車輛行駛軌跡及抑止車輛翻覆之差動式輪胎力矩控制系統

Abstract

在本篇論文中，我們提出了一套車輛運動控制系統，此系統是藉由控制車輛不同的輪胎力矩，進而產生轉動力矩與降低車速，希望達到維持車輛行駛路徑與抑制車輛翻覆的目的，以確保駕駛者行駛安全。此外，我們提出一種新的參考路徑規劃，此參考路徑乃是根據駕駛者當時的駕駛行為所制定，因此，本論文所提出的軌跡控制將控制車輛至接近駕駛者心中預設的路徑。

為了探討車輛行駛的動態行為，我們建立了一個具有20個系統階數的“完整車輛模型”(full car model)，用來模擬實際車輛動態。但如此複雜的數學模型並不容易為其設計控制器，因此我們以簡化的模型為基礎進行控制器設計，接著利用順滑模態控制(sliding mode control)方法，使控制器具有穩健性(robustness)。

最後利用電腦軟體MATLAB來驗證本論文所提出的車輛運動控制系統，並且依據模擬結果作詳細的分析與討論。模擬結果顯示：在一個車輛翻覆的例子中，所提出的控制法則可以成功的使車輛免於翻覆，並且控制車輛軌跡。但是當車身側滑角(body side slip angle)太大時（車輛打滑），所提出的控制法則將無法有效的控制車輛軌跡。

In this thesis, we present a vehicle trajectory following and rollover prevention systems using different wheel torques only. Moreover, we propose a novel reference trajectory design from drivers’ maneuverings. Therefore, the trajectory following controls would try to regulate the vehicle to a trajectory close to drivers’ intentions.

In order to simulate the vehicle dynamics under various driving conditions, a “full-car model” with 20 system states is constructed. However, a full-car model is too complicate for a controller design. A simplified vehicle model, which neglects pitch motions from the full-car model, is used for controller design. The controller is developed from the “sliding mode control” techniques so that it has the robustness to cope with unmodelled dynamics.

Simulation results indicate that, in a vehicle rollover case, the proposed control systems can achieve both trajectory followings and rollover preventions simultaneously. However, the trajectory followings would fail when the vehicle starts to skid.