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Investigation of rotational velocity sensorsTörnquist, Martin January 2008 (has links)
<p><p>To improve the speed measurement of construction equipment, different sensor technologies have been investigated. Many of these sensor technologies are very interesting but to keep the extent of the thesis only two was chosen for testing, magnetic absolute angle sensors using Hall and GMR technology, to investigate if those are a valid replacement for the current measurement system that is using a passive sensor. Tests show that these sensors are capable of speed measurement, but because of noisy angle estimates they need filtering for good speed computation. This filtering introduces a large time delay that is of significance for the quality of the estimate. A Kalman filter has been implemented in an attempt to lower the time delays but since only a very simple model has been used it does not give any improvements over ordinary low pass filtering. For these sensors the mounting tolerance is of great interest. For best performance the offset between the sensor and magnet centres need to be kept small for both sensors. This is due to a non-linearity effect this causes. The distance between the sensors and the magnet is not critical for linearity issues, but only for the quality of the signal, where it might drop out when the distance is too large. This is where the sensor using GMR technology stands out. Compared to the Hall technology sensor, the GMR sensor can handle distances that are more than 10 times larger. The conclusion is that these sensors can be a valid replacement of the current measurement system. They will introduce more functionality with the capability of detecting rotational direction and zero velocity. In an application with more than one sensor they can also be used for more purposes, like detecting slip in clutches etc. Depending on the application, the time delays may not be critical, else more work need to be done to improve the estimate, e.g. with a more advanced model for the Kalman filter.</p></p><p> </p>
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Suspension design for off-road construction machinesRehnberg, Adam January 2011 (has links)
Construction machines, also referred to as engineering vehicles or earth movers, are used in a variety of tasks related to infrastructure development and material handling. While modern construction machines represent a high level of sophistication in several areas, their suspension systems are generally rudimentary or even nonexistent. This leads to unacceptably high vibration levels for the operator, particularly when considering front loaders and dump trucks, which regularly traverse longer distances at reasonably high velocities. To meet future demands on operator comfort and high speed capacity, more refined wheel suspensions will have to be developed. The aim of this thesis is therefore to investigate which factors need to be considered in the fundamental design of suspension systems for wheeled construction machines. The ride dynamics of wheeled construction machines are affected by a number of particular properties specific to this type of vehicle. The pitch inertia is typically high in relation to the mass and wheelbase, which leads to pronounced pitching. The axle loads differ considerably between the loaded and the unloaded condition, necessitating ride height control, and hence the suspension properties may be altered as the vehicle is loaded. Furthermore, the low vertical stiffness of off-road tyres means that changes in the tyre properties will have a large impact on the dynamics of the suspended mass. The impact of these factors has been investigated using analytical models and parameters for a typical wheel loader. Multibody dynamic simulations have also been used to study the effects of suspended axles on the vehicle ride vibrations in more detail. The simulation model has also been compared to measurements performed on a prototype wheel loader with suspended axles. For reasons of manoeuvrability and robustness, many construction machines use articulated frame steering. The dynamic behaviour of articulated vehicles has therefore been examined here, focusing on lateral instabilities in the form of “snaking” and “folding”. A multibody dynamics model has been used to investigate how suspended axles influence the snaking stability of an articulated wheel loader. A remote-controlled, articulated test vehicle in model-scale has also been developed to enable safe and inexpensive practical experiments. The test vehicle is used to study the influence of several vehicle parameters on snaking stability, including suspension, drive configuration and mass distribution. Comparisons are also made with predictions using a simplified linear model. Off-road tyres represent a further complication of construction machine dynamics, since the tyres’ behaviour is typically highly nonlinear and difficult to evaluate in testing due to the size of the tyres. A rolling test rig for large tyres has here been evaluated, showing that the test rig is capable of producing useful data for validating tyre simulation models of varying complexity. The theoretical and experimental studies presented in this thesis contribute to the deeper understanding of a number of aspects of the dynamic behaviour of construction machines. This work therefore provides a basis for the continued development of wheel suspensions for such vehicles. / QC 20110531
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Investigation of rotational velocity sensorsTörnquist, Martin January 2008 (has links)
To improve the speed measurement of construction equipment, different sensor technologies have been investigated. Many of these sensor technologies are very interesting but to keep the extent of the thesis only two was chosen for testing, magnetic absolute angle sensors using Hall and GMR technology, to investigate if those are a valid replacement for the current measurement system that is using a passive sensor. Tests show that these sensors are capable of speed measurement, but because of noisy angle estimates they need filtering for good speed computation. This filtering introduces a large time delay that is of significance for the quality of the estimate. A Kalman filter has been implemented in an attempt to lower the time delays but since only a very simple model has been used it does not give any improvements over ordinary low pass filtering. For these sensors the mounting tolerance is of great interest. For best performance the offset between the sensor and magnet centres need to be kept small for both sensors. This is due to a non-linearity effect this causes. The distance between the sensors and the magnet is not critical for linearity issues, but only for the quality of the signal, where it might drop out when the distance is too large. This is where the sensor using GMR technology stands out. Compared to the Hall technology sensor, the GMR sensor can handle distances that are more than 10 times larger. The conclusion is that these sensors can be a valid replacement of the current measurement system. They will introduce more functionality with the capability of detecting rotational direction and zero velocity. In an application with more than one sensor they can also be used for more purposes, like detecting slip in clutches etc. Depending on the application, the time delays may not be critical, else more work need to be done to improve the estimate, e.g. with a more advanced model for the Kalman filter.
