Ultra Miniaturized Absolute Rotary Encoder Integrated into Hinge Joint

In minimally invasive endoscopy systems, traditional optical tracking solutions commonly employed in computer-assisted surgeries are not applicable due to the lack of line-of-sight. Electromagnetic tracking (EMT), in contrast, has been used as an alternative, but it is limited by its susceptibility to interference from metal objects. The accuracy achieved with EMT is often inadequate for many applications. To address this limitation, for endoscopes based on rotational joints, we propose a novel solution: a miniature absolute rotary encoder integrated into a hinge joint. Our system characterization reveals excellent performance, with a precision of 0.0009° (corresponding to a resolution of 13 bit over a range of 45°) and an accuracy of ±0.2°. These results are achieved within a compact footprint of 2 × 1.5 × 1 mm³, making it suitable for integration into minimally invasive endoscopy systems.