A large subjective error and low measurement efficiency occurs as a result of manual movement and measurement in a traditional Articulated Arm Coordinate Measuring Machine (AACMM) to solve the problem of worse path planning, In this case, it is difficult to adapt the system to the new requirements of online automatic measuring systems. As such, the concept of a self-driven AACMM is proposed which includes a brushless motor and a harmonic reducer, and demonstrates precise shafting in its articulation. A structure for the modular articulation and the torsion estimating model is also proposed. A prototype and experimental device of the Joint2 with a measurement and control circuit, motor and harmonic reducer were built to evaluate the performance and facilitate a series of repeatability experiments. A prototype with a single joint component was developed and repeatability experiments were performed. The single direction measurement data show that to ensure a small repeatability error, the joints should avoid drastic changes in velocity or acceleration when in motion. The data from the measurement of both sides show that when the motor speed of the control machine is less than 1.53 rad/s, the probability that the probe will produce a false trigger signal is small, and the repeatability error is ±2.11″. The experiment also verifies the feasibility of the modular articulation design scheme. These research findings provide a theoretical and experimental basis for studying completely self-driven AACMM.