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Version: QTrobot V1

QTrobot interfaces using ROS Services

Overview

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

Create a python project​

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

cd ~/catkin_ws/src
catkin_create_pkg tutorial_qt_service rospy roscpp -D "Command QTrobot via ROS Services"
cd tutorial_qt_service/src
touch tutorial_qt_service_node.py
chmod +x tutorial_qt_service_node.py

QTrobot speech service​

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

#!/usr/bin/env python3
import sys
import rospy
from qt_robot_interface.srv import *

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

    # define a ros service
    speechSay = rospy.ServiceProxy('/qt_robot/speech/say', speech_say)
    
    # block/wait for ros service
    rospy.wait_for_service('/qt_robot/speech/say') 
   
    try:
        # call a ros service with text message
        speechSay("Hello! This is QT talking using text to speech")
    except KeyboardInterrupt:
        pass

    rospy.loginfo("finsihed!")

ROS Services are defined by srv files, which contains a request message and a response message. First we import all from qt_robot_interface.srv. This will import all srv files that are under qt_robot_interface.srv. We need to use speech_say.

Tip

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

rosservice info /qt_robot/speech/say
Type: qt_robot_interface/speech_say
Args: message
...

Then we defined a service /qt_robot/speech/say and call rospy.wait_for_service() to block until a service is available.

Finally we called a ROS service with a text message to QTrobot speech interface which makes the robot read that message.

QTrobot talk text service​

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 = rospy.ServiceProxy('/qt_robot/behavior/talkText', behavior_talk_text)
rospy.wait_for_service('/qt_robot/behavior/talkText')
behaviorTalkText("I am QT robot!")

QTrobot emotion service​

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 = rospy.ServiceProxy('/qt_robot/emotion/show', emotion_show)
rospy.wait_for_service('/qt_robot/emotion/show')
emotionShow("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 service​

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:

from qt_gesture_controller.srv import gesture_play

gesturePlay = rospy.ServiceProxy('/qt_robot/gesture/play', gesture_play)
rospy.wait_for_service('/qt_robot/gesture/play')
gesturePlay("QT/happy", 0)
Note

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

QTrobot audio service​

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 = rospy.ServiceProxy('/qt_robot/audio/play', audio_play)
rospy.wait_for_service('/qt_robot/audio/play')
audioPlay("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!