Optimum design for passive suspension system of a vehicle to prevent rollover and improve ride comfort under random road excitations

Author(s):  
Abolfazl Seifi ◽  
Reza Hassannejad ◽  
Mohammad A Hamed

The main functions of suspension system are to provide ride comfort for the passengers and vehicle handling (road holding). But, in many studies, full attention to the ride comfort leads to the determination of incorrect suspension system parameters as well as other problems such as rollover and reducing road-holding ability in the vehicle. The aim of this study is to present a method for the optimized design of the vehicle suspension system in order to improve the ride comfort, road holding, workspace and preventing rollover, considering a full vehicle model with 11-DOF. The most important feature of this study is that the prevention of rollover factor and all of suspension functions are considered simultaneously. In this research, in order to assess the ride comfort, the vertical acceleration values of seats that are caused by random road roughness are calculated by power spectral density of road in frequency domain. In the context of prevention of rollover, Fishhook manoeuvre is performed using a mathematical model for the roll motion, and then the dynamic behaviour of the variables is considered in rollover threshold. Then, the optimization problem is solved to minimize the vertical acceleration values and vehicle roll angle by considering the physical limitation and safety of the model. The results of the optimization show that the vertical acceleration, in frequency domain at the desired boundary values (as defined in ISO 2631), decreases and rollover resistance of the vehicle increases.

2019 ◽  
Vol 8 (02) ◽  
pp. 25-30
Author(s):  
Nanda Pranandita

The vehicle suspension system is an important part to minimize the vibration of the vehicle caused by road unevenness. The classification of the road surface in this study is based on the classification of road roughness "Good" according to ISO 8606. The analysis of passive suspension system in this research may explain the frequency response which is received by the motorists while driving. The full car model with 1 DOF riders used in this study, simulated by using the numerical simulation software. The frequency response analysis is done on the vertical movement of the driver. Based on the analysis performed, the highest acceleration of 2.375 m / s2 at a frequency of 3.258 Hz. This value indicates the condition of "Uncomfortable" based on the table of ISO 2631. This condition will cause the rider toexperience dizziness, therefore it is strongly advised motorists to avoid frequencies below 7 Hz.


2014 ◽  
Vol 573 ◽  
pp. 317-321 ◽  
Author(s):  
K. Rajeswari ◽  
Anjali

This paper presents an estimator for a nonlinear active suspension system considering the hydraulic actuator dynamics. PID controller is used to control the Active suspension system of nonlinear quarter car model. Extended Kalman filter is designed to estimate the states from the measurement model perturbed with noise. Simulation results demonstrate the effectiveness of the PID based active suspension system in reducing the vertical acceleration transmitted to the passengers thereby improving the ride comfort. Also the effectiveness of the Extended Kalman filter in estimating the actual vehicle states is demonstrated.


Author(s):  
Yong Guo ◽  
Chuanbo Ren

In this paper, the mechanical model of two-degree-of-freedom vehicle semi-active suspension system based on time-delayed feedback control with vertical acceleration of the vehicle body was studied. With frequency-domain analysis method, the optimization of time-delayed feedback control parameters of vehicle suspension system in effective frequency band was studied, and a set of optimization method of time-delayed feedback control parameters based on “equivalent harmonic excitation” was proposed. The time-domain simulation results of vehicle suspension system show that compared with the passive control, the time-delayed feedback control based on the vertical acceleration of the vehicle body under the optimal time-delayed feedback control effectively broadens the vibration absorption bandwidth of the vehicle suspension system. The ride comfort and stability of the vehicle under random road excitation are significantly improved, which provides a theoretical basis for the selection of time-delayed feedback control strategy and the optimal design of time-delayed feedback control parameters of vehicle suspension system.


