scholarly journals Nonlinear Dynamic Modelling of a Suspension Seat for Predicting the Vertical Seat Transmissibility

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Weitan Yin ◽  
Juyue Ding ◽  
Yi Qiu
Keyword(s):  
Nonlinear Dynamic ◽  
Ride Comfort ◽  
Dynamic Modelling ◽  
Vertical Vibration ◽  
Lumped Parameter Model ◽  
Nonlinear Behaviour ◽  
Seat Suspension ◽  
Lumped Parameter ◽  
Seat Cushion ◽  
Inert Mass

Suspension seats are widely used in heavy vehicles to reduce vibration transmitted to human body and promote ride comfort. Previous studies have shown that the dynamics of the suspension seat exhibits nonlinear behaviour with changed vibration magnitudes. Despite various linear seat models developed in the past, a nonlinear model of the suspension seat capturing the nonlinear dynamic behaviour of the seat suspension and cushion has not been developed for the prediction of the seat transmissibility. This paper proposes a nonlinear lumped parameter model of the suspension seat to predict the nonlinear dynamic response of the seat. The suspension seat model comprises of a nonlinear suspension submodel integrated with a nonlinear cushion submodel. The parameters of the submodels are determined by minimizing the error between the simulated and the measured transmissibility of the suspension mechanism and the force-deflection curve of the seat cushion, respectively. The model of the complete seat is then validated using the seat transmissibility measured with inert mass under vertical vibration excitation. The results show that the proposed suspension seat model can be used to predict the seat transmissibility with various excitation magnitudes.

scholarly journals Ride Comfort Control System Considering Physiological and Psychological Characteristics: Effect of Masking on Vertical Vibration on Passengers

Actuators ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 42 ◽  
Author(s):  
Keigo Ikeda ◽  
Ayato Endo ◽  
Ryosuke Minowa ◽  
Takayoshi Narita ◽  
Hideaki Kato
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Ride Comfort ◽  
Control Method ◽  
Vertical Vibration ◽  
Psychological Characteristics ◽  
Psychological State ◽  
Vibration Acceleration ◽  
Seat Suspension ◽  
Vibration Stress

Active seat suspension has been proposed to improve ride comfort for ultra-compact mobility. Regarding the ride comfort of passengers due to vertical vibration, the authors have confirmed from biometry measurements that reduction of the vibration acceleration does not always produce the best ride comfort for passengers. Therefore, heart rate variability that can quantitatively reflect stress is measured in real time, and a control method was proposed that feeds back to active suspension and confirms its effectiveness by fundamental verification. In this paper, we will confirm the influence of the vibration stress on the psychological state of the occupant by the masking method.

scholarly journals Mathematical Model of Suspension Seat-Person Exposed to Vertical Vibration for Off-Road Vehicles

2019 ◽  
Vol 16 (2) ◽  
pp. 6773-6782
Author(s):  
S. Aisyah Adam ◽  
N. A. A. Jalil ◽  
K. A. Md Razali ◽  
Y. G. Ng ◽  
M. F. Aladdin
Keyword(s):  
Human Body ◽  
Degrees Of Freedom ◽  
Low Frequency ◽  
Coupled System ◽  
Vertical Vibration ◽  
Lumped Parameter Model ◽  
Model Parameters ◽  
Road Vehicles ◽  
Lumped Parameter ◽  
Variable Function

Off-road drivers are exposed to a high magnitude of vibration at low frequency (0.5-25Hz), that can cause harm and possibly attribute to musculoskeletal disorder, particularly low-back pain. The suspension seat is commonly used on an off-road condition to isolate the vibration transmitted to the human body. Nevertheless, the suspension seat modelling that incorporates the human body is still scarce. The objective of this study is to develop a mathematical modelling to represent the suspension seat-person for off-road vehicles. This paper presents a three degrees-of-freedom lumped parameter model. A curve-fitting method is used for parameter identification, which includes the constraint variable function (fmincon()) from the optimisation toolbox of MATLAB(R2017a). The model parameters are optimised using experimentally measured of suspension seat transmissibility. It was found that the model provides a reasonable fit to the measured suspension seat transmissibility at the first peak of resonance frequency, around 2-3 Hz. The results of the study suggested that the human body forms a coupled system with the suspension seat and thus affects the overall performance of the suspension system.  As a conclusion, the influence of the human body should not be ignored in the modelling, and a three-degrees degree-of-freedom lumped parameter model provides a better prediction of suspension seat transmissibility. This proposed model is recommended to predict vibration transmissibility for off-road suspension seat.

