A Cylindrical Triboelectric Energy Harvester for Capsule Endoscopes

Capsule endoscopy is a new technology that has the potential to replace conventional endoscopy in the near future due to its non-invasive nature. A major limitation for their functionality is the limited battery life. We have investigated a triboelectric energyharvester inside a capsule endoscope that can generate power from natural contractions of gastrointestinal (GI) tract. The periodic contacts and separations of two triboelectric materials inside the capsule endoscope create an alternating current that can be used to charge the capsule endoscope battery, which is used for imaging the GI tract. This study presents an analytical closed form solution for the output power of a cylindrical triboelectric energy harvester. Energy harvester sizes have been optimized to maximize the output power

A Review of Locomotion Systems for Capsule Endoscopy

Wireless capsule endoscopy for gastrointestinal (GI) tract is a modern technology that has the potential to replace conventional endoscopy techniques. Capsule endoscopy is a pill-shaped device embedded with a camera, a coin battery, and a data transfer. Without a locomotion system, this capsule endoscopy can only passively travel inside the GI tract via natural peristalsis, thus causing several disadvantages such as inability to control and stop, and risk of capsule retention. Therefore, a locomotion system needs to be added to optimize the current capsule endoscopy. This review summarizes the state-of-the-art locomotion methods along with the desired locomotion features such as size, speed, power, and temperature and compares the properties of different methods. In addition, properties and motility mechanisms of the GI tract are described. The main purpose of this review is to understand the features of GI tract and diverse locomotion methods in order to create a future capsule endoscopy compatible with GI tract properties

Frictional Energy Dissipation in Wavy Surfaces

Accurate estimation and tuning of frictional damping are critical for proper design, safety, and reliability of assembled structures. In this study, we investigate how surface geometry and boundary conditions affect frictional energy dissipation under microslip contact situations. In particular, we investigate the frictional losses of a two-dimensional (2D) deformable wavy surface in contact with rigid plate under specific normal and tangential loading. We also propose a dissipation tuning mechanism by tension-induced wrinkling of a composite surface. This surface is made of stiff strips printed on a compliant substrate. We show that the contact geometry of wrinkling surfaces can be altered significantly by tensile loading and design of the composite surface. Using this, we present frictional dissipation maps as functions of applied tension and one of the geometric parameters in the composite design; spacing between stiff strips. Those maps illustrate the dissipation tuning capability of wrinkled surfaces, and thus present a unique mean of damping control