Cannot move turtlebot3 burger

Lidar data works perfectly fine, however, I cannot move the bot. Can anyone see what I'm doing wrong?

Connectioin Info:

rosshutdown
 setenv('ROS_MASTER_URI','http://10.0.0.4:11311')
 setenv('ROS_IP','10.0.0.4')
rosinit('http://10.0.0.4:11311', 'NodeHost', '10.0.0.169')

Rostopic List

>> rostopic list
/battery_state   
/cmd_vel         
/cmd_vel_rc100   
/diagnostics     
/firmware_version
/imu             
/joint_states    
/magnetic_field  
/motor_power     
/odom            
/reset           
/rosout          
/rosout_agg      
/rpms            
/scan            
/sensor_state    
/sound           
/tf              
/version_info    
>> 

Here is my script:

TurtleBot_Topic.vel = '/cmd_vel';
TurtleBot_Topic.laser = '/scan';

laser_sub = rossubscriber(TurtleBot_Topic.laser);
velocity_pub = rospublisher(TurtleBot_Topic.vel, 'geometry_msgs/Twist');
velocity_msg = rosmessage(velocity_pub);
  
tic
while toc<10
scan_data = receive(laser_sub);
cart = readCartesian(scan_data, 'RangeLimit', [0.12 3.5]);
plot(cart(:,1),cart(:,2), 'o');

velocity_msg.Angular.Z = 0.0;
velocity_msg.Linear.X = 0.2;
send(velocity_pub, velocity_msg);
end

All help is appreciated.

PS: I had a much more detailed report, pressed a wrong key and it all got deleted :(

[Sai Bhargav Avula]

The code looks fine can you update you question with the ROS_MASTER, ROS_IP env variables. It might be network issue.

[Previn Savaya]

rosshutdown
 setenv('ROS_MASTER_URI','http://10.0.0.4:11311')
 setenv('ROS_IP','10.0.0.4')
rosinit('http://10.0.0.4:11311', 'NodeHost', '10.0.0.169')

[Sai Bhargav Avula]

This seems fine. It can be the firewall. You need to allow matlab on some computer.

[Previn Savaya]

I already disabled firewall. Very strange issue. Especially the fact that the lidar Data is received.

Is it possible that the publishers just don’t work? Can I manually check what is being published to what topic? The turtlebot says it is subscribed to all the topics.

[Sai Bhargav Avula]

Try echoing the /cmd_vel topic and check for the values.

vel_msg = rostopic("echo", /cmd_vel)

[Previn Savaya]

Ok, I’m not at my workstation now but as soon as I can I will check it out and update you.

Answer 1

[Previn Savaya]

I believe I solved this issue. It did have something to do with the communication.

I replaced the IP of the turtlebot with the IP of my actual computer that is running matlab and it worked. Not sure why, but it does!

So for my network configuration this is what I have:

ROS MASTER = IP OF VIRTUAL REMOTE DESKTOP (Oracle Virtual Machine) (roscore command runs on this)

ROS IP = IP OF MY PC THAT IS RUNNING MATLAB (My pc's ip address... AKA IPCONFIG in command prompt)

Somehow this solved my problem.