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Getting Started with Turtlesim

Start the roscore:

$ roscore

To compile and start the turtlesim:

$ rosmake turtlesim
$ rosrun turtlesim turtlesim_node

You'll see the turtlesim window:

• 

Nodes

New in ROS hydro As of Hydro turtlesim uses the geometry_msgs/Twist message instead of its own custom one (turtlesim/Velocity in Groovy and older). Also the topic has been changed to cmd_vel (instead of command_velocity before).

turtlesim_node

turtlesim_node provides a simple simulator for teaching ROS concepts.

Subscribed Topics

turtleX/cmd_vel (geometry_msgs/Twist)

• The linear and angular command velocity for turtleX. The turtle will execute a velocity command for 1 second then time out.

Published Topics

turtleX/pose (turtlesim/Pose)

• The x, y, theta, linear velocity, and angular velocity of turtleX.

Services

clear (std_srvs/Empty)

• Clears the turtlesim background and sets the color to the value of the background parameters.

reset (std_srvs/Empty)

• Resets the turtlesim to the start configuration and sets the background color to the value of the background.

kill (turtlesim/Kill)

• Kills a turtle by name.

spawn (turtlesim/Spawn)

• Spawns a turtle at (x, y, theta) and returns the name of the turtle. Also will take name for argument but will fail if a duplicate name.

turtleX/set_pen (turtlesim/SetPen)

• Sets the pen's color (r g b), width (width), and turns the pen on and off (off).

turtleX/teleport_absolute (turtlesim/TeleportAbsolute)

• Teleports the turtleX to (x, y, theta).

turtleX/teleport_relative (turtlesim/TeleportRelative)

• Teleports the turtleX a linear and angular distance from the turtles current position.

Parameters

~background_b (int, default: 255)

• Sets the blue channel of the background color.

~background_g (int, default: 86)

• Sets the green channel of the background color.

~background_r (int, default: 69)

• Sets the red channel of the background color.

mimic

mimic provides a simple interface for making one turtlesim mimic another.

Subscribed Topics

input (geometry_msgs/Twist)

• The input topic for the mimic node. The topic must be remapped to the cmd_vel topic of the desired turtle to mimic.

Published Topics

output (geometry_msgs/Twist)

• The output topic for the mimic node. The topic must be remapped to the cmd_vel topic of the mimicking turtle.