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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.
11

Analytic integration of tolerances in designing precision interfaces for modular robotics

Shin, Sung Ho 28 August 2008 (has links)
Not available / text
12

Design of an autonomous mobile robot for service applications.

De Villiers, Mark. January 2011 (has links)
This research project proposes the development of an autonomous, omnidirectional vehicle that will be used for general indoor service applications. A suggested trial application for this service robot will be to deliver printouts to various network users in their offices. The robot will serve as a technology demonstrator and could later also be used for other tasks in an office, medical or industrial environment. The robot will use Mecanum wheels (also known as Swedish 45° or Ilon wheels) to achieve omnidirectionality. This will be especially useful in the often cramped target environments, because the vehicle effectively has a zero radius turning circle and is able to change direction of motion without changing its pose. Part of the research will also be to investigate a novel propulsion system based on the Mecanum wheel. The robot will form part of a portfolio of service robots that the Mechatronics and Micro Manufacturing (MMM) group at the CSIR is busy developing. Service robots are typically used to perform Dull, Dangerous or Dirty work, where human presence is not essential if the robot can perform the task reliably and successfully. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.
13

Mobile robot and manipulator for rescue missions: traversability, modularity and scalability.

January 2014 (has links)
在世界各地,自然或人為災難隨時可能發生。災難回應作為災難處理的重要環節顯得尤為重要,隨著科學技術的進步和提高,人們希望通過使用各種科學手段來提高災難的回應效率。機器人技術作為21世紀高科技結合的產物被廣泛應用於這一領域。一般情況下,設計者會採用功能集成的思想對機器人進行設計,他們的主要設計思想是根據自己對環境的理解和認知得到機器人的設計需求,然後針對設計需求,通過功能集成和疊加的方式來完成對機器人的設計,採用這種方式機器人一旦設計完畢,其功能也隨之確立並不可更改,這種設計思想是基於環境狀況的,即一旦災難現場的環境不符合預先的設定,機器人的執行能力將大幅下降,同時功能疊加的設計方式會產生功能與功能之間相互約束,影響其專業性。 / 本文介紹了一種基於分散式設計思想的全新設計理念,並且根據這一理念設計了一套基於任務需求的救援機器人系統。機器人系統不會根據設計者對災難現場的預先理解和認知而被一體化設計,相反根據"如何到達"和"如何操作"把機器人系統拆分成移動單元和操作單元兩個環節,針對每個環節分別設計了符合現場需求的通用移動模組和任務執行模組,救援人員可以根據災難現場的即時任務需求而迅速搭建出有針對性的機器人系統任務解決方案,和傳統的機器人系統相比,具適應性廣、靈活性高、針對性強等特點。 / 在本論文中,對三種通用的移動平臺和兩種通用的模組化關節以及一個快速連接器分別進行了結構設計、理論分析及樣機設計,並採用基本的通用模組,根據即時的任務需求構建出有針對性的多個機器人系統。實驗表明該機器人系統可以提供對災難環境有針對性的系統解決方案,具有一定容錯性、經濟性及災難環境的適應性。文章的創新點如下,首次針對于救援機器人提出分散式的設計思想,並以該思想為基礎設計了基於通用模組的救援機器人系統,針對不同任務對移動性能的不同要求設計了三種移動平臺,為滿足不同的救援操作要求設計了兩種模組化關節以及快速連接器。同時,文中為實際的地震救援任務提出了一套救援機器人系統解決方案。 / Natural and man-made disasters nowadays still present a large amount of risk. Disaster response is an important phase of disaster management, and the enhancement of its effectiveness and accountability has attracted an increasing amount of attention. Robots can help rescuers in doing this task because of its wide range of applications. In general, the rescue robot concept assumes one or more targeted tasks while design, and one or a set of robot(s) is/are designed by integrating different functions to accomplish those tasks. Once the design of a robot is finished, its function cannot be changed. However, this kind of design is environment-dependent, as once a disaster environment changes, the execution performance of the robot will reduce. Furthermore the function-integrated design concept may cause internal constraints between functions, and fail to provide a targeted solution for different disaster environments. / This dissertation introduces a novel design concept, based on which a requirement-oriented rescue robot system is developed. This design concept adopts a distributed strategy, according to which tasks are no longer seen as a whole but divided into two parts: traversability and operation. Several functional modules are designed to meet the different requirements of the two parts separately, and the entire robot system can be assembled using different functional modules according to the real-time requirements of the disaster environment. Compared with the traditional rescue robot system, this system can provide a more targeted solution for different disaster situations, and is more adaptable and flexible. / This dissertation details the basic functional modules, including three kinds of mobile bases for traversability and two sets of modular joints for operation, and analyzes a quick connector that makes the connection easier and more convenient. Several possible combinations of the rescue robot system are displayed to show how to construct a rescue robot system according to different requirements. This kind of rescue robot system can provide targeted solutions to different disaster tasks. Robustness is also enhanced, as the replacement of the functional modules is flexible and easy to overhaul. Furthermore, the functional modules can be decomposed and reused to make the robot system more economical. This dissertation makes several contributions. It presents a systematic solution for rescue robot, develops three mobile bases for high traversability and two kinds of modular joints and a quick connector for rescue operation. Furthermore, it also develops a rescue robot system for missions in earthquake. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Yang, Yong. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 226-236). / Abstracts also in Chinese.
14

