A Novel Flexure Piezomotor with Minimized Backward and Nonlinear Motion Effect

Continuous, smooth, and highly linear displacement output with centimeter-scale stroke and nanometer-scale resolution is greatly attractive for an ultraprecision positioning system. On the foundation of piezoelectric actuation and compliant mechanism, a novel linear piezomotor with minimized backward and nonlinear motion property is designed. Specifically, a driving unit capable of $xy$ -direction decoupling displacement output is proposed to make the generated motion linear, and a flexure mechanism is introduced into the contact part to make the motion output continuous and nonbackward. Combined with double driving units and the flexure contact mechanism, a motion generation strategy is presented. For performing the motion generation strategy well, the kinematics model of the piezomotor is established. Then, the dimension parameters are optimized. After theoretical derivations, the piezomotor is analyzed and evaluated by finite-element analysis simulation. Finally, a proper control waveform is designed, and the motion generation performance tests are successfully carried out. The results uniformly confirm that the proposed piezomotor can output ultraprecision motion with 8-nm resolution and 10-mm stroke in a continuous and smooth manner, and the backward and nonlinear effects are successfully minimized within 100 Hz.