Closed-Loop Feedback Control of Magnetically-Activated Gels

Polymer gels that exhibit a change in volume in response to a small change in an environmental parameter such as temperature have been fabricated and studied for several decades. We have developed gels that change volume in response to an applied alternating magnetic field. These gels could serve as actuators in servomechanisms. This paper presents practical techniques for using closed-loop feedback to control the position of magnetically-triggered polymer gels. Experimental results are presented that demonstrate position control of two different types of magneticallytriggered gels using prototype power electronic drives.