Reducing the Risks of Contaminated Flexible Endoscopes and Improving the Margin of Safety with the Reprocessing Process

Gastrointestinal (GI) endoscopy is a minimally invasive, medical procedure that is an important tool for the identification and treatment of disorders of the gastrointestinal tract. Contaminated flexible endoscopes pose a significant risk to patients. Endoscopy associated infections and outbreaks have been reported with multi-drug resistant microorganisms. Inadequate endoscope reprocessing has been associated with infectious outbreaks, but some outbreaks have occurred despite strict adherence to established guidelines. To lessen the risk associated with endoscopy, it is imperative to identify problem areas within current reprocessing standards and develop, evaluate, and implement evidence-based solutions

Design and analysis of a monolithic flexure atomic force microscope

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 175-178).This thesis details the design, manufacture, and testing of a sub-nanometer accuracy atomic force microscope. It was made to be integrated into the Sub-Atomic Measuring Machine (SAMM) in collaboration with the University of North Carolina at Charlotte (UNCC). The microscope uses a tuning fork sensor to gauge its proximity to the sample surface. The sensor is fixed to a stage that is guided to move in one degree of freedom by a monolithic flexure. A piezoelectric actuator drives the moving stage while three capacitance sensors provide a non-contact direct measurement of the displacement. A decoupling flexure prohibits the error motions of the actuator from propagating into the moving stage. A digital control system uses closed loop control to regulate the vertical displacement of the stage. The positioning system demonstrated a 450 Hz -3db closed loop bandwidth and 0.249 RMS noise positioning. A new probe named after its inventor Dr. Terunobu Akiyama is implemented in a feedback control system that adjusts the displacement of the stage in order to maintain a constant gap between the probe and the sample. The system displayed an 8.3 nm RMS positioning noise when set to measure a stationary block of aluminum. The dynamics of the feedback control loop indicate that the system can operate at 27 Hz upon application of a proportional controller. Advanced methods to self excite the tuning fork sensor at resonance by use of a phase locked loop are explored. Follow-up work to integrate the atomic force microscope into the SAMM stage, diminish the electrical noise in the tuning fork, and to implement the phase locked loop circuit are suggested.by Dean Marko Ljubicic.S.M

Design, modelling and validation of a novel extra slender continuum robot for in-situ inspection and repair in aeroengine

The file archived on this repository is a preprint, arXiv:1910.04572v1 [cs.RO], available at: https://doi.org/10.48550/arXiv.1910.04572 (submission history: Mingfeng Wang [v1] Wed, 9 Oct 2019 10:37:12 UTC (1,745 KB)). It has not been certified by peer review. The version of record published by Elsevier is available at https://doi.org/10.1016/j.rcim.2020.102054.In-situ aeroengine maintenance works are highly beneficial as it can significantly reduce the current maintenance cycle which is extensive and costly due to the disassembly requirement of engines from aircraft. However, navigating in/out via inspection ports and performing multi-axis movements with end-effectors in constrained environments (e.g. combustion chamber) is fairly challenging. A novel extra-slender (diameter-to-length ratio < 0.02) dual-stage continuum robot (16 degree-of-freedom) is proposed to navigate in and out confined environments and perform required configuration shapes for repair operations. Firstly, the robot design presents several innovative mechatronic solutions: (i) dual-stage tendon-driven structure with bevelled disks to perform required shapes and to provide selective stiffness for carrying high payloads; (ii) various rigid-compliant combined joints to enable different flexibility and stiffness in each stage; (iii) three commanding cables for each 2-DoF section to minimise the number of actuators with precise actuation. Secondly, a segment-scaled piecewise-constant-curvature-theory based kinematic model and a Kirchhoff-elastic-rod-theory based static model are established by considering the applied forces/moments (friction, actuation, gravity and external load), where the friction coefficient is modelled as a function of bending angle. Finally, experiments were carried out to validate the proposed static modelling and to evaluate the robot capabilities of performing the predefined shape and stiffness

Collective Inspection of Regular Structures using a Swarm of Miniature Robots

We present a series of experiments concerned with the inspection of regular, engineered structures carried out using swarms of five to twenty autonomous, miniature robots, solely endowed with onboard, local sensors. Individual robot controllers are behaviorbased and the swarm coordination relies on a fully distributed control algorithm. The resulting collective behavior emerges from a combination of simple robot-robot interactions and the underlying environmental template. To estimate intrinsic advantages and limitations of the proposed control solution, we capture its characteristics at higher abstraction levels using nonspatial, microscopic and macroscopic probabilistic models. Although both types of models achieve only qualitatively correct predictions, they help us to shed light on the influence of the environmental template and control design choices on the considered nonspatial swarm metrics (inspection time and redundancy). Modeling results suggest that additional geometric details of the environmental structure should be taken into account for improving prediction accuracy and that the proposed control solution can be further optimized without changing its underlying architecture

Design and development of a mobile robotic system for aircraft wing fuel tank inspection

This paper presents the design concept behind a novel remote visual inspection robotic system for fighter jet aircraft wing fuel tank inspection. This work is part of a larger research project which focuses on design, simulation, physical prototyping and experimental validation of a robotic system. Whereas this paper specifically focuses on the development concept of locomotion design choice for the robot. Therefore without an effective mobility method the robot will not be able to fulfill its purpose to access the hazardous confined spaces of the fuel tank. Aircraft wing fuel tank inspection is a challenging area of maintenance which requires a considerable amount of preparation and involvement of several tasks in order to conduct effective Visual and Non Destructive Inspection. The environment of an aircraft wing fuel tank poses several challenges due to both physical and atmospheric constraints which can be detrimental to human personal. This paper introduces an effective locomotion design which should allow the robot to enter and maneuver within confined spaces. The robot is relatively small, approximately 70mm in height and width yet, flexible enough to move within the restricted spaces of the wing. The mobile robot platform is a combination of small track systems that articulate like a snake. An additional mobile platform deploys an inspection sensor to reach the spaces that are unreachable by the robot body. Like other proposed robotic systems this particular proposal differs as it allows the robot to enter from the root of the wing and reach the narrower spaces towards with the wing tip. This paper highlights the stakeholder requirements to illustrate the foundation of the robotic system design. An overview of current complications of wing fuel tank inspection is presented and the analysis of current proposed robotic systems for wing fuel tank inspection. An engineering design methodology approach is followed for this project. Several locomotion methods are evaluated and an innovative locomotion method is illustrated with the use of CAD models. The desired outcome of this research is to eliminate the entry or close contact with the fuel tank by human personal

Modeling and Analysis of Beaconless and Beacon-Based Policies for a Swarm-Intelligent Inspection System

We are developing a swarm-intelligent inspection system based on a swarm of autonomous, miniature robots, using only on-board, local sensors. To estimate intrinsic advantages and limitations of the proposed possible distributed control solution, we capture the dynamic of the system at a higher abstraction level using non-spatial probabilistic microscopic and macroscopic models. In a previous publication, we showed that we are able to predict quantitatively the performances of the swarm of robots for a given metric and a beaconless policy. In this paper, after briefly reviewing our modeling methodology, we explore the effect of adding an additional state to the individual robot controller, which allow robots to serve as a beacon for teammates and therefore bias their inspection routes. Results show that this additional complexity helps the swarm of robots to be more efficient in terms of energy consumption but not necessarily in terms of time required to complete the inspection. We also demonstrate that a beacon-based policy introduces a strong coupling among the behavior of robots, coupling which in turn results in nonlinearities at the macroscopic model level