A Bidirectional Linear Piezoelectric Actuator With High Resolution and Output Maintained Capability

Linear piezoelectric actuators (LPAs) have been widely utilized in precision positioning for their high resolution, fast response, and high stiffness. Existing LPAs are still bothered by returning to their original position when powered off, and usually cannot output bidirectional symmetry displacement due to the utilization of PZT stacks. In this work, an LPA with output maintained capability is proposed, which can output bidirectional symmetry displacement by the designed bidirectional linear device, and it can maintain output displacement when powered off by the cooperation of the linear and clamping devices. A static model is established and validated using finite element methods (FEMs) and experiments. A prototype is fabricated and output characteristics experiments are performed. The experiment results show that the LPA achieves an output range of −6.22 to 5.78 μm and could maintain a displacement range of −3.81 to 3.57 μm when powered off. The output displacement and maintained displacement decreased by 3.9% and 21.1% under a large load of 25 N. A high resolution of 2.0 nm is achieved under a 5 mV step signal. The proposed LPA realizes the curvature adjustment of mirrors and provides a new method for optical system focusing.