scholarly journals Comfort Level Refinement of Military Tracked Vehicle Crew through Optimal Control Study

2018 ◽  
Vol 68 (3) ◽  
pp. 265
Author(s):  
N. V. Ramamurthy ◽  
B. K. Vinayagam ◽  
J. Roopchand
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Controller Design ◽  
Research Work ◽  
Comfort Level ◽  
Lumped Parameter Model ◽  
Tracked Vehicle ◽  
Machine Model ◽  
Seat Suspension ◽  
Suspension Model

Military tracked vehicle and crew are modelled together in this paper as integrated man-machine lumped parameter model, by integrating the simplified 5 degrees of freedom (DoF) tracked vehicle model, including seat and 4 DoF human bio-dynamic model, thus resulting in a 9 DoF simplified vehicle-occupant model. Then the natural frequency of major mass segment namely the chassis mass is obtained through simulation study, for a known road input. The value obtained is compared with that of an earlier research work, for validation of said man-machine model. Then focusing our study locally at crew seat location, parameters of crew seat suspension for ride comfort are optimised using the optimal digital state space controller designed for this purpose by implementing it in a 2 DoF occupant - seat suspension model and its Simulink model constructed. Simulation results illustrate the attainment of the goal by meeting the controller design requirements.

Ergonomic Level Improving of Armoured Fighting Vehicle Crew

2017 ◽  
Vol 68 (1) ◽  
pp. 33
Author(s):  
N. V. Ramamurthy ◽  
B. K. Vinayagam ◽  
Roopchand J.
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Equations Of Motion ◽  
Research Work ◽  
Composite Model ◽  
Seat Suspension ◽  
Lumped Parameter ◽  
Vibration Responses ◽  
Suspension Model ◽  
Parameter Values

<p class="p1">The armoured fighting vehicle (AFV)-occupant composite system is modelled as a lumped parameter system, in this paper, wherein the 4 degrees of freedom (dof) biodynamic occupant model is integrated with 10 dof in-plane AFV model including the crew seat, thus leading to the 14 dof vehicle-occupant composite model and the governing equations of motion are obtained. The composite model is subjected to idealised road input simulating the ground reaction forces. Natural frequencies and the frequency domain vibration responses of various masses of model are obtained. The natural frequency of chassis thus obtained is compared with the result established by an earlier research work, to validate the model. The study is focused on crew seat location. A 2 dof occupant-seat suspension model is formulated and validated through case study. The optimised values of seat suspension parameters for ride comfort are obtained using the said model, through two methods of Invariant points theory and genetic algorithm toolbox of Matlab 2014a software. Acceleration responses of body for the current and optimised parameter values obtained illustrate that comfort of crew is improved with optimised values through minimization in the acceleration responses.</p>

scholarly journals Hybrid modelling of driver seat-cushion coupled system for metropolitan bus

2017 ◽  
Vol 36 (3) ◽  
pp. 214-226 ◽  
Author(s):  
Leilei Zhao ◽  
Changcheng Zhou ◽  
Yuewei Yu ◽  
Fuxing Yang
Keyword(s):  
Ride Comfort ◽  
Dynamic Properties ◽  
Complex Structure ◽  
Coupled System ◽  
Bench Test ◽  
Model Parameters ◽  
Specific Flow ◽  
Hybrid Modelling ◽  
Seat Suspension ◽  
Seat Cushion

For the complex structure of driver seat-cushion coupled system for metropolitan buses, there are still lack of convenient and reliable modelling methods for the system at present. To improve ride comfort, the coupled dynamic model is urgently needed to give insight into the dynamic properties of the coupled system. In this paper, for a standard commercially available seat fitted into metropolitan buses, the coupling between the seat and cushion, the nonlinear damping characteristics of the seat damper, and the elastic properties of the damper mounting bushings have been accounted for in a three degree-of-freedom driver seat-cushion coupled system model. Combing field measurements of the seat suspension excitation and cushion acceleration response, a specific flow of hybrid modelling of driver seat-cushion coupled system without the requirement of further bench tests was presented. The analogy between acceleration responses in the frequency domain and the time courses proves that the model can predict the dynamic characteristics of the coupled system with good accuracy for stationary random excitation. The model parameters were also validated by the corresponding bench test. The results show that the accuracy of the model parameters is sufficient and the hybrid modelling method is reliable, which provide a foundation for the optimal design of seat suspension and/or cushion to further improve ride comfort.

