This study proposes a three-dimensional vibration model of bus with 10 DOF (degree of freedom) based on Dragan Sekulić model to analyze the suspension parameters directly influenced ride comfort. The suspension parameters which include the stiffness and damping parameters are analyzed based on the weighted r.m.s. (root-mean-square) acceleration responses of the space of a driver, passenger in the middle part of the bus and passenger in the rear overhang according to ISO 2631-1:1997. The results show that both stiffness and damping parameters of vehicle suspension have important influences on ride comfort. Especially, the stiffness and damping values of vehicle suspension are within the value ranges (0.5 k 0 ≤ k ≤ 0.75 k 0 ) and (0.5 c 0 ≤ c ≤ 0.75 c 0 ) to improve the ride comfort of driver and passengers.

In order to compare the performance of heavy truck suspension system, a 3D dynamic model with 14 degrees of freedom is developed with the dynamic models of the traditional and new air suspension systems to compare the performance of the air suspension systems for reducing the negative impacts on the road surface when vehicle moves on the different road conditions. Dynamic modes of two different types of the air suspension systems are respectively established and a dynamic load coefficient (DLC) is chosen as objective function which uses Matlab/Simulink software to simulate and determine the values of objective function. The results shown that the performance of the new air suspension system is better than the tradition air suspension for reducing the negative impact on road surface under the different operating conditions of vehicle. Especially, the DLC values of wheels at 3rd axle of vehicle with the new air suspension system are respectively reduced by 6.7 %, 7.0 %, 7.4 %, 7.7 % and 8.5 % in comparison with the traditional air suspension system when vehicle moves on the different pavement conditions a velocity of 20 m/s and fully loaded. In addition, the study results not only can provide a reference for designers but also traffic management to reduce the negative impact on road surface.

This paper presents the effect of in-wheel motor (IWM) suspension system on electric vehicle (EV) ride comfort. To analyze the impact on the vehicle ride comfort caused by IWM suspension system, a dynamic model of quarter vehicle is established with the combination of IWM and road surface roughness excitations. The weighted root-mean-square (r.m.s.) acceleration of the vertical vehicle body (awbz) according to the international standard ISO 2631-1 (1997) is selected as an objective function to analyze the effect of IWM suspension system when the road surface and IWM mass conditions change. The study results indicate that the effect of IWM suspension system on the EV ride quality is significant and the value of awbz reduces by 8.6 % in comparison to without IWM suspension system. The IWM suspension system has significantly improved the EV ride quality when the road surface and IWM mass conditions change.

The purpose of this paper is to improve the performance of air suspension systems for a semi-trailer truck in the direction of reducing the dynamic wheel load acting on road surface (Part 1: modeling and algorithm). To achieve the goal of finding the optimal design parameters for the air suspension systems, a half-vehicle dynamic model under the road-vehicle interaction with 12 degrees of freedom (d.o.f) is established for searching the optimal design parameters of vehicle suspensions using genetic algorithm (GA). Dynamic load coefficient (DLC) is considered as a target function. Two optimal conditions: optimal design of geometrical parameters of air spring suspension systems (Case 1) and optimal design of parameters of air suspension systems (Case 2) are selected in this study. The results of this paper are the basis for optimization and discussion in Part 2 as the results and discussion.

The purpose of this paper is to solve problems about cab’s low-frequency shaking in the direction of forward motion when vibratory roller operates. To solve this problem, a modal test for a single-drum vibratory roller is carried out by the Belgium LMS dynamic testing which is used to identify the model parameters and find out the natural frequency of the vehicle. A Finite Element Analysis (FEA) simulation is carried out to find out the reasons causing the cab’s low-frequency shaking. The model simulation results are found to be in good agreement with the experimental results. Finally, the design parameters of cab’s isolation system are optimized to reach the maximum value of the first-order natural frequency in order to avoid resonance vibration for cab at low frequency and reduce cab’s low-frequency shaking.

The objectives of this study is to compare the performance of the hydro-pneumatic suspension system of heavy truck on cab ride comfort with rubber and leaf springs of suspension systems. To compare the three types of suspension systems, a three-dimensional dynamic model of heavy truck with 15 degrees of freedom (DOF) is established based on Zhou Changfeng model under random excitation of road surface for simulation and analysis. The root mean square (r. m. s) acceleration of the vertical cabin, pitch angle, and roll angle of cabin is chosen as objective functions. Matlab/Simulink software is used to simulate and calculate the values of objective functions. The ride performance of the hydro-pneumatic suspension system on vehicle is analyze and compared to two other supension systems when vehicle operates under different operating conditions. The results show that the values of objective functions with the hydro-pneumatic suspension system are significantly reduced in comparison with the rubber and leaf suspension system. The ride performance of Hydro-pneumatic suspension system is much better than that of the rubber and leaf suspension systems.