CONTROL SYSTEM FOR A NONLINEAR TERFENOL-D ACTUATOR

RECENT ADVANCES IN MATERIAL DEVELOPMENT HAVE BROUGHT A FULL CLASS OF "SMART MATERIALS". ACTIVE NOISE AND VIBRATION CONTROL IS ONE APPLICATION FOR WHICH THESE MATERIALS ARE SUITED. TERFENOL-D IS THE SMART MATERIAL THAT HOLDS THE MOST PROMISE FOR MANY FUTURE APPLICATIONS BECAUSE OF ITS LARGE DISPLACEMENT CAPABILITIES. TERFENOL-D CAN ALSO PRODUCE LARGE FORCES COMPARED TO OTHER ACTUATOR MATERIALS. THE MAJOR DISADVANTAGE OF A TERFENOL-D ACTUATOR, HOWEVER, IS HIGH DISTORTION. RESEARCHERS ARE DEVELOPING A METHOD TO LINEARIZE THIS TYPE OF NONLINEAR DEVICE BY INTEGRATING AN INVERSE FILTER BASED ON A NONLINEAR EXPANSION INTO A LINEAR TYPE FEEDBACK CONTROL SYSTEM. AND SIMULATING THE CLOSED LOOP RESPONSE. THE EFFECTIVENESS OF THIS TYPE OF CONTROL APPROACH IS BENEFICIAL IN CONTROLLING ANY NONLINEAR SYSTEM THAT IS STATIONARY.