Octopus-inspired muscle activation unlocks high-DOF motion from a single actuator

Abstract

While soft robots leverage compliant materials to offer infinite degrees of freedom (DOFs), achieving dexterous motions usually requires numerous actuators, making the robot bulky, complex to assemble, and discontinuously segmented. Here, inspired by the octopus neuromuscular junctions (NMJs), we present similar wire bonding junctions (WBJs) that enable partitioned activation on a single shape memory alloy (SMA) actuator. By utilizing WBJs, soft robots achieve continuous deformation with approximately twice the workspace and manipulability of traditional stacked designs. We demonstrated that modulating voltage across these junctions allows the SMA to actuate variable lengths, maintaining high dexterity while reducing energy consumption up to 40%. With WBJs, one single SMA actuator could master both soft arm manipulator and its end effector. This compact, lightweight architecture enables the soft robot arm to be rolled for low-encumbrance drone deployment and confined-space sampling. Our results demonstrate a new actuation paradigm for achieving high DOF, offering a compact, efficient blueprint for soft robot design.