271 |
Study on the Design Methodology for the Epicyclic-Type Automatic Transmissions of AutomobilesHuang, Ruei-Hong 09 February 2009 (has links)
An automatic transmission is a device that is connected to the back of an engine and sends the power from the engine to the drive wheels. Its job is to keep the engine within a certain angular velocity. Although there are many epicyclic-type automatic transmissions in production, the related configuration design methods are still tedious and prone to human error. A simple and analytic methodology needs to be developed. Therefore, the purpose of this research is to present an efficient methodology for the systematic design of the epicyclic gear transmissions for automobiles. First, fundamentals and gear-shifting operations of the four-speed, five-speed and six-speed epicyclic-type automatic transmissions are illustrated to establish the design requirements. Second, based on the kinematic equations of the fundamental geared entities and the corresponding basic gear ratios, a procedure is applied to execute the kinematic and mechanical-efficiency analyses for the automatic transmissions. Third, two simple clutching-sequence synthesis methods are proposed and illustrated. One is based on the speed ratio equations, and another is based on the lever diagram. Next, a planar-graph representation is presented to arrange the desired clutches for each possible clutching sequence into the epicyclic gear mechanism. Then, the number of teeth of each gear is synthesized from assigning two or three desired speed ratios by the analytic method. Finally, a computer-aided design program for the clutching-sequence synthesis is developed with the considerations of the design requirements. With the above methods, the systematic designs of the 204 epicylic gear mechanisms are given for demonstrating the feasibility of the proposed methodology. The result of this work shows that the seven-link two-DOF epicylic gear mechanisms, the eight-link two-DOF Ravigneaux gear mechanism, and the nine-link two-DOF parallel-connected epicylic gear mechanisms could reach four-, six-, and six-forward speeds at most, respectively.
|
272 |
Study on the Lever Diagrammatical Methodology for the Epicyclic-Type Automatic Transmissions of AutomobilesSu, Bai-jian 31 August 2009 (has links)
¡@An automatic transmission that is a transmission device between the engine and drive wheel, offers the vehicle while increasing and decreasing the speed mainly. Its job keeps the engine within a certain working rotational speed range.¡@Although there are many epicyclic-type automatic transmissions in production, the related design methods of lever diagram is not well developed.¡@Thus, the purpose of this research is to develop a systematic design of the epicyclic gear transmissions for automobiles with lever diagrammatical methodology.¡@First, fundamentals and gear-shifting operations of the four-speed and six-speed epicyclic-type automatic transmissions are illustrated to establish the design requirements.¡@Second, based on the basic theories of lever diagram, a procedure is applied to kinematic analysis for automatic transmission existed, and set up composite lever diagrams of 13 two-DOF seven-link epicyclic gear mechanisms and 190 two-DOF nine-link epicyclic gear mechanisms.¡@Next, a general clutching-sequence synthesis of lever diagrammatical method are proposed and illustrated. According to the limit range of lever dimensions established for four and five coaxial components, the clutching-sequences and the ranges of basic gear ratio of the feasible gear trains can be derived.¡@Finally, the planar-graph representation for arranging desired clutch and the number of teeth based on lever dimensions are applied to design six-forward speeds automatic transmission. The result of this work shows that the seven-link two-DOF epicylic gear mechanisms, and the nine-link two-DOF parallel-connected epicylic gear mechanisms could reach four- and six-forward speeds at most, respectively.
