Development of a magnetic suspension and balance system for sports balls

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K20478
• Project/Area Number (Other): 19H05570 (2019)
• Research Category: Grant-in-Aid for Challenging Research (Pioneering)
• Allocation Type: Multi-year Fund (2020); Single-year Grants (2019)
• Review Section: Medium-sized Section 59:Sports sciences, physical education, health sciences, and related fields
• Research Institution: Yamagata University
• Principal Investigator: Seo Kazuya 山形大学, 理学部, 教授 (60292405)
• Project Period (FY): 2019-06-28 – 2022-03-31
• Keywords: 磁力支持天秤 / スポーツ工学 / 支持干渉 / マグヌス力 / 風洞試験

Outline of Final Research Achievements

A Magnetic Suspension and Balance System has been developed for bluff bodies such as sports balls. The conclusion is summarized as follows: we started with the production of a jig for winding an air-core coil that becomes an electromagnet, and then produced a coil with an inner diameter of 52.5 [mm], an outer diameter of 160 [mm], and a thickness of 35 [mm]. Development of magnetic force and model weight estimation program, manufacture of a sphere and a soccer ball models using epoxy resin, examination of control constant design method for PID control, the establishment of position calibration test using 3-axis stage, manufacture of weights made of brass, which is a non-magnetic material, establishment of a force calibration test method using it, examination of a method of rotating a model supported by magnetic force, examination of a method of subtracting background noise. At last, we succeeded in measuring Magnus force on a rotating model.

Free Research Field

スポーツ工学

Academic Significance and Societal Importance of the Research Achievements

本挑戦的研究では、風洞実験における技術革新の可能性を示し、学術的意義や社会的意義が大きいと考えている。有史以来、風洞試験の99.9%は、測定空間に模型を支柱で固定し、実行されてきた。重力下で試験する限り、支柱で模型を支えざるを得ないが、この支柱が流れを乱してしまう問題（支持干渉）があった。特にボール等の鈍頭物体で、回転しながらの飛翔を模擬した風洞試験では、支柱兼回転軸が完全に風に曝されてしまう問題があった。本挑戦的研究では、この支持干渉問題の解決に挑戦し、回転する模型に働くありのままのマグヌス力の測定に成功した。