<p>Iako se poslednjih godina sve veća paţnja<br />pridaje tehnikama odrţavanja na bazi rizika, i<br />metode tehniĉke dijagnostike implementiraju<br />u sve većem obimu, a dizalice, kao grupa<br />naj&scaron;ire primenjenih sredstava u rukovanju<br />materijalima, uĉestvuju sa ĉak jednom<br />trećinom u svim smrtnim sluĉajevima<br />pojedinih grana industrije, razvoj modela<br />odrţavanja konkretnih tehniĉkih sistema van<br />polja nuklearne i petrohemijske industrije ne<br />napreduje dovoljno brzo. Shodno tome,<br />predmet disertacije je postavka i potvrda<br />dovoljno taĉnog i dovoljno jednostavnog<br />modela odrţavanja sistema dizaliĉnog<br />transporta za &scaron;iru industrijsku primenu.<br />Novopostavljen model odrţavanja sistema<br />dizaliĉnog transporta, sadrţi dva modula -<br />tehniĉki i &bdquo;menadţment― modul. Shodno<br />predloţenom tehniĉkom modulu modela<br />odrţavanja sistema dizaliĉnog transporta,<br />sprovedena je eksperimentalna provera<br />tehniĉkog modula modela in site na dva<br />sistema dizaliĉnog transporta na<br />hidroelektrani &bdquo;HE Đerdap 1― u Kladovu kao<br />i provera faktora &bdquo;menadţment― modula<br />primenom metoda statistiĉke analize<br />(faktorska i analiza pouzdanosti) na uzorku 51<br />preduzeća u cilju dobijanja modifikacionog<br />faktora. Vrednosti modifikacionog faktora<br />odredjuju zahvat tehniĉkog faktora (postupak<br />procene tehniĉkog faktora u celini, vizuelna<br />kontrolu stanja konstrukcije i mehanizama<br />dizalica i statiĉki i dinamiĉki proraĉun modela<br />konstrukcije dizalica ili samo vizuelna<br />kontrola).</p> / <p>Although in recent years, more attention is<br />given to risk-based techniques of<br />maintenance, and methods of technical<br />diagnostics are implemented in an increasing<br />extent, and cranes, as a group of the most<br />widely used resources in material handling,<br />account for one third of all deaths in certain<br />industries, development of specific<br />maintenance models of technical systems<br />outside the field of nuclear and petrochemical<br />industries is not progressing fast enough.<br />Accordingly , the subject of this dissertation is<br />the setting and confirmation of sufficiently<br />accurate and sufficiently simple maintenance<br />model for cranes system transportation for<br />general industrial applications. The newly<br />appointed maintenance model for cranes<br />system transportation, contains two modules -<br />technical and &quot;management&quot; module.<br />According to the proposed technical module<br />of maintenance model for cranes system<br />transportation the experimental verification is<br />carried out on the two cranes systems in<br />power plant &quot;Djerdap 1 &quot; in Kladovo while<br />&#39;management&#39; module factors are proved using<br />the methods of statistical analysis ( factor<br />analysis and reliability) on the sample sized<br />51 in order to obtain the modification factor.<br />The values of modification factor determine<br />the level of technical factors needed (process<br />evaluation of technical factors as a whole, the<br />visual control condition of the structure and<br />mechanisms of cranes and static and dynamic<br />analysis model construction crane or solely<br />visual inspection).</p> / null

Command Generation has been shown to be a practical and effective control scheme for eliminating payload swing on industrial cranes. However, this technology has not been used to its full potential. One reason is that nonlinear crane dynamics degrade the performance of current command generators, making them challenging to use. A second reason is that few crane operators are aware of this technology. Therefore, this thesis strives to alleviate these problems through the completion of three major tasks. First, new command generation algorithms are developed that compensate for nonlinear crane dynamics. Two major sources of non-linear dynamics are targeted: nonlinear drive dynamics, and non-linear physical dynamics of tower cranes. Second, command generation are examined from an educational perspective; both in the classroom and in the working field. Third, three experimental crane devices were built to fulfill the two prior tasks.

No description available.

Along with increased oil prices and rising environmental issues, a demand for alternatives to combustion engine driven hydraulic applications has risen. In the field of mobile hydraulics, the hydraulic applications have traditionally been driven by the combustion engine of the vehicle on which they are mounted. By instead using a battery driven power pack the hydraulic application is able to operate without the engine running, saving fuel costs and reducing sound levels. In this thesis, the concept of using an electric-hydraulic power pack with a variable-speed electric motor and a fixed-displacement hydraulic pump to provide power to a truck-mounted loader crane is investigated. This concept is compared to an electric-hydraulic system imitating the conventional combustion engine system by using a fixed-speed electric motor connected to a variable-displacement pump. The use of a variable speed motor where the speed can be controlled electrically by a control unit creates possibilities of using different control strategies to improve the efficiency and responsiveness of the application. The efficiencies of the two electric-hydraulic systems are compared by constructing a physical test rig and performing measurements in a test lab. The tests have shown an increased efficiency of about 20 \% when using the variable speed configuration. Three different control strategies are also investigated and tested on a simulated model. The simulations show that very good responsiveness and robustness can be achieved by using a hydraulic flow feed forward controller with a complementary pressure feedback controller. Furthermore, by controlling the hydraulic flow to the heaviest of the crane loads entirely with the flow from the hydraulic pump, the hydraulic pressure can be reduced and energy efficiency increased.

