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arXiv 2021年

作者： Duclut, Charlie Paijmans, Joris Inamdar, Mandar M. Modes, Carl D. Jülicher, Frank Max Planck Institute for the Physics of Complex Systems Nöthnitzer Str. 8 Dresden01187 Germany Department of Civil Engineering Indian Institute of Technology Bombay Powai Mumbai400076 India Dresden01307 Germany Center for Systems Biology Dresden Pfotenhauerstrasse 108 Dresden01307 Germany Cluster of Excellence Physics of Life TU Dresden Dresden01307 Germany

In amorphous solids as in tissues, neighbor exchanges can relax local stresses and allow the material to flow. In this paper, we use an anisotropic vertex model to study T1 rearrangements in polygonal cellular networks. We consider two different physical realizations of the active anisotropic stresses: (i) anisotropic bond tension and (ii) anisotropic cell stress. Interestingly, the two types of active stress lead to patterns of relative orientation of T1 transitions and cell elongation that are different. Our work suggests that these two realizations of anisotropic active stresses can be observed in vivo. We describe and explain these results through the lens of a continuum description of the tissue as an anisotropic active material. We furthermore discuss the energetics of the dynamic tissue and express the energy balance in terms of internal elastic energy, mechanical work, chemical work and heat. This allows us to define active T1 transitions that can perform mechanical work while consuming chemical energy. © 2021, CC BY.

关键词： Anisotropy

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Efficiency fairness tradeoff in battery sharing

arXiv

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arXiv 2019年

作者： Chadha, Karan N. Kulkarni, Ankur A. Nair, Jayakrishnan Department of Electrical Engineering Indian Institute of Technology Bombay Mumbai400076 India Faculty at Systems and Control Engineering Indian Institute of Technology Bombay Mumbai400076 India Faculty at Department of Electrical Engineering Indian Institute of Technology Bombay Mumbai400076 India

The increasing presence of decentralized renewable generation in the power grid has motivated consumers to install batteries to save excess energy for future use. The high price of energy storage calls for a shared storage system, but careful battery management is required so that the battery is operated in a manner that is fair to all and as efficiently as possible. In this paper, we study the tradeoffs between efficiency and fairness in operating a shared battery. We develop a framework based on constrained Markov decision processes to study both regimes, namely, optimizing efficiency under a hard fairness constraint and optimizing fairness under hard efficiency constraint. Our results show that there are fundamental limits to efficiency under fairness and vice-versa, and, in general, the two cannot be achieved simultaneously. We characterize these fundamental limits via absolute bounds on these quantities, and via the notion of price of fairness that we introduce in this *** Codes 60J27, 90B22, 60F10 Copyright © 2019, The Authors. All rights reserved.

关键词： Battery management systems

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On a Game between a Delay-Constrained Communication System and a Finite State Jammer 57

On a Game between a Delay-Constrained Communication System a...

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57th IEEE Conference on Decision and control, CDC 2018

作者： Theresa Jose, Sharu Kulkarni, Ankur A. Systems and Control Engineering Indian Institute of Technology Bombay Mumbai400076 India

ISBN: (纸本)9781538613955

This paper considers a zero-sum game between a team of delay-constrained encoder and decoder, and a finite state jammer, with average probability of error as the payoff. The team attempts to communicate a discrete source using a finite blocklength over a finite family of discrete channels whose state is controlled by the jammer. For each strategy of the jammer, the team's problem has nonclassical information structure and hence is nonconvex, whereby a saddle point solution may not exist for the game. Our main contributions consist of a novel lower bound on the min-max and max-min value of the game via a linear programming (LP) relaxation and a new upper bound on the min-max value. These bounds imply that for rates of transmission R satisfying R overline{C}} where underline{C}, overline{C} are precomputable thresholds depending on the channel kernels, the min-max and max-min values of the game approach each other as the blocklength nrightarrowinfty. In the intermediate range, we give a fundamental lower bound on the limiting max-min value, which for a two-state jammer is shown to be frac{1}{2}. © 2018 IEEE.

关键词： Linear programming

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Orbital Pattern Generation for Double-integrator Agents using Consensus Strategy

Orbital Pattern Generation for Double-integrator Agents usin...

