Design, modeling and testing of a novel flexure-based displacement amplification mechanism

This paper presents a novel flexure-based displacement amplification mechanism to increase the effective actuation stroke of piezoelectric actuator. The proposed mechanism consists of two L-shape lever-type mechanism and one bridge-type mechanism. The flexure hinges in this mechanism are all loaded in tension and bending, which can solve the potential buckling problems. The symmetrical distribution of the L-shape lever mechanisms can avoid the bending moments and lateral forces at the driving end to protect the piezoelectric actuator. An analytical model based on the stiffness matrix method for the calculations of displacement amplification ratio, input stiffness and natural frequency of the mechanism is constructed and optimal design is performed under certain constraints. The finite element analysis results are then given to validate the design model and a prototype of the amplification mechanism is fabricated for performances tests. The results of static and dynamic tests show that the proposed mechanism is capable of travel range of 288.3 μm with motion resolution of 50 nm, and the working resonance frequencies of the mechanism without and with the actuator mounted are 155 Hz and 178 Hz, respectively. The finite element analysis and the experimental results show that good static and dynamic performances are achieved, which verifies the effectiveness of the proposed mechanism.