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

Modular robots hold promise of adaptability, robustness, and versatility. Synchronization of modules is critical; if a module is asynchronous, not only will the robot fail to perform tasks properly, but its behavior may be self-destructive through self-collision. To avoid this, modern modular robots tend to have several separate communication systems. Wireless communication is used for interfacing with an external controller and synchronizing all modules, but is power-hungry and prone to congestion with a large number of modules. Neighbor-to-neighbor (local) communication is necessary for configuration discovery and for synchronizing orientations, but cannot connect to wireless. As it stands, local communication is underutilized and wireless communication struggles with scalability due to number. A novel hybrid protocol is presented, where only a fraction of the modules connect to wireless and act as hubs which propagate messages through the local system. This method reduces both energy consumption and global network traffic while maintaining functionality and adding redundancy in communication. Through careful selection of hubs, it is shown that the operational time of a modular robot can be extended by 20%.