Author(s):  
Thomas Lato ◽  
Huiyong Zhao ◽  
Lin Zhao ◽  
Yuping He

This paper presents an energy-regenerative suspension device that is able to harvest some of the wasted energy that is generated in a suspension system. For a traditional road vehicle suspension system, shock absorbers are mainly dissipating energy to reduce vibration. The dissipated energy may be collected to improve the fuel economy of road vehicles. In this research, CarSim and Simulink are used to simulate and determine the harvestable energy in a conventional shock absorber under different operating conditions. A conceptual energy-regenerative absorber is designed and tested using a fabricated prototype. A variable speed motor is implemented to adapt the change of stroke length of a mechanism due to the various road roughness. Instruments, e.g., laser tachometer, pressure gauge, ammeter, voltmeter, and stopwatch, are used to collect data. The simulation and prototype testing results indicate that the proposed energy-regenerative suspension device could harvest dissipated energy to improve vehicle fuel economy.


2018 ◽  
Vol 10 (7) ◽  
pp. 168781401877386 ◽  
Author(s):  
Hongbo Wang

Vehicle suspension system is the key part in vehicle chassis, which has influence on the vehicle ride comfort, handling stability, and security. The extension control, which is not constrained by common control method, could further improve the suspension system performance. The 7 degree-of-freedom suspension model is built. The extension controller is designed according to the function differences. In different extension set domains according to the correlation function, the corresponding control strategy is designed to ensure the suspension system obtains optimal performance in the classical domain and expands the controllable range outside the classical domain as large as possible. By adopting game theory, the domain is optimally divided, and the domain boundary control jump is smoothed by introducing Takagi–Sugeno–Kang fuzzy control into the extension control. Through the simulation and results comparison, it is demonstrated that the extension control could further improve the vehicle ride comfort than the optimal control and the extension control ability can be further promoted through domain game and Takagi–Sugeno–Kang fuzzy control. The analysis of the influence of the extension controller parameter varieties on suspension system performance shows that the error-weighted coefficient and control coefficient have significant effect to the suspension system performance.


2020 ◽  
Vol 10 (22) ◽  
pp. 8167
Author(s):  
Mădălina Dumitriu ◽  
Dragoș Ionuț Stănică

The theoretical research on means to reduce the vertical vibrations and improve the ride comfort of the railway vehicle relies on a mechanical model obtained from the simplified representation of the vehicle, while considering the important factors and elements affecting the vibration behaviour of the carbody. One of these elements is the anti-yaw damper, mounted longitudinally, between the bogie and the vehicle carbody. The anti-yaw damper reduces the lateral vibrations and inhibits the yaw motion of the vehicle, a reason for which this element is not usually introduced in the vehicle model when studying the vertical vibrations. Nevertheless, due to the position of the clamping points of the anti-yaw damper onto the carbody and the bogie, the damping force is generated not only in the yawing direction but also in the vertical and longitudinal directions. These forces act upon the vehicle carbody, impacting its vertical vibration behaviour. The paper analyzes the effect of the anti-winding damper on the vertical vibrations of the railway vehicle carbody and the ride comfort, based on the results derived from the numerical simulations. They highlight the influence of the damping, stiffness and the damper mounting angle on the power spectral density of the carbody vertical acceleration and the ride comfort index.


Author(s):  
A.S. Emam ◽  
H. Metered ◽  
A.M. Abdel Ghany

In this paper, an optimal Fractional Order Proportional Integral Derivative (FOPID) controller is applied in vehicle active suspension system to improve the ride comfort and vehicle stability without consideration of the actuator. The optimal values of the five gains of FOPID controller to minimize the objective function are tuned using a Multi-Objective Genetic Algorithm (MOGA). A half vehicle suspension system is modelled mathematically as 6 degrees-of-freedom mechanical system and then simulated using Matlab/Simulink software. The performance of the active suspension with FOPID controller is compared with passive suspension system under bump road excitation to show the efficiency of the proposed controller. The simulation results show that the active suspension system using the FOPID controller can offer a significant enhancement of ride comfort and vehicle stability.


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