No description available.

The most important issue at a container terminal is to minimize the ship’s turnaround time which is determined by the productivities of quay cranes (QCs). The tandem lift quay cranes have 33% higher productivities than single lift QCs. However, the tandem lift operations bring new challenges to the vehicle dispatching at terminals and this has become a big issue in the application of tandem lift QCs. The vehicle dispatching at terminals is to enhance the QCs’ productivities by coordinating the QCs’ operation schedules and the vehicles’ delivery schedules. The static version of the problem can be formulated as an MILP model and it is a combinational optimization problem. When the type of QC is tandem lift, the problem becomes more complicated because it requires two vehicles side by side under the QC. Thus, the alignments of vehicles have to be considered by coordinating the delivery schedules between vehicles. On the other hand, because the containers are operated alone by the yard cranes, the vehicles could not be grouped and dispatched in pairs all the time. This dissertation investigates the static and dynamic version of the problem and proposes heuristic methods to solve them. For the static version, Local Sequence Cut (LSC) Algorithm is proposed to tighten the search space by eliminating those feasible but undesirable delivery sequences. The time windows within which the containers should be delivered are estimated through solving sub-problems iteratively. Numerical experiments show the capability of the LSC algorithm to find competitive solutions in substantially reduced CPU time. To deal with the dynamic and stochastic working environment at the terminal, the dissertation proposes an on-line dispatching rule to make real-time dispatching decisions without any information of future events. Compared with the longest idle vehicle rule, the proposed priority rule shortens the makespan by 18% and increases the QCs’ average productivities by 15%. The sensitivity analysis stated that the superiority of the priority rule is more evident when the availability of vehicles is not sufficient compared with the frequency of releasing transportation requests.

Detta examensarbete är utfört hos Swisslog under våren 2013. De hade problem med den manuella styrningen av deras pallstaplingskran för höglager, som upplevdes ryckig och svår att kontrollera vid låga hastigheter. Huvudsyftet var att undersöka varför detta fenomen uppstod och hur det kunde lösas med både hård- och mjukvarumässiga metoder. Utöver detta undersöktes hur produktionskostnaden, för delarna av kranen som rör den manuella styrningen, kunde reduceras. Det upplevda fenomenet är känt som biodynamic feedthrough. Det innebär att konstruktionens acceleration matas genom operatörens kropp och skapar en återkoppling till styrdonet, i detta fall en joystick. Operatörens hand ger en oavsiktlig störsignal som gör systemet instabilt som i sin tur skapar en oscillation som ökar i amplitud och är svår eller omöjlig att stoppa. Den föreslagna lösningen är att digitalt lågpassfiltrera styrsignalen från joysticken. Det dämpar de skarpaste spikarna i signalen och förhindrar systemet att ta in de snabba handrörelser som kranens acceleration har skapat. / This bachelor thesis was written at Swisslog, who had a problem with the manual control of their high-bay pallet stacker crane. The ride was perceived rough and hard to control at lower speeds.    The main purpose was to examine the source of the phenomenon and how to solve the problem with both software and hardware. It was also requested to investigate ways to lower production costs of the parts of the crane related to the manual control.   The experienced phenomenon is known as biodynamic feedthrough. It refers to the acceleration of the structure affects the body of the operator causing a feedback loop to the input, in this case a joystick. The hand of the operator causes an involuntary control input and making the system unstable and causing an oscillation increasing in amplitude over time. This may be hard or impossible to stop.   The proposed solution is a low-pass filter applied at the output of the joystick. This attenuates the sharpest spikes from the joystick control signal and prevents the system from receiving the fast hand movements caused by the acceleration of the crane.

Over 95% of imports entering the United States from outside North America arrive via cargo containers by sea at 329 ports of entry. The current layered approach for the detection only scans 5% of cargo bound for the United States. This is inadequate to protect our country. This research involved the building of a gamma-ray radiation detection system used for cargo scanning. The system was mounted on a spreader bar crane (SBC) at the Port of Tacoma (PoT) and the applicability and capabilities of the system were analyzed. The detection system provided continuous count rate and spectroscopic data among three detectors while operating in an extreme environment. In a separate set of experiments, 60Co and 137Cs sources were positioned inside a cargo container and data were recorded for several count times. The Monte Carlo N-Particle (MCNP) code was used to simulate a radioactive source inside an empty cargo container and the results were compared to experimentally recorded data. The detection system demonstrated the ability to detect 60Co, 137Cs, 192Ir, highly-enriched uranium (HEU), and weapons-grade plutonium (WGPu) with minimum detectable activities (MDA) of 5.9 ± 0.4 microcuries (μCi), 19.3 ± 1.1 μCi, 11.7 ± 0.6 μCi, 3.5 ± 0.3 kilograms (kg), and 30.6 ± 1.3 grams (g), respectively. This system proved strong gamma-ray detection capabilities, but was limited in the detection of fissile materials Additional details of this system are presented and advantages of this approach to cargo scanning over current approaches are discussed.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Diss.--Frankfurt am Main--Johann Wolfgang Goethe-Universität, 1991.