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Switching between autonomous control and keyboard control in ROS

asked 2013-11-28 03:48:26 -0500

RB gravatar image

I want to write a C++ program to switch the control from keyboard to autonomous and vice-versa. Will it be feasible in ROS?

Because, my program need to communicate through two packages namely move_base and brown_remotelab (http://wiki.ros.org/brown_remotelab). I can’t visualize the whole scenario and it’s complexity.

Can you give some insight about the situation and some idea to design the program?

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answered 2013-11-28 04:43:35 -0500

dornhege gravatar image

ROS already provides tools for that.

Mux will let you switch an output topic from multiple incoming topics by calling a service, basically what you were asking for.

What might be more convenient to use is the cmd_vel_mux. It lets you define a couple of sources for a cmd_vel topic that are ordered by priorities. From the active topics the one with highest priority is used. Usually one puts autonomous control at the lowest and uses a teleop setup that is silent when no commands are issued. In this case the switch to autonomy will happen automatically when teleop is not used.

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Thanks for your reply. I have one doubt. Are you sure that even if in maze; ROS can produce an effective autonomous plan to achieve a certain goal? Will there be any chance that the Robot halts at various junction like L, T or +?

RB gravatar imageRB ( 2013-12-03 05:40:08 -0500 )edit

Till now I have not achieved autonomous navigation, so I am aware of only cmd_vel topic by teleop. After achieving High level navigation, will there be any auto_cmd_vel (auto tends for autonomous) by move_base node? Again cmd_vel_mux is bang on target and if I can use it then it will be very useful for me, but as I am using USARSimROS (for P3AT robot) and my knowledge regarding kobuki_node is very less. I if cmd_vel of teleop and cmd_vel of move_base must publish messages to mux node; I think. Do, I need to write custom code to link move_base node to mux node?

RB gravatar imageRB ( 2013-12-03 06:37:22 -0500 )edit

This works out of the box. It's intended for the turltebots/kobuki, but independent. The only thing it does is automatically switch between the cmd_vel topics. Usually you'd just remap them accordingly, e.g. move_base's will go to /cmd_vel_mux/autonomy_cmd_vel or something like that.

dornhege gravatar imagedornhege ( 2013-12-04 04:21:45 -0500 )edit

Something like autonomous plans to achieve goals in a maze is out of the scope for this question and a very different problem. Open a new question if you want to inquire about some capabilities of the navigation stack.

dornhege gravatar imagedornhege ( 2013-12-04 04:22:53 -0500 )edit

ok.. Thanks sir @dornhege

RB gravatar imageRB ( 2013-12-04 06:33:40 -0500 )edit

One more question @dornhege; can I assign two different priorities(at time instant t1, priority p1 and in another time instant t2, priority p2) to the same cmd_vel topic?

RB gravatar imageRB ( 2013-12-08 18:29:31 -0500 )edit

I don't know. Maybe just try it?

dornhege gravatar imagedornhege ( 2013-12-08 23:06:10 -0500 )edit

@dornhege cmd_vel_mux (http://wiki.ros.org/cmd_vel_mux) is written for Groovy/hydro. I am using Fuerte. So can I use this package directly by simply modifying subscriber and publisher? Is there any problem with communication between nodelet and normal nodes? I have seen in here http://www.isep.ipp.pt/roswiki/kobuki(2f)Tutorials(2f)Kobuki(27)s(20)Control(20)System.html Where mobile_base has to be a nodelet as well. PLEASE REPLY

RB gravatar imageRB ( 2014-01-29 17:59:24 -0500 )edit

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Asked: 2013-11-28 03:48:26 -0500

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Last updated: Nov 28 '13