Abstract
This paper presents a modular reconfigurable robotic system for search-and-rescue operations in natural catastrophe scenarios, addressing the structural rigidity, limited energy autonomy, and restricted victim-support capabilities of conventional rescue robots. The contributions are organized into four dimensions. First, a modular mechanical architecture is proposed in which modules operate independently or are interconnected through a multifunctional flexible tube providing mechanical coupling, shielded communication, wireless power transfer, and transport of vital supplies; a two-degree-of-freedom leg module enables star-, snake-, worm-, and chain-like configurations. Second, a unified locomotion model for both wheeled and legged configurations is developed through an equivalent-radius formulation, and stability is analyzed using the Zero-Moment Point (ZMP) criterion and the Linear Inverted Pendulum Model (LIPM). Third, a linear control law is formulated to compensate for longitudinal, lateral-slip, and orientation errors, while module coordination is achieved through a de-centralized, fault-tolerant status-message protocol. Fourth, three proof-of-concept prototype versions of modular reconfigurable robots with servo-driven active interconnections were manufactured by additive technologies. For Version 3, a Virtual Reality workflow integrating SolidWorks (version SOLIDWORKS 2023), Blender (version Blender 4.4.3, Unreal Engine 5 version 5.8), and Unreal Engine 5, with full-body inverse kinematics and physics-based simulation, was used to evaluate sensor-driven motion and obstacle avoidance. The results demonstrate the feasibility of a scalable platform able to adapt its locomotion and functional configuration to post-disaster environments