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Australasian Conference on Robotics and Automation 2019, ACRA 2019

作者： Moses, M. Jerome Sinha, Arpita Chung, Hoam IITB Monash Research Academy Powai Mumbai400 076 India Systems and Control Engineering Indian Institute of Technology Bombay Powai Mumbai400 076 India Department of Mechanical and Aerospace Engineering Monash University ClaytonVIC3800 Australia

This article studies the trochoidal pattern formation in multi-agent system. The agents are modeled using double integrator dynamics and the trajectory of the agents resembles trochoidal patterns. The trochoidal pattern formation is attained using a distributed consensus strategy and the interaction among the agents is captured using a graph topology. In this article, we consider the complex interaction represented by weighted directed graphs. We derive the necessary condition of achieving the trochoidal pattern by appropriately placing the eigenvalues of the system. Simulations are carried out to demonstrate the developed theory. © 2019 Australasian Robotics and Automation Association. All rights reserved.

关键词： Multi agent systems

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State Estimation for Non-linear Fully-implicit, Index-1 Differential Algebraic Equation systems

State Estimation for Non-linear Fully-implicit, Index-1 Diff...

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American control Conference

作者： Neeraja Srinivasan Nirav Bhatt Sridharakumar Narasimhan Systems and Control group Indian Institute of Technology Madras Chennai India Department of Biotechnology and member Robert Bosch Centre for Data Science and Artificial Intelligence and Initiative for Biological Systems Engineering Indian Institute of Technology Madras Chennai India Department of Chemical Engineering and member of the Robert Bosch Centre for Data Science and Artificial Intelligence Indian Institute of Technology Madras Chennai India

ISBN: (数字)9781538682661

ISBN: (纸本)9781538682678

The Kalman filter and its variants have been developed for state estimation in semi-explicit, index-1 DAE systems in current literature. In this work, we develop a method for state estimation in non-linear fully-implicit, index-1 differential algebraic equation (DAEs) systems. In order to extend the Kalman filtering techniques for fully-implicit index-1 DAE systems, in the correction step we convert the fully-implicit DAE into a system of ordinary differential equations (ODEs). This is achieved by the index reduction of DAE using the method of successive differentiation of algebraic equations. This is a challenging problem as the fully-implicit DAE system does not contain explicit algebraic states unlike in the semi-explicit case. In this work, we propose a linear transformation of the mass matrix which enables us to find candidate algebraic states for the system. This transformation on the mass matrix is relatively simpler than constructing the transformation matrices in the Weierstrass-Kronecker canonical form. We illustrate our proposed method with two examples, a linear and a non-linear fully-implicit index-1 DAE system.

关键词： Mathematical model Kalman filters Indexes Differential equations State estimation Computational modeling

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Variational collision and obstacle avoidance of multi-agent systems on Riemannian manifolds

Variational collision and obstacle avoidance of multi-agent ...

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European control Conference (ECC)

作者： Rama Seshan Chandrasekaran Leonardo J. Colombo Margarida Camarinha Ravi Banavar Anthony Bloch Indian Institute of Technology Madras Chennai India Instituto de Ciencias Matemáticas (ICMAT) Madrid Spain CMUC University of Coimbra Coimbra Portugal Systems and Control Enginerring Indian Institute of Technology Bombay Mumbai Maharashtra India Department of Mathematics University of Michigan Michigan USA

ISBN: (数字)9783907144022

ISBN: (纸本)9781728188133

In this paper we study a path planning problem from a variational approach to collision and obstacle avoidance for multi-agent systems evolving on a Riemannian manifold. The problem consists of finding non-intersecting trajectories between the agent and prescribed obstacles on the workspace, among a set of admissible curves, to reach a specified configuration, based on minimizing an energy functional that depends on the velocity, covariant acceleration and an artificial potential function used to prevent collision with the obstacles and among the agents. We apply the results to examples of a planar rigid body, and collision and obstacle avoidance for agents evolving on a sphere.

关键词： Manifolds Trajectory Collision avoidance Boundary conditions Acceleration Measurement Tensile stress

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A Systematic Modelling Framework for Commercial Unmanned Hexacopter Considering Fractional Order System Theory

A Systematic Modelling Framework for Commercial Unmanned Hex...

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International Conference on Unmanned Aircraft systems (ICUAS)

作者： Nithya Sridhar N. Sai Abhinay B. Chaithanya Krishna Kaushik Das Arnab Maity Embedded Systems and Robotics Research Group of Tata Consultancy Services Bangalore India Arnab Maity is with the Faculty of Department of Aerospace Engineering Indian Institute of Technology Bombay Mumbai India

ISBN: (数字)9781728142784

ISBN: (纸本)9781728142791

This research work proposes a systematic methodology to model Commercial-Off-The-Shelf Unmanned Aerial Vehicle (UAVs) that belong to the class of multicopters. The modelling framework consists of meticulous analysis of frequency domain and time domain data acquired from the hexacopter. The aim of this work is to model a commercially available UAV to enable the development of an efficient outer loop controller, specific to the intended application. This framework makes use of sine and step response data of the hexacopter's velocities in all the three planar axes corresponding to the global frame of reference. The framework considers the fractional-order model as a potential candidate for the UAV. Hence, it consists of a systematic method to determine the order of the model in integers or fractions, and its parameters. In the modelling process, control theory and fractional order theory have been sufficiently used to best correlate theoretical proposition with experimental outcomes. Also, real world factors and system constraints have been explicated and considered appropriately. The model obtained using the proposed framework has an average error of less than 5% when compared to the real system's response. Additionally, the ill effect of considering a near integer order model for a fractional order system is demonstrated to show the importance of this modelling framework. Further, a linear controller is implemented for the system using the estimated model, and corroborated with real world results.

