Abstract: Controlled bending movement of a flexible elongate rod or filament in response to a bend signal indicative of a desired amount of bending is effected by a strip of shape-changing material disposed on a first side of an elongate rod element, the shape changing material changing shape in response to an actuation signal, thereby causing the filament element to bend, and a sensor including a strain gauge disposed on the rod element on a second side opposite the first side, said sensor sensing the amount of bend in the rod element from strain indicated, and a feedback control comparing the amount of bend of the filament sensed to a desired amount of bend defined by said bend signal and altering the actuation signal as required to make the amount of bend sensed the same as the amount of bend desired.