> sender() File "/home/youbot/catkin_ws/src/youbotleap/scripts/", line 25, in sender msg.positions.joint_uri = "arm_joint_1" AttributeError: 'list' object has no attribute 'joint_uri'

ratneshmadaan gravatar imageratneshmadaan ( 2014-06-11 07:58:51 -0600 )edit

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answered 2014-05-09 21:16:44 -0600

cobhc999 gravatar image

Solved it by changing 'rad' to "rad". Unfortunately there was never an error message or something.

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Asked: 2014-05-08 21:04:23 -0600

Seen: 330 times

Last updated: May 09 '14