SHAPE-MEMORY ALLOY TACTILE FEEDBACK ACTUATOR

SHAPE-MEMORY ALLOYS (SMAS) SUCH AS NITINOL RESPOND TO TEMPERATURE CHANGES BY FRAMATIC ALTERATION OF THEIR PHYSICAL STIFFNESS AND/OR SHAPE. THE SHAPE RECOVERY, WHICH DEPENDS UPON A CRYSTALLINE PHASE CHANGE, MAY BE INITIATED BY HEAT FROM ELECTRICAL RESISTANCE HEATING OF THE SMA ELEMENT ITSELF. ACTUATORS UTILIZING SMAS WHICH EXERT SUFFICIENT FORCE TO BE USED AS TACTILE OUTPUT DEVICES MAY BE MADE VERY MINIATURE. ARRAYS OF SUCH TACTILE STIMULATORS CAN BE USED TO CONVEY INFORMATION, AS IN REFRESHABLE BRAILLE DISPLAYS AND TACTICLE GRAPHICS PADS. A SENSE OF TOUCH MAY BE CONVEYED BY A GLOVE IN WHICH THE WEARER'S FINGERS CONTACT AN ARRAY OF MINIATURE SMA-DRIVEN "DOTS" UNDER COMPUTER CONTROL. SUCH A DEVICE IS USEFUL IN VIRTUAL COCKPIT FLIGHT SIMULATION. THE PROPOSED RESEARCH FOCUSES ON THE DEVELOPMENT OF A COMPACT ARRAY OF PROGRAMMABLE TACTILE ELEMENTS FLEXIBLE ENOUGH TO FIT IN A GLOVE AND FORCEFUL ENOUGH TO GIVE A REALISTIC SENSE OF TOUCH.