147 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
Medical Robotics
No full textThe evolution of robotics in surgery is a new and exciting development. Surgical robotics brings together many disparate areas of research such as: design, development and modeling of robotic systems, nonlinear control, safety in medical robotics, ergonomics in minimally invasive procedures, and last but not the least, surgery. Over the past decade there have been significant advances in basic research and technology that have made it possible for the development of robots for surgery. One of the main advantages of robots is the increased precision and repeatability in carrying out surgical procedures, which were not possible in the past by a human surgeon. Robots and computers in conjunction can perform complex computations at much higher speeds compared to humans. On the other hand, humans are more adept in integrating diverse sources of information and making decisions based on their past experience of working in that field. They are also dexterous on the “human’ ’ scale, have very strong hand-eye coordination and an excellent sense of touch. Robots on the other hand have very good accuracy in carrying out pre-specified tasks, are not prone to fatigue or boredom, can carry out fast computations for surgical planning based on 3-D imaging data and other sensory feedback, and can also be designed for a wide range of operating conditions and scales. There are however severe limitations of robots and humans. One of the main disadvantages of robots is that they have poor judgment capability, limited dexterity and poor hand-eye coordination. Humans on the other hand cannot operate beyond their physical capability (their natural scale of operation) and are prone to tremor and fatigue [Taylor96]. Robots are thus seen more as augmenting human capabilities rather than replacing surgeons. The strengths and weaknesses of humans and robots are summarized in Table 1. Several robotic systems have been developed for surgical procedures. Some of the key areas where robotics has made a significant impact are orthopaedics, neurosurgery, laparoscopic procedures, opthalmic surgery, and cardiac surgery
Towards the development of a humanoid arm by minimizing interaction forces through minimum impedance control
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