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Turtlebot sensor_state all 0s with Gazebo on Fuerte

asked 2013-07-31 10:12:26 -0600

Zayin gravatar image

updated 2014-01-30 21:00:02 -0600

tfoote gravatar image

I am trying to access the bumps wheeldrops sensor from the Turtlebot sensor_state topic. However, the bump sensor is never activated. In fact, if I execute rostopic echo /turtlebot_node/sensor_state, all the sensor_state values are permanently set to 0. In addition, I noticed that the /odom Twist parameter remains 0 even when the robot is moving. Here is my launch file:

    <arg name="use_sim_time" default="true"/>
    <arg name="gui" default="true"/>

    <!-- start gazebo with an empty plane -->
    <param name="/use_sim_time" value="true" />

    <node name="gazebo" pkg="gazebo" type="gazebo" args="-u $(find turtlebot_gazebo)/worlds/" respawn="false" output="screen"/>

    <include file="$(find turtlebot_gazebo)/launch/robot.launch"/>

    <!-- start gui -->
    <group if="$(arg gui)">
        <node name="gazebo_gui" pkg="gazebo" type="gui" respawn="false" output="screen"/>


And here is the simple program that is running as a node:

#include <ros/ros.h>
#include <turtlebot_node/TurtlebotSensorState.h>
#include <geometry_msgs/Twist.h>
#include <ros/rate.h>
#include <iostream>
#include <stdio.h>                        

using namespace std;    
uint8_t bumper;

void bumperCallback(const turtlebot_node::TurtlebotSensorState::ConstPtr& msg);

int main (int argc, char** argv){       

    ros::Time start, end;
    ros::init(argc, argv, "bumper");    
    ros::NodeHandle nodeH;  
    ros::Rate loop_rate(10); //10 Hz.
    geometry_msgs::Twist twist;

    //Bumper subscriber.
    ros::Subscriber bumperSub = nodeH.subscribe<turtlebot_node::TurtlebotSensorState>("/turtlebot_node/sensor_state", 1000, bumperCallback);
    ros::Publisher movingPub = nodeH.advertise<geometry_msgs::Twist>("cmd_vel", 1000);

    //Twist set to navigate forward.
    double forwardSpeed = 0.15;
    twist.linear.x = forwardSpeed; 
    twist.linear.y = 0;
    twist.linear.z = 0;
    twist.angular.x = 0; 
    twist.angular.y = 0; 
    twist.angular.z = 0;

    start = ros::Time::now(); //Time when the robot starts moving.
        if(bumper != 0){
            end = ros::Time::now(); //Time when robot bumped into a wall.
            ROS_INFO("BOOM OUCH");

        else{ //Go forward until the robot bumps into a wall.
            ROS_INFO("Going forward");      

    return 0;

//Fetch the sensor state containing the bumper state.
void bumperCallback(const turtlebot_node::TurtlebotSensorState::ConstPtr& msg){

    bumper = msg->bumps_wheeldrops;
    ROS_INFO("Bumper is %d .", bumper);     

I verified that Gazebo is indeed publishing on "/turtlebot_node/sensor_state" and that my own node is subscribed to it. How can I solve this problem? I've researched similar topics, but I don't see anything wrong with my files based on these.

Note that the following warning is being reported by Gazebo, but I think it's irrelevant:

Warning [] ranges not constructed yet (zero sized)

[Edit] I just noticed these additional errors. I had not seen them before because the RaySensor warning is being displayed thousands of times. Gazebo seems to be running fine, though...

Warning [] Gazebo SDF has no gazebo element
On July 1st, 2012, this formate will no longer by supported
Convert your files using the gzsdf command line tool
You have been warned!

Error [] No Opaque set
[ INFO] [1375303568.841199057]: imu plugin missing <serviceName>, defaults to /default_imu
[ INFO] [1375303568.842760080]: imu plugin missing <xyzOffset>, defaults to 0s
[ INFO] [1375303568 ...
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are u using hydro or groovy? If in hydro, there's still a lot of work to do:

jorge gravatar image jorge  ( 2013-08-22 00:46:06 -0600 )edit

I'm sorry I forgot to mention it. I'm using Fuerte,

Zayin gravatar image Zayin  ( 2013-08-26 04:51:51 -0600 )edit

Oh, I see, thanks! I shouldn't have assumed Gazebo was fully implemented.

Zayin gravatar image Zayin  ( 2013-08-28 04:48:15 -0600 )edit

1 Answer

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answered 2013-08-27 14:20:12 -0600

jorge gravatar image

For the sensor_state 0s, I don't know; probably you will need to dig in the code to see if there's a problem or it's just not implemented. For the 0 velocity on odometry, I took a fast look at the code and it's just not implemented.

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Asked: 2013-07-31 10:12:26 -0600

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Last updated: Aug 26 '13