Speech recognition using ROS and Pocketsphinx

How to install pocketsphinx on ROS Indigo (Ubuntu 14.04).

Install Dependecies

• $ sudo apt-get install gstreamer0.10-pocketsphinx
• $ sudo apt-get install python-gst0.10
• $ sudo apt-get install gstreamer0.10-gconf

Clone and Build Pocketsphinx

• Clone the repository in your catkin src folder:
  • $ git clone https://github.com/mikeferguson/pocketsphinx.git
• Launch the catkin_make command from the catkin workspace folder

Test Pocketsphinx

• Now we can start the speech recognizer:
  • $ roslaunch pocketsphinx turtlebot_voice_cmd.launch
• These are the basic commands can be recognized (see file voice_cmd.corpus in the folder demo):

forward
left
right
back
backward
stop
move forward
move right
move left
move back
move backward
halt
half speed
full speed

• Open another terminal to check if the words are recognized:
• $rostopic echo /recognizer/output

jokla@Dell-PC:~/catkin_ws/src$ rostopic echo /recognizer/output 
data: back
---
data: speed
---
data: move right
---
data: move back
---
data: back
---
data: left
---
data: speed
---
data: left
---
data: move right
---
data: stop
---
data: move right
---
data: move left
---
data: full speed

• To each vocal command corresponds a twist command. For example, this is the twist corresponding to the command “back”:

linear: 
  x: -0.4
  y: 0.0
  z: 0.0
angular: 
  x: 0.0
  y: 0.0
  z: 0.0`

Command Turtlebot robot in Gazebo using voice commands

• Install turtlebot_simulator
  • $ sudo apt-get install ros-indigo-turtlebot-simulator
• Open the launch file turtlebot_voice_cmd and remap the name of the topic cmd_vel to /mobile_base/commands/velocity

<node name="voice_cmd_vel" pkg="pocketsphinx" type="voice_cmd_vel.py" output="screen">
    <remap from="cmd_vel" to="/mobile_base/commands/velocity"/>
 </node>`

In this way the node pocketsphinx publishes the velocities in the topic /mobile_base/commands/velocity and gazebo subscribes to it.

• Launch simulation (click here for more info). Note that Gazebo may update its model database when it is started for the first time. This may take a few minutes.
  • $ roslaunch turtlebot_gazebo turtlebot_world.launch
• Now we can start the speech recognizer:
  • $ roslaunch pocketsphinx turtlebot_voice_cmd.launch
• You should be able to control Turtlebot using your voice.