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Organophosphate exposure in Australian agricultural workers : human exposure and risk assessmentJohnstone, Kelly Rose January 2006 (has links)
Organophosphate (OP) pesticides, as a group, are the most widely used insecticides in Australia. Approximately 5 000 tonnes of active ingredient are used annually (Radcliffe, 2002). The OP pesticide group consists of around 30 identifiably distinct chemicals that are synthesised and added to approximately 700 products (Radcliffe, 2002). OP pesticides are used on fruit, vegetable, grain, pasture seed, ornamental, cotton, and viticultural crops, on livestock and domestic animals, as well as for building pest control. OP pesticides all act by inhibiting the nervous system enzyme acetylcholinesterase (AChE) and as such are termed anticholinesterase insecticides. The phosphorylation of AChE and the resultant accumulation of acetylcholine are responsible for the typical symptoms of acute poisoning with OP compounds. In addition to acute health effects, OP compound exposure can result in chronic, long-term neurological effects. The traditional method of health surveillance for OP pesticide exposure is blood cholinesterase analysis, which is actually biological effect monitoring. However, there are several drawbacks associated with the use of the blood cholinesterase test, including its invasive nature, the need for baseline levels and a substantial exposure to OP pesticide before a drop in cholinesterase activity can be detected. OP pesticides are metabolised fairly rapidly by the liver to form alkyl phosphates (DAPs). Approximately 70% of OP pesticides in use in Australia will metabolise into one or more of six common DAPs. During the last 30 years, scientists have developed a urine test that detects these six degradation products. However, unlike the blood cholinesterase test, there is currently no Biological Exposure Index (BEI) for the urine DAP metabolite test. Workers in the agricultural industry - particularly those involved with mixing, loading and application tasks - are at risk of exposure to OP pesticides. It is therefore important that these workers are able to assess their risk of health effects from exposure to OP pesticides. However, currently in Queensland, workplace health and safety legislation exempts the agricultural industry from hazardous substance legislation that incorporates the requirement to perform risk assessments and health surveillance (blood cholinesterase testing) for OP pesticide exposure. The specific aim of this research was to characterise OP pesticide exposure and to assess the feasibility of using urine DAP metabolite testing as a risk assessment tool for agricultural and related industry workers exposed to OP pesticides. An additional aim among farmers was to conduct an in-depth evaluation of their knowledge, attitudes and behaviours related to handling OP pesticides and how they assess the risks associated with their use of OPs. A cross-sectional study design was used to assess exposure to OP pesticides and related issues among four groups: fruit and vegetable farmers, pilots and mixer/loaders, formulator plant staff and a control group. The study involved 51 farmers in the interviewer-administered questionnaire and 32 in urine sample provision. Eighteen pilots and mixer/loaders provided urine samples and 9 exposed formulation plant staff provided urine and blood samples. Community controls from Toowoomba Rotary clubs provided 44 urine samples and 11 non-exposed formulation plant staff provided blood and urine samples; all groups also provided responses to a self-administered questionnaire. Participant farmers were drawn from the main cropping areas in south-east Queensland - Laidley/Lowood, Gatton, and Stanthorpe. The farmer group was characterised by small owner-operators who often had primary responsibility for OP pesticide mixing and application. Farmers had good knowledge of pesticide-related safety practices; however, despite this knowledge, use of personal protective equipment (PPE) was low. More than half of the farmers did not often wear a mask/respirator (56%), gloves (54%) or overalls (65%). Material Safety Data Sheets were never or rarely read and 88.2% of farmers never or rarely read OP pesticide labels before application. There were also problems with chemical suppliers providing farmers with MSDSs. The majority of farmers (90.2%) reported that they had never had any health surveillance performed and three-quarters had never read about or been shown how to perform a formal risk assessment. The main inhibitors to the use of PPE in the farmers' group included the uncomfortable and cumbersome nature of PPE, especially in hot weather conditions, and the fear of PPE use triggering neighbours' complaints to Government authorities. Factors associated with better PPE use included having positive attitudes and beliefs toward PPE use, higher knowledge scores and low risk perception. Farmers' use of OP pesticides was infrequent, of short duration and involved application via a boom on a tractor, a lower risk application method. Consequently, urine DAP metabolite levels in this group were generally low, with 36 out of 96 samples (37.5%) containing detectable levels. Detectable results