Authors: J.W. Wittwer, L.L. Howell and K.W. Chase
Affilation: Brigham Young University, United States
Pages: 374 - 377
Keywords: joint clearances, precision, mechanical error
Surface micromachining of micro-electro-mechanical systems (MEMS) has inherent limitations that can lead to mechanisms having an undesirable amount of clearance in revolute and prismatic joints. In micro devices, where actua-tion of the mechanisms is often limited by the displacement capabilities of actuators, the effects of joint clearances become significant. This paper details a modeling technique that is suited to the particular sources of clearance found in surface-micromachined mechanisms. Clearance vector models are used where the clearances are represented as vectors having variable lengths and directions. The preci-sion error of any point on any rigid link can be determined, in addition to the error in link angles, by comparison with the ideal (zero clearance) model. A bistable compliant mechanism is used as an example.