以觀察氣泡運動輔助水下載具在水流中之姿態控制

Underwater Vehicle Gesture Control Aided by Air Bubble Motion Observation in a Water Flow

李志偉(Chih-Wei Lee)

指導教授 ： 郭振華

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201610153

摘要

本研究描述仿生機器魚利用雙魚眼攝影機、電子羅盤以及加速度計在一個有水流的環境中，藉由調整姿態以達到節能的控制演算法。在實驗場地中，仿生機器魚在向前運動的過程中會遭受到水流，而造成多餘的能量消耗及控制上的困難。本文根據氣泡與水流流動的相對關係，利用影像處理演算法描述氣泡特徵並萃取出其資訊，透過校正後的雙魚眼攝影機估測仿生機器魚與氣泡的相對位置關係，再利用盧卡斯-卡納德移動物體追蹤演算法及影像金字塔，估測氣泡隨時間變化的位置資訊。另外整合來自電子羅盤及加速度計的資料，根據氣泡流動的觀測資訊，調整仿生機器魚的運動路徑及魚身與水流之攻角，以達到在水流中穩定控制的目的。最後,本論文展示了實驗數據，以驗證此視覺追蹤的回授控制演算法的可行性。

關鍵字:仿生機器魚、水流、氣泡、姿態控制、角點偵測、相機校正、雙眼視覺、盧卡斯-卡納德追蹤演算法、影像金字塔

關鍵字

仿生機器魚 ； 水流 ； 氣泡 ； 姿態控制 ； 角點偵測 ； 相機校正 ； 雙眼視覺 ； 盧卡斯-卡納德追蹤演算法 ； 影像金字塔

並列摘要

This thesis describes the gesture control of a Biomimetic Autonomous Underwater Vehicle (BAUV) in a water flow by utilizing information derived from on board sensors of stereo cameras, a compass, and an accelerometer. In an alternating water flow, the BAUV suffers from drag forces and consumes more energy when it advances. The relationship between air bubbles and water flow is first discussed. The air bubble is detected by Harris corner. The relative position between air bubble and BAUV is estimated based on the calibrated stereo cameras and the bubble is tracked by using Lucas-Kanade method and image pyramid algorithm. By integrating observation information from air bubbles, heading angles and 3-axis accelerations from compass and the accelerometer, the BAUV adjusts its heading angle to optimize the gesture of control in the water flow. Finally, the control algorithm based on the computer vision algorithm is verified by experimental data. The control power consumed in the driving motors are calculated to compare the energy used in a water flow with and without gesture control.

Keywords: BAUV, water current, air bubbles, harris corner, camera calibration, stereo vision, Lucas-Kanade tracking algorithm, image pyramid

並列關鍵字

BAUV ； water current ； air bubbles ； harris corner ； camera calibration ； stereo vision ； Lucas-Kanade tracking algorithm ； image pyramid

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