ranged from 9.00-116.00 mol/mol creatinine. Formulators exposed to OP pesticides were found to have the highest urine DAP metabolite levels (detectable levels 13.20-550.00 mol/mol creatinine), followed by pilots and mixer/loaders (detectable levels 8.40-304.00 mol/mol creatinine) and then farmers. Despite this, pilots and mixer/loaders (particularly mixer/loaders) had the greatest number of samples containing detectable levels (94.4% of samples). The DAP metabolite most frequently detected across all groups was DMTP, which was the only metabolite found in control samples. Levels found in this study are similar to those reported in international research (Takamiya, 1994, Stephens et al., 1996, Simcox et al., 1999, Mills, 2001, Cocker et al., 2002). The observed DAP levels were not associated with a drop in cholinesterase activity among the formulation plant workers, as expected from the literature. Such exposure also is unlikely to be associated with acute health effects. In contrast, there is insufficient scientific knowledge to know whether levels recorded in this study and elsewhere may be associated with long-term, chronic health effects. Notably, DMTP levels also were observed among the presumably 'unexposed' comparison groups. Environmental background level exposures to OPs producing the DAP metabolite DMTP are therefore of potential significance and may be related, at least in part, to consumption of contaminated fruit and vegetables. There is also emerging evidence to suggest that exposure to DAP metabolites themselves through diet and other sources may contribute to the concentration of DAPs, including DMTP in urine, potentially complicating assessment of occupational exposures. Nevertheless, the urine DAP metabolite test was a useful, sensitive indicator of occupational OP pesticide exposure among agricultural workers and may be of use to the industry as part of the risk assessment process. Future research should aim to establish a BEI for the urine DAP test.
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Miljöprestanda för lastbilskran : En studieav olika nyttjandescenarierLundblad, Nora January 2017 (has links)
Denna kandidatuppsats är en studie av miljöprestandan hos en lastbilskran satt i relation till användning av en mobilkran. Miljöprestandan hos lastbilskranen studeras och jämförs med mobilkranens givet ett visst nyttjandescenario. Miljöprestandan mäts i miljöparametrarna: klimatpåverkan, energiförbrukning, energieffektivitet samt partikelutsläpp. Realistiska och mätbara nyttjandescenarier har utarbetats utifrån studiebesök och intervjuer med Vemservice, Jämtlands Mobilkranar och Curt Sillström Åkeri. Kandidatuppsatsen är skriven som en del i den miljöstudie som ingår i utvecklingsprojektet Forskning och utveckling av lastbilars centralram för minskad miljöpåverkan vid tung transport. Projektet drivs av Vemservice (Vemdalsservice AB) och syftar till att utveckla centralramen på en lastbilskran genom att öka dess lyftkapacitet. Projektets mål är att ersätta mobilkranar med lastbilskranar i en högre utsträckning än vad som görs idag. I projektet deltar även teknikkonsultföretaget DRIV Innovation, materialoptimeringstjänsten SSAB Shape samt Mittuniversitetet. En lastbilskran är en lastbil med en kran påmonterad på flaket, med plats på flaket för att transportera gods. Lyftförmågan hos en lastbilskran beror både av kranens styrka och själva lastbilens vrid- och böjhållfasthet. I denna studie har en lastbilskran från Curt Sillströms Åkeri studerats. Lastbilskranens främsta användningsområden är vid nybyggnationer av bostäder, flytt av containrar och bodar på arbetsplatser samt vid flytt av tunga föremål in och ut ur byggnader. Mobilkran kallas det arbetsfordon som har en lyftkran med svängarm monterad på fordonet, den används inte för transport av gods. Mobilkranen i denna studie tillhör Jämtlands Mobilkranar och används främst i lyftarbeten såsom byggande av bostäder och arbeten vid vattenkraftverk. Resultatet av den studerade miljöprestandan baseras på tre specifika nyttjandescenarior. Nyttjandescenarierna innefattade att transportera och lyfta en given mängd gods en given sträcka och tid. Lastbilskranen har högre miljöprestanda än mobilkranen vid jämförelse i de tre scenarierna, dvs. lägre utsläpp och mindre energiförbrukning. Den minsta skillnaden i miljöprestanda uppstår när enbart lyftarbete utförs, då lastbilskranens fulla funktion inte nyttjas då den ej transporterar något gods. Det troligtvis mest typiska nyttjandescenariot är att gods både ska transporteras och lyftas. I detta fall har lastbilskranen flera fördelar tack vare att dess fulla funktion utnyttjas. / This bachelor thesis is a study of the environmental performance of a loader crane in relationship to the usage of a mobile crane. The environmental performance of the loader crane is studied and compared to the mobile cranes performance given a set of specific user scenarios. The environmental performance is measured using the following environmental parameters:climate impact, energy consumption, energy efficiency and particle emissions. Realistic and measurable user scenarios were prepared using information from visits and interviews with Vemservice, Jämtlands Mobilkranar and Curt Sillström Åkeri. The thesis is written as a part