Space station robot: design, mobility and manipulation.

January 2014 (has links)
空間站探索是世界熱點研究問題,空間站巨大因此往往在外太空在軌建造和組裝,因此需要由宇航員和機器人開展大量的艙外工作( Extra-Vehicular Activities,EVAs)。目前,宇航員的艙外工作存在以下三個方面的問題:(1)宇航員在移動攀爬和任務操作相互衝突的問題, 宇航員在艙外工作時不能一邊沿著扶手攀爬,一邊搬運載荷;(2)當前的空間機器人工作空間有限,在空間站表面有許多地方無法達到開展艙體檢查等在軌服務;(3)當前的空間機器人在狹窄空間裡操作效率不高,不能很好地避開障礙物和做精細化靈巧操作。 / 本論文針對以上問題提出了2 個機器人系統,四腿行走機器人( Four-legged Robot Walker, FLRW ) 和圓弧軌道機器人(Circular Rail Robot System , CRRS)。四腿行走機器人擅長多退的扶手攀爬和操作,攀爬和操作可同時開展。四腿行走機器人還有一個可旋轉頭部(可旋轉的視覺系統)來增強攀爬過程中的視覺範圍。圓弧軌道機器人通過移動機器人在圓弧軌道的運動能完全覆蓋空間站的所有工作空間,該系統是在太空應用的第一個弧形軌道系統,同時也有最小的轉彎半徑。 / 本論文對提出的2 個機器人系統的移動性進行了深入的研究,四腿機器人側重在雙臂攀爬的策略、攀爬步態,並開展了全艙攀爬的在軌任務模擬驗證。圓弧軌道機器人開展了艙體軌道系統、多艙體軌道切換器、移動基座平臺、移動平臺驅動和轉彎半徑的深入設計與分析,並且完成了移動軌道平臺的原型樣機試製驗證。 / 本論文對提出的2 個機器人系統的操作臂開展了非球形腕部掛接、冗餘操作臂奇異點辨識研究,提出了一種雅克比初等變換(MJET)演算法進行操作臂奇異分析,該演算法可以將冗餘機械臂的6x7 奇異矩陣轉化到3x4 的子矩陣,大大提高了運算效率。論文還開展了在多移動物體環境下的避障研究,提出了一種即時的多移動物體障礙回避(MMOA)演算法,該演算法採用超曲面函數描述障礙物的包絡,採用偽距離即時計算與移動障礙物距離,取得了控制精度和即時性的平衡。 / 本論文對提出的2 個機器人系統的操作臂開展了動力學建模和在軌裝配研究,採用拉格朗日建模方法對操作臂建模,並與商務軟體ADAMS 對比驗證建模準確度。同時,並運用阻抗控制演算法針對ORU 的在軌抓取、安裝和轉移等在軌任務的實現驗證。 / 最後論文進行了總結和後續工作展望。 / Space station exploration is a global hot research topic. The space stations are usually large in scale so that they have to be fabricated and assembled in space, which involves a large number of Extra-Vehicular Activities (EVAs) by astronauts and robots. There are three main problems of EVA mission. (1) Astronauts experience a conflict between climbing and manipulation during EVA missions, as they cannot carry payloads while handrail climbing. (2) Current space robots have workspace limitations and cannot reach the whole exterior of a space station, making it challenging to carry out inspection and servicing. (3) It is also difficult for robots to avoid obstacles and perform fine manipulation tasks in a compact workspace. / Two robotics systems, the Four-Legged Robot Walker (FLRW) and the Circular-Rail Robot System (CRRS), are proposed to address the above problems. The FLRW is good at handrail climbing as it has multiple, identical legs. It also has a rotatable vision system to enhance its field of view during climbing. The CRRS provides full coverage of the space station workspace, as it is a mobile robot that drives on a circular rail system around the space station. This system is the first design of robotic system with circular-rail in space and also has the smallest turning radius. / The mobility of both robots is addressed. The FLRW analysis focuses on the climbing strategy and climbing gait analysis. The circular rail system, rail switch, mobile platform, driving force and turning radius of CRRS are carefully designed and analyzed. A prototype of the CRRS mobile platform is implemented for verification. / The proposed manipulator is designed with redundant joint and non-spherical-wrists. A Modified Jacobian Elementary Transformation (MJET) approach is proposed to determine all of the singularity conditions. This approach has a singularity isolation feature to reduce the computational workload. A Multiple Moving Obstacle Avoidance (MMOA) approach is proposed for manipulator path planning in a compact workspace. A super-quadric surface function is used to describe the shape of an obstacle, and the pseudo-distance from the manipulator to the obstacle is measured and controlled in real time. This approach achieves a good balance between computational complexity and accuracy. / The proposed manipulator is modeled using the Lagrangian dynamics formulation and the dynamics of the proposed manipulator is verified with the commercial software ADAMS (Automatic Dynamic Analysis of Mechanical Systems). The mathematics model has similar output in ADAMS under a constant torque input and a sine torque input. The Orbital Replacement Unit (ORU) assembly task is implemented using impedance control. Both simulation and hardware tests are completed for verification, and the experimental results show that the controller is good for on-orbit servicing tasks. / The contributions of the thesis are summarized and future work is proposed. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chen, Yongquan. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 131-148). / Abstracts also in Chinese.
15

