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American Control Conference (ACC)

作者： Anna Clarke Per Olof Gutman Technion Autonomous Systems Program (TASP) Technion - Israel Institute of Technology Haifa Israel Faculty of Civil and Environmental Engineering Technion - Israel Institute of Technology Haifa Israel

The Unscented Transform which is the basis of the Unscented Kalman Filter, UKF, is used here to develop a novel predictive controller for non-linear plants, called the Unscented Transform Controller, UTC. The UTC can be seen as the dual of the UKF, the same way as the LQG regulator and the Kalman Filter are related. The UTC is demonstrated on the control of complex maneuvers in free fall of a virtual skydiver the model of which was verified in wind tunnel and free fall experiments.

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Analytical Control Parameters of the Swing Leg Retraction Method using an Instantaneous SLIP Model

Analytical Control Parameters of the Swing Leg Retraction Me...

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IEEE/RSJ International Conference on Intelligent Robots and systems

作者： Natan Shemer Amir Degani Autonomous System Program Technion Haifa 32000 Israel Faculty of Civil and Environmental Engineering Technion Haifa 32000 Israel

ISBN: (纸本)9781479969357

The Spring-Loaded Inverted Pendulum (SLIP) is a widely used model for the description of humans and animals running motion. The SLIP model is, however, sensitive to impact angle for various terrain heights. One known method for increasing the model's robustness to terrain changes is the Swing Leg Retraction (SLR) method. Despite its popularity, an analytic formulation of this method has yet been provided. In this work, using an instantaneous stance phase assumption, we present the increase in robustness of the swing method. This analysis provides a way to isolate the optimal parameters of the SLR. We validate these optimal parameters in simulations and proof-of-concept experiments in a planar environment.

关键词： optimal parameter control parameter wobbling model description analytical control Impact angle Leg

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A Dynamic Model of a Skydiver With Validation in Wind Tunnel and Free Fall

arXiv

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arXiv 2022年

作者： Clarke, Anna Gutman, Per-Olof Technion Autonomous Systems Program Technion - Israel Institute of Technology Haifa32000 Israel Faculty of Civil and Environmental Engineering Technion - Israel Institute of Technology Haifa32000 Israel

An innovative approach of gaining insight into motor skills involved in human body flight is proposed. The key idea is the creation of a model autonomous system capable of virtually performing skydiving maneuvers. A dynamic skydiver model and simulator is developed, comprising biomechanical, aerodynamic, and kinematic models, dynamic equations of motion, and a virtual reality environment. Limb relative orientations, and resulting inertial body angular position and velocity are measured in skydiving experiments in a vertical wind tunnel and in free fall. These experimental data are compared with corresponding simulation data to tune and verify the model for basic skydiving maneuvers. The model is further extended to reconstruct advanced aerial maneuvers, such as transitions between stable equilibria. The experimental data are used to estimate skydiver’s conscious inputs as a function of time, via an Unscented Kalman Filter modified for this purpose. © 2022, CC BY.

关键词： Biomechanics

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An Automatic Control System with Human-in-the-Loop for Training Skydiving Maneuvers: Proof-of-Concept Experiment

arXiv

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arXiv 2022年

A real-time motion training system for skydiving is proposed. Aerial maneuvers are performed by changing the body posture and thus deflecting the surrounding airflow. The natural learning process is extremely slow due to unfamiliar free-fall dynamics, stress induced blocking of kinesthetic feedback, and complexity of the required movements. The key idea is to augment the learner with an automatic control system that would be able to perform the trained activity if it had direct access to the learner’s body as an actuator. The aiding system will supply the following visual cues to the learner: 1. Feedback of the current body posture;2. The body posture that would bring the body to perform the desired maneuver;3. Prediction of the future inertial position and orientation if the body retains its present posture. The system will enable novices to maintain stability in free-fall and perceive the unfamiliar environmental dynamics, thus accelerating the initial stages of skill acquisition. This paper presents results of a Proof-of-Concept experiment, whereby humans controlled a virtual skydiver free-falling in a computer simulation, by the means of their bodies. This task was impossible without the aiding system, enabling all participants to complete the task at the first attempt. © 2022, CC BY.

