multiplexing between two topic

Hi i am using P3AT(USARSim simulator) and want to drive it from my **ROS-Fuerte**. what i want to do is, 1. Driving the robot using keyboard (using teleop_twist_keyboard) 2. Automated navigation of robot (using Navigation stack) I want to drive the robot using keyboard but when i commit mistake(i.e. approaching to hit a wall) the automated behavior need to be activated. by following [this](http://wiki.ros.org/cmd_vel_mux), i have my configuration file **example_cfg.yaml** subscribers: - name: "Human_is_Driving" topic: "teleop_cmd_vel" timeout: 0.5 priority: 5 - name: "MACHINE_TAKES_OVER" topic: "auto_cmd_vel" timeout: 0.5 priority: 5 publisher: "velocity_multiplexer/mux_cmd_vel" **standalone.launch** **resulting rqt graphs of** 1. [teleoperation](https://www.dropbox.com/s/91x7g395wb2n10i/rqt_graph_teleop.png?dl=0) 2. [automated navigation](https://www.dropbox.com/s/iqcy1vnzwxobi92/rqt_graph_move_base.png?dl=0) i am not able to understand the complexity of the problem. please help me to understand ***"how can i switch between cmd_vel used by teleop & cmd_vel used by move_base"***