Vision-Based Motion for a Humanoid Robot

Alkhulayfi, Khalid Abdullah 13 July 2016 (has links)
The overall objective of this thesis is to build an integrated, inexpensive, human-sized humanoid robot from scratch that looks and behaves like a human. More specifically, my goal is to build an android robot called Marie Curie robot that can act like a human actor in the Portland Cyber Theater in the play Quantum Debate with a known script of every robot behavior. In order to achieve this goal, the humanoid robot need to has degrees of freedom (DOF) similar to human DOFs. Each part of the Curie robot was built to achieve the goal of building a complete humanoid robot. The important additional constraints of this project were: 1) to build the robot from available components, 2) to minimize costs, and 3) to be simple enough that the design can be replicated by non-experts, so they can create robot theaters worldwide. Furthermore, the robot appears lifelike because it executes two main behaviors like a human being. The first behavior is tracking where the humanoid robot uses a tracking algorithm to follow a human being. In other words, the tracking algorithm allows the robot to control its neck using the information taken from the vision system to look at the nearest human face. In addition, the robot uses the same vision system to track labeled objects. The second behavior is grasping where the inverse kinematics (IK) is calculated so the robot can move its hand to a specific coordinate in the surrounding space. IK gives the robot the ability to move its end-effector (hand) closer to how humans move their hands.
16

Motion planning algorithms for autonomous robots in static and dynamic environments

Mkhize, Zanele G. N. 01 August 2012 (has links)
M.Ing. / The objective of this research is to present motion planning methods for an autonomous robot. Motion planning is one of the most important issues in robotics. The goal of motion planning is to find a path from a starting position to a goal position while avoiding obstacles in the environment. The robot's environment can be static or dynamic. Motion planning problems can be addressed using either classical approaches or obstacle-avoidance approaches. The classical approaches discussed in this work are: Voronoi, Visibility graph, Cell decomposition and Potential field. The obstacle avoidance approaches discussed in this research are: Neural network, Bug Algorithms, Dynamic Window Approach, Vector field histogram, Bubble band technique and Curvature velocity techniques. In this dissertation, simulation results and experimental results are presented. In the simulation, we address the motion planning issues using points extracted from a map. Algorithms used for simulation are: Voronoi algorithm, Hopfield neural network, Potential field and A* search algorithm. The simulation results show that the approaches used are effective and can be applied to real robots to solve motion planning problems. In the experiment, the Dynamic Window Approach (DWA) is used for obstacle-avoidance, a Pioneer robot explores the environment using an open source system, ROS (Robot Operating System). The experiment proved that DWA can be used to avoid obstacles in real time. keywords Motion planning, autonomous robot, optimal path problems, environment, search algorithm, classical approaches, obstacle avoidance approaches, exploration.
17

