ROS/Gazebo Demos not working

I've tried two of the ROS/Gazebo examples and neither work.

https://www.mathworks.com/help/robotics/ug/pick-and-place-gazebo-with-point-clouds-and-rrt.html

https://www.mathworks.com/help/ros/ug/communicate-with-the-turtlebot.html

In the case of the pick and place example, Matlab freezes when I get to the step Opening and closing the gripper when I exectute the command

[gripAct,gripGoal] = rosactionclient('/my_gen3/custom_gripper_controller/gripper_cmd');

In the case of the turtle example, I can list the topics

>> rostopic list
/clock                        
/cmd_vel                      
/gazebo/link_states           
/gazebo/model_states          
/gazebo/parameter_descriptions
/gazebo/parameter_updates     
/gazebo/set_link_state        
/gazebo/set_model_state       
/imu                          
/joint_states                 
/odom                         
/rosout                       
/rosout_agg                   
/scan                         
/tf                    

however when I try to make the robot move nothing happens i.e. the the turtle robot in the Gazebo simulation does not move.

>> robotCmd = rospublisher("/cmd_vel","DataFormat","struct") ;
>> velMsg = rosmessage(robotCmd);
>> velMsg.Linear.X = velocity;
>> send(robotCmd,velMsg)

Answer 1

[Hari Krishna Kakarla]

Hi Jason Butler,

Thank you for reaching out through MATLAB Answers. I see that you opened the 'Gazebo Recycling World". It looks like simulation is not running in Gazebo World. Please click on play button in the Gazebo Simulator and run your workflow.

I hope it should work fine. Please let me know if you still have any issue.

Thanks

Hari

[Jason Butler]

Hi,

I clicked play in Gazebo as you suggested. Now the arm dances a bit to the right then there is no activity I see some warnings and then it freezes. If I pause Matlab its always at the same execption.