本論文要建立一種單輪式個人載具，尤指可自動前進行走並於行進與轉彎時自動維持平衡的一種全自動平衡電動單輪車。本載具是一輛類似倒單擺架構的獨輪車，使用輪內式馬達作為驅動車輪並安裝一個轉向馬達可自動作動轉向機構的轉向以維持側向穩定性。為了設計轉向馬達的側向控制系統，我們利用Lagrange方程式推導系統動態方程式，對此動態方程式在操作點作線性化用以顯現系統特性以利於實行控制設計。針對此線性系統設計狀態回授控制器，並以軟體模擬分析得知該控制器可以成功地使本載具在不同車速下實現維持側向穩定性及轉向。最後我們根據模型、動態方程式以及模擬驗證，著手設計實驗平台與硬體機構，並整合訊號處理、馬達控制，實現全自動平衡電動單輪車。

In this thesis, modeling, simulation and control of a novel personal mobility electric vehicle are presented. The vehicle is structurally similar to a pedaless unicycle but uses a hub motor as the driving wheel and contains a steering motor which automatically actuates a steering mechanism for steering and maintaining lateral stability. Under a promise that a pitch control system has already been established, in order to design the lateral control system for the steering motor, Lagrange formulation is firstly used to derive the dynamic equation. The dynamic equation is then linearized around an equilibrium point to acquire a linear model for revealing the crucial dynamic characteristics and facilitating the control design. A LQR and a pole placement controller are designed using the linear model. Simulations show that the controller can successfully steer the vehicle and achieve lateral stability under different vehicle speeds. Final, in the experiment, integrating signal processing, motor drive control and mechanical design, accomplish an electrically auto-balanced unicycle.

Contents

Abstract i
中文摘要 ii
Acknowledge iii
Contents iv
List of Figures vii
List of Tables x
1. Introduction 1
1.1 Background & Motivation 1
1.2 Literature Review 4
1.3 Scope and Contents of the Thesis 7
2. System Description and Analysis 8
2.1 Structure of the Unicycle 8
2.2 Model of the Unicycle System 9
2.2.1 Definition of coordinate and variables 9
2.2.2 Assumptions of the system 10
2.3 Dynamics of the Unicycle 12
2.3.1 Derivation of the system dynamics 12
2.3.2 Linearization of the model 18
2.4 Discussion of the system characteristic 19
3. Controller Design and Simulation 23
3.1 Controller Design 23
3.1.1 LQR Controller Design 23
3.1.2 Poles Placement Method 26
3.2 Simulation of the Controllers 28
3.2.1 Simulation of the LQR Controller 28
4. Longitudinal Balancing Control and Blushless DC Motor Control Strategy 32
4.1 Longitudinal direction Model of Unicycle 32
4.2 BLDC Motor Drive & Control 34
4.2.1 Pulse Width Modulation (PWM) 34
4.2.2 Six Step Square Wave & Switch of Four Quadrant 35
4.2.3 Current Control 39
4.3 Pitch Control Strategy 40
5. Implementation of the System 42
5.1 Mechanism and Hardware Configuration 42
5.1.1 Steering and Lateral Balancing Mechanism 44
5.1.2 Sensor module 45
5.1.3 LiFePO3 Battery 47
5.1.4 Actuator and Driver module 47
5.1.5 Upper Level Controller 50
5.2 Signal Processing 51
5.2.1 Sensor Fusion 51
5.2.2 Signal of Potentiometer 53
5.3 Results and Discussions of Experiments 54
5.3.1 Current control of Hub motor 54
5.3.2 Response of Servo motor 55
5.3.3 Data of Riding 55
6. Conclusions and Future Works 58
6.1 Conclusions 58
6.2 Future Works 59
Bibliography 60

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[2] U3-X http://world.honda.com/U3-X/

[3] eniCycle http://www.enicycle.com/

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[10] J.H. Ginsberg, “Advanced engineering dynamics” Cambridge, U.K., Cambridge Univ. Press, 1995.

[11] Y.T. Chen, “Control system design and implementation of a pedaled, self-balanced unicycle,” National Tsing Hua University, 2010.

[12] ADVANCED CONTROL SYSTEM DESIGN Dr. Radhakant Padhi, AE Dept., IISc-Bangalore http://nptel.ac.in/courses/101108047/module9/Lecture%2021.pdf
(Pole placement)

[13] B. L. Chen, “Control System Design and Implementation of a Self-balanced Unicycle with Steering Mechanism”, National Tsing Hua University, 2012

[14] K. H. Huang, “Voltage Control Strategy and Efficiency Analysis of PMSG in the Regeneration Mode”, National Tsing Hua University, 2013

[15] F. K. Wu, T. J. Yeh, C. F. Huang, “Motor control and torque coordination of an electric vehicle actuated by two in-wheel motors,” Mechatronics, Volume 23, Issue 1, February 2013, Pages 46-60.