Analysis and Evaluation of Roll Safety Thresholds of Tractor Semi-Trailer Vehicles during Turning Maneuvers Based on the Yaw Rate of Vehicle Bodies and Roll Safety Factor

This article aims to analyze and evaluate the roll safety thresholds (RSTs) and roll safety zones of tractor semi-trailer vehicles during turning maneuvers, using the roll safety factor (RSF) and yaw rate of the vehicle bodies. To achieve this, a full dynamics model is established using the multibody system method. This model is then used to survey and evaluate the vehicle’s motion state, using ramp steer maneuver (RSM) steering rules. In each survey case, the maximum values of RSF and yaw rate of vehicle bodies are synthesized in 3D data, with an initial velocity range of 40 km/h to 80 km/h and a magnitude of steering wheel angle range of 12.5° to 300°. These 3D data are used to determine the proposed values of RSF, which can be used as examples to set the threshold values of the yaw rate of vehicle bodies and roll safety zones. At a velocity of 60 km/h, the dynamic rollover threshold for proposed roll safety factor (RSF_prop) is equal to 1, with corresponding values of 15.718°/s and 14.962°/s. Similarly, the warning threshold for RSF_prop is equal to 0.6, with values of 9.514°/s and 9.404°/s, and for RSF_prop equal to 0.7, the values are 10.705°/s and 10.625°/s. The control threshold for a vehicle velocity of 60 km/h and RSF_prop equal to 0.9 is calculated as 13.588°/s and 13.339°/s. These results can be used as a basis for developing early warning and control systems for various vehicle operating modes.