Hello Lara,
Though it is possible to control the UR robots via RTDE using MATLAB, the setup process involves certain additional steps and we do not officially support the RTDE interface right now. If you have already established a connection with MATLAB and UR manipulator using RTDE, you can use the motion planning and trajectory generation tools from Robotics System Toolbox to calculate joint configuration or joint trajectory to acheive desired cartesian control.
With the Robotics System Toolbox™ Support Package for Manipulators, we have added a functionality to control the simulated UR manipulator in Gazebo or URSim using MATLAB and ROS interface. You can also refer to the Simulate a Universal Robots UR5 Using MATLAB and Gazebo for Glue Dispensing on a Windshield example to know more about usage of Robotics System Toolbox™ tools for motion planning. Even though we have not verified the functionalities of universalrobot object, available in the support package, with actual hardware, you can refer to this page for some considerations for hardware connection.
