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Implementation and Testing of a Sensor and Control Scheme for a Reconfigurable Smart WheelTsakyridis, Georgios January 2012 (has links)
The DFKI Robotics Innovation Center and the ZARM (Center of Applied Space Technology and Microgravity), developed within a joint program, a Reconfigurable Integrated Multi Robot Exploration System, RIMRES, for demonstrating key technologies required for performing exploratory tasks on the Moon surface and other hostile planetary terrains autonomously. Maximizing eciency and performance while demonstrating key technologies required in the area of autonomy, navigation and locomotion by combining heterogeneous robots into one overall system are the major objectives of the project. For this purposes, two dierent robotic vehicles, connected tidily by unique mechanical and electrical interfaces, can act as independent units if necessary or as one single system. This thesis was written in close collaboration with the German Aerospace Centre (DLR) at the Institute of Space Systems in Bremen and deals with the implementation and testing of a sensor and control scheme for a reconfigurable smart wheel developed within the RIMRES project. Having as starting point the wheel concept design used for the ExoMars mission, where flexible metal spokes were used to enlarge the wheels ground contact area, DLR undertake the development of a smart reconfigurable wheel to incorporate with the RIMRES project. The wheel, equipped with a sensor and control scheme to monitor soil characteristics and parameters, while actively adapt its stiness accordingly. Equivalent to the inflation of a rubber tyre, by increasing the stiness of the wheel the rolling resistance can be minimized when running on hard ground, while decreasing the wheels stiness will maximize the tractive force when running over soft ground. The thesis work focus on the development of such a sensor-control platform. By carefully studying previous approaches and considering several factors and limitations, an all new system is proposed in order to achieve the complex problem of soil characterization and active control of the wheel by meanings of simplicity and high eciency. The outcome solution is subsequently tested to prove the premise. Previous mission, NASA Pathfinder mission, have extendedly proof that surface characterization by sensor equipped wheels is a feasible and pragmatic scenario. Working as "mini-field geologists" space exploration mobile vehicles are a major achievement towards mapping extra-terrestrial planets. Harsh environment conditions, terrain anomalies and uncertainties together with the lost of MER ( Mars Exploration Rovers) Spirit rover failure enhanced the needs for building sensor equipped wheels for soft obstacle detection at a higher mobility performance on soft grounds. DLR, a keystone nowadays in the Aerospace sector,counting several years of experience and important achievement such is the ExoMars rover, a rover with primary objective to search for sign of past and present life on Mars, engaged in constructing such a complex locomotive system. / <p>Validerat; 20121119 (global_studentproject_submitter)</p>
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The wheelchair accessibility of Bloemfontein's guest houses and hotelsPosholi, M., Kokt, D. January 2011 (has links)
Published Article / Wheelchair friendliness is an issue that needs to be taken very serious. Awareness should be created so that the owners of the accommodation establishments have a complete knowledge about wheelchair friendliness. The population of the study covered 16 guest houses and 16 hotels in Bloemfontein and only 11 agreed to participate. Other guest house owners were not interested in the participation. Among those guest houses that participated, only few had wheelchair facilities. It showed that there is a lot of ignorance concerning the topic because other guest house owners thought they were wheelchair friendly, just because there is no step at the entrance. A checklist was compiled from literature and adminstered at each estabilshment.
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The dynamic response of an aircraft wheel to variations in runway frictionWattling, A. G. January 1988 (has links)
No description available.
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Eco-design innovation in small and medium sized enterprisesSmith, Mark T. January 2000 (has links)
No description available.
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The flywheel-powered hybrid urban vehicle; a feasibility study.Justus, Dennis John. January 1973 (has links)
Thesis (M.S.)--Ohio State University. / Includes bibliographical references. Available online via OhioLINK's ETD Center
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Autonomous bucket emptying on haulerBergdahl, Anders January 2011 (has links)
This thesis proposes a method of loading a hauler with an autonomous wheelloader efficiently and with high productivity in the short loading cycle. The mainidea behind the method is to raise the bucket with only the lift until the centerof gravity has reached the height that it will have just as the material will startto fall out of the bucket and on to the hauler. When the center of gravity hasreached that height both lift and tilt will be used simultaneously to keep thecenter of gravity at a constant height. This method is both faster and moreenergy efficient than loading a hauler using only one function at a time. The method has been successfully implemented and validated by loading ahauler with three buckets with the autonomous wheel loader that is developed byVolvo CE in Eskilstuna. / autonomous wheel loader VolvoCE
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Fabrication of Micro Ni-based grinding wheel containing diamond particleHsu, Feng-Yen 02 September 2010 (has links)
In this study, two sizes of diamond grinding wheels which are the diameter of 3 mm with thickness of 0.2 mm and the diameter of 1 mm with thickness of 0.1 mm are fabricated by a creative composite electroforming method. The pure nickel metal is set as anode. The micro cylindrical bar of tungsten carbide acted as spindle of the micro diamond grinding wheel, which is inserted into the hole of ABS mold and the conducting layer pre-coated on the local surface of ABS mold are set as cathode. The nickel sulfate bath mixing a constant amount of diamond particle is selected as electrolyte bath. At the current density of 2.5 ASD, the nickel-diamond composite layer with a constant thickness is electrodeposited on the ABS mold. When the ABS mold is dissolved by using acetone liquid, then the nickel-diamond composite layer could be used as the micro diamond grinding wheel is obtained.
