2. Lattice Automata for Control of Self-Reconfigurable Robots

Self-reconfigurable robots are built from robotic modules typically organised in a lattice. The robotic modules themselves are complete, although simple, robots and have onboard batteries, actuators, sensors, processing power, and communication capabilities. The modules can automatically connect to and disconnect from neighbour modules and move around in the lattice of modules. The self-reconfigurable robot as a whole can, through this automatic rearrangement of modules, change its own shape to adapt to the environment or as a response to new tasks. Potential advantages of self-reconfigurable robots are extreme versatility and robustness. The organisation of self-reconfigurable robots in a lattice structure and the emphasis on local communication between modules mean that lattice automata are a useful basis for control of self-reconfigurable robots. However, there are significant differences which arise mainly from the physical nature of self-reconfigurable robots as opposed to the virtual nature of lattice automata. The problems resulting from these differences are mutual exclusion, handling motion constraints of modules, and unrealistic assumption about global, spatial orientation. Despite these problems the self-reconfigurable robot community has successfully applied lattice automata to simple control problems. However, for more complex problems hybrid solutions based on lattice automata and distributed algorithms are used. Hence, lattice automata have shown to have potential for the control of self-reconfigurable robots, but still a unifying implementation based on lattice automata solving a complex control problem running on physical self-reconfigurable robot is yet to be demonstrated.