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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design, modelling and fabrication of a robotic retractor for colorectal surgery

Tao, Tainyi January 2017 (has links)
This research presents the design, fabrication and controller development of a robotic retractor which driven by a robotic manipulator for laparoscopic colorectal surgery. The system consists of a dual-head fan retractor and a manipulator. The dual-head fan retractor comprises two fan devices, retractor wrist, tubular element and handle. The fan device is facilitated with a fan end-effector, an expansion mechanism and a clutchspring mechanism. Two fan devices have been used in the system to provide an anthropoid hand-holding shape which is specifically advanced for surgical purpose because intestine tends to slip when subject to disturbance and the anthropoid handholding shape can effectively halt that. One of the two fan devices is rotatable which makes the anthropoid hand-holding shape achievable. The retractor wrist possesses a triggering device, based on clutch-spring mechanism, for rotating the rotatable fan device. The clutch-spring mechanism has an impact on rotating the palms of the fan devices. In front of the handle, it is the so called front body which includes two fan devices, retractor wrist and tubular element. The front body can be controlled and is motorised using two motors fixed to the tubular element. The dual-head fan retractor is modelled in SolidWorks, and stress analysis of the retractor has been carried out by SolidWorks Simulation. Then, the mathematical model of the fan blades is developed. A 3-joint manipulator is modelled and controlled by a computed torque PD control approach as part of an investigative study to fit such a system to the retractor for robotic manipulation. Based on this investigation, the retractor is attached to a 2-joint robotic manipulator which has one rotational joint and a prismatic joint. This manipulator is mathematically modelled, and the dynamic equations are obtained. Control methods from Azenha and Khatib are simulated and compared. Azenha & Machado's method has fewer input parameters and less oscillation when utilising the same control gains. Timeoptimal control is then successfully developed for the above 2-joint manipulator. This study clearly indicates that a retractor to be used for laparoscopic surgery can be effectively controlled using a multi-joints and multi degrees of freedom robotic manipulator.
2

Investigation on seat structural integrity and occupant safety in coach rollover

Giahi, Hamid 30 January 2017 (has links)
Motor coaches are an integral part of the transportation system. It was observed that occupant fatalities and serious injuries occur in rollover more frequently than in any other type of accidents for these vehicles. Several regulations such as Economic Commission for Europe Regulation 66 (ECE R66) are issued to minimize the catastrophic consequences of rollover accidents. Passing “Motorcoach safety plan” which is based on a complete vehicle rollover test of ECE R66 will be mandatory in North America in the near future. However, the cost of a single physical test encourages researchers to perform numerical simulations prior to a complete vehicle rollover test. In this thesis, the integrity of a coach seat and the effects of different restraint configurations on the safety of passengers in rollover are numerically studied. To perform this research, a new modeling approach, which is computationally effective and highly suitable for parametric studies, is proposed. Firstly, a detailed model of two seats of a coach is developed and validated against experimental results. Anthropomorphic Test Devices are then introduced to the model and acceleration history of a physical rollover test is imposed on the system. The model is solved using non-linear explicit dynamic Finite Element code LS-DYNA®. Injury criteria values are extracted and compared to the experimental results. An acceptable level of correlation is achieved that confirms the validity of the model and the reliability of the modeling approach. The integrity of the seat in a rollover is analyzed showing the necessity of an anchorage test prior to a whole coach rollover test. The results of a parametric study on the safety of passengers reveal the high probability of partial ejection if the retractor does not lock properly in a rollover. It is also shown that the safety of occupants can be improved if retractor pretensioners be introduced to coaches. / February 2017
3

Framtagning av en ny sårhake / Development of a new surgical retractor

Rosenlund, Angelica, Gren, Pia January 2013 (has links)
Examensarbetet har genomförts i samarbete med innovationsföretaget ProboNova Medical Innovations AB. ProboNova jobbar främst med konceptframtagning av medicintekniska produkter. ProboNova tar sedan en Provisional Patent Application på konceptet och licenserar ut det till ett större företag. Genom att licensera ut koncepten slipper de kostnaderna för kliniska tester bland annat.  Examensarbetet grundades i att ProboNova ville ha hjälp med att ta fram ett koncept på en ny sårhake. Projektet har genomsyrats av designprocessen där förstudie och idégenerering har varit de två dominerande delarna. I slutet av projektet presenterades ett koncept som uppfyllde alla krav och detta koncept togs det senare en Provisional Patent Application på.  Tanken är att examensarbetet ska ge läsaren en bättre förståelse för hur man kan jobba med designprocessen och lära sig fördelarna med att välja en Provisional Patent Application istället för en Nonprovisional ansökan. / The thesis was carried out in cooperation with the company ProboNova Medical Innovation AB. ProboNova works mainly with the concept development of medical devices. Then they take a Provisional Patent Application on the concept and licensing it out to a larger company. By licensing out the concepts they don’t have to take the costs of clinical trials for example.   The thesis was founded in that ProboNova wanted help with developing a concept on a new surgical retractor. The project has been characterized by the design process in which the feasibility studies and brainstorming has been the main parts. At the end of the project a concept was presented. The final concept met all the requirements from ProboNova and from the functional analysis that was done in the feasibility studies. A Provisional Patent Application was taken later on the final concept.    The idea is that the thesis should give the reader a better understanding of how to work with the design process, and learn the benefits of choosing a Provisional Patent Application instead of a Nonprovisional application.
4

