Operating the robot

Launching the robot

If you are not accessing the robot directly, connect to the running OP2 via SSH

ssh robotis@robotis

First we need to kill the default demo program to free the hardware. Run in a terminal on the OP2.

sudo killall demo

Afterwards we can launch the ROS interface (Attention: Depending on your configuration, the robot might stand up)

roslaunch robotis_op_onboard_launch robotis_op_whole_robot.launch 

Check the ROS_MASTER_URI in terminal output (default: ROS_MASTER_URI=http://robotis:11311/).

Troubleshooting: If the robot gets stuck during the launch, kill the process(ctrl+c), reset the actuators and call roslaunch again.

Monitoring on the Notebook

Use the OP2 ROS_MASTER_URI from OP2. Run in a terminal on a PC.

export ROS_MASTER_URI=http://robotis:11311/

Start RViz

roslaunch robotis_op_ui_launch robotis_op_rviz.launch 

In the RViz control panel on the left side you can change “Fixed Frame” from “MP_BODY” to “world” to use the IMU orientation as reference frame for the robot.

Operating the robot

High-level operation

Start the Teleoperation modus

roslaunch robotis_op_teleop robotis_op_teleop_keyboard

Usage instructions will show up in the terminal

Low-level operation

The robot can be operated by sending messages on topics. If you haven't heard about topics, nodes and messages, have a look at the ROS tutorials. To see all available topics

rostopic list

To get more information about a topic rostopic info TOPIC_NAME

Example

rostopic info /robotis_op/cmd_vel 

All topics starting with /robotis_op/ are related to the Robotis OP2.

/robotis_op/j_*/command command a joint position (radian) to the corresponding actuator

Example

rostopic pub /robotis_op/j_shoulder_r_position_controller/command std_msgs/Float64 "data: 0.8" 

/robotis_op/enable_walking enables walking

Example

rostopic pub /robotis_op/enable_walking std_msgs/Bool "data: true" 

/robotis_op/cmd_vel sets the walking velocity and direction

Example

rostopic pub /robotis_op/cmd_vel geometry_msgs/Twist  '{linear: {x: 0.5, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}'

/robotis_op/start_action start a predefined motion sequence

Example

rostopic pub /robotis_op/start_action std_msgs/Int32 "data: 3" 

Additional Tools

Start the rqt_reconfigure GUI to modify parameters while the robot is running

rosrun rqt_reconfigure rqt_reconfigure 

Attention: Be careful when manipulating the control parameters to avoid damage to the robot.

Start rqt_graph to get an overview over the currently running nodes.

rqt_graph