主動式液氣懸吊系統於八輪車輛之連通拓樸及性能分析

Abstract

本研究為探討不同懸吊剛性的調配，對轉彎中的車輛的穩定度及轉向性能的影響做評估。首先吾人先利用車輛各座標軸之力平衡與力矩平衡分析，建立出車輛之動態數學模型，由車輛數學模型可得不同懸吊剛性下之車輛運動動態特性，並利用側向負載轉移係數LTR及最佳轉向性能指標J來分別評估車輛行駛時的穩定度及操縱性。本研究以輸入前輪轉向角進行模擬，並假設側向負載轉移係數之絕對值為1時，即為單邊車輪之正向力和為零，單邊車輪皆離地時作為車體穩定度最低之指標，側向負載轉移係數之絕對值越小即車體穩定度越高；而車輛之最佳轉向性能指標越小，車體越容易達到欲達到之理想軌跡，轉向性能即越強。上述兩種即為判斷穩定度及轉向性能之方法。再探討車輛懸吊系統之剛性、氣體的調配及連通，對車輛穩定度及轉向性能的影響，並找出最適當之調配方法，使得車輛有較高的行駛穩定度及轉向性能。

The purpose of this research is to investigate the relationship between the spring coefficient of the suspension and the dynamic stability and handling of a vehicle during cornering. First, we use the basic dynamic principle to compute the dynamic equations of the vehicle. The equations of motion of the system are used to observe the vehicle dynamic characteristics for different spring coefficients of the suspension. We use lateral load transfer ratio to evaluate the dynamic stability and optimal handling performance index of the vehicle to evaluate the handling. In this research, the cornering angle of the front four wheels is applied to simulate. It is assumed that the absolute value of lateral load transfer ratio equals to 1, which represents that the sum of the normal force of the four wheels in one side equals to zero. In this situation, the four wheels are all lift-off and it represents the lowest dynamic stability. The smaller absolute value of lateral load transfer ratio represents the higher dynamic stability of the vehicle. The smaller the optimal handling performance index of the vehicle is, the easier the vehicle reaches the desired track. The most suitable spring coefficients are obtained to achieve o high stability and handling for the vehicle during cornering.