Igor Maciejewski

Application of the Pareto-optimal approach for selecting dynamic characteristics of seat suspension systems

In this paper, a method for selecting the dynamic characteristics of seat suspension systems is presented. The basic principle of such a method consists in the shaping of nonlinear seat suspension dynamic behaviour for the different requirements defined by machine operators. A combined optimisation procedure has allowed to find the Pareto-optimal system configuration with simultaneous minimisation of conflicted optimisation criteria: the suspended body acceleration and suspension travel. As an example of the proposed method, the seat with a viscous-elastic passive suspension is investigated and its vibro-isolation properties are shaped by the air-spring and shock-absorber force characteristics.

Control system synthesis of seat suspensions used for protection of working machine operators

This paper deals with a novel approach to the control system synthesis of semi-active and active seat suspensions. An original control strategy is discussed in order to increase the effectiveness of vibration isolators used for protection of working machines operators. As an example of the proposed control system design, the suspension systems with a magneto-rheological damper and a pneumatic spring are investigated using a laboratory experimental set-up with seated humans.

Shaping the vibro-isolation properties of horizontal seat suspension:

In this paper, an effective procedure of shaping the vibro-isolation properties of seat suspension system is presented. The simulation model is created to determine the dependence of evaluation criteria to the design parameters by means of which the system characteristics are formed. The developed optimisation procedure allows to find Pareto-optimal system configuration for the conflicted vibro-isolating criteria, i.e. the frequency weighted transmissibility factor used to evaluate dynamic seat comfort based on acceleration signals and the suspension travel. In order to optimise both the conflicted vibro-isolation criteria, a minimising of the transmissibility factor (primary criterion) is proposed taking into account the suspension travel that is transferred to a non-linear inequality constraint. The correctness of proposed procedure is evaluated using experimental research of the best solution of horizontal seat suspension. This research is performed using the passive system with optimal visco-elastic characteristics, which are selected especially for the well-defined input vibration. The satisfactory agreement of experimental and numerical results is obtained for the analysed vibration reduction system.

Modeling and vibration control of an active horizontal seat suspension with pneumatic muscles

In the following paper, the dynamic modeling of a horizontal seat suspension which uses pneumatic muscles for the purpose of active vibration control is discussed. An original control system structure is proposed in order to improve the vibro-isolation properties of a horizontal seat suspension system. The presented control system design is based on inverse models of the pneumatic muscles and the primary controller that calculates the desired active force. By using the configurable control algorithm developed in this paper, it is possible to achieve a significant reduction in vibrations transmitted into the human body with just a slight increasing of the suspension travel. The active seat shows improved performance over the passive system in the 1–10 Hz frequency range. The results presented in this paper are useful in selecting the horizontal vibration control system for improving the comfort of a drive.

Global Sensitivity Analysis of the Vibration Reduction System with Seated Human Body

The paper deals with the global sensitivity analysis for the purpose of shaping the vibroisolation properties of suspension systems under strictly defined operating conditions. The variance-based method is used to evaluate an influence of nonlinear force characteristics on the system dynamics. The proposed sensitivity indices provide the basis for determining the effect of key design parameters on the vibration isolation performance. The vibration transmissibility behaviour of an exemplary seat suspension system is discussed in order to illustrate the developed methodology.

Computational Method for Evaluating the Vibro-Isolation Properties of Suspension Systems Used in Working Machines

In this paper, an effective method for evaluating the vibro-isolation properties of suspension systems is discussed. At first, an effective procedure of reproducing the random vibration in different types of working machines is proposed for the purpose of selecting the dynamic characteristics of vibration reduction systems. In order to calculate the response of a vibration reduction system to various input vibrations, simulation model of the system is developed. Then, the vibro-isolation criteria are formulated to evaluate the vibration reduction system effectiveness for different working conditions. Finally, the multi-criteria optimisation is used to find the compromise solution with respect to the conflicted system requirements.

A Method for Shaping the Dynamic Characteristics of Vibration Isolation Systems

In this paper a method for shaping the dynamic characteristics of vibration isolation systems is presented. The multi-criteria optimisation procedure is utilized in order to find the Pareto-optimal system configuration with simultaneous minimization of conflicted optimisation criteria: the isolated body acceleration and suspension travel. As an example of the proposed method, the seat with a pneuma-hydraulic suspension is investigated and its vibro-isolation properties are shaped by an appropriate selection of the system characteristics. The basic findings of the paper consist in the optimisation procedure that takes into account the nonlinear dynamic behaviour of vibration isolation systems.