• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 198
  • 41
  • 40
  • 7
  • 7
  • 7
  • 7
  • 7
  • 7
  • 6
  • 6
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 402
  • 258
  • 146
  • 141
  • 102
  • 86
  • 57
  • 53
  • 43
  • 41
  • 40
  • 35
  • 30
  • 30
  • 27
  • 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.
271

Manipulator grasping and pushing operations

Mason, Matthew Thomas January 1982 (has links)
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 125-136. / by Matthew Thomas Mason. / Ph.D.
272

Computer graphic representation of remote environments using position tactile sensors

Fyler, Donald Charles January 1981 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Donald Charles Fyler. / M.S.
273

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.
274

Video resolution, frame rate and grayscale tradeoffs under limited bandwidth for undersea teleoperation

Ranadivé, Vivek January 1980 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Vivék Ranadivé. / M.S.
275

Computer simulated visual and tactile feedback as an aid to manipulator and vehicle control

Winey, Calvin McCoy January 1981 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 72. / by Calvin McCoy Winey III. / M.S.
276

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.
277

A study of single laser interferometry-based sensing and measuring technique in robot manipulator control and guidance. Volume 1

Teoh, Pek Loo January 2003 (has links)
Abstract not available
278

Planning of Minimum-Time Trajectories for Robot Arms

Sahar, Gideon, Hollerbach, John M. 01 November 1984 (has links)
The minimum-time for a robot arm has been a longstanding and unsolved problem of considerable interest. We present a general solution to this problem that involves joint-space tesselation, a dynamic time-scaling algorithm, and graph search. The solution incorporates full dynamics of movement and actuator constraints, and can be easily extended for joint limits and work space obstacles, but is subject to the particular tesselation scheme used. The results presented show that, in general the optimal paths are not straight lines, bit rather curves in joint-space that utilize the dynamics of the arm and gravity to help in moving the arm faster to its destination. Implementation difficulties due to the tesselation and to combinatorial proliferation of paths are discussed.
279

Task and motion planning for mobile manipulators

January 2012 (has links)
This thesis introduces new concepts and algorithms that can be used to solve the simultaneous task and motion planning (STAMP) problem. Given a set of actions a robot could perform, the STAMP problem asks for a sequence of actions that takes the robot to its goal and for motion plans that correspond to the actions in that sequence. This thesis shows how to solve the STAMP problem more efficiently and obtain more robust solutions, when compared to previous work. A solution to the STAMP problem is a prerequisite for most operations complex robots such as mobile manipulators are asked to perform. Solving the STAMP problem efficiently thus expands the range of capabilities for mobile manipulators, and the increased robustness of computed solutions can improve safety. A basic sub-problem of the STAMP problem is motion planning. This thesis generalizes KPIECE, a sampling-based motion planning algorithm designed specifically for planning in high-dimensional spaces. KPIECE offers computational advantages by employing projections from the searched space to lower-dimensional Euclidean spaces for estimating exploration coverage. This thesis further develops the original KPIECE algorithm by introducing a means to automatically generate projections to lower-dimensional Euclidean spaces. KPIECE and other state-of-the-art algorithms are implemented as part the Open Motion Planning Library (OMPL), and the practical applicability of KPIECE and OMPL is demonstrated on the PR2 hardware platform. To solve the STAMP problem, this thesis introduces the concept of a task motion multigraph (TMM), a data structure that can express the ability of mobile manipulators to perform specific tasks using different hardware components. The choice of hardware components determines the state space for motion planning. An algorithm that prioritizes the state spaces for motion planning using TMMs is presented and evaluated. Experimental results show that planning times are reduced by a factor of up to six and solution paths are shortened by a factor of up to four, when considering the available planning options. Finally, an algorithm that considers uncertainty at the task planning level based on generating Markov Decision Process (MDP) problems from TMMs is introduced.
280

Research on remote control of reconfigurable modular robotic system

Song, Zhanglei 01 August 2009 (has links)
Serial manipulators, which have large work space with respect to their own volume and occupied floor space, are the most common industrial robots by far. However, in many environments the situation is unstructured and less predictable, such as aboard a space station, a nuclear waste retrieval site, or a lunar base construction site. It is almost impossible to design a single robotic system which can meet all the requirements for every task. In these circumstances, it is important to deploy a modular reconfigurable robotic system, which is suitable to various task requirements. Modular reconfigurable robots have a variety of attributes that are well suited to for these conditions, including: the ability to serve as many different tools at once (saving weight), packing into compressed forms (saving space) and having high levels of redundany(increasing robustness). By easy disassembly and reassembly features, this serial modular robotic system will bring advantages to small and medium enterprise to save costs in the long term. This thesis focuses on developing such a serial reconfigurable modular robotic system with remote control functionality. The robotic arms are assembled by PowerCube Modules with cubic outward appearance. The control and power electronics are fully integrated on the connector block inside of the modules. Those modules are connected in series by looping through, and can work completely independently. The communication between robotic arms and PC controller is connected by the Control Area Network bus. CAN protocol detects and corrects transmission errors caused by electromagnetic interference. The local PC can directly control the robotic arm via Visual Basic code, and it can also be treated as server controller. Client PCs can access and control the robotic arm remotely through Socket communication mechanism with certain IP address and port number. A Java3D model is created on the client PC synchronously for customers online monitoring and control. The forward and inverse kinematic analysis is solved by Vector Algebraic Method. The Neutral Network Method is also introduced to improve the kinematic analysis. Multiple-layer networks are capable of approximating any function with finite number of discontinuities. For learning the inverse kinematics neural network needs information about coordinates, joint angles and actuator positions. The desired Cartesian coordinates are given as input to the neural network that returns actuator positions as output. The robot position is simulated using these actuator positions as reference values for each actuator.

Page generated in 0.038 seconds