Research on Modularized Control Structure Combined with Lane Keeping Control and Tire Anti-slip Strategy for an Automated Vehicle

本研究針對車輛自動駕駛與主動安全控制提出一套模組化設計架構將這兩種領域結合，形成一套完整的輪胎防滑暨車道維持控制系統，自動駕駛部分的車道維持控制根據車輛動態結合前看系統模型，分別以模型預測控制器及強韌控制器達成，主動安全控制部分的輪胎防滑控制策略藉由一套以無損型卡爾曼濾波器為基礎的輪胎暨車輛狀態估測器，透過無損轉換的形式可以將精準度高但複雜的非線性的車輛模型應用於原本線性的卡爾曼濾波器，藉此提升狀態估測效果。估測後的輪胎與車輛狀態值則與通訊模組的與輪胎-地面最大靜摩擦係數一起輸出到防滑控制策略模組，車道維持控制器所輸出的輪胎總扭矩命令則於防滑控制策略模組利用輪胎狀態估測值與摩擦係數計算進行動力分配，達到縱向輪胎防滑作用，而輪胎側向防滑根據半經驗輪胎模型「Magic Formula」進行輪胎滑動分析，找出不同輪胎-地面最大靜摩擦係數下的輪胎側滑角線性區邊界，接著利用輪胎側滑角靜態模型搭配其動態模型的頻域響應分析，決定出對應輪胎側滑角線性區邊界的最大速度邊界，再加以計算出理想速度參考訊號交由車道維持控制器追尋此速度，透過速度控制的方法將兩者結合，加上防滑控制策略模組裡的修轉向修正功能，達成側向輪胎防滑作用。This research proposes a modularized control structure combined with vehicle automatic driving and active safety control technique. This turns out to be a complete vehicle lane keeping control system with tire anti-slip function. For vehicle automatic driving, the vehicle dynamic model combined with look-ahead system is used for designing controllers which are model predictive controller (MPC) and robust H controller to stabilize the vehicle during lane keeping maneuvers. For active safety control strategy, an unscented Kalman filter based tire and vehicle states estimator is used to provide more information to tire anti-slip function block. The nonlinear vehicle model which is more accurate but much complex can be applied to linear Kalman filter through unscented transform without losing its accuracy. The longitudinal anti-slip function uses the estimate results and tire-road maximum friction coefficient from the communication module to distribute the total tire torque command form lane keeping controller to four individual tires. For lateral anti-slip function, the linear boundary of tire sideslip angle with different tire-road maximum friction coefficient is obtained based on semi-empirical tire model as known as magic formula. Every linear boundary of tire sideslip angle has its corresponding maximum speed boundary which is obtained through analyzing the static and dynamic model of tire sideslip angle. Then, the speed boundary will be sent to lane keeping controller as a reference speed signal. Thus, two modules of systems are connected via the speed control scheme. Ultimately, this research uses speed control and steering adjustment to prevent the tire from slipping at lateral axis