Gremlins: an Architectural Framework for Reconfigurable Autonomous Robots

Abstract

The work area of a team of small robots is limited by their inability to traverse a very common obstacle: stairs. We present a complete integrated control architecture and communication strategy for a system of reconfigurable robots that can climb stairs. A modular robot design is presented which allows the robots to dynamically reconfigure to traverse certain obstacles. This thesis investigates the implementation of a system of autonomous robots which can cooperatively reconfigure themselves to collectively travers obstacle such as stairs. We present a complete behaviorand communication system which facilitates this autonomous reconfiguration. The layered behavior-based control system is fault-tolerant and extends the capabilities of a control architecture known as ALLIANCE. Behavior classes are introduced as mechanism for managing ordering dependencies and monitoring a robot's progress through a particular task. The communication system compliments the behavioral control and iimplementsinherent robot failure detection without the need for a base station or external monitor. The behavior and communication systems are validated by implementing them ona mobile robot platform synthesized specifically for this research. Experimental trials showed that the implementation of the behavior control systems was successful. The control system provided robust, fault-tolerant performance even when robots failed to perform docking tasks while recongifuring. Once the robots reconfigure to form a chain, a different control scheme based on gait control tables coordinates the individual movements of the robots. Several successful stair climbing trials were accomplished. Improvements to the mechanical design are proposed.