慣性測量單元之空間座標轉換應用於游泳選手動作分析

Abstract

背景：目前仍缺乏能夠在最小動作干擾下，記錄游泳者從跳台起跳到觸牆之間連續速度的測量設備。因此，在競技游泳領域中，尚未有標準化的方式分析實際游泳過程的前進速度、識別划水階段和推進力。實驗目的：本研究旨在利用易操作和高解析度的設備收集游泳者的動作訊號，從而對游泳過程進行各面向分析。此外，從選手前進的瞬時速度與各項游泳指標比較，可以深入了解人體與水中環境之間的相互作用。方法：為了確保測量準確並最小化累積誤差，我們結合了慣性測量單元（IMU）和輔助工具，例如：行動裝置攝影和自主開發水中位置偵測系統。將 IMU的運動連續訊號使用座標轉換技術和創新的速度演算法進行數據處理。總共進行了三個實際測驗：(1)不同泳速的自由式，(2)評估跳水模式，以及 (3)測量50公尺自由自由式游泳期間的速度變化。結果：運用IMU可量化每次划手週期中的手掌方向和各划手階段持續時間。並以計算出的前進瞬時速度和受試者軀幹的角速度，比較二種跳水技術效益。最後，我們利用IMU瞬時速度訊號來分析游泳全程動作技術所產生的推進力效益。結論：本實驗結合IMU、座標轉換和自主開發位置偵測系統的演算法，期許未來能建立更廣泛應用於不同水平游泳運動員的游泳表現評估系統。

Background: Because the absence of measurement devices recording a swimmer's speed from the starting block to the wall touch with minimal interference, hinders the standardization of evaluating forward speed, stroke phase identification, and propulsive force. Objective : The study aims to collect swimmers’ motion utilizing streamlined and high-resolution equipment, allowing for a comprehensive analysis of swimming patterns. Moreover, the calculation of instantaneous forward speed and the comparison of swimming indicators provide insights into the mechanical interactions in water. Methods: To ensure accurate measurements and minimize cumulative errors, we integrate Inertial Measurement Units (IMUs) and auxiliary tools, such as mobile device and a self-developed detection system. The IMU signal data is processed using coordinate transformation techniques and innovative thrust speed calculation algorithms. We conducting three experiments: (1)freestyle at various speeds, (2)evaluating starting modes, and (3)measuring speed during a 50-meter freestyle swim. Result: We quantify hand direction during each stroke cycle and the stroke phases duration. Analysis of thrust speed, and body angular velocity enables comparative evaluation of two types of starting performance techniques. Finally, we used the IMU instantaneous speed signal to analysis the effective propulsion in different stroke phases. Conclusion: This experiment combines IMUs, coordinate transformation techniques, and a self-developed detection system to establish a swimming performance evaluation system that can potentially be applied for swimmers at different levels.