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Heavy trucks are mostly used for international transportations, with longer highways and long driving hours contributing to corresponding increases in the driver's fatigue that is related to accidents. Therefore, this study aims to improve the truck ride performance using multistage leaf springs and semi-active suspension for the driver seat. This analytical study describes the influence of the truck main suspensions on the performance indices analytically using MATLAB Simulink for different loading conditions in three case studies: fully laden articulated truck (case A), unladen truck (case B), and empty semi-trailer and a multistage leaf springs is considered after designing the main leaf spring stiffness based on particle swarm optimization (case C). This study exhibits a contribution based on the fact that changing the trailer cargo weight has considerable effects on the natural frequency of the vibration modes of the vehicle system, particularly for articulated carriage. Subsequently, the influence of the dynamic interaction of an articulated vehicle between the semitrailer and the tractor on its ride behavior has been investigated. The model has also predicted the effect of total trailer cargo on performance indices for 13 degrees of freedom model of a 6-axle articulated truck semi-trailer vehicle with a random road excitation. Additionally, a semi-active driver seat suspension based on skyhook strategy and seat passive suspension are compared in terms of the power spectral density and root mean square values. The results showed that the truck ride performance is improved significantly, and all the acceleration responses are suppressed dramatically when a designed multistage leaf spring suspension is considered in case C. The current analysis demonstrated that using specific and adjustable suspension parameters can positively enhance the riding behavior of the unladen vehicle. The results showed that the cab, tractor, and trailer acceleration improved by 22%, 21%, and 28%, respectively, which provides a comfort driving trip essentially for long distance traveling.

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Vehicle parameters and operation conditions play a critical role in vehicular handling and stability. This study aimed to evaluate vehicle stability based on cornering tire stiffness integrated with vehicle parameters. A passenger vehicle is considered in which a two-state linear bicycle model is developed in the Matlab/Simulink. The effect of the vehicle parameters on lateral vehicle stability has been investigated and analyzed. The investigated parameters included CG longitudinal position, wheelbase, and tire cornering stiffness. Furthermore, the effects of load variation and vehicle speed were addressed. Based on a Fishhook steering maneuver, the lateral stability criteria represented in lateral acceleration, yaw rate, vehicle sideslip angle, tire sideslip angles, and the lateral tire force were analyzed. The results demonstrated that the parameters that affect the lateral vehicle stability the most are the cornering stiffness coefficient and the CG longitudinal location. The findings also indicated a positive correlation between vehicle properties and lateral handling and stability.

This paper investigates the bandwidth sensitivity of automobile handling, comfort, and stability based on Monte Carlo sensitivity simulations. Performed bandwidth sensitivity simulations include the effects of vehicle geometry and suspension parameters on lateral acceleration, roll angle, front/rear sideslip angles, and yaw rate angle, including both time- and frequency-domain sensitivity analyses. To replicate actual automobile responses, a full-vehicle roll-oriented suspension seven-degree-of-freedom (7-DOF) model was developed and implemented considering a 2-DOF planar two-track model with a nonlinear Pacejka tire model. During the Monte Carlo simulations, 10 mm and 20 mm amplitude sine-wave excitations were used for the left and right sides, respectively, and the frequency was uniformly sampled over the range of 0–30 Hz. Simultaneously, each investigated vehicle parameter varied by ±25% relative to the reference model parameters. These simulations illustrate the sensitivity of the lateral acceleration, roll angle, yaw angle, and sideslip angles to their parameter variations. The results confirm that the road excitation frequency, tire properties, vehicle geometry, and suspension parameters significantly influence the vehicular lateral and roll stabilities when considering the lower and higher peaks and the frequency bandwidths of the lateral and roll stabilities. Interestingly, the longitudinal location of the center of gravity and the tire properties can achieve more significant peak lateral stability responses, as represented by the front and rear sideslip angles and the frequency bandwidth, compared to the other vehicle parameters at high frequencies. Choosing the correct tire properties and vehicle geometry, as well as suspension characteristics, plays an essential role in increasing the vehicular lateral stability and the rollover threshold. Variations in the studied parameters allow for higher vehicular stability when a vehicle is driven on random road surfaces.