Design of a Flexible Hinge for an Atmospheric Dispersion Corrector

Compliant mechanisms often have the ad-vantage of high precision at the cost of a lim-ited range of motion. In this research, a hol-low compliant hinge is developed for use in an Atmospheric Dispersion Corrector (ADC) com-monly found in large telescopes. This device contains two sets of optical prisms to correct for the unwanted dispersion effect that occurs when light meets the atmosphere under an an-gle. These prisms must perform a near-pure rotation around the optical axis, which must not be obstructed by the geometry of the ADC. This study strives to achieve the required deflec-tion range of a single Degree of Freedom design while having sufficiently high unwanted eigen-frequencies, support stiffness, and low stress levels. Many concepts were developed using the software SPACAR Light, of which two could be optimized to meet the requirements of the ADC. Furthermore, the final concepts were modeled in the software SolidWorks and simulated in the Finite Element Method software Ansys. The research showed that a large stroke in combination with low stress levels and high support stiffness is possible through radially symmetric compounded designs. However, a compounded design is underconstrained and has low associated unwanted eigenfrequencies. Both high kinematic- and dynamic performance is achieved through the addition of a kine-matic coupler, or synchronizer. A design called the Compounded Torsion Pivot (CTP) is ex-plored with the addition of such a synchronizer. The monolithic design called the Large Angle Flexure Pivot (LAFP) is also analyzed and ex-panded with a synchronizer. While both de-signs meet the requirements for the ADC, the LAFP ultimately outperforms the CTP with bet-ter kinematic- and dynamic characteristics. Fur-thermore, the LAFP is easier to produce using a combination of Wire EDM and milling.