Analysis and Prediction of Performance of MR Damper at Different Currents and Control Strategies for Quarter Suspension System of a Roadway Vehicle

Ride comfort and vehicle handling are the two major issues to be dealt in the design of suspension systems of automobiles. With passive systems offering contrariety on these two parameters, the alternative systems are being in study. Magnetorheological (MR) damper, a most feasible semi-active device, is one such alternative, which will offer the advantage of dealing with both these issues overcoming contrariety. In this study, the suspension system of a car using MR damper is analysed at 5 different currents viz., 0A, 0.25A, 0.5A, 0.75A, 1A, using 2DOF quarter car model and 4DOF half car models for ride comfort and handling and the comparisons of these are done with same suspension system equipped with regular passive damper. A MR damper is built-up using MR fluid consisting of carbonyl iron powder and silicone oil added with additive. Further, the characteristic of this damper is established by conducting experiments, which in turn is used to identify the parameters of Spencer model for MR damper. Using Spencer model of MR damper, at 5 different currents, the quarter car and half car models of vehicle suspension system are simulated by implementing a semi-active suspension system for analysing the resulting displacement and acceleration in the car body. The ride comfort and vehicle handling performance of each specific vehicle model with passive suspension system are compared with corresponding skyhook, ground hook and hybrid based semi-active suspension systems. The simulation and analysis are carried out using Matlab/Simulink.

Effect of Fuzzy Logic Based-Skyhook Policy with Particle Swarm Optimization for Semi-Active Ride Comfort

This paper presents the effect of the fuzzy logic based-skyhook policy tuned using particle swarm optimization (FLSP-PSO) for semi-active ride comfort of quarter vehicle model. Spencer model was used to represent the magnetorheological damper model and its behavior was investigated in the form of force-displacement and force-velocity characteristics. The fuzzy logic control adopted with the skyhook policy based on Sugeno-type fuzzy was used to enhance the ride performance. An intelligent evolutionary algorithm known as the particle swarm optimization was also adapted in the proposed controller to compute the fuzzy gain scaling. The performance of the FLSP-PSO controller is compared to other controller responses. The effect of the PSO techniques to optimize the FLPS parameters gives a better performance and able to improve the vehicle ride comfort than its counterparts.

Analysis of MR Damper for Quarter and Half Car Suspension Systems of a Roadway Vehicle

Magnetorheological (MR) dampers are evolving as one of the most promising devices for semi-active vibration control of various dynamic systems. In this paper, the suspension system of a car using MR damper is analysed for 2DOF quarter car and 4DOF half car models and then compared with corresponding suspension system using passive damper for ride comfort and handling. Magnetorheological damper is fabricated using a MR fluid of Carbonyl iron powder and Silicone oil added with additive. Experiments are conducted to establish the behaviour of the MR damper and are used to validate Spencer model for MR damper. Further, using the validated Spencer model of MR damper, the quarter car and half car models of Vehicle Suspension system are simulated by implementing a semi-active suspension system for analysing the resulting displacement and acceleration in the car body. The ride comfort and vehicle handling performance of each specific vehicle model with passive suspension system are compared with corresponding semi-active suspension system. The simulation and analysis are carried out using MATLAB/SIMULINK.

Computer-Aided Color Aesthetic Evaluation Method Based on the Combination of Form and Color

This paper presents a new method of color aesthetic evaluation based on the combination of form and color. According to the human visual physiological and psychological characteristics, this paper first proposes a new form-color field theory for the coupled form-color aesthetic evaluation based on the psychophysical field theory and the Moon and Spencer model. Second, it builds a coupled form-color topological graph for describing their interaction and develops a strength calculation algorithm for color harmony based on the new form-color field theory. Finally, it develops an aesthetic measure evaluation model for coupled form-color fields to evaluate the new theory. The experiment results show that the new coupled form-color aesthetic evaluation method is useful and can be integrated into an intelligent evaluation process for color design scheme.

Policy rivalry among industrial states: what can we learn from models of strategic trade policy?

The economic theory of international trade has changed dramatically over the last decade by admitting into its mainstream a body of literature that focuses on the implications of monopolistic and oligopolistic elements in international markets. By applying the tools of the “new” industrial organization in an international context, two new classes of models have emerged: models of intra-industry trade and models of strategic trade policy. The policy implications of models of strategic trade policy were quite disturbing for the economics profession, since these models demonstrated that the classical harmony between national and cosmopolitan welfare maximization does not exist if one assumes opportunities for strategic manipulation of oligopolistic international industries. This article reviews two prominent models of strategic trade policy—the Brander-Spencer model and the Krugman model—and relates them to more familiar earlier concepts, such as Stackelberg's asymmetrical duopoly solution and the venerable infant-industry argument for government intervention. The primary purpose of this article, however, is to provide a synopsis of the large literature addressing the question of whether models of strategic trade policy can give guidance for government policy.