使用前輪轉向控制之自平衡電動機車

Abstract

本論文提出一種使用前輪機構轉向方法，改變機車之車身傾角，使車輛在有速度行駛的情況下依然能夠達到自平衡的穩定狀態，藉此改善機車騎乘所帶來的意外碰撞等安全性問題，並期望能開發出防止機車傾倒的輔助駕駛功能。目前國外車廠已有少量重型自平衡機車概念產品發表，但是通常皆是使用陀螺儀配合飛輪進行車身姿態穩定，由於飛輪需要產生足夠轉動慣量進行車身穩定，飛輪額外的體積及重量為此平衡系統的主要缺點，這會使機車的靈活性及操控性受到限制。針對台灣目前主流速克達(Scooter)機車規格，本論文提出使用前輪轉向自平衡方法，此系統僅在龍頭增加轉向馬達及多連桿機構，相較於陀螺儀飛輪系統能夠有效降低其體積增加量，更符合大眾化速克達機車應用。 本論文透過分析二輪機車的動態性能及各項參數性質後，先建立具有前輪轉向系統的兩輪車完整動態模型，並發現具有前輪轉向的兩輪車系統會具有類似倒單擺的不穩定持續振盪動態，所以本論文提出具有兩輪機車轉向傾角回授控制方法，經由控制器設計確保機車能夠達到自平衡穩定狀態。確認機車自平衡之可行性後，本論文將實際安裝提出的前輪轉向系統在一台白牌電動機車上進行自平衡實測，經由實際機車行駛實驗驗證，證實本論文提出的低重量轉向自平衡系統，可有效在機車直線行駛、轉彎行駛及外擾故意撞擊下皆能夠保持車身穩定，最後也在實際機車進行嘗試導入自平衡輔助駕駛功能，證實在騎士大傾角轉彎時，自平衡模式能夠拉回小於傾角6度的穩定行駛情況。

This thesis proposes a self-balance two-wheeler based on the implementation of front-wheel steering motor and mechanism. The purpose is to realize the two-wheeler attitude control by manipulating the vehicle tilt angle. It is expected to ensure the two-wheeler stability through the motor steering control during the accidental collision instant. There are a few conceptual heavy motorcycles published worldwide with self-balance control. However, these self-balance motorcycles are typically designed based on gyroscopes coupled with heavy flywheels. Due to the angular momentum conversion, a significant amount of momentum generated from the flywheel is required. This is the primary drawback for flywheel based self-balance control because of the limitation on the two-wheeler riding flexibility and maneuverability. Considering the popularity of various scooter-based motorcycles in Taiwan, this paper proposes a novel self-balance system through the front-wheel motor steering control. The proposed steering system only requires an electric AC motor coupled with mechanical linkage. Comparing to existing flywheel-based momentum system, the proposed steering system results in the smaller volume for two-wheeler self-balance. The proposed steering system is well suited for light-weight scooter applications. The thesis develops a comprehensive dynamic model for a two-wheeler with the steering control system. Similar to the inverted pendulum, an unstable oscillation dynamic is identified for the proposed self-balance two-wheeler. To maintain the attitude control stability, this thesis proposes the feedback-based control through the measurement and manipulation of scooter tilt angle. Moreover, a self-balance scooter prototype with the proposed steering control is fabricated for the experimental verification. It is shown that the scooter self-balance attitude can be maintained during the straight-line and chicane racing, as well as the external force impact. Finally, an advance driver assistance is also implemented on the proposed self-balance scooter. It is shown that the scooter attitude stability is maintained within less than 6deg tilt angle under demanded two-wheeler steering conditions.