Actuators via ROS 2 Command Line
This page describes how to use the the Create® 3 robot's actuators using the ROS 21 command line tools.
Audio
Play a sequence of notes
Play a happy sequence once:
ros2 topic pub /cmd_audio irobot_create_msgs/msg/AudioNoteVector "{append: false, notes: [{frequency: 392, max_runtime: {sec: 0,nanosec: 177500000}}, {frequency: 523, max_runtime: {sec: 0,nanosec: 355000000}}, {frequency: 587, max_runtime: {sec: 0,nanosec: 177500000}}, {frequency: 784, max_runtime: {sec: 0,nanosec: 533000000}}]}" -1
Play a sad sequence once:
ros2 topic pub /cmd_audio irobot_create_msgs/msg/AudioNoteVector "{append: false, notes: [{frequency: 369, max_runtime: {sec: 0,nanosec: 355000000}}, {frequency: 300, max_runtime: {sec: 0,nanosec: 533000000}}]}" -1
Play a scary sequence forever:
ros2 action send_goal /audio_note_sequence irobot_create_msgs/action/AudioNoteSequence "{iterations: -1, note_sequence: {append: false, notes: [{frequency: 82, max_runtime: {sec: 1,nanosec: 0}}, {frequency: 87, max_runtime: {sec: 1,nanosec: 0}}]}}"
API documentation on the speakers can be found here.
Driving
Command velocities
You can drive around the Create® 3 robot by publishing standard Twist messages on the /cmd_vel topic.
ros2 topic pub -r 20 /cmd_vel geometry_msgs/msg/Twist "{linear: {x: 0.2, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}"
Drive a distance
The Drive Distance action takes a distance in meters and maximum speed in meters per second.
ros2 action send_goal /drive_distance irobot_create_msgs/action/DriveDistance "{distance: 0.5,max_translation_speed: 0.15}"
Rotate an angle
The Rotate Angle action takes a turn angle in radians and maximum angular speed in radians per second.
ros2 action send_goal /rotate_angle irobot_create_msgs/action/RotateAngle "{angle: 1.57,max_rotation_speed: 0.5}"
Drive an arc
The Drive Arc action takes a arc angle in radians, arc radius in meters, translate direction (1 for forward and -1 for rearward) and and maximum translation speed in meters per second.
$ ros2 action send_goal /drive_arc irobot_create_msgs/action/DriveArc "{angle: 1.57,radius: 0.3,translate_direction: 1,max_translation_speed: 0.3}"
Wall Follow
The Wall Follow action takes a side (1=left, -1=right) and a maximum duration.
ros2 action send_goal /wall_follow irobot_create_msgs/action/WallFollow "{follow_side: 1, max_runtime: {sec: 1, nanosec: 0}}"
Navigate to position
The Navigate to Position action takes a goal position (in meters) and orientation (in radians). The orientation must be specified as part of the message, but it can be ignored by setting achieve_goal_heading to false.
$ ros2 action send_goal /navigate_to_position irobot_create_msgs/action/NavigateToPosition "{achieve_goal_heading: true,goal_pose:{pose:{position:{x: 1,y: 0.2,z: 0.0}, orientation:{x: 0.0,y: 0.0, z: 0.0, w: 1.0}}}}"
Docking
Undock the robot
If the Create® 3 robot is on its dock, you can undock it with the Undock action:
ros2 action send_goal /undock irobot_create_msgs/action/Undock "{}"
Dock the robot
If the Create® 3 robot sees its dock (check the docking documentation for details) you can dock it with:
Galactic
ros2 action send_goal /dock irobot_create_msgs/action/DockServo "{}"
Humble
ros2 action send_goal /dock irobot_create_msgs/action/Dock "{}"
E-Stop
Enable E-Stop
If under the robot's control, its light ring will turn yellow when the motors are disabled.
ros2 service call /e_stop irobot_create_msgs/srv/EStop "{e_stop_on: true}"
Disable E-Stop
ros2 service call /e_stop irobot_create_msgs/srv/EStop "{e_stop_on: false}"
API documentation on the E-Stop is available here.
Light Ring
Multicolor
ros2 topic pub /cmd_lightring irobot_create_msgs/msg/LightringLeds "{override_system: true, leds: [{red: 255, green: 0, blue: 0}, {red: 0, green: 255, blue: 0}, {red: 0, green: 0, blue: 255}, {red: 255, green: 255, blue: 0}, {red: 255, green: 0, blue: 255}, {red: 0, green: 255, blue: 255}]}" -1
Return static control to Create 3 Robot
ros2 topic pub /cmd_lightring irobot_create_msgs/msg/LightringLeds "{override_system: false, leds: [{red: 255, green: 0, blue: 0}, {red: 0, green: 255, blue: 0}, {red: 0, green: 0, blue: 255}, {red: 255, green: 255, blue: 0}, {red: 255, green: 0, blue: 255}, {red: 0, green: 255, blue: 255}]}" -1
Animations
# Note: type 1 is blink and type 2 is spin
ros2 action send_goal /led_animation irobot_create_msgs/action/LedAnimation "{animation_type: 2,max_runtime:{sec: 10,nanosec: 0},lightring:{override_system: true, leds: [{red: 255, green: 0, blue: 0}, {red: 0, green: 255, blue: 0}, {red: 0, green: 0, blue: 255}, {red: 255, green: 255, blue: 0}, {red: 255, green: 0, blue: 255}, {red: 0, green: 255, blue: 255}]}}"
Robot Power
Warning: this turns the robot and payload off immediately
ros2 service call /robot_power irobot_create_msgs/srv/RobotPower "{}"