Browsing by Subject "robotics"
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Item Analysis of Collective Behavior in Robot Swarms(2022-08) Harwell, JohnThis thesis develops new mathematical tools to aid in the design of robot swarmsconsisting of large numbers of simple robots. It develops new ways of measuring these systems, mechanisms to understand how these “simple” systems can nonetheless act intelligently, and models for predicting their behavior under different conditions. Using this tools, future robotic systems will be are more understandable and have better guarantees of individual and collective behavior. The contributions of this thesis are fourfold. First, metrics for quantifying the observable swarm properties of self- organization, scalability, flexibility to changing external environments, and robustness to internal system stimuli, such as sensor and actuator noise and robot failures, are derived. Researcher intuitions about comparative algorithm performance are shown to be well supported by the quantitative results obtained using the derived metrics. Second, the origin of emergent intelligence in task allocating swarms is investigated. Task allocation within the context of relational task graphs with different average node centralities is used to compare an optimal (under constraints) greedy method, which disregards task dependencies, with a non-optimal dependency-aware method which emphasizes collective learning of graph structure. Results show that swarm emergent intelligence is (a) positively correlated with average node centrality and performance, and (b) arises out of learning and exploitation of graph connectivity, rather than content. Third, we determine that the underlying collective dynamics of object gathering in robot swarms can (sometimes) be captured using Poisson-based modeling even when the phenomena modeled are not Poisson distributed, thereby establishing better limits on when Poisson-based modeling can be applied to swarm behaviors. Fourth, we develop some initial properties for graphs representing 3D structures as a partial solution to the parallel bricklayer problem. With these properties, we prove the existence of an appropriate algorithm with which a swarm of N robots can provably construct a 3D structure starting from an empty state.Item Modeling the Human Visuo-Motor System for Remote-Control Operation(2018-05) Andersh, JonathanSuccessful operation of a teleoperated miniature rotorcraft relies on capabilities including guidance, trajectory following, feedback control, and environmental perception. For many operating scenarios fragile automation systems are unable to provide adequate performance. In contrast, human-in-the-loop systems demonstrate an ability to adapt to changing and complex environments, stability in control response, high level goal selection and planning, and the ability to perceive and process large amounts of information. Modeling the perceptual processes of the human operator provides the foundation necessary for a systems based approach to the design of control and display systems used by remotely operated vehicles. In this work we consider flight tasks for remotely controlled miniature rotorcraft operating in indoor environments. Operation of agile robotic systems in three dimensional spaces requires a detailed understanding of the perceptual aspects of the problem as well as knowledge of the task and models of the operator response. When modeling the human-in-the-loop the dynamics of the vehicle, environment, and human perception-action are tightly coupled in space and time. The dynamic response of the overall system emerges from the interplay of perception and action. The main questions to be answered in this work are: i) what approach does the human operator implement when generating a control and guidance response? ii) how is information about the vehicle and environment extracted by the human? iii) can the gaze patterns of the pilot be decoded to provide information for estimation and control? In relation to existing research this work differs by focusing on fast acting dynamic systems in multiple dimensions and investigating how the gaze can be exploited to provide action-relevant information. To study human-in-the-loop systems the development and integration of the experimental infrastructure is described. Utilizing the infrastructure, a theoretical framework for computational modeling of the human pilot’s perception-action is proposed and verified experimentally. The benefits of the human visuo-motor model are demonstrated through application examples where the perceptual and control functions of a teleoperation system are augmented to reduce workload and provide a more natural human-machine interface.Item Natural, Robust, and Multi-Modal Human-Robot Interaction For Underwater Robots(2023-01) Fulton, MichaelIn the mid-twentieth century, robots began to swim in the oceans, lakes, rivers, and waterways of the world. Over the seventy years that have passed since then, autonomous underwater vehicles (AUVS) have slowly been evolving, becoming smaller, more intelligent, and more capable. As they have begun to be deployed in a wider variety of locations and for increasingly complex purposes, excitement over the idea of