Imperfect models lead to imperfect controllers and deriving accurate models from first principles or system identification is especially challenging in networked systems. Instead, data can be used to directly compute ...
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Imperfect models lead to imperfect controllers and deriving accurate models from first principles or system identification is especially challenging in networked systems. Instead, data can be used to directly compute controllers, without requiring any system identification or modeling. In this paper we propose a strategy to directly learn control actions when data from past system trajectories is distributed among multiple agents in a network. The approach we develop provably converges to a suboptimal solution in a finite number of steps, bounded by the diameter of the network, and with a sub-optimality gap that can be characterized as a function of data, and that can be made arbitrarily small. We further characterize the robustness properties of our approach and give provable guarantees on its performance when data are affected by noise or by a class of attacks.
The increasing penetration of renewable and distributed energy resources in distribution networks calls for real-time and distributed voltage control. In this article, we investigate local Volt/VAR control with a gene...
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The increasing penetration of renewable and distributed energy resources in distribution networks calls for real-time and distributed voltage control. In this article, we investigate local Volt/VAR control with a general class of control functions, and show that the power system dynamics with nonincremental local voltage control can be seen as a distributed algorithm for solving a well-defined optimization problem (reverse engineering). The reverse engineering further reveals a fundamental limitation of the nonincremental voltage control: the convergence condition is restrictive and prevents better voltage regulation at equilibrium. This motivates us to design two incremental local voltage control schemes based on the subgradient and pseudo-gradient algorithms, respectively, for solving the same optimization problem (forward engineering). The new control schemes decouple the dynamical property from the equilibrium property, and have much less restrictive convergence conditions. This article presents another step toward developing a new foundation-network dynamics as optimization algorithms-for distributed real-time control and optimization of future power networks.
The utilization of distributed control and optimization is still a challenge issue to achieve reliable communication for resource-constrained networked systems. In this paper, a distributed cooperative communication n...
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The utilization of distributed control and optimization is still a challenge issue to achieve reliable communication for resource-constrained networked systems. In this paper, a distributed cooperative communication nodes control (DCCNC) approach is proposed to achieve higher reliability communication and longer network lifetime for resource-constrained wireless sensor network (WSNs). A DCCNC scheme adopts feedback control approach to determine the appropriate number of node which participates in cooperative communication according to the application reliability requirements. A residue energy notification mechanism is used to notice the minimum residual energy of nodes in a network, then the number of cooperative communication nodes is adjusted according to the difference between the residual energy of nodes and the minimum residual energy of network. In a DCCNC scheme, larger number of participate cooperative communication nodes are adopted in non-hotspots area to achieve high reliability, while less number of participate cooperative communication nodes are adopted in hotspots area to achieve high network lifetime. The theoretical analysis and experimental results show that comparing with previous communications schemes, DCCNC scheme can reduce end to end Data Fail delivering Ratio (DFR) by 57.16-93.29% while retaining network lifetime, and DCCNC approach can also improves lifetime by 3.89-18.75% while retaining weighted end to end (DFR). (C) 2017 Elsevier B.V. All rights reserved.
This paper proposes a cyber-physical framework for investigating distributedcontrol systems operating in the context of smart-grid applications. At the moment, the literature focuses almost exclusively on the theoret...
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This paper proposes a cyber-physical framework for investigating distributedcontrol systems operating in the context of smart-grid applications. At the moment, the literature focuses almost exclusively on the theoretical aspects of distributed intelligence in the smart-grid, meanwhile, approaches for testing and validating such systems are either missing or are very limited in their scope. Three aspects need to be taken into account while considering these applications: (1) the physical system, (2) the distributed computation platform, and (3) the communication system. In most of the previous works either the communication system is neglected or oversimplified, either the distributed computation aspect is disregarded, either both elements are missing. In order to cover all these aspects, we propose a framework which is built around a fleet of low-cost single board computers coupled with a real-time simulator. Additionally, using traffic control and network emulation, the flow of data between different controllers is shaped so that it replicates various quality of service (QoS) conditions. The versatility of the proposed framework is shown on a study case in which 27 controllers self-coordinate in order to solve the distributed optimal power flow (OPF) algorithm in a dc network.
In this paper, a fully distributed secondary-tertiary coordinated control framework for islanded ac microgrids has been proposed. First, the distributed secondary control for frequency restoration, voltage regulation ...
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ISBN:
(纸本)9781728149646
In this paper, a fully distributed secondary-tertiary coordinated control framework for islanded ac microgrids has been proposed. First, the distributed secondary control for frequency restoration, voltage regulation and power sharing has been proposed. Therefore, the system frequency and bus voltages can be maintained at set points. Each DG can follow the tertiary control signals, while the rest load-generation mismatch is proportionally shared among DGs. Then in the tertiary control, optimal power flow of islanded ac microgrids is formulated as an optimization problem and solved by alternating direction method of multipliers. The entire control framework is achieved in a distributed way with sparse communication networks among each agent. A cyber-physical microgrid platform has been built to validate the proposed controller design in a real-time and hardware-in-the-loop condition. A six-bus three-DG microgrid is developed on the platform and the experimental results validate the effectiveness of the proposed method.
We present an algorithm for collision free and socially-aware navigation of multiple robots in an environment shared with human beings, other robots and with the presence of static obstacles. We formulate the problem ...
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ISBN:
(数字)9781728173030
ISBN:
(纸本)9781728173030
We present an algorithm for collision free and socially-aware navigation of multiple robots in an environment shared with human beings, other robots and with the presence of static obstacles. We formulate the problem as a constrained optimization problem, where the cost function is chosen in order for the robotic agents to exhibit bio-inspired behaviors, such as cooperation inside the group and cohesive motion. Some of the constraints are required to avoid collision between the agents and with other obstacles and emanate from the application of Velocity Obstacle approach. The nonholonomic dynamics of the vehicles, is managed through the application of the feedback linearization technique to map the velocities in the control values. In this paper we propose both centralized solution and a completely decentralized solution. The overall strategies are extensively tested in simulations.
We lay out a general framework for reverse-engineering frequency dynamics with general primary frequency control and frequency response, by showing that it is a distributed algorithm to solve a well-defined optimizati...
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We lay out a general framework for reverse-engineering frequency dynamics with general primary frequency control and frequency response, by showing that it is a distributed algorithm to solve a well-defined optimization problem. We further characterize the role of deadband in control, and show that if the aggregated uncontrolled load deviation is nonzero the frequencies will be synchronized, and if however it is zero the frequencies may oscillate but within the deadband. The optimization based model does not only provide a way to characterize the equilibrium and establish the convergence of the frequency dynamics, but also suggests a principled way to engineer frequency control. By leveraging the optimization problem and insights from reverse engineering, we design a distributed realtime frequency control scheme that maintains the frequency to the nominal value while achieves economic efficiency. This work presents a further step towards developing a new foundation-network dynamics as optimization algorithms-for distributed realtime control and optimization of future power networks.
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