|
273 |
Insights into Contractional Fault-Related Folding Processes Based on Mechanical, Kinematic, and Empirical StudiesHughes, Amanda 17 September 2012 (has links)
This dissertation investigates contractional fault-related folding, an important mechanism of deformation in the brittle crust, using a range of kinematic and mechanical models and data from natural structures. Fault-related folds are found in a wide range of tectonic settings, including mountain belts and accretionary prisms. There are several different classes of fault-related folds, including fault-bend, fault-propagation, shear-fault-bend, and detachment folds. They are distinguished by the geometric relationships between the fold and fault shape, which are driven by differences in the nature of fault and fold growth. The proper recognition of the folding style present in a natural structure, and the mechanical conditions that lead the development of these different styles, are the focus of this research. By taking advantage of recent increases in the availability of high-quality seismic reflection data and computational power, we seek to further develop the relationship between empirical observations of fault-related fold geometries and the kinematics and mechanics of how they form. In Chapter 1, we develop an independent means of determining the fault-related folding style of a natural structure through observation of the distribution of displacement along the fault. We derive expected displacements for kinematic models of end-member fault-related folding styles, and validate this approach for natural structures imaged in seismic reflection data. We then use this tool to gain insight into the deformational history of more complex structures. In Chapter 2, we explore the mechanical and geometric conditions that lead to the transition between fault-bend and fault-propagation folds. Using the discrete element modeling (DEM) method, we investigate the relative importance of factors such as fault dip, mechanical layer strength and anisotropy, and fault friction on the style of structure that develops. We use these model results to gain insight into the development of transitional fault-related folds in the Niger Delta. In Chapter 3, we compare empirical observations of fault-propagation folds with results from mechanical models to gain insight into the factors that contribute to the wide range of structural geometries observed within this structural class. We find that mechanical layer anisotropy is an important factor in the development of different end-member fault-propagation folding styles. / Earth and Planetary Sciences
|
274 |
Improved manipulator configurations for grasping and task completion based on manipulabilityWilliams, Joshua Murry 16 February 2011 (has links)
When a robotic system executes a task, there are a number of responsibilities that belong to either the operator and/or the robot. A more autonomous system has more responsibilities in the completion of a task and must possess the decision making skills necessary to adequately deal with these responsibilities. The system must also handle environmental constraints that limit the region of operability and complicate the execution of tasks. There are decisions about the robot’s internal configuration and how the manipulator should move through space, avoid obstacles, and grasp objects. These motions usually have limits and performance requirements associated with them.
Successful completion of tasks in a given environment is aided by knowledge of the robot’s capabilities in its workspace. This not only indicates if a task is possible but can suggest how a task should be completed. In this work, we develop a grasping strategy for selecting and attaining grasp configurations for flexible tasks in environments containing obstacles. This is done by sampling for valid grasping configurations at locations throughout the workspace to generate a task plane. Locations in the task plane that contain more valid configurations are stipulated to have higher dexterity and thus provide greater manipulability of targets. For valid configurations found in the plane, we develop a strategy for selecting which configurations to choose when grasping and/or placing an object at a given location in the workspace.
These workspace task planes can also be utilized as a design tool to configure the system around the manipulator’s capabilities. We determine the quality of manipulator positioning in the workspace based on manipulability and locate the best location of targets for manipulation. The knowledge of valid manipulator configurations throughout the workspace can be used to extend the application of task planes to motion planning between grasping configurations. This guides the end-effector through more dexterous workspace regions and to configurations that move the arm away from obstacles.
The task plane technique employed here accurately captures a manipulator’s capabilities. Initial tests for exploiting these capabilities for system design and operation were successful, thus demonstrating this method as a viable starting point for incrementally increasing system autonomy. / text
|
275 |
Two Dimensional Finite Volume Model for Simulating Unsteady Turbulent Flow and Sediment TransportYu, Chunshui January 2013 (has links)
The two-dimensional depth-averaged shallow water equations have attracted considerable attentions as a practical way to solve flows with free surface. Compared to three-dimensional Navier-Stokes equations, the shallow water equations give essentially the same results at much lower cost. Solving the shallow water equations by the Godunov-type finite volume method is a newly emerging area. The Godunov-type finite volume method is good at capturing the discontinuous fronts in numerical solutions. This makes the method suitable for solving the system of shallow water equations. In this dissertation, both the shallow water equations and the Godunov-type finite volume method are described in detail. A new surface flow routing method is proposed in the dissertation. The method does not limit the shallow water equations to open channels but extends the shallow water equations to the whole domain. Results show that the new routing method is a promising method for prediction of watershed runoff. The method is also applied to turbulence modeling of free surface flow. The κ - ε turbulence model is incorporated into the system of shallow water equations. The outcomes prove that the turbulence modeling is necessary for calculation of free surface flow. At last part of the dissertation, a total load sediment transport model is described and the model is tested against 1D and 2D laboratory experiments. In summary, the proposed numerical method shows good potential in solving free surface flow problems. And future development will be focusing on river meandering simulation, non-equilibrium sediment transport and surface flow - subsurface flow interaction.
