Passenger bus vibration analysis with optimized parameters under diverse operating conditions

This study develops and validates an eight-degree-of-freedom vibration model for a passenger bus to optimize its suspension system under various operating conditions. The mathematical, physical, and simulation models account for driver-induced vibrations, front and rear stabilizer bars, and vehicle–road interactions. Model parameters were calibrated through experiments, showing minimal relative errors between simulations and tests, confirming the model’s reliability. Using Matlab/Simulink, the effects of road roughness, braking, and cornering on vehicle vibrations were analyzed. The optimized rear suspension significantly improves ride comfort and vehicle stability: peak accelerations of the driver and vehicle body were reduced by 50%–60% at critical frequencies, and dynamic loads and pitch–roll accelerations decreased, enabling faster recovery to equilibrium after disturbances. During cornering, the safety index decreased by 33% on average, while the ride comfort index improved by 3.4%–9.3%, demonstrating superior performance in reducing rollover risk and maintaining tire-road contact. These results provide a reliable scientific basis for the design of optimized passenger bus suspensions. The proposed methodology also offers a practical approach for vehicle dynamics research, supporting future developments in automated and structure-optimized vehicle systems.