关键词： Data models Mathematical model Unmanned aerial vehicles Analytical models Frequency-domain analysis Time-domain analysis control theory

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Consensus based Nonlinear Guidance for Cooperative Salvo

Consensus based Nonlinear Guidance for Cooperative Salvo

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control Conference (ICC), 2019 Sixth indian

作者： Abhinav Sinha Shashi Ranjan Kumar Dwaipayan Mukherjee Intelligent Systems & Control Lab Indian Institute of Technology Bombay Mumbai India

ISBN: (数字)9781728138602

ISBN: (纸本)9781728138619

This work focuses on devising cooperative salvo guidance strategies to intercept both moving and stationary targets. Salvo attack aids in overcoming the disadvantages associated with one-to-one engagement, such as countering close-in-weapon systems. The proposed cooperative guidance strategy considers a nonlinear engagement dynamics as well as a time-to-go estimate that accounts for large heading errors, thereby circumventing the problems associated with linearized engagement dynamics. The cooperation among interceptors stems from their interactions over different topologies, leading to consensus in their time-to-go estimates, which ensures salvo attack. Simulations demonstrate the efficacy of the proposed guidance strategies for the various initial engagement conditions.

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Position control of Solar Powered Aerostat for Reliable Power Generation in the Presence of Clouds

Position Control of Solar Powered Aerostat for Reliable Powe...

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International Conference on Nascent Technologies in the engineering Field (ICNTE)

作者： Sowmya Gupta Mira Mitra Leena Vachhani Siddhartha P. Duttagupta Centre for Research in Nanotechnology & Science Indian Institute of Technology Bombay Powai Mumbai India Indian Institute of Technology Kharagpur Kharagpur West Bengal India Systems and Control Engineering Indian Institute of Technology Bombay Powai Mumbai India Indian Institute of Technology Bombay Powai Mumbai India

This paper presents single tethered and bi-tethered position control of a solar-powered aerostat. The objective is to station the aerostat at a desired position anywhere into and on a hemisphere of an allocated radius with constraints applied on tether lengths and controller gains. Optimization is performed to find an optimal set of PID controller gains in order to minimize the total error over the entire trajectory. Two schemes for integral error calculation are proposed in this work. The first scheme implements historical values of the error resulting in adding an unnecessary bias to the output. This is overcome by the use of an error history over a finite horizon when calculating the integral error. Improved performance of the controller with faster convergence for position tracking is achieved by the implementation of the second scheme. In the first scheme, a settling time of approximately 72 s is achieved which is improved to approximately 40 s with the implementation of the second scheme. The conditions for position change of the aerostat are discussed. The results depict a three- dimensional space trajectory of the solar-powered aerostat being relocated to a cloudless new position for reliable solar power generation.

关键词： Winches Payloads Optimization Solar power generation Reliability Aerospace electronics

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Optical Fiber Sensors for Rapid Screening of COVID-19

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Transactions of the indian National Academy of engineering : an international journal of engineering and technology 2020年第2期5卷 233-236页

作者： Pooja Nag Kapil Sadani Soumyo Mukherji Department of Biosciences and Bioengineering Indian Institute of Technology Bombay Mumbai 400076 India. Department of Mechatronics Engineering Manipal Institute of Technology Manipal Academy of Higher Education Manipal 576104 India. Department of Instrumentation and Control Manipal Institute of Technology Manipal Academy of Higher Education Manipal 576104 India.

Rapid diagnosis of coronavirus disease COVID-19 is challenging in developing countries due to diverse clinical presentations and limited healthcare infrastructure. Biosensors hold immense prospects for diagnosis of the disease. Two approaches are proposed: the first involves measurement of host immune response and second, the detection of viruses or viral cell surface proteins using suitable bioreceptors. The article provides an overview of evanescent wave absorbance and localized surface plasmon resonance-based optic fiber platform for potential screening of COVID-19.

关键词： COVID-19 Evanescent wave absorbance Localized surface plasmon resonance Optical fiber sensor SARS-CoV-2

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