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Hough 알고리즘을 통한 HB 모델의 힘 모멘트 측정
김은주(Eunju Kim),변영환(Yung Hwan Byun),박수형(Soo Hyung Park) 한국추진공학회 2019 한국추진공학회 학술대회논문집 Vol.2019 No.11
비행체의 힘과 모멘트를 측정하는 방법에는 밸런스를 이용한 방법과 자유낙하 장치를 이용하는 방법이 있다. 그중 자유낙하 실험은 신호를 받기 위한 별도의 DAQ 시스템 구축과 Deconvolution 과정 없이 힘과 모멘트를 구할 수 있다는 장점이 있다. 선행 연구에서 자유낙하 실험을 통해 힘과 모멘트를 측정하는 방법에는 픽셀을 직접 세주는 방법과 Harrision detector algorithm을 이용하는 방법[1]이 있다. 그러나 두 가지 방법 모두 획득한 사진이 모두 2차원이기 때문에 Yaw angle을 반영하지 못한다는 단점이 있다. 본 연구에서는 선행연구와는 달리 모델에서 직선을 읽고, 그 길이 변화를 파악하는 방법을 연구하였다. 이 방법을 적용하면 한 대의 카메라로 Pitch 각과 Yaw 각을 모두 파악할 수 있다. 실험을 통해 얻은 물체의 직선을 인식하기 위해 사용한 알고리즘은 Hough 알고리즘이다. 알고리즘을 통해 직선의 길이 변화를 파악하면 Pitch 각과 Yaw 각을 모두 파악하여 보다 정확한 힘과 모멘트 측정에 기여 할 수 있다. Methods for measuring the force and moment of an aircraft include the use of balance and the use of free-flight module. Among them, free-flight testing has the advantage of establishing a separate DAQ system to receive signals and obtaining power and moments without the process of deconvolution. Methods for measuring force and moment through free-flight module in prior study include directly count pixels and use the Harrison detector algorithm [1]. However, both methods have the disadvantage of not reflecting the yaw angle because the acquired picture is two dimensions. In this study, we studied how to read straight lines in the model and identify changes in their length, unlike the preceding study. This method allows a single camera to identify both Pitch and Yaw angles. The algorithm used to recognize straight lines of objects obtained through experiments is the Hough algorithm. By identifying the length change of a straight line through the algorithm, both Pitch and Yaw angles can be identified, contributing to more accurate force and moment measurement.
강대임,송후근,홍창선 대한기계학회 1995 대한기계학회논문집 Vol.19 No.9
In order to reduce the systematic error of a build-up system, we have proposed a new test procedure in which all force transducers in a build-up system are rotated by 90.deg. with a base platen fixed on a force standard machine. The setting positions of force transducers on the output of a build-up system were investigated using an orthogonal array. The effects of the parallelism of a build-up system and of the bending moment sensitivity of a force transducer were considered. The experimental results show that the setting position of the base platen hardly affects the output of the build-up system, but the setting positions of force transducers affects it strongly. It reveals that the new test procedure reduces effectively the systematic error of a build-up system.
고대환,송성재 한국기계기술학회 2016 한국기계기술학회지 Vol.18 No.5
Three-dimensional motion analysis systems and force plates are used for gait phase detection and ground reaction force(GRF) or ground reaction moment(GRM) data collection. But force plates as measurement systems are restricted to laboratory environments and have limitations for abnormal walking with foot dragging. Therefore the methods were proposed to compute the GRM from the kinematic data of three-dimensional motion analysis systems. Gait phase detection with kinematic data using foot velocity algorithm(FVA) was performed. The validity of gait phase detection was obtained comparing with the results of force plates. A gait model with 7 segments was composed to compute GRM. The results of gait model with kinematic data were compared with those of force plates. The result of the vertical direction is similar. But anterior-posterior direction and lateral direction show similar tendency with some gaps.