Add position controller for head link

[AndriyPt]

Add position controller to head link the same way as it was done for version 1.0

[MaxZhaloba]

Hi @AndriyPt

I've added the description of head controller to the branch F#136_head_controller but I don't know how to test it.

When I switch to the v1.0 branch, build the project and start simulation, I get such errors:

[INFO] [1545413762.385352, 8180.376000]: Controller Spawner: Loaded controllers: head_position_controller, joint_state_controller, wheel_diff_drive_controller
[INFO] [1545413762.392877, 8180.386000]: Started controllers: head_position_controller, joint_state_controller, wheel_diff_drive_controller
/opt/ros/kinetic/lib/gazebo_ros/gzserver: line 41: 18033 Segmentation fault      (core dumped) GAZEBO_MASTER_URI="$desired_master_uri" GAZEBO_MODEL_DATABASE_URI="$desired_model_database_uri" gzserver $final
[gazebo-2] process has died [pid 17991, exit code 139, cmd /opt/ros/kinetic/lib/gazebo_ros/gzserver --verbose -e ode /home/user/workspace/leobot/base/src/leobot/leobot_gazebo/worlds/artgallery.world __name:=gazebo __log:=/home/user/.ros/log/ddc0bd5e-0546-11e9-85ce-0242ac110002/gazebo-2.log].
log file: /home/user/.ros/log/ddc0bd5e-0546-11e9-85ce-0242ac110002/gazebo-2*.log

Then sending messages to head controller doesn't rotate the head in v1.0 branch.

rostopic pub /head_position_controller/command std_msgs/Float64 0.5

Please advice how to approach this issue.

[AndriyPt]

Hello @MaxZhaloba :)
Why are you switching to v1.0 branch?
In you branch please launch simulation and your controller. List topics using rostopic list command and send position command to your controller. Head should rotate. If not please debug the issue.

[MaxZhaloba]

I haven't found the root cause of segmentation fault issue but after I rebuilt the container this error doesn't occur every time.

I'm using the following command to rotate the camera link:

rostopic pub /head_position_controller/command std_msgs/Float64 0.8