Basic interaction with another simulator using HLA : the Billard example hla

In this tutorial, you will learn / test how to connect Morse with another simulator engine, using HLA. We will use the default example simulator provided by the CERTI implementation, a billard simulator.

Warning

The tutorial assumes that you are familiar with HLA concept.

Setup

First, verify that you have installed the needed Morse HLA stuff, by following the HLA section in the installation notes.

Before running a distributed simulation using HLA/CERTI, it is necessary to launch the RTIG (Run Time Interface Gateway) which will basically do the synchronisation between the different simulators of the federation. So, open a console and execute:

$ rtig

We will now add our first instance to the federation, billard ,a poolroom model provided by CERTI. So, in another console, start:

$ billard -n foo -f Test -F Test.fed

where:

  • foo is the name of the ambassador in the federation
  • test is the name of the federation
  • Test.fed is the name of the file describing the FOM of the federation. It is provided by CERTI.

You can press enter, and normally, you will see a red ball moving. Stop it now.

Reflecting attributes in Morse

We will now show how to define your scenario in order to communicate with this federation.

First, we need to create one robot to reflect the ball in the poolroom.

Warning

As, for the moment, there is no dynamic creation of the robot, robot name should be carefully chosen to match instances from other federates.

foo = Morsy()

The Test.fed shows basically two interesting attributes PositionX and PositionY. In Morse, we will consider the teleport actuator to reflect the position of an external robot.

foo = Morsy()

teleport = Teleport()
foo.append(teleport)

Now, we need to connect this stuff to the HLA world. We use the test_certi_intput which is written exactly for this specific purpose.

from morse.builder import *

foo = Morsy()
foo.scale = [10.0, 10.0, 1]

teleport = Teleport()
teleport.add_stream('hla', 'morse.middleware.hla.certi_test_input.CertiTestInput')
foo.append(teleport)

env = Environment('empty')
env.configure_stream_manager(
        'hla',
        fom = 'Test.fed', name = 'Morse', federation = 'Test', sync_point
        = 'Init', time_sync = True, timestep = 1.0)

ground = bpymorse.get_object('Ground')
ground.scale = [255.0, 55.0, 0.0065]
ground.location = [250.0, 50.0, -0.06]
env.set_camera_clip(0.1, 1000)
env.set_camera_location([250, 50, 350])
env.set_camera_rotation([0.0, 0.0, 0.0])
env.set_camera_speed(10.0)

Warning

The parameters in configure_stream_manager are really important, see the hla middleware documentation for a complete description.

Note

You can play with the timestep value to see how it interacts with other simulators

Note

The ground and env configuration here is not very important, but used to look like more a poolroom.

Now, start again the billard, and in another console, morse. Normally, Morse should be blocked, waiting for the synchronisation point. Press enter in the billard console, and you should see Morsy moving according the ball movement.

Exporting attributes from Morse

Now, we will create another robot, and allow it to reflect its position in the federation. For that, we will use a pose sensor and a keyboard to control it.

bar = Morsy()
bar.translate(x = 12, y = 12)

kb = Keyboard()
bar.append(kb)

pose = Pose()
bar.append(pose)
pose.add_stream('hla', 'morse.middleware.hla.certi_test_output.CertiTestOutput')

If you start again the billard and Morse, you now must see a new black ball on the billard. Moreover, if you move the robot in Morse with the keyboard, you should see the black ball also moving in the billard.

At the end, your file must look like $MORSE_ROOT/share/morse/examples/tutorials/tutorial_hla.py.