a collaborative AUV (co-AUV) has begun to grow, with the continued development of the field. Now we stand upon the cusp of a revolution in the world of underwater work. Thousands of divers the world over could be aided in their work by a co-AUV in the coming years, helping humans to better understand and protect the critical water resources of our planet. However, for this dream to come to fruition, these co-AUVs must be capable of natural, robust communication, rich and accurate perception of their human partners and adaptive operation in an ever-changing environment. Though researchers have been making steps toward this goal, this thesis marks a new stage in the development of the co-AUV. In the following chapters, we present three novel methods of communication, two state-of-the-art perception capabilities, a new capability for diver approach, a new methodology for gestural AUV control, a modular software ecosystem for UHRI, and an adaptive communication controller. Additionally, seven human studies evaluating these systems are presented, five of which were conducted in underwater environments with an unprecedented number of participants. The communication methods presented in Part I are a new direction for the field, emphasizing non-text communication which is easily perceived at a distance, natural and intuitive design over information complexity, and introducing new vectors of communication using motion and sound that have not been previously studied underwater. The perception methods of Part II are more traditional, but push the boundaries of previously developed capabilities in numerous ways: developing a new capability in terms of diver motion prediction, creating a method for estimating the relative distance to a diver using only monocular vision, and creating reconfigurable and dynamic gestural control in a way that has not previously been attempted for AUVs. The capstone of the thesis in Part III is the PROTEUS underwater HRI software system, which could serve as a foundation for a great deal of future research, as well as the first adaptive communication system for AUVs, ACVS. ACVS uses the perception capabilities presented in Part II to determine which of the communication vectors introduced in Part I should be utilized given the context of an interaction, with all of the components implemented within the PROTEUS framework. The research contained in this thesis is highly multidisciplinary, encompassing interaction design, software development, hardware fabrication, the design and administration of human studies, quantitative and qualitative analysis of study results, deep learning system design, training and deployment of neural networks, robot design, and general robotics development. The results of these investigations into UHRI reveal an exciting potential for the field. Nearly every method presented in this thesis has achieved sufficient success in testing to indicate that it could be effectively applied in field environments, especially given some further development. The dream of co-AUVs helping divers in their work is already beginning to come to life, and the algorithms and systems presented in this document have brought us ever closer to that goal. The work that is done by divers is critical for human society and the health of our planet's ecosystems and the aid that collaborative AUVs could render in these environments is invaluable, greatly increasing diver safety and task success rates. This thesis provides novel communication methods, a new state of the art in diver perception, an adaptive communication system, and a software architecture that ties them all together, improving the flexibility and robustness of underwater human-robot interaction and providing a basis for further development along these exciting avenues.Item Oral History Interview with Allen R. Hanson(Charles Babbage Institute, 2022-02) Hanson, AllenThis interview was conducted by CBI for CS&E in conjunction with the 50th Anniversary of the University of Minnesota Computer Science Department (now Computer Science and Engineering, CS&E). Professor Hanson briefly discusses his early education and interests through his graduate education completing his doctorate at Cornell (dissertation was on games and prediction problems). Most of the interview focuses on his career and he was one of the early faculty members of the newly formed Computer Science Department at the University of Minnesota. He discusses the early department, interaction, and teaching, and research. His research focused heavily on vision and computing, pattern recognition, and AI. He partnered on early research with University of Massachusetts Amherst’s Ed Riseman and later left University of Minnesota to join the CS faculty of UMass and lead the lab in this collaboration. Among other topics, he outlines his evolving research, applications in medicine, autonomous vehicles and other areas, as well as reflects on a range of issues on research funding, and computing and society. Finally, he briefly discusses Applied Imaging, Dataviews and concurrent enterprises he led/helped to lead.Item Robot-Aided Assessment of Ankle Motion Sense and Associated Lesion-Symptom Mapping Analysis in Chronic Stroke(2023-06) Huang, QiyinBackground: Compromised ankle proprioception is a strong predictor of balance dysfunction in chronic stroke. However, objective, accurate methods for testing ankle proprioceptive function in clinical settings are not established. Only sparse data on ankle position sense and no systematic data on ankle motion sense dysfunction in stroke are available. Moreover, the lesion sites underlying impaired ankle proprioception have not been comprehensively delineated.Objectives: To address these knowledge gaps, this study aimed: 1) To examine the feasibility and test-retest reliability of a newly developed robotic technology that uses an adaptive psychophysical forced-choice method to obtain quantitative data on ankle position and motion sense acuity in healthy young adults. 