Purpose of Forward Command Controller

edit

Short answer not really:

You can see it in the source code. For position_controllers/JointGroupPositionControllerhttps://github.com/ros-controls/ros_c...

void forward_command_controller::ForwardCommandController<T>::starting(const ros::Time& time)
{
  // Start controller with current joint position
  command_buffer_.writeFromNonRT(joint_.getPosition());
}

For velocity_controllers/JointGroupVelocityController: https://github.com/ros-controls/ros_c...

void forward_command_controller::ForwardJointGroupCommandController<T>::starting(const ros::Time& time)
{
  // Start controller with 0.0 velocities
  commands_buffer_.readFromRT()->assign(n_joints_, 0.0);
}

They both make use of Forward Command Controllerclass but not doing exactly same function.