Modular Self-Assembling Robots

There is a clear trend toward the miniaturization of medical devices for minimally invasive medical procedures, ranging from diagnosis and targeted drug delivery to complex surgical interventions. Current research focuses on increasing the functionality of commercially successful capsule endoscope technology by developing active locomotion and telemetry. The size of such a capsule must not be larger than what a person can swallow without difficulty. One approach to increase functionality while still working within this size constraint is to build a modular robotic system in which the modules are swallowed one at a time, and the final assembly is performed inside the gastrointestinal (GI) tract. This work addresses a fundamental challenge that must be be met for the success of such swallowable modular robots - their self-assembly. We propose to use magnets in a specific configuration on the mating faces of the modules. Our results show that high success rates can be achieved and snake-type robots can be self-assembled with compliant magnetic joints allowing them to adapt to highly irregular paths, such as the small intestine.

One approach to overcome this size constraint is to build a modular robotic system in which the modules are swallowed one at a time and the final assembly is performed inside the GI tract. This allows the size and the complexity of the final robot to be significantly greater than that of its individual modules. If the modules are designed to be heterogeneous, each having a specific dedicated function, the difficulty in fabrication and packaging will be reduced, and relatively large devices could be included in the robotic system. As an example, consider a snake-type robot with heterogeneous modules that assembles in the stomach and then moves through the intestine. At its front end, sensors detect pathologies that are communicated to the surgeon, who decides on the actions to take. A module designed for a specific task executes the commands once the robot has been positioned accurately by an actuation module. As mentioned above, sensors and actuators for pill-sized devices are currently being developed, and each sensor/actuator could constitute an individual module.