Introduction¶

The typical conversation with someone I’ve met over the past years that I’ve been a graduate student inevitably comes to this: “So what do you do in graduate school?”. My reply is “I study how people balance on bicycles”. This is a great conversation starter as almost everyone recalls learning how to ride a bicycle. It is something we weren’t born to do and we almost always remember the feeling of learning the skill. It is typically quite a momentous occasion in most folks’ lives. Usually everyone thinks the research is cool and can identify with it, but the next question (as with most research), is “What application is that good for?”. As an engineer, we are trained to be application minded. It is certainly what drove me to start down this path in the first place. There is an answer to this second question, but over the years I’ve gotten less enthusiastic about trying to justify why I’m working on this project with respect to an immediate application. In many ways this is simply the reality for the growing scientist. It becomes obvious that basic science simply needs to be performed, without regard to what it may or may not accomplish. The benefits down the road are inevitable and there is a large body of evidence to support that. But nonetheless my initial curiosity about bicycle dynamics is rooted in application and it still is in many ways. But I’m content with understanding difficult problems for basic progression in learning and science.

My first inquiries about bicycle dynamics came from my attempts to design a recumbent bicycle frame for my senior design project at Old Dominion University. Recumbents are notorious for not being that easy to ride and we were building one for the annual ASME Human Powered Vehicle challenge which would be especially unusual with an extremely low center of gravity. It needed to be suitable for novice riders to control. I found myself in the design process where one needs to choose the wheel sizes, front end geometry and location and seating position of the rider. As a young engineer is taught, I went looking for technical guidelines to choose these parameters for our bicycle design. But all I came back with were many conflicting ideas from various bicycle fabricators and the book Bicycling Science 2nd Ed [WW82] which gave a synopsis of Jones’ [Jon70] conclusions from his famous study on the stability of bicycles. I studied this in detail and designed my bicycle geometry to be exactly what was specified as good handling by Jones.[1] The bicycle turned out to be rideable (after lots of practice), but this was probably the first time I realized in my engineering career that there isn’t a formula for everything.

These particulars fell onto the back burner as I finished my work at the Langley Full Scale Tunnel and did not re-emerge until a few classes at UC Davis brought these concepts back into my picture. In particular, I attempted to derive the equations of motion of the bicycle in Mont Hubbard’s multi-body dynamics class at the beginning of 2006 and the power to potentially properly answer the questions I had back at Old Dominion seemed to be at my finger tips. Little did I realize that those answers simply introduced more difficult questions and a research project was born.

This dissertation documents most of the work I’ve done and my thoughts on bicycle dynamics, control, and handling at UC Davis and TU Delft since around December 2006.

Reproducibility¶

Over the past few years, I’ve begun realize how reproducibility is crucial for science to improve and grow rapidly, all the while building a deeply intact and strong foundation for future researchers and that it may not be as reproducible as we may all think. With that in mind, I have put a great deal of effort into making my work more accessible, reusable, and ultimately reproducible, which is the cornerstone of all scientific understanding. For the type of work presented here, the majority is computational and the computer along with software have enabled our generation to make the work reproducible without too much extra effort. My intention is provide enough information in the form of data, source code, and writing, that others will have a relatively easy time reproducing my work. This has been mostly possible in the time frame that I’ve had to complete the thesis, but there are some holes in particular with respect to the work done in the earlier years of the project.

Dissertation website¶

I decided to publish my dissertation publicly on the internet from the day I started writing it. The first reason for this is that I want to take full advantage of the ability the web offers for conveying ideas and information, whether it be a video or an interactive program. Paper-based publication is a thing of the past and is an unbelievably limited form of sharing, especially in science. Secondly, I want the process of writing my dissertation to be in the open with the ability for anyone to offer comments, suggestions and edits. Dissertations are traditionally considered to be the work of a single individual, but that is never true. All the research we do as scientists is built upon the works of others and rarely does anyone produce their work without the help of others. Dissertations in the USA are typically very individualistically oriented but I’ve begun to believe that we should strive to move away from the idea that some work is only due to one person and embrace the fact that we need help from many people to complete something like a dissertation for a doctoral degree. So it is best to be collaborative from the beginning with a sufficient mechanism to provide credit where credit is due. I also want this work to be the best it can be, and if others are interested in helping me make it that way then an interactive website is a platform that is capable of promoting this.

I desired to follow these basic rules when writing my dissertation:

• The content should be written presentation format neutral.
• The primary presentation view is through a web browser, but a static PDF version is also available to suit UCD’s archaic submission rules.
• The source code for all the figures, animations, and interactive bits should be included with the dissertation.
• The experimentally collected data should all be available for download and use by others.
• Software tools should be developed if at all possible, instead of disconnected scripts.

Based on these goals, I choose the Sphinx publishing platform for my dissertation. The text source, which is written in reStructuredText, is available along with the source code for the figures at https://github.com/moorepants/dissertation. The HTML version can be viewed and the PDF version downloaded at http://moorepants.github.com/dissertation

Writing Style¶

I generally find scientific writing in my field to be extremely dry. We’ve developed a collective style that removes any material that isn’t technical from the articles and this in turn causes us to gloss over the fact that people are behind all of the reported research. These people have ideas, struggles, mishaps, revelations, and sometimes even fun. But these things weren’t always hidden. Early engineering articles ended with lengthy personal conversations between the reviewers and the authors ([Wil51], [Kon55]) and include much more artistic and beautiful illustrations. Page limits in journal and conference articles force today’s writer to make their writing as dry as possible to maximize the amount of technical content. I’m no writing ace, but have decided to inject some of the humanism that comes along with a project than spans seven years of ones life into this text. I mostly corralled these ramblings in the prefaces and footnotes of the chapters, but some has sneaked into the drier areas too. I hope that these asides give some idea of how all of this work developed and who to attribute the ideas and labor to along with breaking up the monotony of the technical parts of the text. I figured that a dissertation will be one of the few writings in my career that provides a chance to do this.

Attribution¶

As a child, I was programmed to think that any form of plagiarism was evil: you shouldn’t copy anything. But how would we ever make any progress if we didn’t copy and improve on what others have done in the past? The work presented here is mostly based on the work that I have done in the past several years, but there are many other people’s work that is wrapped up in it. Their writings and thoughts will inevitably be present in this text. I do not claim these as my own, but they will be required to tell the story of the research. I will do my best to acknowledge everyone’s work in this thesis, but there will surely be some that I have forgotten. Please let me know if that is so, and I will remedy it.

Notation¶

I attempt to keep notation consistent throughout each chapter, with much of the notation being consistent throughout the dissertation. The extensions chapter has different notation for each model. The notation for the Chapter is given at the end of each Chapter. There are ultimately two notations forms for the bicycle: mine which follows a Kane-like syntax and the one adapted from [MPRS07].

License¶

The written work and data are licensed under the Creative Commons Attribution 3.0 Unported License.

You may share, rework, and use any of the materials provided you cite this work

Moore, J. K., Human Control of a Bicycle, UC Davis Doctoral Dissertation, 2012

All of the source code is licensed explicitly in the src directory under a BSD license.

Footnotes