design of new features in machines and devices,reducing dimensions of equipment and wide use of computer control requires implementation of materials with special properties. in order to create smart computer-controlled drives with desired dynamic characteristics,smart material became desired in many applications. one of successful computer controlled motion application is an implementation fo magneto-rheological materials in such drives. magneto-rheological fluids are a calss of materials whose rheological properties may be rapidly altered by applying a magnetic field 1. these materials usually are liquids with magnetically polarized ferrous particles suspended in a carrier liquid. the particle size in has on the order of micrometers and