Development of a stator-rotor integrated piezoelectric actuator for precise joint rotation of the robotic arm

Piezoelectric rotary actuators are widely used for their high precision and large torque in various fields, such as optical engineering and aerospace. However, traditional piezoelectric rotary motors have a complex structure, requiring separate stator and rotor fixing devices, and they have a low space utilization rate, making them unsuitable for driving joint rotation of robotic arms. To address these issues, a novel stator-rotor integrated piezoelectric actuator is proposed in this paper, which uses the piezoelectric vibrator as both the driving vibration source and the rotor, simplifying the overall structure of the rotary actuator. By using in-plane longitudinal and out-of-plane bending vibration, the actuator achieves high-precision rotation along the diameter of a circular ring, while also providing a hollow structure for optical fibers and wires. Through parametric scanning finite element analysis, the size parameters of the annular rotor are determined. The contact conditions of stator and rotor is analyzed, and an intermittent contact model between stator and rotor is established. The experimental results show that the prototype motor weighs 52 g, has a rotation speed of 1470 deg/s, can bear a load of 63 mN m, and has a minimum resolution of 72 grad. This research demonstrates the great potential of this rotating actuator for use in space optical instruments and aerospace applications.