Modelling and analysis of skyhook and Fuzzy logic controls in semi-active suspension system

Abstract: In this study, the application of type-1 and type-2 fuzzy inference system (FIS) in semi-active seismic vibration control of the College Bridge using magnetorheological (MR) dampers is investigated. For this purpose, a detailed 3D finite element model of the bridge fitted with MR dampers is created in OpenSees. The command voltage of MR dampers is determined by employing both types of FISs in Matlab environment and making connection between both software. The results show the higher performance of the type-2 FIS for reducing the undesirable vibrations than that of type-1. This is because of the fact that the type-2 FIS considers interval membership functions for inputs in order to obtain the command voltage of MR dampers. Moreover, type-2 FIS effectively includes the effect of uncertainties and time delay. The results demonstrate that type-2 fuzzy controller is capable of reducing further the maximum displacement, base shear, and moment of the bridge by 24.6, 22.8, and 39.25%, respectively, compared to the type-1 fuzzy controller.

Abstract: Passive hydraulic dampers are commonly used in the automotive suspension system. Nevertheless, they are suffering from a significant drawback owing to the changing of its characteristics at high-frequency; as a result, decreasing the ride quality due to the increase of the transmitted force, especially at high frequency excitations. The present work developed a semi-active suspension system to solve this problem with its effect. A Skyhook control strategy is used to suppress the positional oscillation of the sprung mass in the presence of road irregularities via the use of the electrohydraulic (EH) damper, as an objective. In order to apply the control strategy used herein, a full-scale quarter-car test platform has been designed and constructed to offer increased testing flexibility at a reasonable cost not found commercially. MATLAB Simulink is applied for modeling the semiactive suspension system. The control strategy using a Sky-hook control was used to enhance the comfort due to the simplicity of this method that can easily be implemented in a real-time embedded application. The control strategy is evaluated for its performance under the road bump excitation. The experimental results were compared with the simulated ones for both passive and semi-active suspension systems, the comparison includes time response analysis of body vertical displacement, and vertical displacement of quarter car structure. KeywordsSuspension System; Robust Control, full scale quarter-car, test rig How to cite this article: B.R. Abdullah, M.N. Hamzah and A.S. Merza, “Design and Control of a Full-Scale Quarter Car Semi-Active Suspension System,” Engineering and Technology Journal, Vol. 37, Part A, No. 10, pp. 416-421, 2019.

Abstract: Developing highly nonlinear control system is a challenging task. In this paper the design and implementation of fuzzy based continuous skyhook controller in a quarter car model has been presented. Rash ride can cause fatigue to the passengers if vehicle is travelling for prolonged period of time. Higher suspension travel results in structural damage and deteriorates the ride comfort. Meanwhile limited road holding affects the entire stability of vehicle. The control methodology designed in this paper is focused to give edge in increasing ride comfort as well as good performance in road holding. Fuzzy control system is designed based on ride oriented continuous skyhook strategy. Robustness of controller is tested and verified using simulation and experimentation. The system is subjected to perform in sinusoidal disturbances. The results show that fuzzy logic gives an enhanced ride comfort, reduced suspension travel and considerable road holding.

Abstract: A fuzzy set is a class of objects with a continuum of grades of membership. Such a set is characterized by a membership (characteristic) function which assigns to each object a grade of membership ranging between zero and one. The notions of inclusion, union, intersection, complement, relation, convexity, etc., are extended to such sets, and various properties of these notions in the context of fuzzy sets are established. In particular, a separation theorem for convex fuzzy sets is proved without requiring that the fuzzy sets be disjoint.

Abstract: This book attempts to find a middle ground by balancing engineering principles and equations of use to every automotive engineer with practical explanations of the mechanics involved, so that those without a formal engineering degree can still comprehend and use most of the principles discussed. Either as an introductory text or a practical professional overview, this book is an ideal reference.

Abstract: A type of force generator which can respond to general feedback signals from a vibrating system in order to control the vibration but which does not require the power supply of a servomechanism is described. Computer simulation studies show that performance comparable to that of fully active vibration control systems can be achieved with the semi-active type of device. Physical embodiments of the concept are discussed and compared to hardware used in active and passive vibration control systems.