[ros-users] how to use pr2_controller_manager with a different robot

Tue Sep 7 22:29:17 UTC 2010

Thanks Stu. I should have replied to Wim's email that I got something
working using a custom ROS node and a hacked version of Cartesian Pose
Controller.

I have a question though: Is there a significant speed difference between
setting up several realtime state publishers as shown below (twist, 2x Pose
stamped, JointState, Float array) compared to making a custom message type
and sending it out on one publisher? The current publish rate is 10Hz but I
am thinking of increasing that to 30Hz+.

Also... are the real-time publishers below doing anything different than
regular publishers, given that they aren't actually working in part of the
pr2_controller manager? It seems I didn't have to call ros::spinOnce()
anywhere to get those to work, but I ended up having to call ros::spinOnce()
every 100ms anyway to get the incoming pose commands to update.

Thanks,
Adam

state_error_publisher_.reset(new
realtime_tools::RealtimePublisher<geometry_msgs::Twist>(node_,
"state/error", 1));
  state_pose_publisher_.reset(new
realtime_tools::RealtimePublisher<geometry_msgs::PoseStamped>(node_,
"state/pose", 1));
  state_pose_desi_publisher_.reset(new
realtime_tools::RealtimePublisher<geometry_msgs::PoseStamped>(node_,
"state/pose_desi", 1));
  joint_state_publisher_.reset(new
realtime_tools::RealtimePublisher<sensor_msgs::JointState>(node_,
"joint_states", 1));
  effort_publisher_.reset(new
realtime_tools::RealtimePublisher<std_msgs::Float32MultiArray>(node_,
"state/effort", 1));

Adam Leeper
Stanford University
aleeper at stanford.edu
719.358.3804

On Tue, Sep 7, 2010 at 2:54 PM, Stuart Glaser <sglaser at willowgarage.com>wrote:

> Hi Adam,
>
> Neither the JTTeleopController nor the CartesianPoseController are
> necessarily PR2 specific, however, both run inside the PR2 controller
> manager, which is PR2 specific.  Controllers can only be run on a
> robot that supports the PR2 controller manager.
>
> Wim's email from Aug 31 describes a few ways to run the pr2 controller
> manager on your own robot.  Following his instructions is your best
> bet to getting any of the controllers running on your robot.
>
> -Stu
>
> On Tue, Aug 31, 2010 at 6:29 PM, Adam Leeper <aleeper at stanford.edu> wrote:
> > Thanks Wim.
> >
> > If robot_mechanism_controllers/CartesianPoseController is generic, is
> there
> > a sample config or launch file for setting the parameters? Sachin sent
> one
> > out earlier for JTTeleop, but I guess that is pr2-specific.
> >
> > Thanks.
> >
> >
> > Adam Leeper
> > Stanford University
> > aleeper at stanford.edu
> > 719.358.3804
> >
> >
> > On Tue, Aug 31, 2010 at 6:17 PM, Wim Meeussen <meeussen at willowgarage.com
> >
> > wrote:
> >>
> >> > When I launch and try to check the status of the controllers using
> >> > pr2_controller_manager list, it hangs and if I kill it the traceback
> >> > says it
> >> > was waiting for 'pr2_controller_manager/list_controllers.' When I run
> >> > the
> >> > pr2 in gazebo, that service is advertised by gazebo itself... so
> >> > obviously I
> >> > have a problem.
> >>
> >> The pr2 controller manager is a library, not an executable. So when
> >> you run in simulation, Gazebo creates the controller manager, and when
> >> you run on the pr2, pr2_ethercat creates the controller manager.  When
> >> you launch "controller_manager.launch", this will only load the
> >> configuration for the controller manager on the parameter server, and
> >> run some supporting nodes (diagnostics, state publisher, etc), but
> >> this will not run the controller manager. Take a look at the
> >> pr2_etherCAT package for an example on how to start the controller
> >> manager.
> >>
> >>
> >> > What is the correct procedure for interfacing my own hardware with
> ros?
> >> > I
> >> > know at some point I need to hook all this up to actual joint data
> >> > coming in
> >> > off my hardware. Can someone point me to an example of how that is
> >> > published? Also, do the CartesianPoseController and JTTeleopController
> >> > work
> >> > with a generic urdf, or are they pr2-specific?
> >>
> >> There are multiple ways to do this:
> >>  * You can create a ROS node for each piece of hardware, and allow
> >> other nodes in your system to interact with the hardware over
> >> topics/services/actions. This is a very easy approach. The
> >> disadvantage is that you won't be able to create a closed loop in hard
> >> realtime, and you won't be able to reuse the controllers we built for
> >> the PR2. But I would think that most people have used this approach
> >> when porting their robot to ROS.
> >>
> >>  * You can implement the hardware interface (pr2_hardware_interface)
> >> for your hardware, and use the controller manager. The pr2 hardware
> >> interface is however PR2 specific, so this approach will only work for
> >> robots that are in some ways similar to the PR2. The hardware
> >> interface for example only supports effort controlled joints.  All the
> >> controllers we built, are using the "JointState" object of the
> >> hardware interface. So, take a look at the class, and see if you could
> >> implement this for your robot.
> >>
> >> The controllers that are not PR2 specific live in stacks that don't
> >> have the pr2-prefix. The robot_mechanism_controllers package for
> >> example contains a set of non-pr2-specific controllers.
> >>
> >>
> >> Hope this helps,
> >>
> >> Wim
> >>
> >>
> >>
> >>
> >> --
> >> --
> >> Wim Meeussen
> >> Willow Garage Inc.
> >> <http://www.willowgarage.com)
> >> _______________________________________________
> >> ros-users mailing list
> >> ros-users at code.ros.org
> >> https://code.ros.org/mailman/listinfo/ros-users
> >
> >
> > _______________________________________________
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> >
> >
>
>
>
> --
> Stuart Glaser
> sglaser -at- willowgarage -dot- com
> www.willowgarage.com
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