Hybrid Wireless–Local Communication via Information Propagation for Modular Robotic Synchronization Applications

Abstract

Modular robots (MRs) are a collection of individual robotic components which interlock in order to construct a full robot. [1] By adjusting the way in which these components connect, a robot can change topology to best suit the environment or task at hand. This adaptability poses advantages over traditional robots, as they can modify their underlying structure to improve performance or achieve tasks which otherwise would be impossible. MRs are particularly useful where the environment or task space is either unknown or very large, which includes disaster recovery, [2] space, [3,4] adaptive furniture, [5] structures, [6] tooling, [7] and education. [8] Failure due to scalability in numbers is a fundamental issue for MRs. Most experimental MRs run with less than 30 modules at a time, such as those listed in Table 1. If an element within a module fails 1% of the time, then one out of 30 modules will statistically fail during 26% of trials. [9] If there is no redundancy in place, the entire robot could fail. Many simulations run with hundreds of modules. [10] If MRs are to have hundreds modules with any sort of stability, then there must be a high degree of redundancy to account for failures. Synchronization of modules is critical. If a module acts out of synchronization with the others, not only will the robot fail to perform tasks properly, but its behavior may be self-destructive through self-collision. Communication therefore is a fundamental topic in MRs, where most robots opt for a combination of different types according to their speciality. Global communication spans the whole robot, while local communication acts just between neighboring modules. Local is necessary for configuration discovery and synchronization between neighbors. If the configuration is known and has a small number of modules, global communication eliminates the need for local communication, but most MRs opt for a combined solution to avoid overloading a single system, as shown in Table 1.The current trend for global communication is toward wireless. [11] Wireless communication allows for MRs to easily synchronize across all modules and interface with an external controller, but suffers from interference and packet loss with many clients. [9] Wireless systems consume far more power than local communication and are enough to negatively impact the performance of a robot. Lastly, there is another trend toward incorporating specialized modules with elements such as wireless cameras and other specific sensors. [10] These data-heavy devices will significantly impact the reliability of the networks with a high number of clients.

Meta‐Module Mutual Assistance: A Bioinspired Design for Self‐Assembly of Modular Space Robot

“…Modular robot is a class of special robot, which is composed of several homogeneous or heterogeneous modules with certain drive and sensing abilities. [ 3 ] Through combining and disassembling modules, modular robot can be organized into different structures with different functions to adapt to complex tasks and environments. [ 4 ] With the rapid development of aerospace technology, modular robot has begun to turn their attention to space exploration, [ 5 ] such as space on‐orbit service and unmanned robotic system for lunar base.…”

Meta-module Mutual Assistance: A Bio-inspired Design for Self-assembly of Modular Space Robot

“…Modular robot is a class of special robot, which is composed of several homogeneous or heterogeneous modules with certain drive and sensing ability (Holdcroft et al, 2022). Through the combining and disassembling modules, modular robot can be organized into different structures with different functions to adapt to complex tasks and environments (Yang et al, 2022;Zhang et al, 2020).…”