Optimization of Pneumatic Vibration Isolation System for Vehicle Suspension

1978 ◽  
Vol 100 (3) ◽  
pp. 500-506 ◽  
Author(s):  
E. Esmailzadeh

The suspension system of a vehicle provides the means by which forces and movements are transferred from the body to the wheels and vice versa. While the general outline of vehicle suspension behavior is fairly well known, little interest has been shown in the detailed dynamic performance of the various components. Air springs are perhaps the most versatile and adaptable type of suspension element. They provide practically frictionless action, adjustable load capacity and simplicity of height control. Initially, a vehicle suspension system with a pneumatic isolator connected to a fixed volume tank via parallel plate restrictor is considered. Here the damping is provided by the flow of air through the restricted passage which has an advantage over the conventional viscous shock absorber. Body movements are only considered to be vertical harmonic displacement. An optimization technique is applied to evaluate the optimum values of many parameters involved for which the maximum transmitted motion to the body would be minimum over the broad frequency range. Theoretical expressions for the transmissibility of the body and the wheel, optimum values of mass ratio, stiffness ratio and damping ratio are presented. Design data are presented nondimensionally for parameter variations which are sufficiently broad to encompass a wide range of practical engineering problems.

Author(s):  
W. G. Ata ◽  
S. O. Oyadiji

The vibration caused by severe road excitation influences off-road vehicle suspension performance. The vibration control of the suspension system is a crucial factor for modern vehicles. Smart control devices (magnetorheological dampers) are proposed as a first step to handle a multiple suspension system of off-road vehicles. The magnetorheological (MR) dampers can be employed as smart dampers for vibration suppression of the suspension system; this is done by varying the produced damping force. In this paper an investigation is presented on the effectiveness of such smart dampers in attenuating the vibration of a multiple suspension system. This goal is accomplished by designing a new fuzzy hybrid controller and studying its effectiveness on the suspension performance. The multiple suspension system considered here comprises a chassis, five wheels and three MR dampers. The chassis is suspended over the five wheels through five compression springs. Three MR dampers are attached to the first, second and the fifth wheel. The stiffness of the wheels is represented by five compression springs. Only the bounce and the pitch of the chassis are considered. The assessment of the proposed model is carried out through a simulation scheme under bump and sinusoidal excitations in the time domain. The excitation of the five wheels is done independently. The simulation is accomplished using the MATLAB/SIMULINK software. The simulation results show the effectiveness and robustness of the new controller in conjunction with MR dampers in vibration suppression. Compared to the passive suspension, the body bounce, body displacement, angular acceleration and pitch angle can be well controlled.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Yanling Liu ◽  
Wentao Zhao ◽  
Xiaofeng Yang ◽  
Long Chen ◽  
Yujie Shen

As a two-terminal mechanical element, the inerter has been successfully applied in various mechanical fields, such as automotive engineering and civil engineering, for passive control and semiactive control. In this paper, a hydraulic electric inerter is considered an active device to suppress the vibration of a vehicle suspension system. The components and working principle of the hydraulic electric inerter are first introduced. On the basis of a force test of the hydraulic electric inerter, nonlinear factors such as friction, the damping force, and the elastic effect are analyzed, and parameter identification methods are adopted to identify the detailed parameters. A dynamic model of the vehicle suspension system employing a nonlinear hydraulic electric inerter is established, and the predictive controller is designed to further improve the vibration isolation performance of the suspension system. Numerical simulations show that the performance of the vehicle ISD (inerter-spring-damper) suspension system is significantly improved compared to the passive suspension. Finally, bench tests are carried out, and the advantages of vehicle ISD suspension are demonstrated. The RMS (root-mean-square) value of the vehicle body acceleration and the RMS value of the suspension working space are reduced by 16.1% and 8.9%, respectively.


2021 ◽  
Author(s):  
Akshaya Kumar Patra ◽  
Bidyadhar Rout ◽  
Dillip Kumar Subudhi ◽  
Saswata Pani ◽  
Narayan Nahak ◽  
...  

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Yujie Shen ◽  
Long Chen ◽  
Yanling Liu ◽  
Xiaoliang Zhang

An ideal inerter has been applied to various vibration engineering fields because of its superior vibration isolation performance. This paper proposes a new type of fluid inerter and analyzes the nonlinearities including friction and nonlinear damping force caused by the viscosity of fluid. The nonlinear model of fluid inerter is demonstrated by the experiments analysis. Furthermore, the full-car dynamic model involving the nonlinear fluid inerter is established. It has been detected that the performance of the vehicle suspension may be influenced by the nonlinearities of inerter. So, parameters of the suspension system including the spring stiffness and the damping coefficient are optimized by means of QGA (quantum genetic algorithm), which combines the genetic algorithm and quantum computing. Results indicate that, compared with the original nonlinear suspension system, the RMS (root-mean-square) of vertical body acceleration of optimized suspension has decreased by 9.0%, the RMS of pitch angular acceleration has decreased by 19.9%, and the RMS of roll angular acceleration has decreased by 9.6%.


1967 ◽  
Vol 89 (4) ◽  
pp. 729-740 ◽  
Author(s):  
Jerome E. Ruzicka

Elementary vibration theory based on transfer response analyses of single-degree-of-freedom systems indicates that an increase in isolation system damping causes a decrease in resonant transmissibility. This theory further specifies that, for viscous-damped systems, an increase in damping decreases the resonant frequency whereas, for Coulomb-damped systems, an increase in damping increases the resonant frequency. It is frequently found in practice that an increase in damping may increase the resonant transmissibility and cause a change in resonant frequency opposite to that predicted by elementary theory. This paper presents a more extensive evaluation of the resonance characteristics of unidirectional vibration isolation systems, including the effects of directly coupled and elastically coupled damping elements. Mathematical models and absolute transmissibility characteristics of viscous and Coulomb-damped vibration isolation systems are discussed and resonance characteristics are analyzed in terms of the resonant frequency ratio, the resonant transmissibility, and the rate of change of these parameters with damping. Design data are presented graphically for parametric variations of stiffness and damping which are sufficiently broad to encompass a wide range of practical engineering problems.


