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Version: QTrobot V2

QTrobot interfaces using ROS Publishers

Overview

 Level:  Basic
 Goal:  learn how to access QTrobot interfaces such as speech, emotion, gesture, etc. in python via ROS publishers
 Requirements:

If you have followed our previous tutorials, you should know how to start coding on QTrobot with python and got the basic knowledge of ROS framework. In this tutorial we will learn about how to access QTrobot interfaces such as speech and audio interface using ROS publishers.

Create a python project​

First we create a python project for our tutorial. let's call it tutorial_qt_publisher and add the required python file:

cd ~/catkin_ws/src
catkin_create_pkg tutorial_qt_publisher std_msgs rospy roscpp -D "Command QTrobot via ROS Publishers"
cd tutorial_qt_publisher/src
touch tutorial_qt_publisher_node.py
chmod +x tutorial_qt_publisher_node.py

QTrobot speech publisher​

Open the tutorial_qt_publisher_node.py file and add the following code:

#!/usr/bin/env python3
import sys
import rospy
from std_msgs.msg import String

if __name__ == '__main__':
    rospy.init_node('my_tutorial_node')
    rospy.loginfo("my_tutorial_node started!")

   # creating a ros publisher
   speechSay_pub = rospy.Publisher('/qt_robot/speech/say', String, queue_size=10)
   rospy.sleep(3.0)

   # publish a text message to TTS
   speechSay_pub.publish("Hello! my name is QT!")

    try:
        rospy.spin()
    except KeyboardInterrupt:
        pass

    rospy.loginfo("finsihed!")

First we imported std_msgs.msg from ROS standard message library. This message is used in /qt_robot/speech/say to communicate with QTrobot speech (TTS) interface.

Tip

How do we know which message type an interface uses? well, There is a useful command in ROS which tells you that:

rostopic info /qt_robot/speech/say
Type: std_msgs/String
...

Then we created a publisher to '/qt_robot/speech/say' topic and wait for few seconds to establish the connection with the interface.

Tip

In the above example, for simplicity we used few seconds of delay using sleep function. A more appropriate way is to wait and check until the connection with a subscriber is established:

# wait for publisher/subscriber connections
wtime_begin = rospy.get_time()
while (speechSay_pub.get_num_connections()) :
    rospy.loginfo("waiting for subscriber connections")
    if rospy.get_time() - wtime_begin > 5.0:
        rospy.logerr("Timeout while waiting for subscribers connection!")
        sys.exit()
    rospy.sleep(0.5)

Finally we published a text message to QTrobot speech interface which make the robot read that message.

QTrobot talk text publisher​

The /qt_robot/behavior/talkText interface is similar to /qt_robot/speech/say interface with the only different that the talkText interface asks QTrobot to move his lips while reading the text messages. To try it, just add the following lines to our code:

behaviorTalkText_pub = rospy.Publisher('/qt_robot/behavior/talkText', String, queue_size=10)
behaviorTalkText_pub.publish("Hello! my name is QT!")

QTrobot emotion publisher​

Now lets show an emotion on QTrobot face. QTrobot comes with plenty of predefined emotion animations. You can find the complete list of the available emotions either using the QTrobot Educator app or by looking into the ~/robot/data/emotions folder in QTRP.

Add the following lines to our code to show the 'happy' emotion under 'QT' category on QTrobot face:

emotionShow_pub = rospy.Publisher('/qt_robot/emotion/show', String, queue_size=10)
emotionShow_pub.publish("QT/happy")
Note

As it shown in the above example, you should not give the emotion's file extension (.avi) to the interface!

QTrobot gesture publisher​

Now lets play a gesture with QTrobot. QTrobot comes with plenty of predefined gestures. You can find the complete list of the available gestures either using the QTrobot Educator app or by looking into the ~/robot/data/gestures folder in QTRP.

Add the following lines to our code to play the 'clapping' gesture under 'QT' category:

gesturePlay_pub = rospy.Publisher('/qt_robot/gesture/play', String, queue_size=10)
gesturePlay_pub.publish("QT/clapping")
Note

As it shown in the above example, you should not give the gestures's file extension (.xml) to the interface!

QTrobot audio publisher​

Now lets play an audio file on QTrobot. QTrobot comes with some audio examples. You can find the complete list of the available audios either using the QTrobot Educator app or by looking into the ~/robot/data/audios folder in QTRP. QTrobot can play both audio wave and mp3 files.

Add the following lines to our code to play the 'Komiku_Glouglou' audio file under 'QT' category:

audioPlay_pub = rospy.Publisher('/qt_robot/audio/play', String, queue_size=10)
audioPlay_pub.publish("QT/Komiku_Glouglou")
Note

As it shown in the above example, you do not need to give the audio's file extension (.wav or .mp3) to the interface!