Nonlinear characteristics of compliant bridge-type displacement amplification mechanisms

Compliant bridge-type mechanisms have been extensively utilized as displacement amplifiers, but most of the existing mathematical models were developed based on linear assumptions, incapable of revealing nonlinear characteristics. In this paper, an arm is regarded as a variable thickness beam that covers both lumped and distributed configurations, and thus a nonlinear closed-form model of compliant bridge-type mechanisms is developed through considering load effect. Then, application limitations, displacement amplification ratio, input compliance, and influence of actuator are discussed to quantitatively evaluate the influences of design parameters and capture the nonlinear characteristics of compliant bridge-type mechanisms. Finally, the analytical model is verified by finite element analysis (FEA) and experiments, and the results show that the proposed model can accurately predict the deformation of compliant bridge-type mechanisms.