A Soft Everting Pneumatic Deployment Cap for Secure Payload Delivery in Robotic Endoscopy

Payload delivery in endoscopic and robotic interventions has the potential to extend diagnostic and therapeutic capabilities through selective deployment of drugs, micro-robots or other medical devices. However, reliably delivering small and delicate objects through long tool channels associated with flexible instruments or continuum robot platforms remains challenging. Approaches that retain payloads at the tool tip and enable selective deployment represent a promising solution. Previous systems following this strategy have commonly relied on complex magnetically triggered designs or material changes to deliver cargo on demand. These can be slow to trigger or require specific payload designs, limiting versatility. In this work, we propose a fully soft pneumatically driven deployment cap based on a hybrid combination of an eversion skin and an elastomer body. We introduce the concept, develop a model capturing the deployment profile, and present a prototype design of 13.5 mm diameter, 26 mm length, and 2.5 g. We demonstrate repeatable deployment of various objects within the scale range of 2−5 mm, and show sequential delivery of two objects in a simulated endoscopic task in under 45 s.