可變軸距單人載具之軸距最佳化與轉向控制

The Wheelbase Optimization and Steering Control for a Various Wheelbase Vehicle

陳欽舜(Ching-Shuen Chen)

指導教授 ： 蕭耀榮

國立臺北科技大學/機電學院/車輛工程系所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00286

摘要

本論文之研究方向主要發展四輪轉向車輛在不同車速之對應最佳軸距，並於轉彎時使車輛之重心側滑角為零及追隨目標之偏轉角速度。此四輪轉向控制可讓車輛在低速、高速及變換車道時，有良好之操控性增加行車安全。
本論文首先進行理論基礎探討。以輪胎力學為出發點，延伸討論到阿克曼轉向、自行車轉向運動分析，並將車輛視為在平坦路面行駛的剛體，四輪可以獨立轉向和獨立驅動，先進行簡化之自行車模型之四輪轉向車輛運動分析，再建立三自由度四輪轉向車輛模型。其次根據車身幾何關係及車身穩定性，求出最佳之前軸臂與後軸臂之長度組合。接著進行不同車速下最佳軸距之分析計算，此部分先模擬得到車輛在轉彎時對不同車速與不同軸距之側傾角度、偏轉角速度及重心側滑角，再利用工程最佳化法得到不同車速所要對應的軸距。最後同時控制前輪與後輪轉向角，設計模糊控制達到車輛轉彎時具有零重心側滑角及適當之偏轉角速度。

關鍵字

四輪轉向控制 ； 軸距最佳化 ； 可變軸距

並列摘要

This thesis mainly developes the optimal wheelbase for a variable wheelbase vehicle under different vehicle speeds, and also develops a four-wheel turning control algorithm. This algorithm can keep the vehicle having zero slip angle and proper yaw rate in turning. With the aid of this four-wheel turning control, a four-wheel variable wheelbase vehicle can have good drivibility at different vehicle speeds, which increase the driving safety.
In this thesis, it explores the related theories first. It discusses the tire model, Ackerman steering and bicycle models. It’s supposed that the vehicle is rigid, four–wheel steering and four–wheel driving. This thesis analyzes the four-wheel steering vehicle motion by simplified bicycle models. And then builds a 3-DOF(three-degree-of-freedom) four-wheel steering vehicle model for control and simulation. Therefore, the optimal pairs of front and rear axle arm lengths can be derived from the car body geometric relationships and vehicle stability. This thesis then uses simulated vehicle parameters (roll angle, yaw rate and sideslip angle) to find the optimal wheelbase for different vehicle speeds. Eventually, a fuzzy turning controller is designed to obtain zero sideslip angle and proper yaw rate by controlling the steering angles of front and rear wheels.

並列關鍵字

four-wheel steering control ； wheelbase optimization ； various wheelbase

參考文獻

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