Performance Optimisation Of Mobile Robots In Dynamic Environments

This dissertation, "Performance Optimisation of Mobile Robots in Dynamic Environments" by Wenkai, Zhu, 朱文凯, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Rousing applications of robot teams abound over the past three decades, but ferocious demands for viable systems to coordinate teams of mobile robots in dynamic environments still linger on. To meet this challenge, this project proposes a performance optimisation system for mobile robots to make the team performance more reliable and efficient in dynamic environments. A wide range of applications will benefit from the system, such as logistics, military, and disaster rescue. The performance optimisation system comprises three main modules: (1) a task allocation module to assign tasks to robots, (2) a motion planning module to navigate robots, and (3) a graphical simulation module to visualise robot operations and to validate the methodologies of performance optimisation. The task allocation module features a closed-loop bid adjustment mechanism for auctioning tasks to capable robots. Unlike most traditional open-looped methods, each of the robots evaluates its own performance after completing a task as feedback correction to improve its future bid prices of similar tasks. Moreover, a series of adjustments are weighed and averaged to damp out drastic deviations due to operational uncertainties. As such, the accuracy of bid prices is improved, and tasks are more likely allocated to suitable robots that are expected to perform better by offering more reliable bids. The motion planning module is bio-inspired intelligent, characterised by detection of imminent neighbours and design flexibility of virtual forces to enhance the responsiveness of robot motions. Firstly, while similar methods unnecessarily entail each robot to consider all the neighbours, the detection of imminent neighbours instead enables each robot to mimic creatures to identify and only consider imminent neighbours which pose collision dangers. Hence, redundant computations are reduced and undesirable robot movements eliminated. Secondly, to imitate the responsive motion behaviours of creatures, a virtual force method is adopted. It composes virtual attractive forces that drive the robots towards their targets and, simultaneously, exerts virtual repulsive forces to steer the robots away from one another. To enhance the design flexibility of the virtual forces, a twosection function and, more significantly, a spline-based method are proposed. The shapes of force curves can be flexibly designed and adjusted to generate smooth forces with desirable magnitudes. Accordingly, robot motions are streamlined and likelihood of robot collisions reduced. The graphical simulation module simulates and visualises robot team operations, and validates the proposed methodologies. It effectively emulates the operational scenarios and enables engineers to tackle downstream problems earlier in the design cycle. Furthermore, time and costs of robotic system development in the simulation module are considerably cut, compared with a physical counterpart. The performance optimisation system is indeed viable in improving the operational safety and efficiency of robot teams in dynamic environments. It has substantially pushed the frontiers of this field, and may be adapted as an intelligent control software system for practical operations of physical robot teams to benefit various applications. DOI: 10.5353/th_b4961790 Subjects: Mobile robots - Mathematical models

For several decades now, mobile robots have been integral to the development of new robotic systems for new applications, even in nontechnical areas. Mobile robots have already been developed for such uses as industrial automation, medical care, space exploration, demining operations, surveillance, entertainment, museum guides and many other industrial and non-industrial applications. In some cases these products are readily available on the market. A considerable amount of literature is also available; not all of which pertains to technical issues, as listed in the chapters of this book and its companion. Readers will enjoy this book and its companion. They will utilize the knowledge gained with satisfaction and will be assisted by its content in their interdisciplinary work for engineering developments of mobile robots, in both old and new applications. This book and its companion can be used as a graduate level course book or a guide book for the practicing engineer who is working on a specific problem which is described in one of the chapters. The companion volume for this book, Designs and Prototypes of Mobile Robots, is also available from Momentum Press.

For several decades now, mobile robots have been integral to the development of new robotic systems for new applications, even in nontechnical areas. Mobile robots have already been developed for such uses as industrial automation, medical care, space exploration, demining operations, surveillance, entertainment, museum guides and many other industrial and non-industrial applications. In some cases these products are readily available on the market. A considerable amount of literature is also available; not all of which pertains to technical issues, as listed in the chapters of this book and its companion. Readers will enjoy this book and its companion and will utilize the knowledge gained with satisfaction and will be assisted by its content in their interdisciplinary work for engineering developments of mobile robots, in both old and new applications. This book and its companion can be used as a graduate level course book or a guide book for the practicing engineer who is working on a specific problem which is described in one of the chapters. The companion volume for this book, Mobile Robots for Dynamic Environments, is also available from Momentum Press.

