Use the change controllers plugin to either change the control type PWM - Torque or load different types of controllers. Simply click on one of the controller type buttons, and it will call a service from the pr2_controller_manager to unload the currently running controllers if necessary, and load the ones you selected. You can also stop the currently running controller from this plugin. If you change the control type (PWM - Torque) the controller type buttons will become unresponsive for 3 seconds while waiting for the motor control hardware to complete the change.