四輪車穩態轉向軌跡之預測分析

Abstract

本研究在探討四輪車有側滑角時之穩態轉向行為。首先針對四輪 車穩態轉向的相關理論作探討，應用運動學與牛頓力學理論，建立幾何關係式與力平衡方程式，發展四輪車轉向數學模型，並分成有驅動力和簡化之無驅動力兩種數學模式。由於無法得到解析解，利用全域搜尋之數值方法求得數值解，而數值方法可以包括電腦輔助分析與人工挑選兩部份。以前輪理想阿克曼轉向幾何之數值分析結果印證模型的合理性，進而利用此模型分析(1)後輪理想阿克曼轉向幾何，(2)前輪平行轉向幾何，(3)前輪前束搭配阿克曼轉向，(4)前輪外展搭配阿克曼轉向，(5)前輪阿克曼轉向，後單輪可以獨立轉向，(6)僅有單一輪轉向。綜合這些模式的數值分析結果，探討四輪車穩態轉向行為。利用本研究所發展之模型及分析方法對重心左右配置、不同轉向幾何之轉向機構、單輪轉向的影響與各個車輪之側滑與磨耗，均可以有更精確完整的了解。

Study on the steady turning behavior of four-wheel vehicles as the four tires develop slip angles is presented. Based on kinematics and dynamics, the geometry equations and force equilibrium equations are established to develop the 4-wheel independent steering mathematical model, which includes tractive forced and non-tractive forced. Because of the difficulties in finding out the analytical solutions, a numerical method is developed. The numerical method includes computer aided programming and manual-selection. The front wheel ackerman steering is studied and the numerical results are verified. Then, the other modes(1) rear wheel ackerman steering, (2) front wheel parallel steering, (3)front wheel toe-in with ackerman steering, (4)front wheel toe-out with ackerman steering, (5) front wheel ackerman steering and rear single wheel independent steering, (6) single wheel steering, are analyzed. With these numerical results, the steady turning behavior of four-wheel vehicles is realized.With this mathematical model and numerical method established in the study, the effect of lareral weigh distribution, different types of steering geometry, single wheel steering on turning behavior and slip and wear of each tire can be thoroughly realized.