The solution is increase the value of the safetycontrollerk_vel parameter in the file "iiwa14.xacro", which is the model that i am using, and it started to work properly. I haven't got time to see what to do this parameter so it isn't good adjust. I wrote 2.8 (line 14 in my iiwa14.xacro file)instead of 2, that was the default value.

If could anyone help to know how to configure safetycontrollerk_vel parameter i will really aprecciate it.

You should use "yourmodelrobotxacrofile.xacro".

ATTENTION: The next file is .xacro not .cpp but gazebo forum didn't let me upload in .xacro format.

C:\fakepath\iiwa14.cpp

Next, I explain in detail my failure.

I'm using in gazebo the iiwa 14 robot from Salvatore Virga stack: https://github.com/IFL-CAMP/iiwa_stack.

I want to command the robot by effort and to measure the efforts from each joint so i change the default Hardware Interface " PositionJointInterface " for " EffortJointInterface "

C:\fakepath\iiwa_gazebo.launch

The problem is that the joint 2 hasn't got force enough to move the robot and it went down to the floor. Firstly i believed that it was a pid problem by a bad setting of proportional, derivative and integral values. After i tested high and small pid values the failure continue so i was looking for in the differents files about limitation in the effort.

C:\fakepath\iiwa_control.yaml

But i discovered that the limitation wasn't in the effort if not in the velocity ( safetycontrollerk_vel) because i used higher values for:

           max_effort
           max_velocity
           joint_damping

And the robot continued without it can't move its joint 2. But increasing the safetycontrollerk_vel, it is fix.