Enhanced ride comfort using nonlinear seat suspension with high-static-low-dynamic stiffness

2020 ◽  
Vol 51 (4-5) ◽  
pp. 63-76 ◽  
Author(s):  
Chun Cheng ◽  
Yan Hu ◽  
Ran Ma
Keyword(s):  
Ride Comfort ◽  
Structural Parameters ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
Low Frequency ◽  
Coupled Model ◽  
Human Model ◽  
Vehicle Speed ◽  
Seat Suspension ◽  
Low Frequency Vibration

To attenuate the low-frequency vibration transmitted to the driver, a nonlinear seat suspension with high-static-low-dynamic stiffness is designed. First, the force and stiffness characteristics are derived. The nonlinear suspension can achieve the quasi-zero stiffness at the static equilibrium position when the structural parameters are properly designed. Then, a car-seat-human coupled model which consists of a quarter car model, a seat suspension, and a 4 degree-of-freedom human model is established to predict the biodynamic response of the driver. Finally, the isolation performance of the high-static-low-dynamic stiffness seat suspension under two typical road excitations is evaluated separately based on the numerical method. The effects of stiffness ratio, damping ratio, and vehicle speed on the ride comfort are investigated. The results showed that the nonlinear seat suspension outperforms the equivalent linear counterpart and can achieve the best ride comfort when the quasi-zero stiffness condition is satisfied.

Modelling and validation of a seat suspension with rubber spring for off-road vehicles

2017 ◽  
Vol 24 (18) ◽  
pp. 4110-4121 ◽  
Author(s):  
Leilei Zhao ◽  
Yuewei Yu ◽  
Changcheng Zhou ◽  
Fuxing Yang
Keyword(s):  
Vibration Isolation ◽  
Ride Comfort ◽  
Low Frequency ◽  
Model Parameters ◽  
Seat Suspension ◽  
System A ◽  
Low Frequency Vibration ◽  
New Type ◽  
Suspension Model ◽  
Better Than

To improve seat performance of low-frequency vibration isolation, this paper investigates a new type of seat suspension with a hollow composite rubber spring. To better describe the real system, a nonlinear suspension model was built. Then, the model parameters were identified and validated, the results show that the model is workable and the identified parameters are acceptable. The acceleration transmissibility of the new suspension was also analyzed by test and simulation. The resonant frequencies measured are close to the simulated under different excitation amplitudes, and all the relative deviations of the resonant frequency are less than 2.0%. Finally, in order to make clear how much the new suspension is better than the traditional suspension with the coil spring, the comparison of ride comfort was conducted under different working conditions. The results show that the new suspension can more effectively attenuate the low frequency from the uneven ground, meanwhile, it can provide a more stable support so that the driver can control the vehicle effectively. The model proposed can be used to predict the performance of the new seat suspension. The new suspension and the model provide a valuable reference for broadening the type of the seat suspension and exploring the optimal performance.

On the Effects of Mistuning a Force-Excited System Containing a Quasi-Zero-Stiffness Vibration Isolator

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Ali Abolfathi ◽  
M. J. Brennan ◽  
T. P. Waters ◽  
B. Tang
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Vibration Isolator ◽  
Linear Vibration ◽  
Vibration Isolators ◽  
Zero Dynamic ◽  
Low Frequency Vibration ◽  
Excited System ◽  
Better Than

Nonlinear isolators with high-static-low-dynamic-stiffness have received considerable attention in the recent literature due to their performance benefits compared to linear vibration isolators. A quasi-zero-stiffness (QZS) isolator is a particular case of this type of isolator, which has a zero dynamic stiffness at the static equilibrium position. These types of isolators can be used to achieve very low frequency vibration isolation, but a drawback is that they have purely hardening stiffness behavior. If something occurs to destroy the symmetry of the system, for example, by an additional static load being applied to the isolator during operation, or by the incorrect mass being suspended on the isolator, then the isolator behavior will change dramatically. The question is whether this will be detrimental to the performance of the isolator and this is addressed in this paper. The analysis in this paper shows that although the asymmetry will degrade the performance of the isolator compared to the perfectly tuned case, it will still perform better than the corresponding linear isolator provided that the amplitude of excitation is not too large.

