UCLA · Translational 1-DOF Compliant Micro-Mirror

Designed and analyzed a flexure-based micro-mirror for high-speed translational motion targeting adaptive optics and LiDAR applications. Using the Freedom and Constraint Topologies (FACT) design methodology, two distinct compliant mechanism topologies were synthesized and compared to achieve a 1-DOF translational degree of freedom while eliminating parasitic errors and avoiding under/over-constraint conditions.

The selected final design employs six hybrid limbs arranged in a symmetric, axisymmetric configuration around a 1 mm² circular mirror stage. Each limb contributes a 5-DOF type-1 freedom space, and their combination — over-constrained by one degree for symmetry-driven precision — produces a purely translational output with the center of mass coinciding with the center of stiffness. This alignment eliminates differential static/dynamic actuation behavior, enabling a single linear actuator to drive the system.

Performance was validated through analytical twist-wrench mass and stiffness matrix analysis in MATLAB, confirmed by FEA in SolidWorks using silicon material properties. Results: first natural frequency 11,667.8 rad/s (1,857 Hz), second natural frequency 146,869.4 rad/s (23,375 Hz) — satisfying the required order-of-magnitude separation between modes. The design is thermally stable, microfabricable via 3D printing as a single part, and estimated to cost under $5 in material.