Optimal "Belt-in-Seat" : A study to evaluate the optimal positioning of a Belt in a car's frontal seats

Bryggman, Elin January 2020 (has links)
The world is continuously moving, and so are the life on it. As our society is constantly evolving and the width of human needs are rising, do organization need to provide new solutions that can satisfy our needs. Consequently, every designer is going to meet new challenges whenever the situation calls for it. This is the situation that CEVT’s engineers have found themselves in and the reason as to why this engineering project has become relevant for their industrial development and innovation. The seatbelt designers at CEVT’s Restraints department have encountered a situation where it forces them to change their product as it can no longer be installed in the cars’ B-pillars. The company must investigate alternative positionings with regard to the car's new design criteria in order to recreate or improve the functionalities in both safety and comfort of their seatbelt system. My project objective is to investigate alternative positionings and components that are part of the classic three-point seatbelt system with an aim to ensure good user experience in the area of comfort. By the end of this thesis I ought to have answered the following Mission Statement: “Determine the most optimal positioning and components of the seatbelt system to reduce inertia for a fontal Belt-in-Seat, where the system’s performance should be comparable to the users’ experience from an installation of a seatbelt in a B-pillar.” To establish the best component combination out of the parts delivered from Autoliv AB and secure an optimal placement for the involved parts, have I followed the three-stage process described by IDEO (2015). The Inspiration phase has included a Literature study, benchmarking, analytical assessments of user needs as well as prepared and performed of a test on the seatbelt system. The Ideation phase was focusing on establishing a placement for the system's components through a brainstorming so that it could be mounted in a seat prototype prepared for the user experience tests performed. The last phase, Implementation, consisted of an analysis that was focusing on the feedback received from users of different anthropometry. But also concentrated on summarizing all data collected throughout the project to select the final concept for this assignment. / Världen och allt liv på jorden är i ständig rörelse. När samhället strävar efter utveckling uppkommer samtidigt nya behov hos människan och dess omgivning, vilket gör att olika organisationer och företag behöver leverera nya lösningar och designa artefakter för att tillfredsställa människans behov. Varje designer kommer att möta nya utmaningar när en situation tvingar dem att ändra sina produkter. Detta är en situation som CEVT:s bilbältesdesigners står inför och anledningen till att detta arbete blivit aktivt för företagets industriella utveckling inom innovation. Situationen som tvingar konstruktörerna att ändra bältessystemets design är att systemet inte längre kan monteras i passagerarbilens B-stolpar. Därför måste företaget undersöka alternativa positioneringar som överensstämmer med bilens designkriterier för att återskapa bältets funktionalitet som berör både säkerhet och komfort av deras bältessystem. Arbetets syfte är att undersöka alternativa positioneringar och de inkluderade komponenterna som utgör ett klassiskt tre-punkts bälte med målet att säkerställa en god användarupplevels inom området komfort. I slutet av projektet skall jag ha uppfyllt följande Mission Statement: “Bestäm den mest optimala positioneringen och komponenter av ett säkerhetsbältes system för att reducera krafterna från ett bältes-integrerat framsäte, en ’Belt-in-Seat’, där systemets prestandard skall vara jämförbart med användarens upplevelse av en installation av bältet i bilens B-stolpe.”   Jag har följt IDEOs (2015) tre-stegs process för att säkerställa den bästa kombinationen av komponenter som har tillhandahållits av Autoliv AB samt fastställa en optimal placering av varje komponent i systemet. Inspirationsfasen har inkluderat en litteraturstudie, benchmarking, analytiska bedömningar av användarens behov samt förberett och genomfört ett test på bältesystemets prestandard. Ideationsfasen fokuserade på att etablera en placering för systemets komponenter genom en brainstorming så att dessa kunde monteras i en sätesprototyp som förberetts inför testerna för att evaluera användarens komfortupplevelse. Den sista fasen, Implementation, bestod av en analys som fokuserade på feedbacken från testpersonerna som erhöll olika antropometri. Fasen kretsade kring att sammanfatta all data som samlats in genom hela projektet för att välja det slutliga konceptet för uppgiften.

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