In this thesis, a pedaled, self-balanced, personal mobility vehicle named LegwayII, is developed. The vehicle is structurally similar to a pedaled unicycle but uses a brushless DC (BLDC) hub motor as its main driving wheel. For this one-wheel vehicle, it is intended that the unstable longitudinal dynamics is stabilized by a feedback control system but the lateral balancing and steering are manually controlled by the rider via a passive steering mechanism. The steering mechanism consists of a main pulley, a timing belt and a pair of cables, springs, tension-adjusting devices, and idle pulleys. This study is firstly devoted to the dynamic modeling of the steering mechanism. It is shown from analyzing the model that there is a critical speed beyond which the unicycle becomes open-loop stable in the lateral direction so that the rider can turn the handle to steer the unicycle as the conventional bicycle. The dynamic model is then used for conducting simulations for selecting appropriate design parameters. An experimental prototype is constructed based on the analysis result and the steering performance is experimentally verified.

Abstract i
Acknowledgement ii
Contents iv
List of Figures vi
List of Tables vii
Chapter 1 Introduction 1
1.1. Motivation 1
1.2. Literature Survey 4
1.3. Scope and Contents of the Thesis 5
Chapter 2 System Analysis 6
2.1 System Configuration 6
2.2 System Model 10
2.2.1 Kinetic Energy 10
2.2.2 Potential Energy 13
2.2.3 Dynamic Equation 14
2.2.4 Linearized Dynamics 16
Chapter 3 Simulation and Design Analysis 18
3.1 Simulation 18
3.1 Design Analysis 22
Chapter 4 Control Method and Control Strategy 25
4.1 Control Method 25
4.1.1 PD Controller 25
4.1.2 ZTC Controller 25
4.2 Control Strategy 26
Chapter 5 Hardware configuration and Experimental Evaluation of the Steering Performance 30
5.1 Hardware Configuration 30
5.1.1 Motor 30
5.1.2 Motor Drive Module 31
5.1.3 Power Source 32
5.1.4 Sensor Module 33
5.2 Experimental Evaluation 35
Chapter 6 Conclusion 38
Bibliography 39

[1] Segway. Available from: http://www.segway.com/.
[2] U3-X. Available from: http://asimo.honda.com/innovations/U3-X-Personal-Mobility/.
[3] Toyota-winglet. Available from: http://www.toyota.co.jp/en/news/08/0801_1.html.
[4] M.A. Karkoub, M.Parent, Modelling and non-linear feedback stabilization of a two-wheel vehicle. Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering, 2004. 218: p. 675-686.
[5] Z. S. and K. Yamafuji, Postural stability of a human riding a unicycle and its emulation by a robot. Robotics and Automation, IEEE Transactions on, 1997. 13(5): p. 709-720.
[6] Y.Naveh, et al., Nonlinear Modeling and Control of a Unicycle. Dynamics and Control, 1999. 9: p. 279–296.
[7] Y.S. X. and S.K.W. Au, Stabilization and path following of a single wheel robot. Mechatronics, IEEE/ASME Transactions on, 2004. 9(2): p. 407-419.
[8] Enicycle. Available from: http://www.enicycle.com/.
[9] J.H. Ginsberg , Advanced engineering dynamics 1995, Cambridge, U.K., Cambridge Univ. Press.
[10] R. Chunlei and N.H. McClamroch. Stabilization and asymptotic path tracking of a rolling disk. in Decision and Control, 1995., Proceedings of the 34th IEEE Conference on. 1995.
[11] C.F. Huang, T.J.Yeh., Control of a Pedaled, Self-balanced Unicycle with Adaptation Capability, Unpublished.
[12] P. C. Krause, O.Wasynczuk, S. D. Sudhoff, Analysis of electric and machinery drive systems. 2nd ed. 2002, New York: Wiley-IEEE.
[13] Y.T. Chen , Control system design and implementation of a pedaled, self-balanced unicycle in Power Mechanical Engineering. 2010, National Tsing Hua University.