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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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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.
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The Correlation Between Biomechanical Loads and Psychophysical RatingsLang, Andrew Wilson 06 November 2000 (has links)
Psychophysics is defined as the scientific study of the relationship between stimuli and sensation. It has been used extensively over the last three decades for evaluation and design of manual materials handling tasks in many industries. Despite this, much is still not known about how subjective ratings, the core of the psychophysical methodology, relate to physical (biomechanical) loads. A fundamental assumption of this method is that humans are capable of estimating biomechanical and physiological loads that are placed on the body. Based on this assumption, estimates that are obtained through the methodology are used as an indicator of physical loads and stresses, and are assumed to be related to injury risk.
An experiment was performed to achieve two primary goals:1) determine the correspondence between biomechanical loads (moments at the elbow, shoulder and torso) and subjective ratings of joint loads, as well as subjectively determined maximal loads and 2) determine whether any particular joint (i.e. low back, shoulder, elbow) is the limiting factor when a subject determines a maximally acceptable load. Participants were instructed to pose in four different postures, one serving as a baseline (neutral, or 'familiar') posture, while the remaining three varied moments at the elbow, shoulder and torso. While in each of these postures, participants determined a maximum acceptable static load (MASL). Ratings of perceived exertions for specific joints were also reported, as well as whole body ratings while supporting various fractions of the MASL.
Experimental findings indicated that subject and posture effects neared significance as main effects on the magnitude of MASL. Strength was shown to be, at best, a weak predictor of MASL. Though no conclusive evidence was found to indicate that a specific joint is the limiting factor when determining maximum acceptability, trends in the data suggested that the low back and shoulder are possible candidates. Overall, the results of the study indicated that humans consider more than simple joint moments when forming perceptions of efforts and acceptability during static load handling. / Master of Science
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The use of EMG for load prediction during manual liftingChan, Sonya 15 October 2007 (has links)
The Ergonomics Research Group at Queen’s University, supported by the Workplace and Safety Insurance Board, has been developing an on-line system to estimate peak and cumulative joint loading in the workplace. This study will aid the project by examining the muscle activation levels (MALs) in upper extremity and trunk muscles during a manual lifting task using both hands. It was hypothesized that MAL’s are correlated with the magnitude of the load in the hands and thus could be used to predict the load which in turn will be used to predict the lower back moments. Alterations in the muscle activation patterns due to lifting different loads were examined.
Electromyographic signals (EMG) and kinematic data were recorded from different sites on the trunk and upper limb as subjects lifted a load from the floor to a shelf using squat, stoop and freestyle lift techniques. All raw EMG data were processed to obtain the linear envelopes (LE) which provides estimates of the MAL’s. The peak, mean and area of the linear envelopes were calculated. Using regression analysis, a relationship between the parameters and load lifted was found to exist. A non-linear parallel cascade type architecture was used to develop a model to predict the load in the hands. The model uses the EMG parameters as inputs and fits the data via linear and non-linear cascades to the output, i.e. the load in the hands.
A model was successfully developed for the squat lift posture using the area, peak and mean of the zero-normalized EMG LE recorded from the erector spinae (L4 level), with a prediction error of ± 1.03kg and for the stoop posture, a prediction error of ± 2.34kg. Given the predicted loads, moments in the lower back were computed using the method of Hof (1992). / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2007-09-28 16:15:23.077
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A cognitive model to support the design of training for physical tasks for enhanced knowledge transfer : the case of manual handling trainingNicholls, Jacqueline Anne January 1996 (has links)
No description available.
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Three-Dimensional Dynamic Biomechanical Model for Lifting and Lowering Activities: Systematic Review, Critical Appraisal and Model DevelopmentRINDER, MARIA M. 03 July 2007 (has links)
No description available.
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A general lifting equation based on total mechanical workSONBOL, AMR M. 07 July 2004 (has links)
No description available.
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Lifting aid for roof top tents : Produktutveckling med ergonomi / Lyfthjälpmedel för montering av taktältSvensson, Daniel, Rönneke, William January 2024 (has links)
This thesis focuses on the development of a lifting device for roof mounted tents at the requestof Thule with the focus on improving the ergonomics during installation and removal of roofmounted tents on vehicles, while also enabling the process for one to two users. The work isstructured according to the Double Diamond model and uses established product developmentmethods to ensure a systematic process.The preliminary study consists of an analysis of ergonomic risk factors during heavy liftingusing the Swedish Work Environment Agency's (Arbetsmiljöverket) assessment template andRapid Upper Limb Assessment (RULA). These tools were used to evaluate current users ownsolutions for lifting roof mounted tents.After screening and selecting developed concepts, an existing plasterboard lift was modified tocreate a prototype. Modeling work was carried out in SolidWorks, where various componentsand modifications were visualized and tested before being integrated into the plasterboard lift.The final prototype integrates functions that enable tilt and lifting of the roof tent, whichreduces the need for manual lifting and thus the risk of physical damage because of overloadsas well as minimizing needed storage space.The prototype was tested and evaluated where the results showed an improvement inergonomics and ease of use during lifting, facilitating movement of roof mounted tents betweenvehicles and storage while being able to be stored together with the tent with minimal impacton space requirements.Lastly, the work suggests further strength tests and investigation of better suited lift functionsfor future development to improve safety and lifting device efficiency. / Detta examensarbete fokuserar på utvecklingen av en lyftanordning för taktält på begäran avThule med huvudfokus att förbättra ergonomin vid på- och avmontering av taktält på fordonoch förenkla momentet för en till två personer. En framtagen lösning ska även bidra till minskadbränsle- och energiförbrukning för fordonet då det ska vara enklare och mer inspirerande attmontera av taktältet från fordonet när det inte är planerat att användas.Arbetet är strukturerat enligt Double Diamond-modellen och använder etableradeproduktutvecklingsmetoder för att säkerställa en systematisk process.Förstudien består av analys av ergonomiska riskmoment vid tunga lyft med hjälp avarbetsmiljöverkets bedömningsmall och Rapid Upper Limb Assessment (RULA). Dessa verktyganvändes för att utvärdera nuvarande användares egna lösningar för lyft av taktält. Eftersållning och val av framtagna koncept modifierades en befintlig gipsskivlyft för att skapa enprototyp. Modelleringsarbete utfördes i SolidWorks, där olika komponenter och modifieringarvisualiserades och testades innan de integrerades i gipsskivlyften. Den slutliga prototypenintegrerar funktioner som möjliggör ”tilt” och lyft av taktält vilket minskar behov av manuellalyft och därmed risken för fysiska skador som konsekvens av överbelastningar.Prototypen testades och utvärderades där resultaten visade en förbättring av ergonomi ochanvändarvänlighet under lyft av taktält, underlättar förflyttning av taktält mellan fordon ochförvaring samtidigt som den kunde förvaras tillsammans med taktält med minimal påverkanpå krav av utrymme.Sammanfattningsvis föreslår arbetet ytterligare hållfasthetstester och undersökning av bättrelämpade hissfunktioner för framtida utveckling för att förbättra säkerheten ochlyftanordningens effektivitet.
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