Design of the Joint Structure Using a Magnetic Coupling with Linear Motion

Abstract

This study introduces a robot joint structure utilizing magnetic coupling for non-contact power transmission and braking. The proposed design arranges permanent magnets on the motor shaft and the power-receiving shaft to transmit power via axial magnetic coupling mechanism. During braking, the structure allows linear movement to disengage from the motor shaft. This disengagement prevents power transmission during normal braking and utilizes a fixed magnet array on the opposite side for effective braking in a stopped state. In abnormal braking scenarios, the magnetic coupling characteristic ensuring power transmission is halted by disengaging the coupling, even if the motor continues to rotate, thereby avoiding continuous collisions typical in rigid coupling methods. The design was validated before experiments using magnetic films to verify the correct magnet arrangement. Experiments confirmed the power transmission in a noload state and demonstrated the braking test of disengagement action. Future research will focus on applying this structure to practical robotic applications, aiming to develop telescopic mechanisms or alternative motor configurations to maintain robust connections between moving components.