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A 2-DOF Monolithic Compliant Rotation Platform Driven by Piezoelectric Actuators

To realize high-precision rotation angle adjustment in micro-/nanomanipulation, a novel monolithic two-degrees-of-freedom (2-DOF) pure rotation platform is designed, fabricated, and tested in this article. The rotation platform is driven by two piezoelectric actuators. Rotation decoupling is realized based on three Hooke's joints, and a large rotation range is obtained based on two bridge-type mechanisms. Compared with other rotation platforms, the developed 2-DOF pure rotation platform has the advantages of fewer actuators due to rotation decoupling design and larger working frequency range due to compact structure and monolithic fabrication. An analytical model is established to calculate transmission ratio and input stiffness. The dominant parameters are determined based on sensitivity analysis. Finite-element analysis is conducted to investigate the characteristics of the rotation platform. Experimental tests are carried out to investigate the performance of the rotation platform. Decoupling test results show that the maximum rotation angles in the X- and Y-axis are 2.04 and 2.12 mrad, respectively, and the X- and Y-axis relative coupling errors are 2.03% and 2.09%, respectively. Closed-loop control results show that the settling time is 40 ms and the resolutions in both X- and Y-axis are 5 μrad.