Development,modeling and analysis of a differential lever-bridge amplification mechanism

The displacement amplification mechanism is commonly utilized in micro/nano-manipulating systems to enhance the output stroke of piezoelectric actuators. Aiming at large amplification ratio, this paper proposes a symmetrical dual-stage amplification mechanism consisting of a differential lever mechanism and a half-bridge mechanism. With consideration of the coupling effect between the dual-stage amplification mechanism, a kinematic modeling method is developed for the symmetrical differential lever-bridge hybrid (SDLBH) mechanism on top of the static balance and constraint conditions of the branch chain. In particular, the force-deformation relationship of the flexible hinge is derived according to the flexibility matrix method. Based on the path constraint conditions of the branch chain, the static equilibrium equation as well as the displacement constraint conditions are obtained. Consequently, the input-output model of the SDLBH mechanism is established, which is capable of accurately predicting the amplification ratio and the mechanical stiffness. Finite element simulations and real time experiments on the SDLBH prototype effectively validate the mechanical performance as well as the accuracy of proposed modeling method. The performance sensitivity of the developed SDLBH mechanism is further analyzed by the Taguchi method, aiming to offer the optimization guideline for real applications.