Adds a simple demo with multiple robots lifting the same overweight block

[arjo129]

Note: Not sure if we really should be keeping this stuff in mbzir_ign or we should have a mbzirc_demos package.

This demo demonstrates using multiple robots to lift the same overweight block.

Requires gazebosim/gz-physics#345

To Test (Edited by Aaron)

Make sure you have the right branch of gz-physics set up. Launch the test world file:

ign gazebo /your/path/to/mbzirc_ws/src/mbzirc/mbzirc_ign/worlds/test/multi_drone_lift.sdf

In another terminal run:

ros2 launch mbzirc_ign multi_uav_lift_demo.launch.py

You should see the drones spawn. After that run the simulators and let the robots fall onto the block. When the robots are resting on the block run:

ros2 run mbzirc_ign multi_uav_demo.py -z 3

You should see the robots lift the block up.

For the dragging demo, replace the above steps with

# launch world
ign gazebo /your/path/to/mbzirc_ws/src/mbzirc/mbzirc_ign/worlds/test/multi_drone_drag.sdf

# launch demo
ros2 launch mbzirc_ign multi_uav_drag_demo.launch.py

# start drones
ros2 run mbzirc_ign multi_uav_demo.py -z 3 -x 1 -y 4

# to detach
ros2 run mbzirc_ign multi_uav_demo.py -d

Signed-off-by: Arjo Chakravarty arjo@openrobotics.org

[iche033]

works for me!

[iche033]

Note: Not sure if we really should be keeping this stuff in mbzir_ign or we should have a mbzirc_demos package.

yeah if we end up adding more examples in the future, we can add a separate package for them

[iche033]

CI looks good. Merging first. Will still require gazebosim/gz-physics#352 to work