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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the 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.
1

Improvement of operator's environment in excavator

Håkansson, Jon January 2004 (has links)
According to the report Ergonomic on-Site Assessment of Excavator Work, one big problem is the risk of falling accidents when entering and exiting the cab. The solution could be lowering the cab to the ground in front of the machine, this could also help during cleaning of windows. The mechanism needed for this operation could also be used for adjusting the cabin in height and tilting it, in order to solve the problem with neck and back injuries. In Umeå I had a meeting with professor Ivan Westerlund at SLU (Swedish Agricultural University) who taught me about ways to reduce vibrations by different undercarriages. It would be possible to have a principle similar to the terrain vehicles and tanks produced by Hägglunds. They are equipped with an active suspension system, making it possible to drive in high speed with track-undercarriage. By using this techniqe it would be possible to merge the two different excavators into one, a stable machine while working and a comfortable fast machine during transport. A fuelcell powerplant would be well suited, considering sound level and pollution in urban environment and especially underground worksituations. With less need for maintenance the risk for falling accidents gets minimized. As a bonus, maybe the waste water could be used for spraying, to avoid dust when needed. Today´s underground-operating machines are tied up with a waterhose which affects the mobility to a high level. Since i want to concentrate on a flexible machine adapted for roadtransport, my benchmark is the Volvo EW 180, their biggest wheeled excavator, produced today.
2

Markberedning med traktorgrävare, prestation och kostnad

Johansson, Bengt January 2012 (has links)
This study investigated the performance and cost of scarification with a tractormounted excavator. Due to variations in terrain conditions the performance variedbetween 0.08 and 0.11 ha/E15h and, with a machine cost of 366 SEK/h, the cost ofscarification varied between 3 330 and 4 750 SEK/ha.
3

Konstrukční návrh minirypadla / Design of mini excavator

Švarc, Pavel January 2014 (has links)
This diploma thesis can be divided into two main sections. The first stage contains research about mini excavators and is focused on main parts of this machines and their structural design. The second stage follow the first one and its goal is create own design of mini excavator according to chosen parameters. Parts of the second stage are execution of basic calculations, techno-economic evaluation and risk analysis. At the end there is created 3D model of designed mini excavator and summary of his properties and parameters. Goal of the whole diploma thesis is design the competitive mini excavator.
4

Secondary Controlled Swing Drive

Pettersson, Karl January 2008 (has links)
<p>The purpose of the thesis has been to design and simulate different concepts of a secondary controlled swing drive for a wheel excavator. Secondary control is a known technology in the field of hydraulics that offers precise positioning as well as the possibility of energy recuperation. Secondary control is today used in certain industrial applications and is rather unemployed in mobile machinery. An excavator moves high loads in cyclic motions which are ideal conditions for energy recuperating systems. A study of the potential of a secondary controlled swing drive is therefore interesting. The focus has been on testing different circuit architectures and emergency brake concepts.</p><p>The results of the design process have been three types of circuit architectures and two types of hydraulic safety concepts. The results of the simulation have shown that the open and closed circuit architecture have similar energy efficiency. The closed circuit with low pressure accumulator however offers the best controllability. At least 20% energy savings can be achieved by storing thekinetic energy when braking.</p><p>A hydraulic emergency brake must function, independent on the direction of rotation of the excavator during a failure. The first principle recognises the rotation direction and changes the swivel angle of the secondary unit so that a braking torque is created. In the second principle a pressure difference is built up over the secondary unit that always results in a braking torque. Simulationshave shown that the principle with recognition of the speed direction is the most effective safety concept.</p>
5

Secondary Controlled Swing Drive

Pettersson, Karl January 2008 (has links)
The purpose of the thesis has been to design and simulate different concepts of a secondary controlled swing drive for a wheel excavator. Secondary control is a known technology in the field of hydraulics that offers precise positioning as well as the possibility of energy recuperation. Secondary control is today used in certain industrial applications and is rather unemployed in mobile machinery. An excavator moves high loads in cyclic motions which are ideal conditions for energy recuperating systems. A study of the potential of a secondary controlled swing drive is therefore interesting. The focus has been on testing different circuit architectures and emergency brake concepts. The results of the design process have been three types of circuit architectures and two types of hydraulic safety concepts. The results of the simulation have shown that the open and closed circuit architecture have similar energy efficiency. The closed circuit with low pressure accumulator however offers the best controllability. At least 20% energy savings can be achieved by storing thekinetic energy when braking. A hydraulic emergency brake must function, independent on the direction of rotation of the excavator during a failure. The first principle recognises the rotation direction and changes the swivel angle of the secondary unit so that a braking torque is created. In the second principle a pressure difference is built up over the secondary unit that always results in a braking torque. Simulationshave shown that the principle with recognition of the speed direction is the most effective safety concept.
6

