The base retains a differential drive, although pulleys now apply a 10:1 gear ratio to the smart servos on joints 1/2 and 3 -- shown above. This gear ratio increases the servos' precision from 0.29 degrees to 0.029 degrees, assuming the belts are under tension and do not slip. Also because of this gear ratio, Dynamixel AX-12A servos allow the manipulator to operate at 1/8 of the servos' stall torque. Dynamixel recommends operating at no more than 1/5 of the stall torque for smooth motions. Since these servos are 1/3 the cost of those listed in the conceptual design, the manipulator's cost decreases. Some of this recuperated cost will purchase the timing belts/pulleys.

The motor dynamics must be separated from the smart servo's built-in controller. An experimental method will use empirical feedback data to model the motor independent of the controller. The closed loop simulation will include the controller, while the open loop simulation will not.

For the open loop simulation, each rigid body must have its motion modeled. As such the inverse kinematics are based on motor angles rather than angles corresponding to the manipulator's geometry. The manipulator thus contains the differential gears for a total of 10 rigid bodies. Despite not having mass parameters including the pulleys, the open loop simulation will be verified before next Monday.