Add Oberon7 arm and gripper

[iche033]

Replaces #68

Depends on gazebosim/gz-sim#1405 and gazebosim/gz-sim#1406

Ported and integrated the oberon7 arm from DAVE / UUV simulator. The arm and gripper model.sdf files are generated using urdf files from:
https://github.com/Field-Robotics-Lab/uuv_manipulators/tree/master/oberon7/oberon7_description
https://github.com/Field-Robotics-Lab/dave/tree/master/urdf/manipulators/dave_oberon7_description

The spawn launch file is updated to take two additional arguments: arm and gripper to specify the arm and gripper model to use. Currently we only have one arm but we will need be able to swap out the oberon7 gripper with the suction gripper from #63.

The arm must be spawned with the usv. Currently it only has one mounting position on the usv for the arm. More maybe added in the future.

Usage:

# launch simple demo world
ros2 launch ros_ign_gazebo ign_gazebo.launch.py ign_args:="-v 4 -r simple_demo.sdf"

# spawn usv with oberon7 arm and oberon7 gripper.
# if gripper is not specified, it'll just use the default one which is the oberon7 gripper
ros2 launch mbzirc_ign spawn.launch.py name:=usv world:=simple_demo model:=usv type:=usv x:=15 y:=0 z:=0.3 R:=0 P:=0 Y:=0 arm:=mbzirc_oberon7_arm gripper:=mbzirc_oberon7_gripper

Try publishing topics to control the arm and gripper joints:

# arm
ros2 topic pub --once /usv/arm/joint/azimuth/cmd_pos std_msgs/msg/Float64 'data: 0.5'
ros2 topic pub --once /usv/arm/joint/shoulder/cmd_pos std_msgs/msg/Float64 'data: 0.5'
ros2 topic pub --once /usv/arm/joint/elbow/cmd_pos std_msgs/msg/Float64 'data: 0.5'
ros2 topic pub --once /usv/arm/joint/roll/cmd_pos std_msgs/msg/Float64 'data: 0.5'
ros2 topic pub --once /usv/arm/joint/pitch/cmd_pos std_msgs/msg/Float64 'data: 0.5'
ros2 topic pub --once /usv/arm/joint/wrist/cmd_pos std_msgs/msg/Float64 'data: 0.5'
# gripper
ros2 topic pub --once /usv/arm/gripper/joint/finger_left/cmd_pos std_msgs/msg/Float64 'data: 0.5'
ros2 topic pub --once /usv/arm/gripper/joint/finger_right/cmd_pos std_msgs/msg/Float64 'data: 0.5'

You can also echo the joint states

ros2 topic echo /usv/arm/joint_states

ros2 topic echo /usv/arm/gripper/joint_states

Here's the tf tree:

[caguero]

I'm following your instructions but I don't see the arm mounted in the USV when I run: ros2 launch mbzirc_ign spawn.launch.py name:=usv world:=simple_demo model:=usv type:=usv x:=15 y:=0 z:=0.3 R:=0 P:=0 Y:=0 arm:=mbzirc_oberon7_arm gripper:=mbzirc_oberon7_gripper

[caguero]

Just checking, should this topic be the same as the one used for the arm joint states?

[iche033]

I've seen both cases before:

• /joint_states
• /<namespace>/joint_states

I think other packages like moveit subscribes to /joint_states by default but can be configured to subscribe to namespaced topics.

I changed to the form /<namespace>/joint_states for the arm and gripper in 00ed7c1. It's now:

/usv/arm/joint_states
/usv/arm/gripper/joint_states

The user can remap them back to /joint_states if they wish.

[caguero]

```shell
ros2 launch mbzirc_ign spawn.launch.py name:=usv world:=simple_demo model:=usv type:=usv x:=15 y:=0 z:=0.3 R:=0 P:=0 Y:=0 arm:=mbzirc_oberon7_arm gripper:=mbzirc_oberon7_gripper

Forget this comment, I can see the arm now after cleaning and rebuilding.

[caguero]

The fingers of the gripper start completely closed. I can open the fingers but I can't close them entirely anymore.

[iche033]

The fingers of the gripper start completely closed. I can open the fingers but I can't close them entirely anymore.

hmm I'm trying to reproduce this. Here's what I'm doing but I see that the fingers are able to close. What are the joint cmds you're using?

# open gripper
ros2 topic pub --once /usv/arm/gripper/joint/finger_right/cmd_pos std_msgs/msg/Float64 'data: 1'
ros2 topic pub --once /usv/arm/gripper/joint/finger_left/cmd_pos std_msgs/msg/Float64 'data: 1'

# close gripper
ros2 topic pub --once /usv/arm/gripper/joint/finger_right/cmd_pos std_msgs/msg/Float64 'data: 0'
ros2 topic pub --once /usv/arm/gripper/joint/finger_left/cmd_pos std_msgs/msg/Float64 'data: 0'

[caguero]

ros2 topic pub --once /usv/arm/gripper/joint/finger_right/cmd_pos std_msgs/msg/Float64 'data: 1'

Works for me as well. It was doing it in the wrong way.

[caguero]

Ready to approve, just a minor question about the joint states from the gripper.