2) To determine the extent and magnitude of ankle motion sense impairment observed in adults with chronic stroke and how such impairment coincides with position sense dysfunction using the robotic system. 3) To identify the brain lesions associated with ankle position and motion sense dysfunction. Methods: To verify aim 1, experiments 1 and 2 were conducted successively. Forty healthy adults (20 in each experiment, mean ± SD age 24 ± 3.9 years, F: 17) were recruited. The feasibility and test-retest reliability of the system were determined in Experiment 1. Experiment 2 was conducted to improve the motion sense test paradigm that controlled for confounding factors (time and position) that a person might use as motion cues to make a perceptual judgment of ankle joint motion. To verify aim 2 and 3, twelve stroke survivors (mean ± SD age, 54 ± 10.9 years, on average 6 years post-stroke, 10 ischemic, 2 hemorrhagic lesions), and 13 neurotypical adults participated. During the testing, the robot passively plantarflexed a participant’s ankle to two distinct positions or at two distinct velocities. Participants subsequently indicated which of the two movements was further/faster. Based on the stimulus-response data, a psychometric function was obtained, and just-noticeable-difference (JND) thresholds, as a measure of bias, and intervals of uncertainty (IU), as a measure of precision were derived. For adults with stroke (n = 11), lesion-symptom analyses identified the brain lesions associated with observed proprioceptive deficits in adults with stroke. Results: For aim 1, objective data on position sense acuity (JND threshold: 0.80° ± 0.10°, IU: 0.84° ± 0.41°) and motion sense acuity (JND threshold: 0.73°/s ± 0.11°/s, IU: 0.60°/s ± 0.29°/s) were obtained in experiment 1. Additionally, moderate-to-excellent test-retest reliability of the system has been established based on the JND threshold for position sense (average intraclass correlation coefficient (ICC) = 0.86 [0.50 - 0.98], standard error of measurement (SEM) = 0.0173°) and motion sense (average ICC = 0.88, SEM = 0.0197°/s). In experiment 2, the results showed that the mean JND motion sense threshold increased almost linearly from 0.53°/s at the 10°/s reference to 1.6°/s at 20°/s (p < 0.0001). Perceptual uncertainty increased similarly (median IU = 0.33°/s at 10°/s and 0.97°/s at 20°/s; p < 0.0001). Both measures were strongly correlated (rs = 0.70). For aim 2, 83% of adults with stroke exhibited abnormalities in either position or motion sense, or both. JND and IU measures were significantly elevated compared to the control group (JNDPosition: +77%, p = 0.03; JNDMotion: +153%, IUPosition: +148%, and IUMotion: +78%, all p < 0.01). The JND and IU values of both senses were strongly positively correlated (rs = 0.56-0.62). For aim 3, lesions in the primary somatosensory, posterior parietal, motor cortices, insula, and temporoparietal regions (supramarginal, superior temporal, Heschl's gyri) were associated with deficits in both senses. Meanwhile, lesions in the medial/lateral occipital cortex were linked to impaired position sense, and temporal pole lesions were associated with impaired motion sense. Moreover, temporal pole lesions were significantly related to motion sense deficit (z-score = 3.26). Conclusion: This research demonstrated that the proposed robot-aided test produces quantitative data on human ankle position and motion sense acuity. It yields two distinct measures of proprioceptive acuity (i.e., bias and precision) as part of a comprehensive analysis of proprioceptive function. Using the robot-aided assessment, this study documented the initial data on the magnitude and prevalence of ankle position and motion sense impairment in adults with chronic stroke. Proprioceptive dysfunction was characterized by elevated JND thresholds and increased uncertainty in perceiving ankle position/motion. Associated cortical lesions for both proprioceptive senses were largely overlapping, but temporal pole lesions were independently linked to motion sense dysfunction.Item Robotic Roadway Message and Symbol Painter Implementation(Minnesota Department of Transportation, 2016-09) Rosandich, Ryan GThe goals of this project were to develop a large-scale vehicle-mounted robotic roadway message painter that could be run by a single operator, and to develop software to enable the device to automatically paint various messages and symbols on roadways. A completely new articulated robot arm was design and constructed, complete