Gap Analysis and Diagnosis for Mechanical Assembly using X-rays CT Scanning

• Project/Area Number: 18H01354
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 18030:Design engineering-related
• Research Institution: The University of Tokyo
• Principal Investigator: Suzuki HIromasa 東京大学, 大学院工学系研究科(工学部), 教授 (40187761)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000); Fiscal Year 2020: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2019: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000); Fiscal Year 2018: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
• Keywords: 産業用X線CT装置 / リバースエンジニアリング / アセンブリ解析 / 画像処理 / 産業用X線CT / 距離変換

Outline of Final Research Achievements

We have developed an evaluation method that computes gap between parts in an assembly using the 3D CT image taken by scanning the whole assembly. The method is theoretically based on a multi-phase implicit function and computes the amount of the gap using its medial axes. We also developed a prototype software to evaluate this algorithm and showed that a large gap more than a few voxels can be measured precisely while those under the voxel size can be also estimated. Using this algorithm, the distribution of the gap between the parts in an assembly can be measured.

Academic Significance and Societal Importance of the Research Achievements

機械製品は部品を組み立てることによって構成されるが、特にスイッチなどの可動部品を含む場合は、組立状態における部品の隙間を正確に計測することが難しかった。X線CTは非破壊で内部も含めて画像化できるので、本研究ではそのようなCT画像を用いて、隙間量を計測する手法を開発した。隙間量は、例えばスイッチの寿命に影響し、また触覚などの感性品質にも影響するために重要な品質ファクターであったが、これまで計測する手段が限られていた。本研究による手法によって、このような課題に対する一つの評価方法を提案することができた。

Research Products

• [Presentation] A Method for Void Inspection in X-ray CT Images Based on Golden Part Generated from a Set of Accepted Parts (2021)
  • Author(s): Hiromasa Suzuki, Xiangning Mao, and Yutaka Ohtake
  • Organizer: 19th International Conference on Geometry and Graphics (ICGG2020)
  • Int'l Joint Research
• [Presentation] Gap Generation for 3D Printed Assembly by Using Signed Distance Fields (2020)
  • Author(s): Junhyuk Lee, Yutaka Ohtake, Tatsuya Yatagawa, Hiromasa Suzuki
  • Organizer: 18th International Conference on Precision Engineering (ICPE2020)
  • Int'l Joint Research
• [Presentation] Accurate surface extraction on CT volume using gradients obtained by differentiating FDK formula (2019)
  • Author(s): Yukie Nagai, Yutaka Ohtake and Hiromasa Suzuki
  • Organizer: iCT 2019 Conference
  • Int'l Joint Research
• [Presentation] X線CT画像を用いたアセンブリ品の部品位置同定に関する研究 (2018)
  • Author(s): 高橋諒、鈴木宏正、大竹豊他
  • Organizer: 2018年度精密工学会秋季大会講演論文集