The cable-driven mechanism is usually used in robotic systems for the efficient transmission of forces or torques from actuators to the end-effector. However, the control design is challenging for these systems due to...
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A Norm-Optimal Iterative Learning control (NOILC) solution is developed for the problem when tracking is only required at a subset of isolated time points along the trial duration. Well-defined convergence properties ...
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A significant difficulty associated with achieving high scan speeds in scanning probe microscopes is that the probe is required to scan the sample in a zig-zag (raster) pattern. The fast axis of the scanner is require...
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A significant difficulty associated with achieving high scan speeds in scanning probe microscopes is that the probe is required to scan the sample in a zig-zag (raster) pattern. The fast axis of the scanner is required to track a non-smooth signal that contains frequency components beyond its mechanical bandwidth. Therefore, fast raster scans lead to distortions in the obtained image. This paper proposes analysis and design methods for a nonlinear but smooth scan pattern, known as Lissajous pattern, which enables us to achieve high-quality images at very high scan speeds where raster scanning typically leads to significant image distortions. Criteria are also proposed and formulated for constructing Lissajous trajectory and calculating the parameters and resolution. Together with the implementation of an internal model controller for high precision tracking, the proposed method is successfully employed to scan images in high speeds using a low resonance frequency SPM platform of only 825 Hz.
We propose a distributed learning algorithm for fair scheduling in common-pool games. Common-pool games are strategic-form games where multiple agents compete over utilizing a limited common resource. A characteristic...
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We propose a distributed learning algorithm for fair scheduling in common-pool games. Common-pool games are strategic-form games where multiple agents compete over utilizing a limited common resource. A characteristic example is the medium access control problem in wireless communications, where multiple users need to decide how to share a single communication channel so that there are no collisions (situations where two or more users use the medium at the same time slot). We introduce a (payoff-based) learning algorithm, namely aspiration learning, according to which agents learn how to play the game based only on their own prior experience, i.e., their previous actions and received rewards. Decisions are also subject to a small probability of mistakes (or mutations). We show that when all agents apply aspiration learning, then as time increases and the probability of mutations goes to zero, the expected percentage of time that agents utilize the common resource is equally divided among agents, i.e., fairness is established. When the step size of the aspiration learning recursion is also approaching zero, then the expected frequency of collisions approaches zero as time increases.
This paper proposes an event-based scheme to control a networked control system and to manage the radio-modes of its smart sensor node. The smart node is battery driven and is in charge of sensing the system and compu...
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ISBN:
(纸本)9781467320658
This paper proposes an event-based scheme to control a networked control system and to manage the radio-modes of its smart sensor node. The smart node is battery driven and is in charge of sensing the system and computing the control law which is sent to the receiver using a wireless channel. To save energy and to limit the amount of communication with the receiver, the smart node combines two techniques: event-based control and radio-mode management. The control law and radio-mode switching policy are derived jointly in a predictive finite receding horizon optimization problem. We derive a Model Predictive controller using Dynamic Programming and we prove the stability of the obtained control law using the Input-to-State Stability framework. The main contribution of this paper is to take into account several low consuming radio-modes, e.g. Idle and Sleep and the energy-transition costs between modes. Most of the existing literature only considers one mode when the radio is not transmitting, i.e., the scheduling problem. As illustrated via simulations, our proposal has the potential of significant energy savings.
In this article, synchronization of FitzHugh-Nagumo (FHN) neurons is considered. Adaptive controller based on active compensation is adopted to drive the slave neuron to track the master neuron. Sufficient condition f...
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In this article, synchronization of FitzHugh-Nagumo (FHN) neurons is considered. Adaptive controller based on active compensation is adopted to drive the slave neuron to track the master neuron. Sufficient condition for asymptotic stability of the close-loop system is derived. Numerical simulation results are given to confirm the adaptive controller is valid.
This paper examines the problem of estimating the parameters describing system models of quite general nonlinear and multi-variable form. The approach is a computational one in which quantities that are intractable to...
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This paper examines the problem of estimating the parameters describing system models of quite general nonlinear and multi-variable form. The approach is a computational one in which quantities that are intractable to evaluate exactly are approximated by sample averages from randomized algorithms. The main contribution is to illustrate the viability and utility of this approach by examining how high computational loads can be simply managed using commodity hardware. The proposed algorithms and solution architectures are profiled on concrete examples.
This paper considers a Bayesian approach to linear system identification. One motivation is the advantage of the minimum mean square error of the associated conditional mean estimate. A further motivation is the error...
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This paper considers a Bayesian approach to linear system identification. One motivation is the advantage of the minimum mean square error of the associated conditional mean estimate. A further motivation is the error quantifications afforded by the posterior density which are not reliant on asymptotic in data length derivations. To compute these posterior quantities, this paper derives and illustrates a Gibbs sampling approach, which is a randomized algorithm in the family of Markov chain Monte Carlo methods. We provide details on a numerically robust implementation of the Gibbs sampler. In a numerical example, the proposed method is illustrated to give good convergence properties without requiring any user tuning.
In this paper we propose a decentralized nonlinear controller that has the ability to enhance the transient stability and achieve voltage regulation simultaneously for multimachine power systems. This paper extends th...
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ISBN:
(纸本)9781467315906
In this paper we propose a decentralized nonlinear controller that has the ability to enhance the transient stability and achieve voltage regulation simultaneously for multimachine power systems. This paper extends the existing work on the construction of TS fuzzy model using linearly independent functions from nonlinear systems. This approach is based on Takagi-Sugeno (T-S) fuzzy controller via parallel distributed compensation (PDC) method. The stability analysis and control design problems can be reduced to linear matrix inequality (LMI) problems. Based on only local measurements, the designed fuzzy state feedback controller guarantees stability and satisfies desired transient responses. The proposed controller is applied to two-generator infinite bus power system. Simulation results illustrate the performance of the developed approach regardless of the system operating conditions.
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