scholarly journals A Review of Low-Frequency Active Vibration Control of Seat suspension Systems

2019 ◽  
Vol 9 (16) ◽  
pp. 3326 ◽  
Author(s):  
Zhao ◽  
Wang
Keyword(s):  
Vibration Control ◽  
Active Vibration Control ◽  
Low Frequency ◽  
Control Algorithms ◽  
Seat Suspension ◽  
Suspension Systems ◽  
Low Frequency Vibration ◽  
Recent Developments ◽  
Active Vibration ◽  
Artificial Neural Network Ann

As a major device for reducing vibration and protecting passengers, the low-frequency vibration control performance of commercial vehicle seating systems has become an attractive research topic in recent years. This article reviews the recent developments in active seat suspensions for vehicles. The features of active seat suspension actuators and the related control algorithms are described and discussed in detail. In addition, the vibration control and reduction performance of active seat suspension systems are also reviewed. The article also discusses the prospects of the application of machine learning, including artificial neural network (ANN) control algorithms, in the development of active seat suspension systems for vibration control.

scholarly journals Modeling a Mechanical Molecular Spring Isolator with High-Static-Low-Dynamic-Stiffness Properties

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhanyong Li ◽  
Qian Chen ◽  
Fengshou Gu ◽  
Andrew Ball
Keyword(s):  
Vibration Isolation ◽  
Dynamic Properties ◽  
Piecewise Linear ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Isolation System ◽  
Isolation Technique ◽  
Piston Cylinder ◽  
Low Frequency Vibration ◽  
Stiffness Model

A mechanical molecular spring isolator (MMSI) is proposed for the purpose of isolating the low-frequency vibration of a heavy payload. The MMSI is a passive vibration isolation technique mimicking molecular spring isolator characteristics of high-static-low-dynamic stiffness (HSLDS). An MMSI consists of a piston-cylinder container filled with the liquid and some hydraulic spring accumulators. The piston would support a lump of mass and be subjected to a specific external vibration excitation force. Those accumulators can get intercommunication by the liquid to produce the transformation from high static stiffness to low dynamic stiffness. The stiffness model of the MMSI with several identical accumulators is established based on the hydrostatic law. After that, some parameters that significantly influence the stiffness characteristics are studied. Results show that the stiffness property of this kind of MMSI demonstrates a piecewise linearity of three segments. It applies the averaging method to acquire amplitude-frequency and phase-frequency relationships of the piecewise linear vibration isolation system. An inevitable jump phenomenon may occur when the exciting force reaches the critical value. The vibration isolation performance is evaluated by energy transmissibility. Finally, an experimental prototype was designed to carry out quasi-static and dynamic experiments to verify the stiffness model and the dynamic properties as an HSLDS vibration isolator.

Vibration Isolation Characteristics of Euler Strut Spring Used in Low Frequency Vibration Isolation System

2012 ◽  
Vol 248 ◽  
pp. 475-480
Author(s):  
Guan Jun Zhang ◽  
Xiang Zhu ◽  
Ran Xu ◽  
Tian Yun Li
Keyword(s):  
Vibration Isolation ◽  
Structural Parameters ◽  
Low Frequency ◽  
Resonant Frequencies ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Low Frequency Vibration ◽  
Steel Material ◽  
Internal Resonant ◽  
Spring Maximum

Recently, the Euler strut is used as the supporting spring in the low frequency isolation. An Euler spring is a column or strut of steel material which is compressed elastically beyond its buckling load, which makes the ratio of the isolated mass to the mass of the supporting spring maximum, and greatly increasing the internal resonant frequencies of the isolator. In this research, the unique mechanical properties and the expressions of the displacement transmissibility of the Euler strut are deduced. The influences of structural parameters of the strut on the stiffness and vibration isolation characteristics are investigated in detail. The results show that the Euler strut has the potential in low frequency vibration isolation, and the length and breadth of the strut can influence the stiffness, transmissibility and critical loading mass respectively.

scholarly journals Dynamic characterization of controlled multi-channel semi-active magnetorheological fluid mount

