Decoding modular reconfigurable robots: A survey on mechanisms and design

The intrinsic modularity and reconfigurability of modular reconfigurable robot (MRR) systems confer advantages such as versatility, fault tolerance, and economic efficacy, thereby showcasing considerable potential across diverse applications. The continuous evolution of the technology landscape and the emergence of diverse conceptual designs have generated multiple MRR categories, each described by its respective morphology or capability characteristics, leading to some ambiguity in the taxonomy. This paper conducts a comprehensive survey covering a wide range of mechanism and design aspects of MRR systems, spanning from 1985 to 2023. It introduces an innovative, unified conceptual framework for understanding MRR hardware, which encompasses three pivotal elements: connectors, actuators, and homogeneity. Through the utilization of this trilateral framework, this paper systematically interprets and classifies MRR systems over the years, aiming to provide a structured taxonomy perspective and enhance understanding of MRR. It explains the fundamental attributes characterizing MRR systems and their compositional aspects, providing insights into their design, technology, functionality, and categorization. Augmented by the proposed trilateral framework, this paper also elaborates on the trajectory of evolution, prevailing trends, principal challenges, and potential prospects within the field of MRR.