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published_or_final_version / abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

Chow Ying-ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 78-83). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Objectives - Visual Navigation for Legged Robots --- p.1 / Chapter 1.2 --- Summary of Results --- p.3 / Chapter 1.3 --- Hardware Issues --- p.4 / Chapter 1.4 --- Contributions --- p.4 / Chapter 1.5 --- Organization of the Thesis --- p.4 / Chapter Chapter 2 --- Previous Work --- p.6 / Chapter 2.1 --- Vision Based Navigation --- p.6 / Chapter 2.1.1 --- Homography --- p.7 / Chapter 2.1.2 --- Ground Plane Obstacle Detection --- p.9 / Chapter 2.1.3 --- Regression --- p.12 / Chapter 2.2 --- Control Strategy --- p.13 / Chapter Chapter 3 --- System Overview --- p.16 / Chapter Chapter 4 --- Obstacle Detection by Fast Homography Estimation --- p.20 / Chapter 4.1 --- Ground Feature Extraction --- p.21 / Chapter 4.2 --- Ground Feature Correspondence --- p.21 / Chapter 4.3 --- Ground Homography Estimation --- p.24 / Chapter 4.3.1 --- Input point transformation --- p.24 / Chapter 4.3.2 --- Initial estimation --- p.26 / Chapter 4.3.3 --- Robust estimation --- p.27 / Chapter 4.4 --- Obstacle Detection --- p.29 / Chapter 4.5 --- Local Obstacle Map (LOM) on Ground --- p.33 / Chapter 4.5.1 --- Extraction from accumulative evidence --- p.34 / Chapter 4.5.2 --- Time-delay compensation --- p.34 / Chapter Chapter 5 --- Obstacle Avoidance by a Fuzzy Controller --- p.36 / Chapter 5.1 --- Gait Pattern --- p.38 / Chapter 5.2 --- Fuzzy Logic Controller --- p.42 / Chapter 5.2.1 --- Controller Inputs --- p.42 / Chapter 5.2.2 --- Controller Outputs --- p.43 / Chapter 5.2.3 --- Inference mechanism --- p.46 / Chapter Chapter 6 --- Implementation --- p.49 / Chapter 6.1 --- Hardware components --- p.49 / Chapter 6.1.1 --- VisionBug --- p.49 / Chapter 6.1.2 --- RF transmitter / receiver modules: --- p.52 / Chapter 6.2 --- Perception --- p.55 / Chapter 6.3 --- Image Calibration --- p.56 / Chapter 6.4 --- Motion Calibration: --- p.58 / Chapter 6.5 --- Software Programs --- p.66 / Chapter 6.5.1 --- Computational complexity --- p.68 / Chapter Chapter 7 --- Experimental Results --- p.69 / Chapter 7.1 --- Real Navigation Experiments --- p.70 / Chapter 7.2 --- Error Analysis of LOM --- p.73 / Chapter Chapter 8 --- Conclusion and future work --- p.76

Wang Hesheng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 70-73). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Contents --- p.v / List of Figures --- p.vii / List of Tables --- p.viii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Visual Servoing --- p.1 / Chapter 1.1.1 --- Position-based Visual Servoing --- p.4 / Chapter 1.1.2 --- Image-based Visual Servoing --- p.5 / Chapter 1.1.3 --- Camera Configurations --- p.7 / Chapter 1.2 --- Problem Definitions --- p.10 / Chapter 1.3 --- Related Work --- p.11 / Chapter 1.4 --- Contribution of This Work --- p.15 / Chapter 1.5 --- Organization of This Thesis --- p.16 / Chapter 2 --- System Modeling --- p.18 / Chapter 2.1 --- The Coordinates Frames --- p.18 / Chapter 2.2 --- The System Kinematics --- p.20 / Chapter 2.3 --- The System Dynamics --- p.21 / Chapter 2.4 --- The Camera Model --- p.23 / Chapter 2.4.1 --- Eye-in-hand System --- p.28 / Chapter 2.4.2 --- Eye-and-hand System --- p.32 / Chapter 3 --- Adaptive Image-based Visual Servoing --- p.35 / Chapter 3.1 --- Controller Design --- p.35 / Chapter 3.2 --- Estimation of The Parameters --- p.38 / Chapter 3.3 --- Stability Analysis --- p.42 / Chapter 4 --- Simulation --- p.48 / Chapter 4.1 --- Simulation I --- p.49 / Chapter 4.2 --- Simulation II --- p.51 / Chapter 5 --- Experiments --- p.55 / Chapter 6 --- Conclusions --- p.63 / Chapter 6.1 --- Conclusions --- p.63 / Chapter 6.2 --- Feature Work --- p.64 / Appendix --- p.66 / Bibliography --- p.70