This book presents the recent research advances in linear and nonlinear control techniques. From both a theoretical and practical standpoint, motion planning and related control challenges are key parts of robotics. Indeed, the literature on the planning of geometric paths and the generation of time-based trajectories, while accounting for the compatibility of such paths and trajectories with the kinematic and dynamic constraints of a manipulator or a mobile vehicle, is extensive and rich in historical references. Path planning is vital and critical for many different types of robotics, including autonomous vehicles, multiple robots, and robot arms. In the case of multiple robot route planning, it is critical to produce a safe path that avoids colliding with objects or other robots. When designing a safe path for an aerial or underwater robot, the 3D environment must be considered. As the number of degrees of freedom on a robot arm increases, so does the difficulty of path planning. As a result, safe pathways for high-dimensional systems must be developed in a timely manner. Nonetheless, modern robotic applications, particularly those requiring one or more robots to operate in a dynamic environment (e.g., human–robot collaboration and physical interaction, surveillance, or exploration of unknown spaces with mobile agents, etc.), pose new and exciting challenges to researchers and practitioners. For instance, planning a robot's motion in a dynamic environment necessitates the real-time and online execution of difficult computational operations. The development of efficient solutions for such real-time computations, which could be offered by specially designed computational architectures, optimized algorithms, and other unique contributions, is thus a critical step in the advancement of present and future-oriented robotics.

A text that makes the mathematical underpinnings of robot motion accessible and relates low-level details of implementation to high-level algorithmic concepts. Robot motion planning has become a major focus of robotics. Research findings can be applied not only to robotics but to planning routes on circuit boards, directing digital actors in computer graphics, robot-assisted surgery and medicine, and in novel areas such as drug design and protein folding. This text reflects the great advances that have taken place in the last ten years, including sensor-based planning, probabalistic planning, localization and mapping, and motion planning for dynamic and nonholonomic systems. Its presentation makes the mathematical underpinnings of robot motion accessible to students of computer science and engineering, rleating low-level implementation details to high-level algorithmic concepts.

The presence of mobile robots in diverse scenarios is considerably increasing to perform a variety of tasks. Among them, many developments have occurred in the fields of ground, underwater, and flying robotics. Independent of the environment where they move, navigation is a fundamental ability of mobile robots so that they can autonomously complete high-level tasks. This problem can be efficiently addressed through the following actions: First, it is necessary to perceive the environment in which the robot has to move, and extract some relevant information (mapping problem). Second, the robot must be able to estimate its position and orientation within this environment (localization problem). With this information, a trajectory toward the target points must be planned (path planning), and the vehicle must be reactively guided along this trajectory considering either possible changes or interactions with the environment or with the user (control). Given this information, this book introduces current frameworks in these fields (mapping, localization, path planning, and control) and, in general, approaches to any problem related to the navigation of mobile robots, such as odometry, exploration, obstacle avoidance, and simulation.

Mobile robots have been increasingly applied in many different scenarios, such as space exploration and search and rescue, where the robots are required to travel over uneven terrain while outdoors. This book provides a new framework and the related algorithms for designing autonomous mobile robotic systems in such unknown outdoor environments.

For several decades now, mobile robots have been integral to the development of new robotic systems for new applications, even in non-technical areas. Mobile robots have already been developed for such uses as industrial automation, medical care, space exploration, demining operations, surveillance, entertainment, museum guides and many other industrial and non-industrial applications. In some cases these products are readily available on the market. A considerable amount of literature is also available; not all of which pertains to technical issues, as listed in the chapters of this book and its companion. Readers will enjoy this book and its companion and will utilize the knowledge gained with satisfaction and will be assisted by its content in their interdisciplinary work for engineering developments of mobile robots, in both old and new applications. This book and its companion can be used as a graduate level course book or a guide book for the practicing engineer who is working on a specific problem described in one of the chapters. The companion volume for this book, Designs and Prototypes of Mobile Robots, is available separately.