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 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.

Ride Dynamics of a Flexible Multibody Model of an Urban Bus

2007 ◽  
Author(s):  
G. Georgiou ◽  
A. Badarlis ◽  
S. Natsiavas
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Equations Of Motion ◽  
Differential Algebraic Equations ◽  
Accurate Information ◽  
Algebraic Equations ◽  
Multibody Model ◽  
Road Excitation ◽  
Urban Bus ◽  
Stiffness And Damping

Dynamic response of a large order mechanical model of an urban bus is investigated. The emphasis is first put on developing a quite complete model, which can be utilized in order to extract sufficiently reliable and accurate information related to its dynamics in a fast way. Since some of the components of the bus undergo large rigid body rotation, in addition to motion resulting from their deformability, a multibody dynamics framework is adopted. This implies that the resulting equations of motion appear in the form of a strongly nonlinear set of differential-algebraic equations, which are difficult to handle even numerically. In fact, the modeling becomes more involved because all the significant nonlinearities appearing in the interconnections of the structural components and especially in the front and rear suspension subsystems of the bus are taken into account. In order to alleviate some of these complexities, the number of degrees of freedom of each component, associated with its deformability, is reduced drastically by applying an appropriate coordinate condensation methodology. Finally, this model is employed and numerical results are obtained for motions resulting from typical road excitation. In particular, selected response quantities related to ride comfort are examined for characteristic combinations of the bus suspension stiffness and damping parameters.

scholarly journals SIMULATION OF MATHEMATICAL MODEL FOR MONORAIL SUSPENSION SYSTEM UNDER DIFFERENT TRACK CONDITIONS

2018 ◽  
Vol 79 (2) ◽  
pp. 15-31
Author(s):  
Wafi A. Mabrouk ◽  
M. F. L. Abdullah
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Dynamic Performance ◽  
Equations Of Motion ◽  
Research Work ◽  
Suspension System ◽  
Dynamic Responses ◽  
Central Difference ◽  
Central Difference Method ◽  
Model Features

Designing a new monorail suspension system for an existing monorail bogie to accommodate larger cars, locomotives and more passengers is a difficult and complicated problem to solve. This paper introduces a simulation of a mathematical model for a monorail suspension system that can be used as an analytical tool to investigate and predict the behavior of the model under different speeds and track conditions. In this paper, the simulation is performed to predict some dynamic characteristics monorail suspension system. This research work concentrates on the simulation of 15 degrees of freedom full-car Monorail suspension system. The model features the Monorail body, Front bogie, and rear bogie geometries, adopted equations of motion of the monorail suspension system and system matrices. Numerical Central Difference method was used to obtain the system responses subject to sinusoidal Track excitations. Three Track scenarios that have different loads and different driving speeds were conducted to investigate the monorail suspension system. The system results are analysed in terms of their dynamic responses. Fourier Fast transforms was used to calculate the frequency ranges of dynamic responses. As a result, some very important characteristics of the Monorail suspension system were revealed, with indicators that help to understand the effects of driving speeds and different loads, which can be used to better understand the system dynamic performance, to improve Monorail suspension system designs flaws detection.

Vehicle Active Suspension with Four-Degrees of Freedom of Optimizing the Value of K Based on Genetic Algorithm

2011 ◽  
Vol 308-310 ◽  
pp. 1673-1678
Author(s):  
Yan Yan Zuo ◽  
Cai Bao Yan ◽  
Nan Yang
Keyword(s):  
Genetic Algorithm ◽  
Optimal Control ◽  
Optimal Control Theory ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Control Method ◽  
Active Suspension ◽  
Obvious Effect ◽  
Comprehensive Performance ◽  
Suspension Model

A vehicle active suspension model with 1 / 2 ，four-degrees of freedom is established and by combining genetic algorithm with optimal control theory，the author presents a new control method of active suspension that is to optimize the value of K controlled by LQG in default of road input based on genetic algorithm and makes a simulation in the environment of Matlab / Simulink. By simulation and analysis，the result indicates that，this method has an obvious effect on improving comprehensive performance of vehicles，such as ride comfort and operate stability and so on.

Chaos Control of Vehicle Nonlinear Suspension System with Multi-Frequency Excitations by Nonlinear Feedback

2011 ◽  
Vol 55-57 ◽  
pp. 1156-1161
Author(s):  
Jing Yue Wang ◽  
Hao Tian Wang ◽  
Li Min Zheng
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Control Method ◽  
Chaotic Behavior ◽  
Time History ◽  
Suspension System ◽  
Vehicle Suspension ◽  
Nonlinear Feedback ◽  
Suspension Model ◽  
Vehicle Suspension System

Vehicle suspension system with hysteretic nonlinearity has obvious nonlinear characteristics, which directly cause the system to the possibility of existence of bifurcation and chaos. Two degrees of freedom for the 1/4 body suspension model is established and the behavior of the system under road multi-frequency excitations is analyzed. In the paper, it reveals the existence of chaos in the system with the Poincaré map, phase diagram, time history graph, and its chaotic behavior is controlled by nonlinear feedback. Numerical simulation shows the effectiveness and feasibility of the control method with improved ride comfort. The results may supply theoretical bases for the analysis and optimal design of the vehicle suspension system.

Modeling and Simulation of Motorcycle Ride Comfort Based on Bump Road

2010 ◽  
Vol 139-141 ◽  
pp. 2643-2647 ◽  
Author(s):  
Dong Mei Yuan ◽  
Xiao Mei Zheng ◽  
Ying Yang
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Lagrange Equation ◽  
Equations Of Motion ◽  
Vertical Displacement ◽  
Dynamics Model ◽  
Body Dynamics ◽  
Space Formulation ◽  
Simulation Results ◽  
Multi Body

Through analyzing the motion when motorcycle runs on the bump road, the 5-DOF multi-body dynamics model of motorcycle is developed, the degrees of freedom include vertical displacement of sprung mass, rotation of sprung mass, vertical displacement of driver, and vertical displacement of front and rear suspension under sprung mass. According to Lagrange Equation, the differential equations of motion and state-space formulation are derived. Then bump road is simulated by triangle bump, and input displacement is programmed by MATLAB. With the input of bump road, motorcycle ride comfort is simulated, and the simulation results are verified by experiment results combined with two channels tire-coupling road simulator. It indicates that the simulation results and experiment results match well; the 5-DOF model has guidance for development of motorcycle ride comfort.

Vibration Modes of Helical Planetary Gears

2009 ◽  
Author(s):  
Tugan Eritenel ◽  
Robert G. Parker
Keyword(s):  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Rigid Bodies ◽  
Three Dimensions ◽  
Lumped Parameter Model ◽  
Vibration Modes ◽  
Planetary Gears ◽  
Gear Mesh ◽  
Modal Properties ◽  
Lumped Parameter

This paper examines the vibration modes of single stage helical planetary gears in three dimensions with equally spaced planets. A lumped-parameter model is formulated to obtain the equations of motion. The gears and shafts are modeled as rigid bodies with compliant bearings at arbitrary axial locations on the shafts. A translational and a tilting stiffness account for the force and moment transmission at the gear mesh interface. The modal properties generalize those of two-dimensional spur planetary gears; there are twice as many degrees of freedom and natural frequencies due to the added tilting and axial motion. All vibration modes are categorized as planet, rotational-axial, and translational-tilting modes. The modal properties are shown to hold even for configurations that are not symmetric about the gear plane, due to, for example, shaft bearings not being equidistant from the gear plane. Computational modal analysis are performed to numerically verify the findings.

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.

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.

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