关键词： Learning systems

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Minimum Time Optimal Control of Second Order System With Quadratic Drag and State Constraints

Minimum Time Optimal Control of Second Order System With Qua...

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IEEE Annual Conference on Decision and Control

作者： Ayal Taitler Ilya Ioslovich Erez Karpas Per-Olof Gutman Technion Autonomous Systems Program Technion Israel Institute of Technology Haifa Israel Faculty of Civil and Environmental Engineering Technion Israel Institute of Technology Haifa Israel Faculty of Industrial Engineering and Management Technion Israel Institute of Technology Haifa Israel

ISBN: (数字)9781728113982

ISBN: (纸本)9781728113999

The problem of mixed discrete-continuous task planning for mechanical systems, such as aerial drones or other autonomous units, can often be treated as a sequence of point-to-point trajectories. The minimum time optimal solution between points in the plan is critical not only for the calculation of the trajectory in cases where the goal has to be achieved quickly but also for the feasibility checking of the plan and the planning process itself, especially in the presence of deadlines and temporal constraint. In this work, we address the minimum time problem for a second-order system with quadratic drag, under state (velocity) and control (acceleration) constraints. Closed-form expressions for the trajectory are derived and the optimality is proven using the Pontryagin Maximum Principle. Simulations supporting the results are provided and compared with those of an open source academic optimal control solver.

关键词： Trajectory Optimal control Acceleration Planning Optimization System dynamics Riccati equations

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Analytic modeling and experiments of tri-layer, electro-thermal actuators for thin and soft robotics

Analytic modeling and experiments of tri-layer, electro-ther...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Gal Tibi Ela Sachyani Michael Layani Shlomo Magdassi Amir Degani Technion's Autonomous Systems Program Technion - Israel Institute of Technology Haifa Israel Casali Center Hebrew University of Jerusalem Jerusalem Israel Civil and Environmental Engineering Department Israel Institute of Technology Haifa Israel

By bonding micron-thin polymer layers with an electrically conductive layer, we can utilize the bi-metal effect to create a soft, thin, electrically-activated thermal actuator (ETA), which can be used in printed soft robots. Using ETAs have shown quite remarkable potential in previous works. However, to reveal their true capabilities, we propose to utilize a multi-layered ETA. In this research, we analytically model the actuator for both the bi-, and more importantly, tri-layer ETAs and analyze their behavior. We develop a simple intuitive model to better explain the benefits of the tri-layer actuation and to estimate the optimal design parameters. We verify the models by conducting an experiment to measure the curvature change for different third layer thicknesses. The experiments show a significant improvement in performance of the tri-layer actuators and display a good fit between the simplified analytic model and the full model.

关键词： Actuators Analytical models Robot sensing systems Polymers Elasticity Springs

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ARCSnake: Reconfigurable snake-like robot with Archimedean screw propulsion for multi-domain mobility

arXiv

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arXiv 2021年

作者： Richter, Florian Gavrilov, Peter V. Lam, Hoi Man Degani, Amir Yip, Michael C. The Department of Electrical and Computer Engineering University of California San Diego San DiegoCA92093 United States The Department of Mechanical and Aerospace Engineering University of California San Diego San DiegoCA92093 United States The Faculty of Civil and Environmental Engineering The Technion Autonomous Systems Program Technion - Israel Institute of Technology Haifa3200003 Israel

