Compliant leverage mechanism design for MEMS applications

Compliant microleverage mechanisms, including single- and multistage, can be used in micro-electro-mechanical system (MEMS) to transfer an input force/displacement to an output to achieve mechanical and/or geometry advantages. This thesis presents the original systematical study on this mechanism with primary focus on the design theory and synthesis issues of the mechanism.; Starting from the basic nomenclature, definition and classification of the mechanism, an extensive first-order analytical model and a second-order refined one are built for the single-stage microleverage mechanism, the basic element of all microleverage mechanisms. The amplification factor depends not only on the ideal leverage ratio (L/l), the geometry of the lever, but also the axial and bending spring constant of the output system. Good agreement is obtained between the results of second-order analytical modeling and those of FEM simulation with SUGAR, a MEMS simulation tool.; The compliance match theory developed applies to the two-stage microleverage mechanism. The axial spring constant of the lever stage close to the output needs to be in a specific region (Region II and III) in order for the entire mechanism to effectively amplify force. The increased resistance of a microlever to rotational or axial displacement when the output and pivot are at the different side of the lever arm leads to lower amplification factor.; The maximum amplification factor of a multistage microlever was derived in terms of the given output system and minimum flexure beam dimension. The design of microleverage mechanism in a resonant accelerometer is illustrated at each step to present the theory. The leverage mechanism for displacement amplification is analyzed with application in a disk-drive suspension and a micro-valve.; Experimental verification of the analytical equations and SUGAR simulation was carried out at both the micro- and macro-scale. A 1S-2D (first stage first kind lever with output and pivot at same side, second stage second kind with pivot and output at different side) type of mechanism was fabricated by the SOI-MEMS process for inertial force amplification in a resonant accelerometer. A macro-scale aluminum model was built and the testing results agree qualitatively with the analytical and SUGAR predictions.