Self-reconfiguring modular robot

Modular self-reconfiguring robotic systems are autonomous kinematic machines with variable morphology. Beyond conventional actuation, sensing and control typically found in fixed-morphology robots, self-reconfiguring robots are also able to change their own shape by rearranging the connectivity of their parts, in order to adapt to new circumstances, perform new tasks, or recover from damage.

Motivation and inspiration

There are two key motivations for designing modular self reconfiguring robotic systems.

• Functional motivation: Self reconfiguring robotic systems are potentially more robust and adaptive than conventional systems. Since robot parts are interchangeable (within a robot and between different robots), machines can replace faulty parts autonomously. The reconfiguration ability also allows a robot or a group of robots to disassemble and reassemble machines to form new morphologies that are better suitable for new tasks, such as changing from a legged robot to a snake robot and then to a wheel robot.

• Economic motivation: Self reconfiguring robotic systems can potentially lower overall robot cost by making a range of complex machines out of a single (or relatively few) types of mass-produced modules.

Both these motivations have not yet been realized. It is generally agreed that a modular robot will be inferior in performance to any custom robot tailored for a specific task. The advantage of modular robotics is only apparent when considering multiple tasks that would normally require a set of different robot.

Inspiration

The need for self-reconfiguring robotic structures is to some extent inspired by envisioned scenarios such as long-term space missions that require a self-sustaining robotic ecology that can handle unforeseen situation. A second source of inspiration are biological systems: Many complex and rich biological structures are self-constructed out of a relatively small repertoire of lower-level building blocks (cells or amino acids, depending on scale of interest). This architecture lies at the crux allows biological systems’ ability to physically adapt, grow, heal, and even self replicate – capabilities that would be desirable in many engineered systems.

Structure and control

Modular robots are usually composed of multiple building blocks of a relatively small repertoire, with some standardized docking interfaces that allow transfer of mechanical forces and moments, electrical power and communication.

Challenges and opportunities

These added degrees of freedom make modular robots more versatile in their potential capabilities, but also incur a performance tradeoff and increased mechanical and computational complexities.