At present staging branch of the UR ROS driver provides the cartesian position control. However, the repository mentioned in the setup instructions for the robot description files only includes the xacro files for CB3 series robots. If my understanding is correct, there are significant physical difference between CB3 series and e series of robots, and this difference will result into incorrect inverse kinematics model.
How the cartesian control algorithm incorporating these differences without the robot model ?
Please have a look at the calibration_devel branch as mentioned inside the documentation. This contains descriptions for all 7 robot models.
Apologies for missing the branch specifier.