2021 ◽  
Vol 12 (2) ◽  
pp. 751-764
Author(s):  
Zhihong Lin ◽  
Mingzhong Wu
Keyword(s):  
High Frequency ◽  
Optimization Design ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Vehicle Model ◽  
Mr Fluid ◽  
Unbalanced Force ◽  
Low Frequency Vibration ◽  
Engine Mount

Abstract. In this paper, a novel structure of a controlled multi-channel semi-active magnetorheological (MR) fluid mount is proposed, including four controlled channels and one rate-dip channel. Firstly, the magnetic circuit analysis, rate-dip channel optimization design, and MR fluid mount damping analysis are given. Secondly, the mathematical model of the controlled multi-channel semi-active MR fluid mount is constructed. We analyze the effect of controlled multi-channel closing on the dynamic characteristics of the mounts and the effect of the presence or absence of the rate-dip channel on the low-frequency isolation of the mount. Finally, the controlled multi-channel semi-active MR fluid mount was applied to the 1/4 vehicle model (a model consisting of an engine, a single engine mount, a single suspension and a vehicle frame), with the transmissibility of the engine relative to the vehicle frame at low frequency and the transmissibility of the engine reciprocating unbalanced force to the vehicle frame magnitude at high frequency as the evaluation index. Numerical simulation shows the following points. (1) The controllable multi-channel semi-active MR fluid mount can achieve adjustable dynamic stiffness and damping with applied 2 A current to different channels. (2) With known external excitation source, applied currents to different controllable channels can achieve the minimum transmissibility and meet the mount wide-frequency vibration isolation requirement, while adding a rate-dip channel can improve the low-frequency vibration isolation performance of the MR fluid mount. (3) Switching and closing different controllable channels in the 1/4 vehicle model can achieve the minimum transmissibility of low-frequency engine vibrations relative to the vehicle frame and high-frequency engine vibrations reciprocating an unbalanced force to the vehicle frame. Therefore, the design of the controllable multi-channel semi-active MR fluid mount can meet the wide-frequency isolation.

scholarly journals Nonlinear Dynamic Study of Oscillation System Featuring Quasi-Zero and Asymmetric Stiffness

2021 ◽  
Author(s):  
Thanh Danh Le ◽  
Minh Ky Nguyen ◽  
Ngoc Yen Phuong Vo
Keyword(s):  
Vibration Isolation ◽  
Sliding Friction ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Force Model ◽  
Oscillation System ◽  
Time Dynamic ◽  
Bifurcation Phenomenon ◽  
Low Frequency Vibration ◽  
Approximate Polynomial

Abstract This paper will broaden our previous works about the asymmetric and quasi-zero stiffness oscillator named AQZSO. In this paper, the dynamic stiffness of the AQZSO will be investigated. Then, the condition for which the minimum dynamic stiffness is quasi-zero around the equilibrium position is also determined. By using Multi-Scale method, the fundamental resonance response of the AQZSO subjected to the vibrating base is analyzed, in which the dynamic stiffness is expressed as a fifth-order approximate polynomial through expanding Taylor series. The stability of the response is then found out via nonlinear Routh-Herwitz criterion. Moreover, because of existing the sliding friction between the cylinder and piston, the nonlinear and varying-time dynamic characteristics, the complex dynamic response of the AQZSO is the need for discovery by performing direct integration of the original dynamic equation through using 5th-order Runge-Kutta algorithm. In this work, the friction force model of cylinder will be identified through virtual prototyping technique and genetic algorithm. Additionally, the Poincáre map is also employed to analyze the bifurcation phenomenon, coexistence of multiple solutions. The traction basin of the period-1, period-2 and period-3 solution is determined, indicating that the attractor basin is influenced by the asymmetric of the stiffness curve. This research will offer a useful insight to design low frequency vibration isolation systems.

scholarly journals Design and Theoretical Analysis of High-Static-Low-Dynamic Stiffness Torsion Vibration Isolator Based on Oblique Springs

2021 ◽  
Vol 2101 (1) ◽  
pp. 012028
Author(s):  
Zhirong Yang ◽  
Lintao Li ◽  
Jiacheng Yao ◽  
Qingkai Wang
Keyword(s):  
Harmonic Balance ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Vibration Isolator ◽  
Torsion Vibration ◽  
Low Frequency Vibration ◽  
Torsion Stiffness ◽  
Ihb Method ◽  
Peak Value