Mitigation of biodynamic response to vibratory and blast-induced shock loads using magnetorheological seat suspensions

2005 ◽  
Vol 219 (6) ◽  
pp. 741-753 ◽  
Author(s):  
Y-T Choi ◽  
N M Wereley
Keyword(s):  
Human Body ◽  
Lumped Parameter Model ◽  
Shock Load ◽  
Shock Loads ◽  
Seat Suspension ◽  
Military Vehicles ◽  
Lumped Parameter ◽  
Suspension Model ◽  
Yield Force ◽  
Constant Yield

The mitigation of biodynamic response to vibratory and blast-induced shock loads using a magnetorheological (MR) seat suspension is addressed in this study. To this end, an MR seat suspension model for military vehicles including seated personnel is constructed in terms of a detailed lumped parameter model. The lumped parameter model of the human body consists of four parts: pelvis, upper torso, viscera, and head. From the model, the governing equation of motion of the MR seat suspension considering the human body is derived. Based on this equation, a semi-active nonlinear optimal control algorithm appropriate for the MR seat suspension is developed. The simulated control performance of the MR seat suspension is evaluated under three different excitations of sinusoidal and random vibration and tremendous shock load due to a mine explosion. In addition, the mitigation of injuries to humans due to such a shock load is evaluated and compared with a passive hydraulic seat suspension and a passive MR seat suspension with a constant yield force.

Mitigation of Biodynamic Response to Vibratory and Blast-Induced Shock Loads Using Magnetorheological Seat Suspensions

Aerospace ◽  
2003 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley
Keyword(s):  
Human Body ◽  
Control Algorithm ◽  
Random Vibration ◽  
Lumped Parameter Model ◽  
Shock Load ◽  
Hydraulic Damper ◽  
Seat Suspension ◽  
Military Vehicles ◽  
Lumped Parameter ◽  
Suspension Model

This study investigates biodynamic response mitigation to three different excitations of sinusoidal and random vibrations and shock load using a magnetorheological (MR) seat suspension. In doing so, an MR seat suspension model for military vehicles, with a detailed lumped parameter model of the human body, was developed. The lumped parameter model of the human body consists of four parts: pelvis, upper torso, viscera and head. From the model, the governing equation of motion of the MR seat suspension considering the human body was derived. Based on this equation, a semi-active nonlinear optimal control algorithm appropriate for the MR seat suspension was developed. The simulated control performance of the MR seat suspension was evaluated under three different excitations of sinusoidal and random vibration and tremendous shock load due to a mine explosion. In addition, the mitigation of injuries to humans due to such shock load was also evaluated and compared with the passive seat suspension using a passive hydraulic damper.

Optimized Biodynamic Shock Attenuation Performance Using an Adaptive Seat Suspension

2011 ◽  
Author(s):  
Harinder J. Singh ◽  
Norman M. Wereley
Keyword(s):  
Equations Of Motion ◽  
Lumped Parameter Model ◽  
Local Optimum ◽  
Shock Attenuation ◽  
Energy Absorber ◽  
Seat Suspension ◽  
Lumped Parameter ◽  
Cubic Polynomial ◽  
Yield Force ◽  
Vertical Impact

Design optimization-based techniques are presented for the minimization of biodynamic loads of a seated occupant subjected to a shock due to an initial velocity vertical impact. A 95th percentile male occupant was modeled using a multiple degree-of-freedom biodynamic lumped parameter model (BLPM) seated on a vertically stroking adaptive seat suspension with a semi-active magnetorheological energy absorber (MREA). The governing equations of motion of the adaptive MREA-based seat suspension with biodynamic lumped parameter model were developed. The variation of magnetorheological yield force with respect to the energy absorber stroke was shaped using cubic polynomial for the maximum shock attenuation. Three cost functions were devised with a common goal of minimizing biodynamic decelerations. Constraints were established based on limitation of MREA stroke and, yield force as well as stroking load. The MREA yield force and damper stroke were crucial parameters for improved biodynamic response mitigation to shock loads. A globally optimized biodynamic response was analyzed among several local optimum responses for better shock attenuation.

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