Industrial problems, like pipeline inspection and railway track geometry inspection inside tunnels, require accurate offline estimation of the state trajectories, to determine the infrastructure parameters, say pipeli...
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In this work, the notions of formation and rigidity (first developed for formation control in Euclidean spaces) are recast in a general framework of principal fiber bundles and a control law is derived for second orde...
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In this work, the notions of formation and rigidity (first developed for formation control in Euclidean spaces) are recast in a general framework of principal fiber bundles and a control law is derived for second order systems for driving the system to a given formation. The Euclidean inter-agent distance measurements and congruence transformations are generalised as output maps and Lie group actions respectively, to capture more generic scenarios.
We study the problem of policy estimation for the Linear Quadratic Regulator (LQR) in discrete-time linear timeinvariant uncertain dynamical systems. We propose a Moreau Envelope-based surrogate LQR cost, built from a...
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Feedback linearization (FL) is a powerful tool to enable control synthesis for nonlinear systems. Since FL is a local construction, an important notion is the domain of validity of the procedure, and in particular, qu...
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Feedback linearization (FL) is a powerful tool to enable control synthesis for nonlinear systems. Since FL is a local construction, an important notion is the domain of validity of the procedure, and in particular, quantitative estimates of these domain of applicability of the procedure. Such quantification is missing in the existing literature and this article fills in this niche using the mathematical tool of the implicit function theorem. The results provide lower bounds on the region in which a given discrete time system is feedback linearizable.
The classical notion of controllability provides us with a boolean variable — whether a given system is controllable or not. However, often as engineers we seek a notion of how ‘controllable’ a given system is, so ...
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The classical notion of controllability provides us with a boolean variable — whether a given system is controllable or not. However, often as engineers we seek a notion of how ‘controllable’ a given system is, so as to classify systems that are ‘easier to control’ from those which are ‘difficult to control’. In this article we derive a quantitative measure of controllability for bilinear systems defined on the Lie group of rotations SO(3). Our controllability measure is based on the worst case cost of transferring the system from a given initial condition to a given final condition arbitrarily chosen over a set of interest. Here we consider a few frequently encountered cost functions such as control energy optimization and time optimal control, and obtain a relation between the worst case cost and the system parameters.
Laser Interferometer Gravitational wave Observatory (LIGO) is a gravitational wave antenna used to detect the infinitesimal contraction and expansion of space by a passing gravitational wave. LIGO comprises several su...
Laser Interferometer Gravitational wave Observatory (LIGO) is a gravitational wave antenna used to detect the infinitesimal contraction and expansion of space by a passing gravitational wave. LIGO comprises several subsystems which isolate the optics from seismic noise. Of these, we focus on the quadruple pendulum suspension system and attempt to design a stabilizing controller for a simpler version of the system, the two wire simple pendulum. A nonlinear model of the two wire simple pendulum based on the Euler-Lagrange theory is derived. This is linearised about an equilibrium and a stabilising controller using a robust control paradigm called $H_{\infty} $ synthesis, is explored as a candidate design paradigm for the two wire simple pendulum. In particular, in this broad framework of $H_{\infty} $ synthesis we adopt a technique called coprime factorisation. Different types of uncertainties like parametric and nonlinear uncertainties have also been considered and an upper bound on the nonlinear uncertainties in the system is determined
Industrial problems, like pipeline inspection and railway track geometry inspection inside tunnels, require accurate offline estimation of the state trajectories, to determine the infrastructure parameters, say pipeli...
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ISBN:
(数字)9798331517212
ISBN:
(纸本)9798331517229
Industrial problems, like pipeline inspection and railway track geometry inspection inside tunnels, require accurate offline estimation of the state trajectories, to determine the infrastructure parameters, say pipeline GPS coordinates, rail-track's attitude and placement, etc. These problems are cursed with loss of observability due to the unavailability of localization data, like GPS, inside pipelines and tunnels. In addition, the states at the start and end of the recorded data are observable but not accurately or entirely known. Furthermore, a deviation is observed in the initial calibration of the Inertial Measurement Unit (IMU) sensors, and hence the recorded data are approximated sensor readings. Since the accuracy of these estimated outcomes impacts the maintenance cost of the infrastructure, it is essential to obtain the best possible estimate from the offline available sensor data. In this work, we propose an optimization-based solution to estimate the entire trajectory and self-calibrate the sensor readings, simultaneously. In particular, we formulate an offline state trajectory estimation problem with self-calibration features for the sensor readings, compute the gradients for the decisions, and propose a Lagrangian-based gradient descent algorithm. We compare the results with the state-of-the-art Extended Kalman Filter and show improvement in the mean square error values of the estimates.
In this article, we dwell into the class of so-called ill-posed Linear Inverse Problems (LIP) which simply refer to the task of recovering the entire signal from its relatively few random linear measurements. Such pro...
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In this article, we dwell into the class of so-called ill-posed Linear Inverse Problems (LIP) which simply refer to the task of recovering the entire signal from its relatively few random linear measurements. Such problems arise in a variety of settings with applications ranging from medical image processing, recommender systems, etc. We propose a slightly generalized version of the error constrained linear inverse problem and obtain a novel and equivalent convex-concave min-max reformulation by providing an exposition to its convex geometry. Saddle points of the min-max problem are completely characterized in terms of a solution to the LIP, and vice versa. Applying simple saddle point seeking ascend-descent type algorithms to solve the min-max problems provides novel and simple algorithms to find a solution to the LIP. Moreover, the reformulation of an LIP as the min-max problem provided in this article is crucial in developing methods to solve the dictionary learning problem with almost sure recovery constraints.
Limited bandwidth and limited saturation in actuators are practical concerns in controlsystems. Mathematically, these limitations manifest as constraints being imposed on the control actions, their rates of change, a...
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Given a compact subset of a Banach space, the Chebyshev center problem consists of finding a minimal circumscribing ball containing the set. In this article we establish a numerically tractable algorithm for solving t...
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