本論文主旨在開發一套四軸的水下機械手臂。為了縮小機械手臂與後備系統的體，我們採用直流伺服馬達作為動力源，使機械手臂有平面定位，腕部旋轉及爪部開閉的功能。機械臂使用的電源，可由無人遙控載具的連結電纜來提供，以便減少能量轉換單元的設置，讓機械手臂能裝配在中小型載具上。硬體設計中，最先考慮的是馬達的選用與配置，由於防水與固定結構會因馬達尺寸外型而有很大的改變。且後級馬達的配置設計，有助於前級馬達的負載改善。本論文中，機械臂的臂身與馬達水密箱，皆設計成圓柱狀以方便O型環的設置，而機械手臂中旋轉軸的水密方式，採用油封來作為水密元件。最後夾爪連桿的設計，商確夾爪運動模式後，以運動鏈的設計理論，經過機構合成，設計出六桿、單自由度的連桿組。機械夾爪的定位控制器以Visual Basic為設計平台，Jacobian控制器為主體，比例控制器為輔，設計一套夾爪定位控制程式，控制率為50Hz。並且推導一個以馬達定位角度為變數的函數，作為重力補償，使得手臂在不同定位點，都有相同的定位精度。夾爪定位馬達的驅動是以DA卡與直流伺服驅動器作結合，藉由電壓的改變來決定馬達的轉向與轉速來驅使夾爪定位。而機械夾爪旋轉與開閉，是透過DIO驅動繼電器，改變馬達的電源輸入極性，來決定爪部旋轉方向與開閉狀態。機械手臂定位響應良好，在移動速度為20mm/sec下，定位誤差皆小於±1mm。

The goal of this thesis is to design and fabricate a four degrees freedom underwater manipulator for small to midsize remotely operated vehicles. DC servo motors were used to actuate the manipulator joints such that the size and the necessary auxiliary components can be reduced. In terms of hardware design process, the selection of servo motors and their arrangement is the key to the overall performance of the manipulator. The design of any joint, including its location and fixture to the frame, is coupled with that of the neighboring joints such that the design itself is an iterative process. Proper choice of the torque and power of an actuator not only reduces its size but also ease the loading the joints proximal to the base. In this project, the water resistance between stationary and rotary interfaces are achieved by O-ring and mechanical seals respectively. A gripper, synthesized and analyzed with kinematic chain theory, was implemented with a single degree freedom six-bar linkage as the end-effector of the manipulator. Because the robot is designated to operate in underwater environment, the dynamics of the system is relative slow and insignificant. Therefore, the only the linearized kinematics of the manipulator is concerned, and the motion controller is implemented with Jacobian in Visual Basic. Under 50 Hz servo rate, gravity compensation is added for operation in the air, and in the water as well. For the operating speed limited to 20 mm/sec, the overall positioning error is confined to be less than 1 mm for all time.

第一章 緒論
1.1 前言………………………………………………… 1
1.2 文獻回顧…………………………………………… 1
1.3 論文目的…………………………………………… 2
第二章 機械結構設計
2.1 前言………………………………………………… 3
2.2 傳動系統設計……………………………………… 3
2.3 水密元件的選用…………………………………… 7
2.4 機械手臂臂身設…………………………………… 11
2.5 機械夾爪設計……………………………………… 16
第三章 控制器與介面電路設計
3.1 前言………………………………………………… 22
3.2 運動分析…………………………………………… 22
3.3 Jacobian…………………………………………… 24
3.4 Visual Basic實現Jacobian控制器……………… 26
3.5 重力補償…………………………………………… 30
3.6 馬達驅動介面電路………………………………… 31
第四章 機械手臂定位響應
4.1 前言………………………………………………… 35
4.2 重力補償對機械手臂定位的影響………………… 35
4.3重力補償後機械手臂於空氣中定位響應…………… 37
4.4重力補償後機械手臂於水中定位響應……………… 38
第五章 結論與未來展望
5.1研究成果……………………………………………… 39
5.2討論與改進…………………………………………… 42
5.3未來發展……………………………………………… 44

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