Design and Control of a Flexure Microscopic Rotation Converter With Submicroradian Resolution

Microscopic rotation plays a pivotal role in achieving precise alignment across diverse scientific and technological domains. To achieve submicroradian resolution, a flexure microscopic rotation converter that transforms translational input into refined rotation is proposed. By serially connecting a differential displacement reducer and a Scott–Russell inverter, the device inverts and significantly reduces translational input to generate high-precision rotation. A kinetostatic model was developed to optimize the converter’s parameters, specifically aiming to minimize conversion ratio variation. The conversion performances of the optimized design were validated by a finite element model. The prototype test shows that the average conversion ratio is 1 µrad/µm with a linearity of 0.44%. By adopting an internal model controller, the microscopic rotation converter achieves dynamic performance with tracking error less than 5.31% across the frequency range from 1 to 100 Hz.