Achievements and future directions in self-reconfigurable modular robotic systems

In this study, a comprehensive review of achievements in the self-reconfigurable modular robotics field and future directions are given. Self-reconfigurable modular robots (SRMRs) are known as autonomous kinematic machines that can change their shape by rearranging the connectivity of their modules to perform new tasks, adapt to changing circumstances, and recover from damage. Versatility, reliability, and low-cost are the fundamental promises of SRMRs when compared with conventional robots. This study emphasized the achievements in the field considering the promises and identified the gaps to be filled in the future. The main distinguishing feature of an SRMR is the capability of configuring its shape during operation. Flexibility in shape supported by appropriate controller strategies brings flexibility in task assignment. Classification of SRMRs is enriched by adding a new section based on assigned tasks to the robot. In addition, the classification based on mechanical and controller design aspects is thoroughly inspected in our study. A new subsection of material selection is introduced in the mechanical design aspects section. Adding these sections to the classification is the main difference between our study and the previous review studies. It is expected that the SRMRs field will have more interactions with materials science in the future. The study is concluded by emphasizing the promises of SRMRs and giving a future vision of the field.