Dynamic Modeling Of An Excavator During Digging And Simulating The Motion

Ozunlu, Ozcan Mutlu 01 January 2008 (has links) (PDF)
The aim of this study is to perform the dynamic force analysis of a 3-degrees-of-freedom excavator during digging the soil and to simulate the motion on computer screen. Standard load calculations are done statically, therefore the effects of forces changing with time on the system cannot be observed. The dynamic analysis method used in the thesis is Recursive Newton &ndash / Euler Method and the numerical analysis method for simulation is 4th Order Runge &ndash / Kutta Method. After this study, the effects of sudden velocity changes / i.e, accelerational movements on construction machines, positions of bodies and dynamic forces on joints will be appointed and it will be possible to plan and control the motion.
7

Dynamic modeling of an excavator during digging and simulating the motion

Ozunlu, Ozcan Mutlu 01 January 2008 (has links) (PDF)
The aim of this study is to perform the dynamic force analysis of a 3-degrees-of-freedom excavator during digging the soil and to simulate the motion on computer screen. Standard load calculations are done statically, therefore the effects of forces changing with time on the system cannot be observed. The dynamic analysis method used in the thesis is Recursive Newton &ndash / Euler Method and the numerical analysis method for simulation is 4th Order Runge &ndash / Kutta Method. After this study, the effects of sudden velocity changes / i.e, accelerational movements on construction machines, positions of bodies and dynamic forces on joints will be appointed and it will be possible to plan and control the motion.
8

Rozšíření použitelnosti rypadla Mecalac 714 MW / Upgrade of application of excavator MECALAC 714 MW

Cikánek, Martin January 2008 (has links)
This thesis deals with the use-expansion of Mecalac 714 MW excavators. There are three modifications of this device which improve its applicabibility and versatility in constructional machines branch. The first modification is creating additional frame for additional devices transportation. The second one is mechanical enlargement of supporting feet for better stabilisation during working regime. The third one is creating the device for transportation of materials stored on pallets. This thesis presents the description of all devices, the way of fastening to the excavator, stability calculatoins and the calculatoin of economic demandingness.
9

Development of a Virtual Reality Excavator Simulator: a Mathematical Model of Excavator Digging and a Calculation Methodology

Park, Borinara 20 December 2002 (has links)
Virtual Reality (VR) simulators have become popular because of two distinctive merits. One is the capability to transfer data and information to users in an intuitive way by means of 3-D high-quality graphics output and real input devices. The other is the capability to represent physical systems in mathematical models so that meaningful responses of the systems can be predicted. Previous efforts in VR excavating machine simulator development, however, showed a lack of balance between the fidelity of the model of the physics and the visual representation of the simulated equipment. In order to ensure that a VR construction excavator simulator provides convincing operating results to users, the focus of simulator development needs to be shifted to interaction of physically valid soil and the excavator machine. This research aims to contribute to the development of a VR construction excavator simulator system by proposing a mathematical model of excavator digging and a calculation methodology. The mathematical model of excavator digging provides physically meaningful soil-bucket interaction information to a simulator. The calculation methodology provides systematic and efficient computation methods to ensure the seamless integration of the excavator digging model with a VR simulator system as well as adequate system speed. As a result, the simulator is realized as an engineering process tool equipped with real-time interactivity. / Ph. D.
10

Teleoperated Control of Hydraulic Equipment for Hazardous Material Handling

Fleming, Michael Ryals 21 January 2004 (has links)
Traditionally, teleoperation has been an expensive and lengthy process. This thesis shows that by incorporating off-the-shelf technology into a modular design, teleoperation can be developed rapidly and inexpensively. Within six months and a hardware cost of $20k, a group of Virginia Tech students and faculty converted a Case CX-160 excavator to teleoperated control. With full wireless functionality of the excavator's six degrees-of-freedom, ignition, and remote cameras at 3000 ft., the teleoperated design meets or exceeds customer demands. For over a year, the teleoperated excavator has demonstrated effectiveness, robustness, and durability in multiple unexploded ordnance (UXO) site remediation projects. / Master of Science

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