Learning Mobile Manipulation

Watkins, David Joseph January 2022 (has links)
Providing mobile robots with the ability to manipulate objects has, despite decades of research, remained a challenging problem. The problem is approachable in constrained environments where there is ample prior knowledge of the environment layout and manipulatable objects. The challenge is in building systems that scale beyond specific situational instances and gracefully operate in novel conditions. In the past, researchers used heuristic and simple rule-based strategies to accomplish tasks such as scene segmentation or reasoning about occlusion. These heuristic strategies work in constrained environments where a roboticist can make simplifying assumptions about everything from the geometries of the objects to be interacted with, level of clutter, camera position, lighting, and a myriad of other relevant variables. The work in this thesis will demonstrate how to build a system for robotic mobile manipulation that is robust to changes in these variables. This robustness will be enabled by recent simultaneous advances in the fields of big data, deep learning, and simulation. The ability of simulators to create realistic sensory data enables the generation of massive corpora of labeled training data for various grasping and navigation-based tasks. It is now possible to build systems that work in the real world trained using deep learning entirely on synthetic data. The ability to train and test on synthetic data allows for quick iterative development of new perception, planning and grasp execution algorithms that work in many environments. To build a robust system, this thesis introduces a novel multiple-view shape reconstruction architecture that leverages unregistered views of the object. To navigate to objects without localizing the agent, this thesis introduces a novel panoramic target goal architecture that takes previous views of the agent to inform a policy to navigate through an environment. Additionally, a novel next-best-view methodology is introduced to allow the agent to move around the object and refine its initial understanding of the object. The results show that this deep learned sim-to-real approach performs best when compared to heuristic-based methods in terms of reconstruction quality and success-weighted-by-path-length (SPL). This approach is also adaptable to the environment and robot chosen due to its modular design.
18

Design of an Aquatic Quadcopter with Optical Wireless Communications

Unknown Date (has links)
With a focus on dynamics and control, an aquatic quadcopter with optical wireless communications is modeled, designed, constructed, and tested. Optical transmitter and receiver circuitry is designed and discussed. By utilization of the small angle assumption, the nonlinear dynamics of quadcopter movement are linearized around an equilibrium state of zero motion. The set of equations are then tentatively employed beyond limit of the small angle assumption, as this work represents an initial explorative study. Specific constraints are enforced on the thrust output of all four rotors to reduce the multiple-input multiple-output quadcopter dynamics to a set of single-input single-output systems. Root locus and step response plots are used to analyze the roll and pitch rotations of the quadcopter. Ultimately a proportional integral derivative based control system is designed to control the pitch and roll. The vehicle’s yaw rate is similarly studied to develop a proportional controller. The prototype is then implemented via an I2C network of Arduino microcontrollers and supporting hardware. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
19

Development of a morphing autonomous underwater vehicle for path and station keeping in complex current environments

Unknown Date (has links)
This thesis explores the feasibility of using morphing rudders in autonomous underwater vehicles (AUVs) to improve their performance in complex current environments. The modeling vehicle in this work corresponds to the Florida Atlantic University's Ocean EXplorer (OEX) AUV. The AUV nonlinear dynamic model is limited to the horizontal plane and includes the effect of ocean current. The main contribution of this thesis is the use of active rudders to successfully achieve path keeping and station keeping of an AUV under the influence of unsteady current force. A constant ocean current superimposed with a sinusoidal component is considered. The vehicle's response is analyzed for a range of current frequencies. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
20

Design of a low cost, high speed robot for poultry processing

Anderson, Eric William 10 August 2004 (has links)
In poultry plants in the United States, a water chiller is used to chill WOGs (de-feathered birds without giblets). After exiting the chiller these birds are manually transferred from a conveyor belt to shackles for further processing. The current process is less than ideal. The labor pool for jobs such as these is continuing to shrink and labor turnover is a constant problem. The rates of repetitive motion injury reported are high and are continuing to rise. In addition, many poultry producers see this as a bottleneck in the process. Automation has the potential to alleviate these problems. The high variability of this task, cost restrictions, and special design considerations associated with meat handling equipment make automation of this task challenging. Industrial robots have traditionally been limited to tasks with low variability. This task has high variability. They are presented on the conveyor belt in a wide variety of positions and orientations. Most robotic automation systems consist of a commercially available industrial robot, a specialized end effector and a control scheme. The economics of this task prohibit the use of a commercially available industrial robot, as there are no industrial robots on the market that will offer a short enough payback. Robots have not yet been adapted to meat handling processes, and existing robotic designs are not well suited to the task. In designing a low cost, high-speed robot for poultry processing the requirements of the robot are defined and a variety of robot architectures, constructions, and materials are explored. Simple modifications to the existing shackle and conveyor setup to make the task easier for a robot are also explored. After the robot requirements are defined a large group of possible designs are developed. The possible designs are systematically evaluated and/or eliminated until a single design is selected. The forward and reverse kinematics for this robot are developed. A singularity analysis is carried out. A proof of concept model is built. A prototype is modeled and a dynamic analysis of that prototype is carried out. The design is finalized based on the results of the dynamic analysis.

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