Development of an Ultra‑Light Micro Servo with High Torque Density

As a key actuator for precise position control in compact mechanical and electronic systems, the micro servo is widely used in micro unmanned aerial vehicles (UAVs), missile warheads, robotic joints, and tactical communication terminals. Targeting the design challenges of ≤ 0.5 g-class servos—namely torque density, dynamic response, and disturbance rejection—this study proposes and implements an integrated scheme based on a coreless cup micro DC motor, a hybrid reduction mechanism combining a worm and a sector gear, an off-axis 3D Hall sensor calibration system, and a 3.3 V single-supply drive and control circuit. A first-edition prototype, independently tested, achieved a rotation travel of 149°, total mass of 0.617 g, dynamic response time of 76 ms, 4.6% overshoot, and 0.8% steady-state error, validating the feasibility and advantages of the design.