Joselito (Jose) Macabante was born and raised on Oahu. He is currently a senior at the University of Hawaii at Manoa, pursuing a Bachelor of Science in Mechanical Engineering. Jose currently serves as the Secretary of the American Society of Mechanical Engineers (ASME) UH M?noa collegiate chapter as well as being a Pledge in Pi Tau Sigma, the International Honor Society for Mechanical Engineering. Jose is also a Peer Mentor at Kapi?olani Community College ?Imi Na?auao Peer Mentor Program. He hopes to gain real-world problem solving and project experience from this opportunity. In his free time, he enjoys playing video games, listening to music, and working out.
Home Island: Oahu
High School:Â
Institution when accepted: University of Hawaii at Manoa
Designing Encoder-Based Position & Velocity Feedback System Concepts for DKIST’s Aperture Cover
Project Site:Â Daniel K. Inouye Solar Telescope, Pukalani, HI
Mentors: James Hoag, Gary Foster & Wade Bortz
Project Abstract:
The Daniel K. Inouye Solar Telescope (DKIST) is the most powerful solar observatory in the world and is designed to revolutionize our understanding of the Sun and its dynamic processes. Currently, the position feedback system of the DKIST’s aperture cover relies solely on end-of-travel limit switches, so only three position states can be determined: closed, in-between (during motion), and open. This system provides no feedback on the aperture cover’s position during the in-between stage, with the entire process taking about two minutes. Furthermore, variations in the load on the aperture cover at a shutter altitude greater than 20° can cause the cover to stick at the in-between position, failing to trigger the upper limit switch. This lack of confirmed open or closed position readings prevents the subsequent proper inflation of the cover seals. Although the drive assemblies on the aperture cover contain motor encoders that can be used to interpolate the cover’s position from the rotation of the drive assembly, initial findings using the interpolated values have shown some inconsistencies. In order to address these issues, and to provide a more accurate positional measurement of the aperture cover during the open and close process, design concepts for a new position and velocity sensing encoder-based system were created and analyzed using SolidWorks. The proposed design concepts aim to address these issues by providing operators with an instantaneous readout of the aperture cover’s precise position and velocity during the open and close process. Multiple encoder-based systems were analyzed, then narrowed down to two: a rack-and-pinion system and an optical/tape encoder system. The final designs integrate with the current shutter structure and central module, utilizing pre-existing designs and aspects of the assembly. The concepts presented here all demonstrate that implementing an encoder-based position and velocity sensing system is feasible and should serve as a basis for future designs.