[ros-users] robot_state_publisher question

I am using the robot_state_publisher to convert my joint angles to tf
transforms. However, it seems that the robot_state_publisher doesn't
like it when you send it different joints at different times. In other
words, robot_state_publisher doesn't maintain any state...



For example, my urdf has 2 joints:

Base -> joint1 -> link1 -> joint2 -> link2



If I send it joint1, then at a later time I send it joint 2, I get this
error:



Node: /robot_state_publisher

Time: 1285876513.251897000

Severity: Error

Location:
/home/arm_user/darpa_arm_software/stacks/robot_model/robot_state_publish
er/src/robot_state_publisher.cpp:RobotStatePublisher::publishTransforms:
78

Published Topics: /rosout, /tf

Could not compute link poses. The tree or the state is invalid.



But if I send both joints at once, then everything is fine. This seems
like a major limitation to me. Am I missing something?



I am using boxturtle. And am using robot_state_publisher running as a
node.



Thanks,

-Ben



Ben Axelrod

Research Scientist

iRobot Corporation

8 Crosby Drive, Mail Stop 8-1

Bedford, MA 01730

(781) 430-3315 (Tel)

(781) 960-2628 (Fax)

baxelrod@irobot.com <mailto:ofitch@irobot.com>