528 research outputs found
Motion Planning And Control Of Cooperative Robotic Systems
No full textMOTION PLANNING AND CONTROL OF COOPERATIVE ROBOTIC SYSTEMS Jaydev P. Desai Vijay Kumar James P. Ostrowski This thesis addresses the problem of motion planning for cooperative robotic systems. The problem of motion planning for a robotic system is stated as: Given initial positions and orientations and goal positions and orientations for a collection, C, of robots, in workspace, W, generate a continuous trajectory for C avoiding contact with the obstacles, O i , subject to various dynamical constraints of the system. Because robots are physical systems subject to continuous laws of motion and driven by continuous actuators, we formulate the motion planning problem as an unconstrained variational problem using tools from optimal control and calculus of variations in the first part of the thesis. We develop a general framework for solving motion planning problems involving equality and inequality constraints. In the second part of the thesis, we study planar human manipulation and de..
Acoustic Masking of a Stealthy Outdoor Robot Tracking a Dynamic Target
No full textThis work is motivated by the desire to covertly track mobile targets, either animal or human, in previously unmapped outdoor natural environments using off-road robotic platforms with a non-negligible acoustic signature. The use of robots for stealthy surveillance is not new. Many studies exist but only consider the navigation problem to maintain visual covertness. However, robotic systems also have a significant acoustic footprint from the onboard sensors, motors, computers and cooling systems, and also from the wheels interacting with the terrain during motion. All these can jepordise any visual covertness. In this work, we experimentally explore the concepts of opportunistically utilizing naturally occurring sounds within outdoor environments to mask the motion of a robot, and being visually covert whilst maintaining constant observation of the target. Our experiments in a constrained outdoor built environment demonstrate the effectiveness of the concept by showing a reduced acoustic signature as perceived by a mobile target allowing the robot to covertly navigate to opportunistic vantage points for observation
13th International Symposium on Experimental Robotics
No full textThe International Symposium on Experimental Robotics (ISER) is a series of bi-annual meetings which are organized in a rotating fashion around North America, Europe and Asia/Oceania. The goal of ISER is to provide a forum for research in robotics that focuses on novelty of theoretical contributions validated by experimental results. The meetings are conceived to bring together, in a small group setting, researchers from around the world who are in the forefront of experimental robotics research. This unique reference presents the latest advances across the various fields of robotics, with ideas that are not only conceived conceptually but also explored experimentally. It collects robotics contributions on the current developments and new directions in the field of experimental robotics, which are based on the papers presented at the 13th ISER held held in Québec City, Canada, at the Fairmont Le Château Frontenac, on June 18-21, 2012. This present thirteenth edition of Experimental Robotics edited by Jaydev P. Desai, Gregory Dudek, Oussama Khatib, and Vijay Kumar offers a collection of a broad range of topics in field and human-centered robotics.
The DLR MiroSurge surgical robotic demonstrator
No full textThis chapter gives a brief overview of the DLR MiroSurge versatile surgical robotic demonstrator, its major components, mechatronic design and control paradigms. Central component is the robot arm Miro based on intelligent mechatronic technology developed at DLR. The system is adapted to various medical applications by attaching various instruments, e.g., the dedicated instrument MICA, and a surgeon workstation providing HD 3D vision and haptic feedback. Furthermore, a selection of current research topics concerning novel MIRS applications and system components are introduced
Characterization and Control of Biological Microrobots
No full textThis work addresses the characterization and control of Magnetotactic Bacterium (MTB) which can be considered as a biological microrobot. Magnetic dipole moment of the MTB and response to a field-with-alternating-direction are characterized. First, the magnetic dipole moment is characterized using four tech-niques, i.e., Transmission Electron Microscope images, flip-time, rotating-field and u-turn techniques. This characterization results in an average magnetic dipole mo-ment of 3.32×10−16 A.m2 and 3.72×10−16 A.m2 for non-motile and motile MTB, respectively. Second, the frequency response analysis of MTB shows that its ve-locity decreases by 38% for a field-with-alternating-direction of 30 rad/s. Based on the characterized magnetic dipole moment, the magnetic force produced by our magnetic system is five orders-of-magnitude less than the propulsion force gener-ated by the flagellum of the MTB. Therefore, point-to-point positioning of MTB cannot be achieved by exerting a magnetic force. A closed-loop control strategy is devised based on calculating the position tracking error, and capitalizes on the fre-quency response analysis of the MTB. Point-to-point closed-loop control of MTB is achieved for a reference set-point of 60 mm with average velocity of 20 mm/s. The closed-loop control system positions the MTB within a region-of-convergence of 10 mm diameter
Motion Planning and Control of Cooperative Robotic Systems
No full textThis thesis addresses the problem of motion planning for cooperative robotic systems. The problem of motion planning for a robotic system is stated as:
Given initial positions and orientations and goal positions and orientations for a collection, C, of robots, in workspace, W, generate a continuous trajectory for C avoiding contact with the obstacles, Oi, subject to various dynamical constraints of the system.
Because robots are physical systems subject to continuous laws of motion and driven by continuous actuators, we formulate the motion planning problem as an unconstrained variational problem using tools from optimal control and calculus of variations in the first part of the thesis. We develop a general framework for solving motion planning problems involving equality and inequality constraints.
In the second part of the thesis, we study planar human manipulation and develop a computational model for friction-assisted dual arm manipulation tasks incorporating the dynamics of the musculo-skeletal system. We show that our computational model predicts the force distribution and object trajectory in voluntary, relaxed movements. We further study similar tasks in the vertical plane and our experimental findings suggest that there is a great degree of repeatability in trajectories and velocity profiles across trials and subjects.
In the third part, we focus on extending this computational model to plan and control cooperative robotic systems. We solve the dynamic motion planning problem for a system of cooperating robots in the presence of geometric and kinematic constraints, and test the resulting open-loop trajectories on the experimental testbed.
In the last part of the thesis, we explore the application of the motion planning algorithms when the number of robots in C is very large. Because of increased computational time, we use optimal sensor-based closed loop motion plans. These are combined with the framework of graph theory and optimal control to guarantee provable measure on the performance of the entire system.
The main contributions of the thesis are: (a) studying trajectory generation and force distribution in human dual arm manipulation; and (b) a set of motion planning algorithms for cooperating robot systems subject to dynamic constraints
Towards the Holy Grail: combining system dynamics and discrete-event simulation in healthcare
No full textThe idea of combining discrete-event simulation and system dynamics has been a topic of debate in theoperations research community for over a decade. Many authors have considered the potential benefits ofsuch an approach from a methodological or practical standpoint. However, despite numerous examples ofmodels with both discrete and continuous parameters in the computer science and engineering literature,nobody in the OR field has yet succeeded in developing a genuinely hybrid approach which truly integratesthe philosophical approach and technical merits of both DES and SD in a single model. In this paperwe consider some of the reasons for this and describe two practical healthcare examples of combinedDES/SD models, which nevertheless fall short of the “holy grail” which has been so widely discussed inthe literature over the past decade
Clinical outcomes in the Google era: The PB Desai Oration, ASICON 2013
No full textThis article is based upon the PB Desai Oration which was given by the author in Ahmedabad on 28th December 2013 at the National Congress of the Association of Surgeons of India at the invitation of the Executive Board of the Indian Association for Surgical Oncology.</p
Magnetoresistance in triphenyl-diamine derivative blue organic light emitting devices
No full textCopyright 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 103, 043706 (2008) and may be found at
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