Modelling and multi-criteria optimisation of passive seat suspension vibro-isolating properties

In the analysis of vibration systems, classical transfer functions are used. Usually, it is the ratio of Fourier or Laplace transforms. The wavelet transfer function is proposed in this work. In this paper, the wavelets transfer function is the ratio of output and input wavelet transforms. It is considered as a distinctive correlation of the output and input system signals. The wavelet transform consists of coefficients, where the first is a scale and second time shift. To get input and output signals in the human body-seat system the dedicated test stand was made. The stand consists of a seat, moved by special shaker, which is used as a mechanical vibration device. The control program included in the source file is taken to imitate angular position of the engine. Motor shaft is connected with exciter's moving parts and stand base, which influences directly on the seat position. The disturbance signal usually simulates a horizontal road influence on a driver. It can be considered as a low-frequency signal. It is measured by accelerometers called inertial sensors, which are placed on the platform of the shaker. The output signal is measured by an accelerometer placed on a seat and on the human head. Both signals are recorded by the Inertia Studio software wireless in the real time. After the measurement, the signals are transformed into wavelet coefficients by using Matlab package functions. The transfer function and its visualization are presented in two dimensions scale-time. The scale is related to frequency (pseudo-frequency). By the transfer function it is possible to analyze the systems, evaluate safety, compare the systems, and many more.

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“…All transformations are calculated according formula (3). The input signal I(t) is measured by sensor 1.…”

Section: The Methodology Of Wavelet Transfer Functionmentioning

confidence: 99%

The wavelet transfer function of a human body–seat system

Błażejewski

Głowiński

Maciejewski

2018

Journal of Low Frequency Noise, Vibration and Active Control

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“…Reducing the seat acceleration results in large seat suspension strokes, which are physically bounded [2]. Thus, this constraint is considered in the optimisation problem, such that the maximum allowable seat suspension travel ( , ) was assumed to be 45 mm.…”

Section: Optimisation Processmentioning

confidence: 99%

“…This vibration reduces ride comfort and can cause long-term health problems, as the human body is most sensitive to vertical vibration in the frequency range of 4-8 Hz [1,2]. Consequently, seat suspensions are practicable and cost-effective solutions that are used in vehicles to overcome these effects.…”

Section: Introductionmentioning

confidence: 99%

The Control of an Active Seat Suspension Using an Optimised Fuzzy Logic Controller, Based on Preview Information from a Full Vehicle Model

2018

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Abstract:The use of suspension preview information obtained from a quarter vehicle model (QvM) to control an active seat has been shown by the authors to be very promising, in terms of improved ride comfort. However, in reality, a road vehicle will be subjected to disturbances from all four wheels, and therefore the concept of preview enhanced control should be applied to a full vehicle model. In this paper, different preview scenarios are examined, in which suspension data is taken from all or limited axles. Accordingly, three control strategies are hypothesized-namely, front-left suspension (FLS), front axle (FA), and four wheel (4W). The former utilises suspension displacement and velocity preview information from the vehicle suspension nearest to the driver's seat. The FA uses similar preview information, but from both the front-left and front-right suspensions. The 4W controller employs similar preview information from all of the vehicle suspensions. To cope with friction non-linearities, as well as constraints on the active actuator displacement and force capabilities, three optimal fuzzy logic controllers (FLCs) are developed. The structure of each FLC, including membership functions, scaling factors, and rule base, was sequentially optimised based on improving the seat effective amplitude transmissibility (SEAT) factor in the vertical direction, using the particle swarming optimisation (PSO) algorithm. These strategies were evaluated in simulation according to ISO 2631-1, using different road disturbances at a range of vehicle forward speeds. The results show that the proposed controllers are very effective in attenuating the vertical acceleration at the driver's seat, when compared with a passive system. The controller that utilised suspension preview information from all four corners of the car provided the best seat isolation performance, independent of vehicle speed. Finally, to reduce the implementation cost of the "four suspension" controller, a practical alternative is developed that requires less measured preview information.

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“…It is worth noting that in all these cases the effectivity of the applied DA is dependent from the right choice of the system, the maximal amplitude of the excitation and others. Therefore it is necessary to optimize the system parameters after the tuning of DA [6,7,8]. The DA are chosen to work in narrow frequency ranges, therefore the FFT analysis has to be made, or the system parameters and the DA parameters can be set at once using optimization by genetic algorithms with a defined objective function.…”

Section: Introductionmentioning

confidence: 99%

Effect of Dynamic Absorber Configuration on the Reduction of Vibration

Orečný¹,

Segľa²,

Huňady³

et al. 2014

AJME

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The article deals with passive suspension system of a seat employing two types of dynamic absorbers.The methodology how to design such a system is explained in the paper. The first type of dynamic absorber is composed by two masses connected to the seat by springs and dampers in parallel configuration. The second one is composed by two sprung masses connected to the seat in the series. The parameters of the seat suspension system and the dynamic absorber parameters were all determined by an optimization process based on genetic algorithms. The objective function for the optimization was to minimize the seats displacements. The vibration reduction of the seat is compared for both investigated cases.

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Modelling and multi-criteria optimisation of passive seat suspension vibro-isolating properties

Cited by 83 publications

References 9 publications

The wavelet transfer function of a human body–seat system

The wavelet transfer function of a human body–seat system

The Control of an Active Seat Suspension Using an Optimised Fuzzy Logic Controller, Based on Preview Information from a Full Vehicle Model

Effect of Dynamic Absorber Configuration on the Reduction of Vibration

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