Abstract A torsion vibration isolator composed of oblique springs with high-static-low-dynamic stiffness (HSLDS) is proposed to attenuate the transmission of torsion vibration along the shipping shaft in this paper. It is good at in low frequency vibration isolation as it can significantly reduce the resonance frequency of the system with the same load capability. Firstly, the model of HSLDS torsion vibration isolator is introduced in this paper. Secondly, the non-dimensional torsion stiffness is formulated using mechanics theory, and the HSLDS characteristic of designed torsion vibration isolator is verified. Finally, the torque transmissibility is analyzed using the Increment Harmonic Balance (IHB) method, and the effects of the system parameters on it are analyzed. The results show that the resonant frequency increases accordingly as the stiffness ratio and the excitation torque are increased. However, the peak value of the torsion transmissibility is decreased as the damper ratio increasing.

scholarly journals Vibration Analysis and Modeling of an Off-Road Vibratory Roller Equipped with Three Different Cab’s Isolation Mounts

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Vanliem Nguyen ◽  
Jianrun Zhang ◽  
Vanquynh Le ◽  
Renqiang Jiao
Keyword(s):  
Dynamic Model ◽  
Ride Comfort ◽  
Three Dimensional ◽  
Low Frequency ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Nonlinear Dynamic Model ◽  
Obvious Effect ◽  
Low Frequency Vibration ◽  
Power Spectral

This study proposes a dynamic model of the vibratory roller interacting with the off-road deformed terrain to analyze the low-frequency performance of three different cab’s isolation mounts under the different operating conditions. In order to evaluate the ride comfort of the vibratory roller with the different cab’s isolation mounts, a three-dimensional nonlinear dynamic model is established. The power spectral density (PSD) and the weighted root mean square (RMS) of acceleration responses of the vertical driver’s seat, cab’s pitch, and roll vibrations are chosen as objective functions in the low-frequency range. Contrastive analysis of low-frequency vibration characteristics of the vibratory roller with the traditional rubber mounts, the hydraulic mounts, and the pneumatic mounts is carried out. Experimental investigations are also used to verify the accuracy of models. The research results show that the hydraulic mounts have an obvious effect on mitigating the cab vibration and improving the ride comfort in comparison with the traditional rubber mounts and the pneumatic mounts.

scholarly journals The control of an active seat with vehicle suspension preview information

2017 ◽  
Vol 24 (8) ◽  
pp. 1412-1426 ◽  
Author(s):  
Abdulaziz Alfadhli ◽  
Jocelyn Darling ◽  
Andrew J Hillis
Keyword(s):  
Objective Function ◽  
Ride Comfort ◽  
Control Method ◽  
Low Frequency ◽  
Experimental Tests ◽  
Cost Effective ◽  
Effective Control ◽  
Vehicle Suspension ◽  
Control Force ◽  
Seat Suspension

This paper presents a novel, simple and reliable control strategy for an active seat suspension, intended for use in a vehicle, which attenuates the harmful low-frequency vertical vibration at the driver’s seat. An advantage of this strategy is that it uses measurable preview information from the vehicle suspension. The control force is calculated from this preview information and controller gains obtained by optimising an objective function using a genetic algorithm (GA) approach. The objective function optimises ride comfort in terms of the Seat Effective Amplitude Transmissibility factor, taking into account constraints on both the allowable seat suspension stroke and actuator force capacity. This new controller is evaluated using both simulation and experimental tests in both the frequency and time domains. The simulation model is based upon a linear quarter vehicle model and a single degree of freedom seat suspension. Experimental tests are performed using a multi-axis simulation table and an active seat suspension. Finally, the performance of the active seat suspension is analysed and compared to a passive system, demonstrating significant acceleration attenuation of more than 10 dB across a broad frequency range. Consequently, this has the potential to improve ride comfort and hence reduce the driver’s fatigue using a reliable and cost-effective control method.

Sign in / Sign up

Export Citation Format

Share Document