The Dynamixel

To build a mini robot you need to have small motors to drive the articulation of each joint. In Hubo's case It uses a complex set of multiple motors and drive belts in combination with Harmonic Drive systems to produce movements and have holding torque to stand and move. This method work wonders for Hubo but is not a good system for a small system for reasons that it is bulky and very expensive. On top of the mechanical complexity it needs to have custom motor controllers to drive the motor train as well. Small Humanoids can use a off the self package that includes a motor, gear set, encoder, and controller. These servos are far more cost effective, light weight, and have far less overhead to program the included controller. The servo package we chose for this project is the Robotis Dynamixel. Robotis is actually a Korean based Company that sells robot kits such as the Bioliod Humanoid. They sell many other accessories and servos for people interested in building custom Humanoids like ourselves. We deiced to go with the RX-28 that supplies 28N.m of torque for leg servos and RX-10 (10N.m) for the upper body.