四輪轉向實驗車輛的建構與控制之研究

Abstract

本研究建立了一台四輪轉向實驗車輛，並利用此實驗平台估測轉移函數以及設計控制器。文中提出的控制器可以使實驗車輛之側向加速度及旋轉速度追隨一組參考訊號。為了使控制器設計過程更為簡單，首先將車輛的轉移函數解耦合為兩個單輸入單輸出系統，並透過幾個初步實驗了解感測器特性與車輛動態，實驗結果將一併考慮入控制器設計的過程。將控制器套入實驗平台可以發現，側向加速度與旋轉速度實驗值的頻率與參考訊號相當接近，但實驗值的增益卻比參考訊號大。調整控制器增益後，實驗數據顯示，側向加速度與旋轉速度實驗值增益與參考值之間的誤差小於原本的控制器，實驗值的頻率與參考訊號仍幾乎相同，且於其他頻段也沒有出現異常的峰值。由實驗結果可知，使用調整增益前後之控制器，實驗平台的側向加速度與旋轉速度都有出現追隨參考訊號的趨勢。

This study sets up a four-wheel-steer experimental vehicle, experimentally evaluates transfer functions, and designs controllers on this experimental platform. The controllers presented in this thesis can make lateral acceleration and yaw rate of the experimental vehicle follow reference signals. In order to simplify the controller design process, first, the transfer functions of vehicle would be decoupled into two single-input single-output systems. The characteristics of sensors and vehicle dynamics are investigated through several preliminary experiments. These experimental results are taken into consideration in the controller design process. According to the controller experimental results, frequency of lateral acceleration and yaw rate are really similar to the frequency of reference signals, but the gains of experimental values are larger than reference signals’. After adjustment of the controller gain, experimental data show that the errors between experimental and reference values are reduced. The frequency of experimental data and reference signals are still almost the same and there are no distinct peaks in other frequencies of experimental data. From the experimental results of before and after the controller gain adjustment, the lateral acceleration and yaw rate both follow the reference signals with reasonable accuracy.