ABSTRACT Robotic systems in confined environments rely on compact and dexterous actuators. In minimally invasive surgery, cable‐driven mechanisms remain standard but require high locking forces, causing tendon fatigue and friction. Magnetic actuation eliminates the need for cable transmissions but suffers from low load‐bearing capacity and lacks coaxial rotation. We present a magnetic rotary actuator (MAGTWIST) that exploits a traveling wave to achieve a large motion range, stepless rotation, and controllable (un)locking. MAGTWIST features an undulating belt, inspired by peristalsis, and made from a thermo‐responsive polymer. Torque generated by an applied magnetic field engages sliders with the undulation, inducing localized deformation that forms a traveling wave around a circular path. Switching between (un)locked states is done by Joule heating. Heating softens the belt within 3.0 s, allowing the wave to travel in a circle arc of up to 270°. Cooling restores stiffness within 5.3 s, halting the wave and achieving stepless shape‐locking. Once stiffened, actuation torque rises from 4.5 to 250 N·mm, securing the rotary position and increasing load‐bearing capacity. The tubular design with an inner and outer diameter of 4 and 8 mm integrates as an end‐effector in a robotic manipulator, as demonstrated through gripping and in situ shape transitions during minimally invasive surgical tasks.
Frieler et al. (Sat,) studied this question.