Exploring and navigating in extreme environments, such as caves, oceans, and planetary bodies, are often too hazardous for humans, and as such, robots are possible surrogates. These robots are met with significant locomotion challenges that require traversing a wide range of surface roughnesses and topologies. Previous locomotion strategies, involving wheels or ambulatory motion, such as snake platforms, have success on specific surfaces but fail in others which could be detrimental in exploration and navigation missions. In this paper, we present a novel approach that combines snake-like robots with an Archimedean screw locomotion mechanism to provide multiple, effective mobility strategies in a large range of environments, including those that are difficult to traverse for wheeled and ambulatory robots. This work develops a robotic system called ARCSnake to demonstrate this locomotion principle and tested it in a variety of different terrains and environments in order to prove its controllable, multi-domain, navigation capabilities. These tests show a wide breadth of scenarios that ARCSnake can handle, hence demonstrating its ability to traverse through extreme terrains. Copyright © 2021, The Authors. All rights reserved.

关键词： Screws

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Yet Another Algorithm for the Computation of Polyhedral Positive Invariant Sets

Yet Another Algorithm for the Computation of Polyhedral Posi...

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IEEE Conference on Control Technology and Applications

作者： Daniel Y. Rubin Hoai-Nam Nguyen Per-Olof Gutman Autonomous Systems Program Israel Institute of Technology Haifa Israel Control Signal and System Department IFP Energies Nouvelles Lyon France Faculty of Civil and Environmental Engineering Israel Institute of Technology Haifa Israel

We present a new algorithm for the computation of polyhedral positive invariant sets. A set given by its half-spaces is used to yield an optimized positive invariant set w.r.t. a given autonomous system. The algorithm requires the solution of a single semi-definite program followed by a linear program. Extensions to the plant uncertain case, and to a symmetric set case are presented. Two numerical examples demonstrate the algorithm usage and capabilities.

关键词： Yet Another Algorithm Computation Polyhedral Positive Invariant Sets

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Mapping geographical inequalities in childhood diarrhoeal morbidity and mortality in low-income and middle-income countries, 2000-17: analysis for the Global Burden of Disease Study 2017 (vol 395, pg 1779, 2020)

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LANCET 2020年第10239期395卷 1762-1762页

作者： Reiner, R. C., Jr. Hay, S., I Institute for Health Metrics and Evaluation University of Washington Seattle WA United States Department of Global Health School of Medicine University of Washington Seattle WA United States Department of Health Metrics Sciences School of Medicine University of Washington Seattle WA United States College of Health and Medical Sciences Haramaya University Harar Ethiopia Department of Epidemiology and Biostatistics Haramaya University Harar Ethiopia Department of Medical Laboratory Sciences Haramaya University Harar Ethiopia School of Nursing and Midwifery Haramaya University Harar Ethiopia School of Pharmacy Haramaya University Harar Ethiopia School of Public Health Haramaya University Harar Ethiopia Haramaya University Harar Ethiopia Advanced Diagnostic and Interventional Radiology Research Center Tehran University of Medical Sciences Tehran Iran Cancer Biology Research Center Tehran University of Medical Sciences Tehran Iran Cancer Research Institute Tehran University of Medical Sciences Tehran Iran Department of Economics and Management Sciences for Health Tehran University of Medical Sciences Tehran Iran Department of Environmental Health Engineering Tehran University of Medical Sciences Tehran Iran Department of Epidemiology and Biostatistics Tehran University of Medical Sciences Tehran Iran Department of Health Management and Economics Tehran University of Medical Sciences Tehran Iran Department of Microbiology Tehran University of Medical Sciences Tehran Iran Department of Pharmacology Tehran University of Medical Sciences Tehran Iran Digestive Diseases Research Institute Tehran University of Medical Sciences Tehran Iran Endocrinology and Metabolism Research Center Tehran University of Medical Sciences Tehran Iran Hematology-Oncology and Stem Cell Transplantation Research Center Tehran University of Medical Sciences Tehran Iran Iran National Institute of Health Research Tehran University of Medical Sciences Tehran Iran Metabolomics and

