EndoPil: A Magnetically Actuated Swallowable Capsule for Weight Management: Development and Trials.

Intragastric balloons (IGBs), by occupying the stomach space and prolonging satiety, is a promising method to treat obesity and consequently improves its associated comorbidities, e.g. coronary heart disease, diabetes, and cancer. However, existing IGBs are often tethered with tubes for gas or liquid delivery or require endoscopic assistance for device delivery or removal, which are usually uncomfortable, costly, and may cause complications. This paper presents a novel tetherless, magnetically actuated capsule (EndoPil) which can deploy an IGB inside the stomach after being swallowed and being activated by an external magnet. The external magnet attracts a small magnet inside the EndoPil to open a valve, triggering the chemical reaction of citric acid and potassium bicarbonate to produce carbon dioxide gas, which inflates a biocompatible balloon (around 120 mL). A prototype, 13 mm in diameter and 35 mm in length, was developed. Simulations and bench-top tests were conducted to test the force capability of the magnetic actuation mechanism, the required force to activate the valve, and the repeatability of balloon inflation. Experiments on animal and human were successfully conducted to demonstrate the safety and feasibility of inflating a balloon inside the stomach by an external magnet.

Dynamic Modeling of Cable Driven Elongated Surgical Instruments for Sensorless Grip Force Estimation.

Haptic feedback plays a key role in surgeries, but it is still a missing component in robotic Minimally Invasive Surgeries. This paper proposes a dynamic model-based sensorless grip force estimation method to address the haptic perception problem for commonly used elongated cable-driven surgical instruments. Cable and cable-pulley properties are studied for dynamic modeling; grip forces, along with driven motor and gripper jaw positions and velocities are jointly estimated with Unscented Kalman Filter and only motor encoder readings and motor output torques are assumed to be known. A bounding filter is used to compensate for model inaccuracy and to improve method robustness. The proposed method was validated on a 10mm gripper which is driven by a Raven-II surgical robot. The gripper was equipped with 1-dimensional force sensors which served as ground truth data. The experimental results showed that the proposed method provides sufficiently good grip force estimation, while only motor encoder and the motor torques are used as observations.

Co-located haptic and 3D graphic interface for medical simulations.

We describe a system which provides high-fidelity haptic feedback in the same physical location as a 3D graphical display, in order to enable realistic physical interaction with virtual anatomical tissue during modelled procedures such as needle driving, palpation, and other interventions performed using handheld instruments. The haptic feedback is produced by the interaction between an array of coils located behind a thin flat LCD screen, and permanent magnets embedded in the instrument held by the user. The coil and magnet configuration permits arbitrary forces and torques to be generated on the instrument in real time according to the dynamics of the simulated tissue by activating the coils in combination. A rigid-body motion tracker provides position and orientation feedback of the handheld instrument to the computer simulation, and the 3D display is produced using LCD shutter glasses and a head-tracking system for the user.