Probabilistic Method for Assessing the Stability of Multi-Axle Vehicles When Braking

The solution to the problem of stability of a multi-axle vehicle during braking is connected with the determination of the dynamic distribution of normal road reactions between the axles. To assess the stability of the vehicle is used as an indicator of the stability factor representing the ratio of the stabilizing moment to moment, the perturbing skid. When the values of the stability coefficient is greater than or equal to unity, the movement is stable, and otherwise it is unstable. For a multi-axle vehicle, determining the dynamic normal road reactions on the axles is possible after disclosing the static uncertainty of the physical model of the car, which is a multi-support beam. The solution to this problem involves the use of the "three sigma" rule. The maximum possible value of the stability coefficient is realized with the most favorable distribution of the total normal road reactions between the axles, ensuring the maximum value of the stabilizing moment and the minimum value of the disturbing moment. The minimum (most unfavorable) value of the stability coefficient corresponds to the minimum value of the stabilizing moment and the maximum value of the moment of the disturbing one. A probabilistic method is proposed for determining the stability index of multi-axle vehicles when braking on the model of the normal distribution of the stability coefficient.