Flexure Design for Eight-Bar Rectilinear Motion Mechanism

Abstract

This paper replaces the hinged pivots of an eight-bar linkage with flexure joints in order to achieve a flexure-connected linkage system that guides rectilinear movement of its end-effector. The goal is a linkage design that can be reduced in size to provide a suspension for the proof masses of a MEMS gyroscope. The symmetric design of the linkage and its long travel relative to other MEMS suspensions has the potential to provide a number of advantages, such as the reduction of quadrature error. The design presented yields 0.1% deviation over its range of movement. An example also presents the driving linkage of the MEMS gyroscope, which is also designed as flexure connected linkage. INTRODUCTIONThis paper presents an eight-bar linkage in which the hinged pivots have been replaced by flexures in order to guide the rectilinear movement of a MEMS gyroscope. The flexure-connected eight-bar linkage provides a long-travel rectilinear suspension for the proof masses in the MEMS gyroscope, which reduces quadrature error.Existing rectilinear motion linkages have 10 bars, see Kempe (1877) [4]. Our goal is an eight-bar linkage that guides rectilinear movement with low error and with no link overlap so the hinged joints can be replaced with flexures. A flexure allows movement through bending of its elements. An example of application of flexure pivots can be seen from a 2-DOF flexure