A robot designed for a single purpose can perform some specific task well but poorly on some other task, especially in a different environment. A fixed-architecture machine is acceptable if the environment is structured, but for tasks in unknown environments, a robot with the ability to change shape to suit the new environment and the required functionality is more likely to succeed than is its fixed-architecture counterpart. Our vision for ultimate robotic design and functionality is to create vastly more versatile robots by building them out of simple modules with general self-reconfiguration capabilities. Hundreds of small, relatively limited, modules would be able to autonomously organize and reorganize as geometric structures to best fit the terrain on which the robot has to move, the shape of the object the robot has to manipulate, or the sensing needs for the given task. This function mimics the organizational principles of biological systems; a simple living cell does not do too much by itself, but a collection of cells can be organized to form a climbing inchworm, a crawling crab, or a running child. Large collections of small robots will someday actively organize themselves as the most optimal geometric structure under the local environmental conditions to perform coordinated and useful work, such as repairing a damaged structure, transporting artifacts, or manipulating surface properties. Modular re-configurable robots have a number of other advantages over their more traditional, fixed architecture counterparts. First, they support multiple modalities of locomotion and manipulation. For example, if a particular robot system needs to climb stairs, it would reconfigure itself so it can crawl up stairs. If it needs to cross a gap or
reach a window, just in- time bridges and towers might be created.