Purely Central Piezoelectric Stick-slip Rotary Stage without Driving Redundancy

Given the performance requirements of large rotation angle, high resolution, high load capacity, and compact structure in precision posture adjustment, a purely central stick-slip rotary stage with force magnification characteristics is designed using a piezoelectric actuator to drive compliant mechanisms. Actuation redundancy is avoided by single-actuator driving, meanwhile the clamping force magnification characteristics can be regulated by changing the tilt angle of the bridge driving mechanism. Firstly, compliant mechanisms with hybrid straight circular and leaf-type flexible hinges are used to design a bridge mechanism containing a pair of centrosymmetric driving feet, which are combined with a circular slide to achieve non-redundant, purely central rotation while magnifying the clamping force. Then, the single-step rotation angle, force magnification, and stress of the rotary stage are analyzed by finite element simulation and compared with the theoretical calculation. Finally, an experimental test platform is built to verify the performance of the designed rotary stage. The overall size of the rotary stage is 86 mm×86 mm×32 mm, and the maximum load in experiments is 9 kg with a 150 V input voltage. Also, the angular resolution is 0.10 μrad.