Nonlinear coupled dynamic effects in flexure-amplified piezoelectric valve with an analytical transfer function

Abstract

There have been a number of publications on designing flow control valves with piezoelectric actuators or their amplified alternatives for potential use in high-speed fluid control devices. However, less attention is focused on the coupled and nonlinear dynamic behaviors of piezo-hydraulic systems. In the present study, it is theoretically demonstrated that the hydraulic nonlinear and coupled dynamic behaviors have a large influence on the flow characteristic of flexure-amplified piezoelectric valve. To this end, the analytical transfer function of a typical two-stage flow control valve driven by mechanically amplified piezoelectric stacks is derived to capture its coupled and nonlinear dynamic characteristics. The modeling process involves a multi-domain dynamic issue with electro-mechanical dynamics of piezoelectric stacks, elasto-mechanical dynamics of compliant mechanisms and hydraulic dynamics. The structural parameters among piezoelectric stack, compliant amplifying mechanism and hydraulics are optimally matched based on the analytical transfer function. An optimum prototype is also fabricated and experimentally evaluated. The obtained results clearly show the key role of optimizing the coupled dynamic parameters in designing flexure-amplified piezoelectric flow control valves.