Moreover, in the study, the effects of electroforming method, composition of the electrolyte and current density on the surface quality of nickel-diamond composite layer are investigated. From the experiment results, it can be know that at the current destiny of 2.5 ASD, the covered area of diamond particle in this composite layer is 54.19% using the external hanging pump. And the flatness on the surface of this composite layer electroformed in the nickel sulfamate bath is better than that in nickel sulfate bath.
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The aerodynamic interaction of a rotating wheel and a downforce producing wing in ground effectDiasinos, Sammy , Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW January 2009 (has links)
The performance of current open wheeler race cars depends heavily on the effectiveness of the aerodynamic package of which the front wing and wheels make a significant contribution. Previous investigations have focused on the aerodynamic characteristics of each of these bodies in isolation. Investigations that have considered both working in unison have conflictingly reported that the wheel presence aids or hinders the wing???s performance while the wheel???s aerodynamic performance has been neglected. In order to obtain a more thorough understanding of the interaction of a wing and wheel, experimental results were used to validate a computational model used to investigate a wing and wheel in isolation and in combination. The combined wing and wheel investigation demonstrated that three main interactions can occur, depending on the selection of wing span, angle of attack and height used, while the wheel width and track were found to have little influence. The three interacting states differ in the path that the main and secondary wing vortices take around the wheel and the subsequent variation in the combined wake structure. In general, the wing in the presence of the wheel reduced the wing???s ability to generate downforce by up to 45% due to the high pressure regions generated forward of the wheel. This was also found to alleviate the adverse pressure gradients experienced by the wing, and also reduce the drag by up to 70%. For this reason, the downforce loss phenomenon was observed to occur at a height 0.08c to 0.32c lower in comparison to the same wing in isolation, dependant on the wing span. Wheel lift and drag values were also observed to reduce in the presence of a wing by up to 65% and 38% respectively due to the influence of the wing???s flow structures have on the wake of the wheel. As a result,it was shown that the combined wing and wheel downforce and drag optima differed by up to 75% and 25% respectively to those which would be estimated if the two bodies were investigated individually and the results summed highlighting the importance of investigating these two bodies in unison.
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FAMILY DINNER TIME: ASSESSING THE EFFECTIVENESS OF A "MEAL WHEEL" TO PROMOTE CONVERSATIONBerry, Kelsey Ann 01 May 2012 (has links)
Research has shown that there are many benefits to families who communicate and have meals together. Families who sit together for meals are more likely to: eat more nutritiously, have teens that are less likely to be involved in risky behavior, and have children with better language skills and academic scores (The National Center on Addiction and Substance Abuse, 2010). The current study evaluated the effectiveness of a "Meal Wheel" to promote parent and child conversation during meals among families with a history of child abuse and neglect. The Meal Wheel was a wooden Lazy Susan that had interchangeable picture frames containing conversation topics. Four families living in southern Illinois participated in the study as part of their parent training services received by Project 12-Ways. Two families received standard Project 12-Ways Meal Training which consisted of explaining, modeling, and prompting steps involved in completing the Meal Routine. The "Meal Wheel" was used with all four families during meal and limited instructions were given for completing steps within the meal routine. The results indicated increases in both parent and child positive verbals and decreases in negative affect and verbals for all 4 families who participated. The limitations of the study and its implications for families, especially families with a history of child abuse and neglect, are discussed.
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On the active guidance of railway vehiclesPowell, Andrew January 1998 (has links)
The conflict between stability and curving has been well documented since the dawn of the railways. Advances in computer technology and deeper understanding of the complex mechanics of the wheel-rail interface have led to the study of innovative designs. This thesis outlines the need for steering systems for railway applications. A number of innovative passive solutions have been proposed to reduce the conflict between stability and curving. Comparisons of some of these solutions show that significant benefits can be obtained by using uncommon configurations.
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