Lam Kin Kwan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 67-70). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Visual Servoing --- p.1 / Chapter 1.1.1 --- System Architectures --- p.2 / Chapter 1.1.1.1 --- Position-based Visual Servoing --- p.2 / Chapter 1.1.1.2 --- Image-based Visual Servoing --- p.3 / Chapter 1.1.2 --- Camera Configurations --- p.4 / Chapter 1.2 --- Problem Definition --- p.5 / Chapter 1.3 --- Related Work --- p.6 / Chapter 1.4 --- Contribution of This Work --- p.9 / Chapter 1.5 --- Organization of This Thesis --- p.10 / Chapter 2. --- System Modeling --- p.11 / Chapter 2.1 --- Coordinate Frames --- p.11 / Chapter 2.2 --- System Kinematics --- p.13 / Chapter 2.3 --- System Dynamics --- p.14 / Chapter 2.4 --- Camera Model --- p.15 / Chapter 2.4.1 --- Eye-in-hand Configuration --- p.18 / Chapter 2.4.2 --- Eye-and-hand Configuration --- p.21 / Chapter 3. --- Adaptive Visual Servoing Control --- p.24 / Chapter 3.1 --- Controller Design --- p.24 / Chapter 3.2 --- Parameter Estimation --- p.27 / Chapter 3.3 --- Stability Analysis --- p.30 / Chapter 4. --- Experimental Studies --- p.34 / Chapter 4.1 --- Experimental Setup --- p.34 / Chapter 4.1.1 --- Hardware Setup --- p.34 / Chapter 4.1.2 --- Image Pattern Recognition --- p.35 / Chapter 4.1.3 --- Experimental Task --- p.36 / Chapter 4.2 --- Control Performance with Different Proportional Gains and Derivative Gains --- p.39 / Chapter 4.3 --- Control Performance with Different Adaptive Gains --- p.41 / Chapter 4.4 --- Gravity Compensator --- p.50 / Chapter 4.5 --- Control Performance with Previous Image Positions --- p.51 / Chapter 4.6 --- Kinematic Controller --- p.56 / Chapter 5. --- Conclusions --- p.61 / Chapter 5.1 --- Conclusions --- p.61 / Chapter 5.2 --- Future Work --- p.62 / Appendix --- p.63 / Bibliography --- p.67

Shen Yantao. / "April 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 117-122). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

One of the major problems that obstruct the development of adaptive visual servoing is the fact that the image Jacobian or the interaction matrix cannot be linearly parameterized by the unknown parameters. To solve this problem, we propose a depth-independent interaction matrix, which is obtained by eliminating the depth in the traditional interaction matrix. Using this depth-independent interaction matrix in controller design, it is possible to make the unknown parameters appear linearly in the closed-loop dynamics. As a result, we can use an adaptive algorithm, similar to that proposed by Slotine and Li [1], to estimate the unknown parameters on-line. To guarantee the convergence of the image errors, in the parameter adaptation we combine the Slotine-Li algorithm with an on-line gradient descending minimization algorithm of the errors between the real and estimated image coordinates of the feature points. On the basis of the depth-independent interaction matrix and the new adaptive algorithm, we first propose an adaptive controller for image-based visual servoing of point features using both uncalibrated eye-in-hand and fixed cameras. Then, we extend the controller to visual servoing using line features with an eye-in-hand camera. Next, we present a dynamic controller for trajectory tracking of feature points on a robot manipulator in 3D general motion using fixed uncalibrated camera. To avoid performance decaying caused by measurement errors of the visual velocity, we also propose a new controller for dynamics visual tracking without using visual velocities. Finally, we design a new controller for locking a moving object in 3-D space at a particular position on the image plane of a camera mounted on a robot by actively moving the camera. The asymptotic stabilities of the system under the control of the proposed methods are rigorously proved by the Lyapunov theory with the nonlinear robot dynamics fully taken into account. The performances of the controllers have been verified by experiments on a 3 DOF robot manipulator. / The contribution of this thesis can be summarized as follows: First, a depth-independent interaction matrix is proposed for mapping the image errors onto the joint space. Second a new adaptive algorithm has been developed to estimate the unknown parameters. Finally, new methods to position and tracking control of robots with uncalibrated visual feedback in both eye-in-hand and fixed camera configuration are proposed. / Visual servoing is an approach to control motion of a robot manipulator using visual feedback signals from a vision system and has received extensive attention in recent years. Many existing methods work based on an assumption that the parameters of the vision system are accurately calibrated, while the calibration process is tedious. Furthermore, most of the controllers are designed using the kinematics relationship only, without considering the nonlinear dynamics of robots, so that they are not suitable for high performance and fast visual servoing tasks. Aiming at solving those two problems, this thesis addresses dynamic position and tracking control of robots with uncalibrated visual feedback. Both the fixed camera and eye-in-hand camera configurations are considered. / Wang, Hesheng. / "August 2007." / Adviser: Yun-Hui Liu. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1294. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 160-169). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

A comparative study of three six-axis force sensors selected after an extensive literature survey is presented. A sensor to measure ground contact force at each foot of a walking machine is recommended. Principles of force sensing are reviewed and characteristics of sensing elements are discussed. Results of simulation of three six-axis force sensors are presented as behavior curves, sensitivity plots and compliance matrices. These simulations use finite element techniques. Condition numbers of compliance matrices are presented as a measure of overall sensor performance. Estimates of manufacturing costs are included as a final selection criterion. / Graduation date: 1994