of the environmental study that is included in the developmental project “Forskning och utveckling av lastbilars centralram för minskad miljöpåverkan vid tung transport”. The project is managed by Vemservice (Vemdalsservice AB) and the purpose of the project is to develop the frame on a loader crane by increasing the capacity for lifting. The goal of the project is to replace mobile cranes with loader cranes to a higher degree than what is currently the case. The projects participants are also made up by the technology consulting DRIV Innovation, SSAB Shape and also Mid Sweden University. A loader crane is a truck with a crane mounted on its flatbed and also room on the flatbed for the transport of goods. The lifting capabilities of a loader crane is dependent on the strength of the crane and the rigidity of the frame of the truck itself. In this thesis, a loader crane from Curt Sillström Åkeri AB is studied. The main usage of the loader crane in this study is in construction, the moving of work site sheds and in the moving of heavy objects in and out of houses. A mobile crane is a work vehicle with a crane and swing arm mounted on the back of the vehicle. The mobile crane in this study belongs to Jämtlands Mobilkranar and is primary used for heavy lifting in construction and work at a hydro power plant. As opposed to the loader crane, the mobile crane is not used for the transport of goods. The resulting environmental performance was based on three specific user scenarios. The user scenarios consisted of lifting and transporting a given amount of goods for a specified distance and time. When a comparison is made between the loader crane and mobile crane for total emissions and energy consumption in each user scenario, the loader crane has a larger environmental performance. The smallest difference in environmental performance arises when lifting is the only work being done, due to the fact that the full capacity of the loader crane is not utilized since it is not used to transport goods. Likely the most typical user scenario consists of goods being both transported and lifted. In this case the loader crane has a number of advantages because its full capacity is being utilized. / <p>2018-02-01</p>
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Hákový nosič kontejnerů NKH 8A340 / Hooclift NKH 8A340Doleček, Ladislav January 2012 (has links)
This master thesis analyses hook loader NKH 8A340. For calculation of load states was used the dynamic simulation in program MSC.ADAMS. This results were used like a input data to solve the construction with finished element method. After evaluation of results were made design changes of hook loader. Part of this thesis contains drawings of modified parts of hook loader.
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Ramenový nosič kontejnerů NKR130V / Skip loader NKR130VDerka, Lukáš January 2012 (has links)
This master’s thesis deals with a strength analysis of the main frame and loading arms of a skip loader. For a calculation of load states is used a dynamic simulation and its results are used as a boundary conditions for the strength analysis using finite element method (FEM). The results of the analysis is evaluated and on theirs basis are designed a construction improvements. The part of the thesis is drawings documentation of the construction improvements.
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Vysokovýklopná lopata / High loading shovelPetro, Roman January 2009 (has links)
This diploma thesis solves construction project high dumping shovel for back hoe loader New Holland B100 and B110. There are described operating conditions in the introduction, transport material and technical parameters for back hoe loader B100, B110. There are mentioned possible construction’s solutions and own design. Follow the kinematics analysis of material’s dumping and the static analysis on shovel and frame. This is connected with following peg’s control and the solidity analysis of shovel and frame for different load cases, where the MFE was used
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Design stavebního nakladače / Design of front loaderGroch, Luboš January 2012 (has links)
In my thesis I aim on design of front loader, which is most adapted to human operator. Human needs, repairman needs and requirements of civilization are fully respected. Loader is designed for near future.
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Vysokovýklopná lopata pro nakladač / High loading shovel for loaderRajdl, Marek January 2015 (has links)
This diploma thesis deals with design of the high loading shovel for the loader Komatsu WA380. The aim is to find constructional solutions of the high loading shovel for a minimal dumping height of 4 500 mm, for the bucket width of 3 000 mm and for the bucket volume of 5 m3. The thesis contains a brief description of the high loading shovel and description of basic constructional components. It also contains choices of basic constructional components, a calculation of the necessary force to tilt the bucket and a static analysis. Stress control of the bucket, the frame and the pegs forms the final part of the thesis. The thesis is accompanied by the necessary technical drawings.
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