Intelligent Vibration Control System with Actuators using MR Fluid

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This project is on an intelligent vibration control system with actuators using MR fluid. MR fluid is known as a class of functional fluids whose rheological properties can be controlled by the applied magnetic field strength. By applying MR fluid to some conventional damper, semi-active dampers may be realized, and their damping properties can be controlled by an external applied signal. MR fluid is generally composed of ferromagnetic, micron-sized particles suspended in liquid such as mineral oil or silicone oil, and the particles are dispersed uniformly in the liquid by strong surface active agent without magnetic field. Under magnetic field, the particles aggregate and form chain-like cluster structures. When some shear deformation is applied to MR fluid, the clusters may scrub or brush the opposite surface and friction force may be produced, which show Bingham plastic behavior of the fluid. The friction force strongly depends on the strength of magnetic flux density, and it is very important to make closed loop magnetic circuit.In the present project, the equivalent magnetic permiability of MR fluid was first estimated in order to predict MR effect of the semi-active actuators .The cluster formation under a magnetic field is simulated by Cellular Automata, which is known as a discrete modeling technique. Considerting the simulated particle structures, magnetic analysis was carried out by FEM code and equivalent permiability was estimated. Based on the results obtained above, a variable damper was constructed and set on a structural model. The MR damper was controlled by an intelligent control system composed of neural network. It was shown experimentally that an intelligent vibration control system was realized by the conbination of MR fluid and neural network control system.