This paper describes research and parametric analyses of braking effectiveness and directional stability for golf cars, personal transport vehicles(PTVs) and low speed vehicles (LSVs). It is shown that current designs, which employ brakes on only the rear wheels, can lead to rollovers if the brakes are applied while traveling downhill. After summarizing the current state of existing safety standards and brake system designs, both of whichappear deficient from a safety perspective, a previously developed dynamic simulation model is used to identify which parameters have the greatest influence on the vehicles¦ yaw stability. The simulation results are then used to parametrically quantify which combination of these factors can lead to yaw induced rollover during hard braking. Vehicle velocity, steering input, path slope and tire friction are all identified as important parameters in determining braking stability, the effects of which on rollover propensity are presented graphically. The results further show that when vehicles are equipped with front brakes or four-wheel brakes, the probabilityofa yaw induced rollover is almost entirely eliminated. Furthermore, theparametric charts provided may be used as an aid in developing guidelinesfor golf car and PTV path design if rear brake vehicles are used. (A) Reprinted with permission from Elsevier.
Abstract