Graduation Year


Document Type




Degree Granting Department

Mechanical Engineering

Major Professor

Craig Lusk, Ph.D.

Committee Member

Daniel Hess, Ph.D.

Committee Member

Jose Porteiro, Ph.D.


Bistable, Compliant, Spherical


Compliant bistable mechanisms are mechanisms that have two stable equilibrium positions within their range of motion. Their bistability is mainly due to the elasticity of their members. This thesis introduces a new type of bistable micromechanisms, the Bistable, Spherical, Compliant, four-bar Micromechanism (BSCM). Theory to predict bistable positions and configurations is also developed. Bistabilty was demonstrated through testing done on micro-prototypes. Compared to the mathematical model of the BSCM, Finite element models of the BSCM indicated important qualitative differences in the mechanism's stability behavior and its input-angle-input torque relation. The BSCM has many valuable features, such as: Two stable positions that require power only when moving from one stable position to the other, accurate and repeatable out-of-plane motion with resistance to small perturbations. The BSCM may be useful in several applications such as active Braille systems and Digital Light Processing (DLP) chips.