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1

H∞ active control of a vehicle suspension system exited by harmonic and random roads

Marzbanrad J., Zahabi N.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 1

171--180

EN

This paper proposes a controller based upon H∞ control approach in order to improve the vehicle performance under two different road profiles. In this study, there are two control targets that they are car body travel and suspension deflection. In fact, H∞ controller is responsible for minimizing the infinity norm of two subsystems. The first one is from car body travel to road disturbance and second is from suspension deflection to road disturbance. These two control targets must be improved by a logical control input that is determined by H∞ control approach. In order to improve the performance of the quarter-car, weighting functions are also defined. Disturbance that is the system input is considered as two types of road profiles, harmonic and random. The results show that the H∞ controller is able to improve the quarter-car performance for both roads. In addition, the sensitivity analysis is done to show that the active suspension system is able to work when sprung mass changes as may be occurred when passengers added.

2

Quarter car model to evaluate behaviour under road and body excitation

Niculescu A. I., Jankowski A., Kowalski M., Sireteanu T.

Journal of KONES

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2017

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Vol. 24, No. 1

265--273

EN

The paper presents a quarter car model two degrees of freedom (wheel and body), with vertical guiding system, the model being equipped with suspension stroke limiters and with excitation by wheel and/ or by body. The model reproduces elastic and damping characteristics of wheel and of rebound and compression stopper bumpers, the spring elastic characteristic and the shock absorber damping characteristic on rebound and compression, function piston speed. The road profile is generated with simple or summation of harmonic functions, or by reproducing real roads. The forces acting on full vehicle body e.g. aerodynamic and inertial forces are reproduced in the proposed quarter model by vertical forces reduced to the analysed quarter part. Thus, the model can be used for evaluation the vertical and horizontal stability at acceleration, deceleration, pitch and roll, at aerial forces, the body ground clearance and the comfort. The model can evaluate the influence of the damping and elastic characteristics of suspension and wheel, of the static position, of the vehicle load state, of the road profile and of the external forces, to the vehicle behaviour

3

Generation of virtual track profiles using experiments and computer simulations

Hejman M., Lukes V.

Journal of Theoretical and Applied Mechanics

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2008

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Vol. 46 nr 2

435-442

EN

An advantage of computer simulations of structures is the prediction of dynamic properties, loading, strength, fatigue life stability, etc. A new goal of computer simulations is the fatigue life analysis of vehicle structures or that parts. A ”virtual track profile” (mathematical description of the track profile) can solve the problem of proper excitation. The paper describes one possible approach of virtual track profile generation. Experimental data and computer simulations are used for the profile generation.

PL

Jedną z korzyści płynących z symulacji komputerowych jest możliwość przewidywania właściwości dynamicznych, obciążeń, wytrzymałości, stabilności zmęczeniowej itp. różnych konstrukcji. W pracy przedstawiono nowy cel analizy wspomaganej komputerowo - badania wytrzymałości zmęczeniowej pojazdów i ich podzespołów. Zaprezentowano metodę "wirtualnego profilu drogi" (matematycznego opisu profilu drogi) do rozwiązania problemu wymuszenia kinematycznego pochodzącego od nierówności jezdni. W pracy zawarto opis jednego z możliwych sposobów generowania wirtualnego profilu drogi. W rozważaniach zastosowano symulacje komputerowe oraz oparto się na pomiarach doświadczalnych.