Armadillo-inspired active morphing skeletons for soft machines

Armadillos can rapidly reconfigure their body into a rigid, enclosed sphere in active response to external threats, combining adaptive shape change with robust mechanical protection, which is rarely achieved in engineered systems. This rapid reconfiguration is achieved through real-time sensing and muscle activation, while the synergistic coordination of the exoskeleton and endoskeleton provides structural stiffness and impact resistance. Inspired by this natural strategy, we present an active morphing skeleton called morpho-interlocking protective module (MIPM). The architecture integrates curvature-conforming segmented exoskeleton with a spine-inspired interlocking endoskeleton framework, forming a coordinated load-bearing skeleton. A muscle-like liquid crystal elastomer composite layer drives structural transformation, while an embedded sensing layer detects external threats and autonomously triggers localized Joule heating for actuation of the liquid crystal elastomer layer. This enables multimodal morphing behaviors such as curling, rolling, and grasping, without compromising the structural integrity. The MIPM withstands impact, puncture, and concentrated loading while carrying and protecting fragile payloads in harsh conditions. An integrated Bluetooth module facilitates wireless, untethered operation, broadening its applicability to hazardous or inaccessible environments. By combining adaptive morphology, real-time sensory feedback, and on-demand mechanical stiffening within a unified internal-external skeletal framework, this work presents a previously unidentified paradigm for concurrent morphing and protection, with broad applicability across adaptive systems ranging from soft robotics to next-generation flexible electronics.