with a control system, operator interface, paint delivery system, truck mount, and mobile power supply. The system was thoroughly tested, and programs were written to allow the robot to paint several symbols and messages on a roadway. The programs were tested and fine-tuned indoors, and then tested outdoors once the robot was mounted on a truck. An important finding of this research is that the traditional markings used by MnDOT are not ideal for robot application. Robotic painting can be better accommodated by altering the outlines of the markings somewhat, and by using directional hash lines to fill in the symbols rather than solid paint. These machine-made markings are faster to apply and use less paint, and in the end may be more effective for motorists than the traditional markings. The robotic roadway painter developed during this project has the potential to completely change the way in which markings are painted on roadways. The device has demonstrated the ability to paint roadway markings using an articulated robot arm mounted on the front of a vehicle. Expected benefits of the deployment of such a device include improved operator safety, improved productivity, and improved flexibility in roadway marking operations.Item Simulation and Control of Nonholonomic Differential Drive Mobile Platforms(2017-12) Norr, ScottAbstract This thesis explores the application of non-linear control techniques to an inexpensive robot with limited computing ability. A basis for the kinematic description of the Differential Drive Mobile Robot (DDMR) is presented. The dynamics of wheeled robots are developed. The state space of DDMR platforms is found to be non-linear. A control law, based on a paper by Kanayama, is developed and determined to be bounded by a Lyapunov function and asymptotically stable. Using MATLAB, the entire closed-loop system is modeled with difference equations. Methods for tuning the control gains are explored. A modest prototype robot is constructed using a modest 8-bit processor. Reasonable correlation between the physical robot and the simulated robot is observed. Constraints do not hinder the robot’s ability to successfully implement a non-linear control scheme. The MATLAB simulation and physical robot correlate well. The control law is shown to be practical for inexpensive robotic platforms.Item Supporting data for "Shaping contactless radiation forces through anomalous acoustic scattering"(2022-09-15) Stein, Matthew; Keller, Sam; Luo, Yujie; Ilic, Ognjen; ilic@umn.edu; Ilic, Ognjen; University of Minnesota Ilic Research GroupWaves impart momentum and exert force on obstacles in their path. The transfer of wave momentum is a fundamental mechanism for contactless manipulation, yet the rules of conventional scattering intrinsically limit the radiation force based on the shape and the size of the manipulated object. Here, we show that this intrinsic limit can be broken for acoustic waves with subwavelength-structured surfaces (metasurfaces), where the force becomes controllable by the arrangement of surface features, independent of the object’s overall shape and size. Harnessing such anomalous metasurface scattering, we demonstrate complex actuation phenomena: self-guidance, where a metasurface object is autonomously guided by an acoustic wave, and tractor beaming, where a metasurface object is pulled by the wave. Our results show that bringing metasurface physics of acoustic waves, and its full arsenal of tools, to the domain of mechanical manipulation opens new frontiers in contactless actuation and enables diverse actuation mechanisms that are beyond the limits of traditional wave-matter interactions.Item The Topological Complexity of Spaces of Digital Images(2019-06) Kandola, Shelley BurrowsThe motivation of this dissertation is to study image processing algorithms through a topological lens. The images we focus on here are those that have been segmented by digital Jordan curves as a means of image compression. The algorithms of interest are those that continuously morph one digital image into another digital image. Digital Jordan curves have been studied in a variety of forms for decades now. Our contribution to this field is interpreting the set of digital Jordan curves that can exist within a given digital plane as a finite topological space. Computing the topological complexity of this space determines the minimal number of continuous motion planning rules required to transform one image into another, and determining the motion planners associated to topological complexity provides the specific algorithms for doing so. In Chapter 2, we develop tools for computing the topological complexity of finite spaces, with an emphasis on spheres, joins, and wedge sums. The main result of Chapter 4 is that our space of digital Jordan curves is connected, hence, its topological complexity is finite. To build up to that, we use Chapter 3 to prove some results about paths and distance functions that are obvious in Hausdorff spaces, yet surprisingly elusive in $T_0$ spaces. We end with Chapter 5, in which we study applications of these results. In particular, we prove that our interpretation of the space of digital Jordan curves is the only topologically correct interpretation.