|
276 |
Traktoriaus ir priekabos su varančiaisiais ratais kinematinio suderinamumo tyrimas / Kinematic compatibility of tractors and trailers with all weel drive systemPatašius, Irmantas 28 May 2012 (has links)
Darbo tikslas: ištirti transporto priemonės sudarytos iš traktoriaus ir priekabos su varančiaisiais ratais kinematinį suderinamumą, dinaminius bei ekonominius rodiklius ir nustatyti racionalios eksploatacijos sąlygas. Darbe nagrinėjami transporto priemonės sudarytos iš traktoriaus ir priekabos su varančiaisiais ratais kinematinis suderinamumas, dinaminiai bei ekonominiai rodikliai, esant išjungtiems priekabos varantiesiems tiltams bei įjungtiems vienam ir dviem priekabos varantiesiems tiltams. Nustatyta, kad transporto priemonei, važiuojant suartu lauku, kurio drėgnis 5 cm gylyje - 19,8 %, kietis - 0.85 MPa, o kietis 15 cm gylyje - 1,08 MPa, racionalu įjungti tik vieną priekabos varantįjį tiltą (kartu su traktoriaus užpakaliniu varančiuoju tiltu). Čia vieno priekabos varančiojo tilto įjungimas duoda teigiamus rezultatus važiuojant tiek su 4500 kg kroviniu, tiek ir be krovinio. Važiuojant vėžėmis per suarta dirvą be krovinio yra racionalu abu priekabos varančiuosius tiltus išjungti, o vežant krovinį įjungti vieną priekabos varantįjį tiltą. / Work aim: To investigate a vehicle consisting of a tractor-trailer-wheel drive with the compatibility of kinematic, dynamic and economic indicators and the rational exploitation conditions. The work deals with a vehicle consisting of a tractor and trailer with wheel drive . Kinematic compatibility, dynamic and economic indicators ,when the trailer driwing axles is off and on. It was found that a motor vehicle while driving convergence field, the moisture content at a depth of 5 cm - 19.8%, hardness - 0.85 MPa, and hardness at a depth of 15 cm - 1.08 MPa, it is reasonable to activate only one trailer driving axle the drive (with drive to the rear axle). This single drive axle trailers activation produce positive results in driving the 4500 kg load or without load. Going through the tracks plowed soil without load is reasonable to both drive axles off the trailer and cargo transport trailers for the drive to activate a axle.
|
277 |
Feature Extraction Workflows for Urban Mobile-Terrestrial LiDAR DataMCQUAT, Gregory John 27 May 2011 (has links)
Mobile Terrestrial LiDAR (MTL) is an active remote sensing technology that uses laser-based ranging and global positioning systems (GPS) to record 3D point location measurements on surfaces within and near transportation corridors, such as along a railroad track or a street. This thesis examines geovisualization for improving user-oriented workflows and also examines geographic object-based image analysis (GEOBIA) for the development of automated feature extraction. A LiDAR sensor-centric perspective during the data acquisition phase is used to organize data for the user and to transform the data into a 2D reference frame for object-oriented image analysis of MTL data.
Organizing the display of MTL data relative to the scanner presented new opportunities for visualization techniques and was an effective method for communicating space that was scanned, or not, in an urban scene. It offers new avenues for quality assessment of MTL survey of urban environments by explicitly displaying gaps in data coverage. A number of techniques for navigating and visualizing data from a sensor-perspective are examined.
A novel sensor-perspective transformation of MTL data from three to two dimensions enables analysis of MTL data in common GIS and image-processing environments. GEOBIA software (Definiens’ eCognition) is used to construct a procedural feature extraction workflow. The procedures are constructed with semantic classes, data processing rules and functions that drive geometric segmentation and feature recognition. Geometric regularities in urban scenes and knowledge about spatial and semantic relationships are incorporated into the rule set. The results are fluidly integrated back into a GIS environment.
