Adaptive Vibration Control by a Variable-Damping Dynamic Absorber Using ER Fluid

This paper describes a variable-damping dynamic absorber applying Electrorheological (ER) fluid to the damping element of a conventional-type dynamic absorber. A prototype of variable-damping dynamic absorber was constructed and its performance was verified with a three-story structural model. The special ability of the present dynamic absorber is to reduce the vibration amplitude at several frequencies by a single dynamic absorber. ER fluid is functional fluid whose yield shear stress can be changed by the applied electric field strength. Because of its peculiar property, ER fluid has been applied to various mechanical components such as shock absorbers and engine mounts for vehicles, clutches, valves, etc. One of the practical ways in applying ER fluid to mechanical components may be to expand the performance of conventional mechanical components by combining ER fluid effectively with them. In this sense, this paper shows a successful application of ER fluid to a conventional-type dynamic absorber. An adaptive neural network control system composed of a forward model network for system identification and a controller network was introduced to control the variable-damping element of the dynamic absorber. The numerical simulations show good agreements with the experimental results.