2011 ◽  
Vol 148-149 ◽  
pp. 516-519
Author(s):  
Jun Tao Fei ◽  
Jing Xu

This paper attempts to establish the vibration control technology based on neural network control. First, the dynamic model of vehicle suspension system is discussed, and the linear passive suspension model and nonlinear spring suspension model of the vertical acceleration are compared. It is shown that the performance of nonlinear spring suspension is better than that of the linear passive suspension model. Because of the great advantages of the neural network in dealing with the nonlinear property, secondly, model reference neural control module is introduced in the suspension system to realize the optimization of the body vertical acceleration. Simulation results demonstrate the effectiveness of the neural network adaptive controller with application to vehicle suspension.


2011 ◽  
Vol 383-390 ◽  
pp. 2012-2017 ◽  
Author(s):  
Guo Quan Yang ◽  
You Qun Zhao

In this paper, a semi-active suspension system has been proposed to improve the ride comfort, and a 2 DOF vehicle system is designed to simulate the actions of vehicle suspension system. The purpose of a suspension system is to support the vehicle body and increase ride comfort. The aim of the work described in the paper was to illustrate the application of fuzzy logic technique to the control of a continuously damping automotive suspension system. The ride comfort is improved by means of the reduction of the body acceleration caused by the car body when road disturbances from smooth road and real road roughness. Based on MATLAB fuzzy control toolbox, fuzzy controller is designed. Simulation analysis of suspension system is preceded by using MATLAB/Simulink7.0. The result shows that this control can improve the body acceleration, suspension distortion etc.


Author(s):  
Xiang Gao ◽  
Junchuan Niu ◽  
Ruihao Jia ◽  
Zhihui Liu

In order to reuse the energy dissipated by magneto-rheological (MR) damper, a self-powered MR damper is designed and analyzed theoretically. The main thrust of this work is establishing the mechanical-electromagnetic coupling model of quarter vehicle suspension based on self-powered MR damper, whilst the energy conversion efficiency of self-powered MR damper with electromagnetic parameters changing is investigated. The magnetic circuit model is formulated firstly. The influence of electromagnetic parameters on current in MR damper is analyzed systemically in frequency domain. A multi-objective optimization method is performed to determine the electromagnetic parameters. Subsequently a quarter vehicle suspension system with self-powered MR damper is introduced. The mechanical-electromagnetic coupling model is established. The frequency response function is derived under random road excitation. The vibration isolation capability of the proposed quarter vehicle suspension system is addressed in time and frequency domain respectively. Compared to passive control, the amplitude of sprung mass velocity, acceleration and transmissibility are reduced by 51%, 78% and about 10 dB in time and frequency domain respectively. Finally the energy conversion efficiency of self-powered MR damper with magnetic parameters changing under random road excitation is discussed. The vibration isolation performance of self-powered MR damper is more effective than passive control, especially in resonance range of the suspension system.


Author(s):  
Hamid Taghavifar ◽  
Subhash Rakheja

An accurate estimation of the harvestable energy from a vehicle suspension under typical operating conditions is vital for design and implementation of efficient energy harvesters in vehicles. In this study, a generic three-dimensional model of a commercial vehicle is formulated by integrating nonlinear models of suspension components and tires to determine the harvestable power considering the effects of suspension parameters and road characteristics. The component characteristics of the suspension system and tires are obtained through the reported laboratory-measured data acquired under an extensive range of loading conditions. The vehicle model is subsequently employed to investigate the harvestable energy potential considering variations in the driving speed, chassis load, road waviness and roughness, suspension and tire stiffness, compression mode damping ratio, and asymmetric suspension damping over the most possible ranges of running conditions. The results suggested significant influences of these parameters, while the driving speed, damping asymmetry factor, compression mode damping ratio, and road condition revealed the most pronounced effect on the harvestable power. The results obtained in terms of root mean square and power spectral density of harvestable power are also indicative that rough terrains yield incomparably larger magnitudes of energy dissipation than relatively smooth road classes defined in ISO 8608:1995, and thereby suggestive of the greater potential of energy recovery from commercial vehicles on off-road surfaces.


2019 ◽  
Vol 8 (3) ◽  
pp. 1625-1637

A novel efficient control scheme for an active vehicle suspension system is to be designed and simulated in this paper. A half car model has been designed and controlled using two different schemes of standard fuzzy control and bounded interval fuzzy control using MATLAB/SIMULINK. The bounded interval fuzzy control is designed to reduce the uncertainties in the fuzzy sets system and solve the non-linear control problem that the standard fuzzy control cannot handle it. It should be noted that fuzzy logic system is capable of dealing with imprecise concepts and numerous vague but the design of membership functions is nontrivial task. This is because of uncertainty degree that is caused due to road inputs profiles, fuzzy knowledge rules and immeasurable disturbance. The proposed method is expected to be able to mimic the heuristic knowledge of design the membership functions which depends on degree of uncertainty. The membership functions will be generated online during the process in order to deal with uncertainties. The simulation results have demonstrated that the proposed control exhibits better performance and stability as compared to standard fuzzy logic. In addition, the proposed scheme presents a preferable solution and balancing achievement between ride comfort and handling performance. These results demonstrated that the body accelerations and tire dynamic loads will be reduced for the vehicle suspension system in either automobiles or robotics suspension systems.


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