一種以馬達調控之扭力分配差速器對車輛動態之影響

Abstract

本研究提出一種以馬達調控之扭力分配差速器，並分析此機構特性與對車輛動態之影響。本研究之扭力分配差速器機構(Torque Vectoring Differential, TVD)是以一般差速器為基礎搭配行星齒輪組和馬達，來達到扭力分配之功能。此機構將引擎動力分別輸出至四個車輪，並藉由馬達提供的動力使扭力可在四輪之間進行調整。本研究首先推導此機構之動態方程式，並使用數值模擬方法進行分析，包含可替換之駕駛模型、動力分配模型、輪胎模型、車輛模型，以求得不同操作情形與環境下之車輛動態表現。模擬情境為假設引擎提供定扭力，首先分析車輛行駛於不同路況時之防滑功能，再就車輛直線行駛時，在單輪打滑及雙輪打滑之情況下，探討馬達啟動後對車輛驅動力、車身偏擺角速度之影響。最後討論轉向時扭力分配情況對車身偏擺角速度之影響。結果顯示此扭力分配差速器可在車輛遭遇打滑時保有較佳的驅動力，能在扭力分配的過程中避免車身偏擺角速度的增加，並可在轉向時提升車輛之轉向能力。

A type of motor-controlled torque vectoring differential is presented and analyzed in this study. The torque vectoring differential (TVD) in the study is based on open differentials with additional planetary gears and motors, which is capable of distributing torque. The engine power is transmitted to four wheels and the motors power is capable of controlling engine power between four wheels. The dynamic equations of the TVD are derived from the study, solved by Matlab and verified by SimulationX. In order to analyze the TVD, the study builds the program which is developed in Matlab and composed of driving model, power model, tire model and vehicle model. By the program, we can obtain the vehicle dynamics in different driving conditions. The study will analyze the limit-slip function in different road conditions with a fixed input engine torque, and the increase of the yaw rate when the vehicle is cornering. The study explains the effect of the traction and the yaw rate by starting motors. The result shows that the TVD can retain traction without increasing the yaw rate when tires slip and enhance the performance of cornering.