I now found out a bit more. I now realize that by setting the
commanded_effort_ of a JointState is the way commands are sent (not via
messages or other). I also see that Gazebo is has a plugin to
replicate the controller_manager, that uses the URDF description to set
up a robot model and simulation joint motions. So, at the VERY least,
if I want to use Gazebo, I'll need to make sure that I load a
pr2_mechansim_model of the Robot that is consistent with the model used
by Gazebo.
Does this sound correct?
to have it's own ros_controller_manager that does the same for Gazebo.
So, my intuition is that if I write
On 06/14/2011 10:53 AM, Patrick Beeson wrote:
> Great. I look froward to trying this out once it's released.
>
> One or two quick questions that are not at all clear. Will (in the
> new tool chain) my custom JointTrajectoryAction controller also need
> to be a pr2_controller in order to use my URDF model with Gazebo? I
> was going to make a joint_trajectory_action_node that communicated
> directly with my hard in soft real-time to start. This wasn't going
> to be a pr2_controller at all. But I will want to be able to use the
> urdf model to control the arm in Gazebo. My understanding is that
> right now, somewhere, something allows controllers to run in
> simulation instead of on the ethercat hardware. I can't seem to find
> a good example that shows where exactly the line in drawn between sim
> and real, but it looks like the default Gazebo pr2 sim AND the pr2 arm
> hardware both use
> robot_mechanism_controllers/src/joint_trajectory_action_controller.cpp.
> Examining that controller, I find it VERY difficult to understand how
> the low-level joint commands are being set (they seem to be copied
> into a RealTimeBox that is never intialized, so I don't know where
> they go from there). So is the sim joint communication happening
> below this? Do I need to do something special to talk to simulated
> joints in Gazebo versus on my hardware? Another way of asking, if I
> write a joint_trajectory_action_controller to talk to my specific
> hardware, will I need to write another to talk to Gazebo? And Do
> these need to be pr2_controllers?
>
>
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