A general two-port dynamic stiffness model and static/dynamic comparison for three bridge-type flexure displacement amplifiers. (15th March 2019) - Ling, Mingxiang
Highlights: A two-port dynamic stiffness model is built for three bridge-type amplifiers. Kinetostatics and dynamics can be calculated with the same model. Optimal geometric parameters are found and analyzed. The three amplifiers are compared in terms of kinetostatics and dynamics. Several design criteria are summarized and recommended. Abstract: Bridge-type compliant mechanisms (BTCM) are frequently used as displacement amplifiers in the precision manipulation. There have been a considerable number of studies on the kinetostatic modeling and analysis of BTCM in the past decade but less on the dynamics or finding optimal geometric parameters in terms of both kinetostatics and dynamics. To this end, this paper presents a two-port dynamic stiffness model to describe the simultaneous kinetostatics and dynamics of three popular bridge-type compliant mechanisms from the perspective of input and output ports. The displacement amplification ratio, input/output stiffness, natural frequencies and dynamic response of these three BTCM can be efficiently and accurately solved just by changing geometric parameters with the same model. With the two-port dynamic stiffness model, the dynamic modeling of BTCM is simplified as a statics-similar problem differing from the ubiquitous Lagrange-based dynamic methods in previous studies. Of particular interest for model application is to exploit the optimal geometric parameters in each BTCM and then compare the three BTCM in terms of kinetostatics and dynamics to provide quantitative insight for designers. At last, several design criteria for these BTCM are summarized and recommended based on the parameter influence analysis. In particular, the rhombic amplifier has higher dynamic frequency and smaller input stiffness under the same output displacement, while the parallel and aligned amplifiers have larger output stiffness which is benefit for providing larger output force.