Development and assessment of a novel hydraulic displacement amplifier for piezo-actuated large stroke precision positioning

In recent years, piezo-actuated micro/nano positioning stages emerge as a significant tool in the nanotechnology. However, the shortcomings of small positioning stroke and hysteresis of piezoelectric actuators have constrained their further development and applications. In this paper, a novel piezo-actuated hydraulic displacement amplifier (PHDA) based on Pascal´s law and area differential principle is first proposed aiming to solve the contradictions among positioning stroke, positioning resolution and mechanism dimension in piezo-actuated micro/nano positioning stages. After a series of optimal designs, the proposed PHDA mechanism is fabricated and experimentally tested. In this study, a piezoelectric (PZT) actuator P-840.20 with open-loop travel of 30 μm is employed, the experimental results indicate that the displacement amplification ratio can reach up to 34.6, thus the maximum output displacement can achieve up to around 1.02 mm. Both theoretical derivation and prototype test results testify the well performance of the proposed mechanism. This new amplifier can be widely extended to practical precision manipulation applications in case of large motion range required.