Abstract: The instability condition is calculated and analyzed when the rubber tire vehicle enters the curve to provide the basis for the sliding vehicle protection in curves in this paper. The roll acceleration threshold of vehicle rollover is derived by analyzing the force of the sliding vehicle in the roll plane. The formula for calculating steady-state steering radius of vehicle is obtained by establishing a two-degree-of-freedom model of vehicle, calculating the entry speed of sliding vehicle and deriving the entry steering angle under Ackermann steering conditions. The parameters of the instability calculation of the sliding vehicle are given. MATLAB/Simulink is used to simulate the instability of the vehicle entering the corner with the sliding distance from 25 m to 200 m. The results show that when the sliding distance is 0~100 m, the operating margin of the steering wheel is 2.85°, and the vehicle has the risk of scratch collision. When the sliding distance is greater than 100 m, the lateral acceleration of the vehicle is greater than 5.16 m/s2 , and the vehicle will roll over.

Key words: vehicle sliding; roll acceleration threshold; steady turning radius; curve protection

摘要： 对无轨胶轮车失速入弯的失稳情况进行计算分析，为车辆失速弯道防护提供依据。通 过对失速车辆在侧倾平面内进行受力分析，推导出车辆侧翻的侧倾加速度阈值；建立车辆二 自由度模型，计算失速车辆入弯车速，推导阿克曼转向条件下的入弯转向角，得到车辆稳态 转向半径计算式。给出失速车辆的失稳计算的相关参数，采用 MATLAB/Simulink 对失速距离 为 25 m 至 200 m 的车辆入弯失稳情况进行数值模拟，结果表明：失速距离为 0～100 m 时， 车辆转向盘的操作余量为 2.85°，车辆存在剐蹭碰撞风险；失速距离大于 100 m 时，车辆侧 向加速度大于 5.16 m/s2，车辆会发生侧翻。

关键词: 车辆失速；侧倾加速度阈值；稳态转向半径；弯道防护