7,419 research outputs found
H∞ control for networked systems with random communication delays
Copyright [2006] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This note is concerned with a new controller design problem for networked systems with random communication delays. Two kinds of random delays are simultaneously considered: i) from the controller to the plant, and ii) from the sensor to the controller, via a limited bandwidth communication channel. The random delays are modeled as a linear function of the stochastic variable satisfying Bernoulli random binary distribution. The observer-based controller is designed to exponentially stabilize the networked system in the sense of mean square, and also achieve the prescribed H∞ disturbance attenuation level. The addressed controller design problem is transformed to an auxiliary convex optimization problem, which can be solved by a linear matrix inequality (LMI) approach. An illustrative example is provided to show the applicability of the proposed method
Safe Adaptive Control of Hyperbolic PDE-ODE Cascades
Adaptive safe control employing conventional continuous infinite-time
adaptation requires that the initial conditions be restricted to a subset of
the safe set due to parametric uncertainty, where the safe set is shrunk in
inverse proportion to the adaptation gain. The recent regulation-triggered
adaptive control approach with batch least-squares identification (BaLSI,
pronounced ``ballsy'') completes perfect parameter identification in finite
time and offers a previously unforeseen advantage in adaptive safe control,
which we elucidate in this paper. Since the true challenge of safe control is
exhibited for CBF of a high relative degree, we undertake a safe BaLSI design
in this paper for a class of systems that possess a particularly extreme
relative degree: ODE-PDE-ODE sandwich systems. Such sandwich systems arise in
various applications, including delivery UAV with a cable-suspended load.
Collision avoidance of the payload with the surrounding environment is
required. The considered class of plants is hyperbolic PDEs
sandwiched by a strict-feedback nonlinear ODE and a linear ODE, where the
unknown coefficients, whose bounds are known and arbitrary, are associated with
the PDE in-domain coupling terms that can cause instability and with the input
signal of the distal ODE. This is the first safe adaptive control design for
PDEs, where we introduce the concept of PDE CBF whose non-negativity as well as
the ODE CBF's non-negativity are ensured with a backstepping-based safety
filter. Our safe adaptive controller is explicit and operates in the entire
original safe set
Technology for large space systems: A special bibliography with indexes (supplement 03)
A bibliography containing 217 abstracts addressing the technology for large space systems is presented. State of the art and advanced concepts concerning interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, solar power satellite systems, and flight experiments are represented
Adaptive Control
Adaptive control has been a remarkable field for industrial and academic research since 1950s. Since more and more adaptive algorithms are applied in various control applications, it is becoming very important for practical implementation. As it can be confirmed from the increasing number of conferences and journals on adaptive control topics, it is certain that the adaptive control is a significant guidance for technology development.The authors the chapters in this book are professionals in their areas and their recent research results are presented in this book which will also provide new ideas for improved performance of various control application problems
Machine Learning Accelerated PDE Backstepping Observers
State estimation is important for a variety of tasks, from forecasting to
substituting for unmeasured states in feedback controllers. Performing
real-time state estimation for PDEs using provably and rapidly converging
observers, such as those based on PDE backstepping, is computationally
expensive and in many cases prohibitive. We propose a framework for
accelerating PDE observer computations using learning-based approaches that are
much faster while maintaining accuracy. In particular, we employ the
recently-developed Fourier Neural Operator (FNO) to learn the functional
mapping from the initial observer state and boundary measurements to the state
estimate. By employing backstepping observer gains for previously-designed
observers with particular convergence rate guarantees, we provide numerical
experiments that evaluate the increased computational efficiency gained with
FNO. We consider the state estimation for three benchmark PDE examples
motivated by applications: first, for a reaction-diffusion (parabolic) PDE
whose state is estimated with an exponential rate of convergence; second, for a
parabolic PDE with exact prescribed-time estimation; and, third, for a pair of
coupled first-order hyperbolic PDEs that modeling traffic flow density and
velocity. The ML-accelerated observers trained on simulation data sets for
these PDEs achieves up to three orders of magnitude improvement in
computational speed compared to classical methods. This demonstrates the
attractiveness of the ML-accelerated observers for real-time state estimation
and control.Comment: Accepted to the 61st IEEE Conference on Decision and Control (CDC),
202
Optimal boundary control of dynamics responses of piezo actuating micro-beams
AbstractOptimal control theory is formulated and applied to damp out the vibrations of micro-beams where the control action is implemented using piezoceramic actuators. The use of piezoceramic actuators such as PZT in vibration control is preferable because of their large bandwidth, their mechanical simplicity and their mechanical power to produce controlling forces. The objective function is specified as a weighted quadratic functional of the dynamic responses of the micro-beam which is to be minimized at a specified terminal time using continuous piezoelectric actuators. The expenditure of the control forces is included in the objective function as a penalty term. The optimal control law for the micro-beam is derived using a maximum principle developed by Sloss et al. [J.M. Sloss, J.C. Bruch Jr., I.S. Sadek, S. Adali, Maximum principle for optimal boundary control of vibrating structures with applications to beams, Dynamics and Control: An International Journal 8 (1998) 355–375; J.M. Sloss, I.S. Sadek, J.C. Bruch Jr., S. Adali, Optimal control of structural dynamic systems in one space dimension using a maximum principle, Journal of Vibration and Control 11 (2005) 245–261] for one-dimensional structures where the control functions appear in the boundary conditions in the form of moments. The derived maximum principle involves a Hamiltonian expressed in terms of an adjoint variable as well as admissible control functions. The state and adjoint variables are linked by terminal conditions leading to a boundary-initial-terminal value problem. The explicit solution of the problem is developed for the micro-beam using eigenfunction expansions of the state and adjoint variables. The numerical results are given to assess the effectiveness and the capabilities of piezo actuation by means of moments to damp out the vibration of the micro-beam with a minimum level of voltage applied on the piezo actuators
Delay-Adaptive Boundary Control of Coupled Hyperbolic PDE-ODE Cascade Systems
This paper presents a delay-adaptive boundary control scheme for a coupled linear hyperbolic PDE-ODE cascade system with an unknown and
arbitrarily long input delay. To construct a nominal delay-compensated control
law, assuming a known input delay, a three-step backstepping design is used.
Based on the certainty equivalence principle, the nominal control action is fed
with the estimate of the unknown delay, which is generated from a batch
least-squares identifier that is updated by an event-triggering mechanism that
evaluates the growth of the norm of the system states. As a result of the
closed-loop system, the actuator and plant states can be regulated
exponentially while avoiding Zeno occurrences. A finite-time exact
identification of the unknown delay is also achieved except for the case that
all initial states of the plant are zero. As far as we know, this is the first
delay-adaptive control result for systems governed by heterodirectional
hyperbolic PDEs. The effectiveness of the proposed design is demonstrated in
the control application of a deep-sea construction vessel with cable-payload
oscillations and subject to input delay
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