多動力馬達電動車兼顧轉向安全之節能動力分配策略

Abstract

傳統的車輛控制器採用串聯式節能與安全策略，將車身穩定系統與動力分配系統獨立進行設計，但這樣的設計方法沒有考慮各系統的交互作用，本研究透過馬達特性說明車身穩定系統所產生的直接偏擺力矩，會使動力分配系統的能耗表現變差。 本研究提出兼顧轉向安全之節能動力分配策略，採用並聯式節能與安全策略，目的是在車輛穩定性佳時降低直接偏擺力矩而改善能耗，因此以β-γ相位穩定圖判斷車輛穩定性，同時整合滑模控制，設計本研究之車身穩定系統。 透過模型迴路與硬體迴路平台驗證本研究策略，實驗結果顯示相較於串聯式節能與安全策略，並聯式節能與安全策略能夠為粒子群最佳化動力分配帶來1%~5%的續航力提升； 能為固定比例動力分配帶來4.5%~7%的續航力提升。 故本研究的策略能確保車輛控制器以更小的直接偏擺力矩帶來轉向行駛的穩定性，在兼顧轉向安全的條件下，提升車輛轉向行駛時的節能表現。

Traditional vehicle controller adopts a series energy saving and safty (SES) strategy, which independently designs vehicle stability system and power distribution system. However, traditional design method didn’t consider the interaction of each system. So, this research uses characteristics of motor to illustrate that direct yaw moment produced from vehicle stability system adversely affects the energy saving performance of the power distribution system. This research proposes energy saving strategy with steering stability for an electric vehicle driven by multiple motors, which adopts a parallel energy saving and safety (PES) strategy, and the goal is that the controller reduces direct yaw moment to achieve energy consumption improvement when vehicle has good stability. This research uses β-γ phase plane to judge vehicle stability, and it integrates with sliding mode control to design a vehicle stability system. This research verifies the strategy by model in the loop (MIL) and hardware in the loop (HIL) platform. Experimental results show that compare with SES strategy, PES strategy saves 1%~5% of energy when vehicle uses particle swarm optimization (PSO) as power distribution; and 4.5%~7% of energy when constant proportion (CP) is used as power distribution. Thus, the strategy of this research makes sure the controller can produce smaller direct yaw moment to stabilize the vehicle. The vehicle can then remain stable and achieve higher energy-saving performance.