The cob_head_axis package provides a configurable node for operating the axis of the head.


The cob_head_axis node takes in trajectory_msgs/JointTrajectory messages and send this directly to the hardware. The joint states can be received by topics and the axis can be initialized, stopped or recovered via services.

Action Result

joint_trajectory_action/result (pr2_controllers_msgs/JointTrajectoryActionResult)
  • -

Action Feedback

joint_trajectory_action/feedback (pr2_controllers_msgs/JointTrajectoryActionFeedback)
  • -

Subscribed Topics

command (trajectory_msgs/JointTrajectory)
  • Receives direct commands.

Published Topics

/joint_states (sensor_msgs/JointState)
  • Publishes the joint states of all modules.
/diagnostics (diagnostic_msgs/DiagnosticArray)
  • Publishes the diagnostic information about the state of the robot.


init (cob_srvs/Trigger)
  • Initializes the node and connects to the hardware.
stop (cob_srvs/Trigger)
  • Stops immediately all hardware movements.
recover (cob_srvs/Trigger)
  • Recovers the hardware after an emergency stop.
set_operation_mode (cob_srvs/Trigger)
  • Sets the operation mode for the node.
set_default_vel (cob_srvs/SetDefaultVel)
  • Sets the default velocity.


~CanDevice (string, default: Required)
  • Can module specifier, e.g. PCAN, ESD
~CanBaudrate (int, default: Required)
  • Baudrate of can module, e.g. 1000, 500,...
~ModId (int, default: Required)
  • Modul ID
~JointName (String, default: Required)
  • The name of the joint in the robot description of the axis
~HomingDir (int, default: Required)
  • -
~HomingDirIn (int, default: Required)
  • -
~GearRatio (double, default: Required)
  • -
~EnoderIncrementsPerRevMot (int, default: Required)
  • -
~operation_mode (string, default: Required)
  • -


All hardware configuration is done in the cob_hardware_config package. A sample parameter file in "cob_hardware_config/cob3-3/config/head.yaml" could look like this

CanDevice: PCAN:0
CanBaudrate: 500
ModId: 17
JointName: head_axis_joint
HomingDir: 1
MotorDirection: 1
HomingDigIn: 9
GearRatio: 62.5
EnoderIncrementsPerRevMot: 2000
operation_mode: position

Wiki: cob_head_axis (last edited 2012-03-09 15:48:06 by NadiaHammoudeh)