The Dynamixel package that is provided by ROS is really useful to control multi-joint manipulators or mobile robots using Dynamixel motors. It’s possible to find a nice tutorial here.
One tutorial about the torque joint controller can be found here. The detail is that, in order to get this step-by-step working, you should setup the motor to wheel mode ON. For this, there is some scripts in the dynamixel package. Which you can install from apt-get as usual.
Using the package you could run:
$ rosrun dynamixel_driver info_dump.py -p /dev/ttyUSB0 10
To get some information about your motors, and:
$rosrun dynamixel_driver set_servo_config.py --ccw-angle-limit=0 -p /dev/ttyUSB0 10
To change your motor (in this case id = 10), to wheel mode on. To change it back make sure you set --ccw-angle-limit=1023 or the max value your motor supports.
That’s all.