Artificial Potential Field Controllers for Robust Communications in a Network of Swarm Robots

Abstract

An active area of research in the robotics community is swarm control, where many simple robots work together to execute tasks which are beyond the capability of any single robot acting alone. Yet in order for the swarm members to work together effectively they must maintain a reliable and robust wireless communication network among themselves. The project was to create a motion control law which could fulfill the dual and sometimes conflicting requirements of executing a primary mission, while maintaining a robust mobile wireless communication network among the swarm members. The success or failure in sending or receiving a wireless message is inherently probabilistic, but the odds of success increase considerably based upon the spatial arrangement of the swarm members. This imposes a variety of constraints on each robot's motion. Each robot sending a message should: 1. maintain a line of sight to the receiving robot; 2. stay within close proximity of the receiving robot (range dictated by the transmitter power); and 3. increase the overall redundancy of the swarm by maintaining requirements 1 and 2 for two or more receiving robots simultaneously. To this end, several artificial potential field controllers have been developed and simulated to determine their success in controlling the swarm. At a higher level, the project addressed the challenge of composing a motion control law to achieve the primary mission, while maintaining as many communication constraints as possible. This project included a proof-of-concept implementation of the motion control law on real robots. In addition, this project simulated and statistically analyzed the controller to determine its effectiveness at achieving the primary mission and maintaining a robust communication network. The effectiveness of the control law was seen both in simulation and experiment. Overall the robustness of the swarm was increased 200-300% in the scenarios considered.