Bio-inspired Soft Growing Robots for Medical Applications

Conventional endoscopes need to be pushed into the body, e.g., the colon, stomach, and lungs. This insertion process generates normal forces and friction between the endoscope and the environment (e.g., the colon), which limits how far the endoscope can be pushed in and also uncomfortable procedures for the patient. However, if we look at nature, e.g., the root of a bean penetrating into the soil, the root is not pushed into the soil; instead, the root keeps lengthening at the tip but its main stem does not move with respect to the environment. There is no or little friction in the process due to the absence of relative sliding. In this way, the flexible/soft root can reach deeper into the hard soil. This phenomenon can be adopted for robot navigation, that is, soft-growing robots. A soft growing robot is simply a flexible tube with a portion of its material being inverted inside its hollow channel. When air pressure is supplied into the tube, the inverted material can be everted out to the tip of the tube, which actually lengthens the tube and mimics the tip growth feature of the root of beans. Theoretically, there is no friction between the robot and the environment for the robot to reach further. This frictionless navigation makes soft-growing robots promising in searching, rescuing, and medical applications.

Our goal is to develop next-generation robotic endoscopic devices based on the tip-growth concept of soft growing robots; these devices will have the superior capability of accessing difficult-to-reach areas in a narrow and cluttered environment, for instance, the small intestine, the deep branches of lungs, and even blood vessels. We achieve this goal by focusing on both the fundamental engineering aspects (e.g., actuation, sensing, modeling, and control) of soft growing robots and the clinical requirements and constraints.