Investigation of alternative approaches to handling MTL data such as those carried out in this thesis are essential if this technology is to see widespread use. / Thesis (Master, Geography) -- Queen's University, 2011-05-24 13:10:15.198
|
278 |
RTK-teknikens användningsområdenMårelius, Nicklas January 2015 (has links)
Syftet med denna uppsats var att undersöka om RTK – tekniken (Real Time Kinematik) i framtiden kan komma att användas vid lotsning i Sverige, ombord på fartyg med begränsat vattendjup under kölen. Squateffekten påverkar fartyg vid passage över grunda partier i farleder och i kanaler. För att minska ner på squateffekten så kan man minska ned på farten eller ändra fartygets trim. Studien har utformats utefter en kvalitativ metod, som handlar om att man väljer att bearbeta och analysera sin information genom att verbala analysmetoder används. Detta har genomförts genom att intervjua ett antal utvalda lotsar som både är insatta samt mindre insatta i tekniken. På så sätt belystes olika aspekter på tekniken och ifall det finns andra områden som lotsarna kan ha nytta utav denna utrustning i sitt dagliga arbete. Vid genomförandet av uppsatsen valdes en systematisk litteraturstudie. Sökningar genomfördes globalt för att få fram information om var det skett olyckor pga. squateffektens inverkan samt vilka länder som genomfört tester ombord med RTK-tekniken. Resultatet av ett användande av RTK-tekniken är att lotsar och sjöbefäl har möjlighet att få reda på hur fartyget rör sig och när det då utsätts för squateffekten. Detta för RTK-tekniken har möjlighet att ge information om hur fartyget rör sig med en noggrannhet på 3-4 centimeter i alla led samt få en exaktare hastighet även i sidled. Det finns även möjlighet att få fram en tredimensionell bild över fartyget. Resultat visar också att det finns ett behov och intresse för fler tester med RTK-tekniken. Med stöd av RTK-tekniken finns det möjlighet att få fram en bättre positionering och att ha en bättre översikt på hur fartyget rör sig samt i vilken hastighet. Resultatet visade också att tekniken är användbar för lotsarna och på vilket sätt den kan underlätta i deras dagliga arbete. / The purpose of this study was to investigate whether RTK - technology (Real Time Kinematic) in the future may be used for piloting in Sweden, on board vessels with limited depth of water under the keel. The squat effect cured vessels when they passing over an area of shallow waters in a fairway or a channel. To reduce the squat effect it can be done to increase the speed or change the trim of the vessel. The study has been designed along a qualitative method, which is about one chooses to process and analyze their information by verbal analysis methods. This has been carried out by interviewing a number of selected pilots that are both familiar and less familiar with the technology. In this way, highlighted various aspects of the technology and whether there are other areas that pilots can use this equipment in their daily work. In the implementation of the essay was elected a systematic literature. It was conducted a global search to obtain information about where the accident occurred of the squat effect and which countries that have been tested this technology onboard. The result of the RTK-technology is that pilots and ship's officers have the opportunity to find out how the vessel is moving and when it is exposed of the squat effect. The RTK-technology are able to provide information how the vessel move with an accuracy of 3-4 centimeters at every stage and get a more exact speed even in sideways. It is also possible to obtain a three-dimensional image of the vessel. The results confirm that there is a need and an interest for further testing with the RTK-technology. The results also showed that the technology is useful for the pilots and how it can useful for them in their daily work.
|
279 |
Realtime Motion Planning for Manipulator Robots under Dynamic Environments: An Optimal Control ApproachOgunlowore, Olabanjo Jude January 2013 (has links)
This report presents optimal control methods integrated with hierarchical control framework to realize real-time collision-free optimal trajectories for motion control in kinematic chain manipulator (KCM) robot systems under dynamic environments.
Recently, they have been increasingly used in applications where manipulators are required to interact with random objects and humans. As a result, more complex trajectory planning schemes are required. The main objective of this research is to develop new motion control strategies that can enable such robots to operate efficiently and optimally in such unknown and dynamic environments. Two direct optimal control methods: The direct collocation method and discrete mechanics for optimal control methods are investigated for solving the related constrained optimal control problem and the results are compared.
Using the receding horizon control structure, open-loop sub-optimal trajectories are generated as real-time input to the controller as opposed to the predefined trajectory over the entire time duration. This, in essence, captures the dynamic nature of the obstacles. The closed-loop position controller is then engaged to span the robot end-effector along this desired optimal path by computing appropriate torque commands for the joint actuators.
Employing a two-degree of freedom technique, collision-free trajectories and robot environment information are transmitted in real-time by the aid of a bidirectional connectionless datagram transfer. A hierarchical network control platform is designed to condition triggering of precedent activities between a dedicated machine computing the optimal trajectory and the real-time computer running a low-level controller.
Experimental results on a 2-link planar robot are presented to validate the main ideas. Real-time implementation of collision-free workspace trajectory control is achieved for cases where obstacles are arbitrarily changing in the robot workspace.
|
280 |
Software Development For Man-machine Interface For An Industrial RobotCengiz, Mahir Cihan 01 December 2003 (has links) (PDF)
In this study, a robotic software, which controls the robot, is developed.
The robot considered is a six degree of freedom robot and it is designed and
manufactured in METU. User can send the robot anywhere in space within its
workspace, in any orientation. Forward and inverse kinamatics can be executed
according to the needs.
Simulation framework is embedded into the software for the 3D
visualisation of the robot. Any movements can be simulated on the screen.
Software also generates the path for the given points. Then generated path
is simulated on the screen. All position, velocity and acceleration graphics of
joints can be examined for the generated path.
|
Page generated in 0.0417 seconds