the eyeball rov: an underwater remotely operated vehicle

The Eyeball ROV: An Underwater Remotely Operated VehicleFeaturing Advances in Rotational Actuation, Communication, and

Localization

byIan Charles Rust

B.S., Mechanical Engineering, Massachusetts Institute of Technology, 2010

Submitted to the Department of Mechanical Engineering in Partial Fulfillment of theRequirements for the Degree of

Master of Sciencein fUC

Mechanical Engineering

at the

MASSACHUSETTS INSTITUTE OF TECHNOLOGYARCHIVES

September 2011

0 2011 Massachusetts Institute of Technology, All rights reservedThe author hereby grants to MIT permission to reproduce and to distribute publicly paper and

electronic copies of this thesis document in whole or in part in any medium now known orhereafter created.

Signature of Author...............................................

eyment of Mechanical EngineeringAugust 5, 2011

C ertified by ..........................................V H. Harry Asada

Ford Professor of Mechanical EngineeringThesis Supervisor

A ccepted by ........................................................David E. Hardt

Chairman, Department Committee on Graduate StudiesDepartment of Mechanical Engineering

The Eyeball ROV: An Underwater Remotely Operated VehicleFeaturing Advances in Rotational Actuation, Communication, and

Localization

by

Ian Charles Rust

Submitted to the Department of Mechanical Engineeringon August 5, 2011 in Partial Fulfillment of the

Requirements for the Degree of Master of Science inMechanical Engineering

ABSTRACT

The design for a spherical Remotely Operated Vehicle (ROV) with a camera, called theEyeball ROV due to motions similar to the human eye, is presented in this thesis. The ROVfeatures an actuation scheme that utilizes a two-axis gimbal for changing the location of thecenter of mass of the ROV. This creates continuous and unlimited rotations in place on the partof the ROV, allowing the camera to be panned and tilted. A model of the ROV is presented, andcontrol was tested in both simulation and experiments. In addition, a dual-use system for bothcommunication and localization of the ROV is presented. This novel dual-use system usesvisible blue light (-470nm) to relay data in addition to providing a beacon with which theorientation and position in space of the ROV was estimated. This localization algorithm wasimplemented using an Extended Kalman Filter (EKF), and was tested in both simulations andexpenments.

Thesis Supervisor: H. Harry AsadaTitle: Ford Professor of Mechanical Engineering

Acknowledgments

I would firstly like to thank Mitsubishi Heavy Industries, and my contact there, Mr. Jun

Fujita, for funding the research presented in this thesis.

I would also like to thank Professor H. Harry Asada for his guidance in completing this

thesis. We have had an academic relationship since my time as an undergraduate, and I have

found no one better to help me shape my ideas into reality. Several undergraduate students have

also helped with various portions of this project, so I would like to thank both Ashley Fletcher

and Hellen Lopez for their invaluable help.

In addition, I would like to like to thank my parents, Greg and Kathleen Rust. From an

early age they taught me the importance of clear and logical thought, the value of intellectual

creativity, and the importance of dedication and hard work. Without such lessons, constant words

of encouragement, and equally constant boxes of cookies sent through the mail, I would

doubtlessly not have been as well equipped to perform the presented research.

Lastly, I would like to thank Karen Dubbin for reminding me of the reason why I spent

all those late nights working and the reason why I came home at the end of them.

Table of Contents

Chapter ............................................................................................................... 151.1. The Need for Inspection of Nuclear Reactors........................................................................ 15

1.2. Inspection Strategies...................................................................................................................17

1.3. Outline of the W ork Presented............................................................................................... 18

Chapter 2 The Eyeball ROV ......................................................................................................... 212.1. Design Requirements..................................................................................................................21

2.2. M echanical Design ...................................................................................................................... 23

2.3. Dynamicg .................... - -...-................................................................................. 31

2.3.1. Gravitational Forces............................................................................................................35

2.3.2. Actuator Singularity ............................................................................................................ 36

2.4. Control .....................................---.... -..... --............................................................................. 38

2.4.1. Formulation of the Control Input.......................................38

2.4.2. Reduction of the Dynamics ........................................................................................ 40

2.4.3. Open Loop Stability ................................................................................................. 41

2.4.4. Stability Augmentation .............................................. 43

2.4.5. Proportional Control...........................................................................................................44

2.5. Simulations ......................................................... 46

2.6. Experiments...... ....................................................................................................... 49

2.7. The Eyeball ROV: A Summary.....................................................................................................52

Chapter 3 Visible Light Based Communication and Localization: A Dual-Use System......... 553.1. Underwater W ireless Communication. ................................................................................... 55

3.2. M aintaining Line of Sight............................................................................................................57

3.3. Orientation Estimation ..................................................................................................... 59

3.3.1. Traditional Orientation Angle Estimation ADuam......................... ........ 59

3.3.2. The Photodiode Array ............................................................................ 60

3.3.3. Kalman Filter Implementation .. .................................. ................................... ...... 63

3.3.4. Experimental Setup ............................................................................................................ 66

3.3.5. Comments On Range.................................................................................... ............ 70

3.3.6. Results.... ............................................................................................................. 72

3.4. Full Planar Localization............................................................................. 75

3.4.1. Extension of the Dual Use System ........................................................................... ..75

3.4.2. Kinematic Model......................................................... ............ ..... ......... 75

3.4.3. Dynamic Model ................................................................-- - - - - - 77

3.4.4. Simulation Results.............................................................................. ..... 83

3.4.5. Experimental Results................................................................................ 85

3.4.6. Conclusions from the Planar Localization Algorithm......................................................95

C hapter 4 C onclusion............................................................................................----.........- 97

Chapter 5 A ppendices................................................................................ .. -----... --------........... 105

5.1. Appendix 1 - Physical Parameters of the Eyeball ROV.............................................................106

5.2. Appendix 2 - Physical Parameters used in Simulation of the Localization Algorithm..........107

5.3. Appendix 2 - Physical Parameters used in Experiments of the Localization Algorithm...........108

List of Figures

Figure 1 - Map of the United States, with the locations and ages of Nuclear Reactors marked [2]........................................................................................................................................................ 16Figure 2 - Diagram of a Pressurized Water Reactor (PWR). Note that the section of the reactor tobe inspected, namely the primary cooling cycle, is circled [3].................................................. 16Figure 3 - Diagram detailing the general inspection task undertaken by the ROV. It must swimthrough both the reactor and associated piping systems in order to acquire video data of variousinspection sites......