Summary Background Across low-income and middle-income countries (LMICs), one in ten deaths in children younger than 5 years is attributable to diarrhoea. The substantial between-country variation in both diarrhoea incidence and mortality is attributable to interventions that protect children, prevent infection, and treat disease. Identifying subnational regions with the highest burden and mapping associated risk factors can aid in reducing preventable childhood *** We used Bayesian model-based geostatistics and a geolocated dataset comprising 15 072 746 children younger than 5 years from 466 surveys in 94 LMICs, in combination with findings of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017, to estimate posterior distributions of diarrhoea prevalence, incidence, and mortality from 2000 to 2017. From these data, we estimated the burden of diarrhoea at varying subnational levels (termed units) by spatially aggregating draws, and we investigated the drivers of subnational patterns by creating aggregated risk factor *** The greatest declines in diarrhoeal mortality were seen in south and southeast Asia and South America, where 54·0% (95% uncertainty interval [UI] 38·1-65·8), 17·4% (7·7-28·4), and 59·5% (34·2-86·9) of units, respectively, recorded decreases in deaths from diarrhoea greater than 10%. Although children in much of Africa remain at high risk of death due to diarrhoea, regions with the most deaths were outside Africa, with the highest mortality units located in Pakistan. Indonesia showed the greatest within-country geographical inequality; some regions had mortality rates nearly four times the average country rate. Reductions in mortality were correlated to improvements in water, sanitation, and hygiene (WASH) or reductions in child growth failure (CGF). Similarly, most high-risk areas had poor WASH, high CGF, or low oral rehydration therapy *** By co-analysing geospatial trends in d

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Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study (vol 2, pg 144, 2021)

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LANCET GLOBAL HEALTH 2021年第4期9卷 E408-E408页

作者： Steinmetz, Jaimie D. Vision and Eye Research Institute Anglia Ruskin University Cambridge United Kingdom Biomedical Informatics Seoul National University Hospital Seoul South Korea Institute for Health Metrics and Evaluation University of Washington Seattle WA United States Department of Health Metrics Sciences School of Medicine University of Washington Seattle WA United States Institute of Health Services Research Yonsei University Seoul South Korea Department of Ophthalmology University of Washington Seattle WA United States Department of Mathematics Imperial College London London United Kingdom WHO Collaborating Centre for Public Health Education and Training Imperial College London London United Kingdom Department of Primary Care and Public Health Imperial College London London United Kingdom School of Population and Global Health University of Melbourne Carlton VIC Australia School of Optometry and Vision Science UNSW Sydney NSW Australia Brien Holden Vision Institute Sydney Australia Department of Ophthalmology University of Adelaide Adelaide SA Australia Department of Parasitology and Mycology Jahrom University of Medical Sciences Jahrom Iran Department of Clinical Sciences University of Sharjah Sharjah United Arab Emirates Ophthalmic Research Center Shahid Beheshti University of Medical Sciences Tehran Iran Department of Ophthalmology Shahid Beheshti University of Medical Sciences Tehran Iran Research Institute for Endocrine Sciences Shahid Beheshti University of Medical Sciences Tehran Iran Ophthalmic Epidemiology Research Center Shahid Beheshti University of Medical Sciences Tehran Iran Health Services Management Department Qazvin University of Medical Sciences Qazvin Iran Department of Systems Populations and Leadership University of Michigan Ann Arbor MI United States Department of Medicine Sofia Ismail Memorial Medical Centre Bogura Bangladesh The Fred Hollows Foundation Sydney NSW Australia Berhan Public Health & Eye Care Consultancy Addis A

Hospital El Salvador: a novel paradigm of intensive care in response to COVID-19 in central America. Lancet Glob Health 2021;9: e241?42?In this Comment, the conflict of interest statement should have included the following: ?By virtue of their roles within a public hospital or the Ministry of Health, MB, LC, WH, and XS are government employees. The findings and conclusions in the Comment are only those of the authors.? This correction has been made as of Feb 26, 2021.

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