PolyBot - Modular, self-reconfigurable robots Modular, self-reconfigurable robots show the promise of great versatility, robustness and low cost. Polybot is a modular, self-reconfigurable system that is being used to explore the hardware reality of a robot with a large number of interchangeable modules. Three generations of Polybot have been built over the last three years which include ever increasing levels of functionality and integration. Polybot has shown versatility, by demonstrating locomotion over a variety of terrain and manipulating a variety of objects. Polybot is the first robot to demonstrate sequentially two topologically distinct locomotion modes by self-reconfiguration. Polybot has raised issues regarding software scalability and hardware dependency and as the design evolves the issues of low cost and robustness are being addressed while exploring the potential of modular, self-reconfigurable robots