Magnetic Soft Actuator Using Composite Elastomer and Electropermanent Magnet for Haptic Displays

A soft actuator integrating a composite elastomer with an electropermanent magnet (EPM) frame is demonstrated for programmable haptic displays with zero static power. The actuator combines out-of-plane magnetized elastomer segments with compliant non-magnetic regions to maximize deflection due to torque and achieve deformations up to 450% of their thickness in magnetic fields as low as 20 mT. Integrating the elastomer composite with an EPM frame to make a tactile unit cell (taxel) allows the elastomer to maintain its deformation at zero static power, and consume only 3.0 J of energy for each switching event. Multiple taxels are combined to prototype a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3\times 2$</tex> braille-inspired display to demonstrate the actuator's potential in soft haptic interfaces.