Controls and Control Theory Commons^™

The Wireless Control Network: A New Approach For Control Over Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam

George J. Pappas

We present a method to stabilize a plant with a network of resource constrained wireless nodes. As opposed to traditional networked control schemes where the nodes simply route information to and from a dedicated controller (perhaps performing some encoding along the way), our approach treats the network itself as the controller. Specifically, we formulate a strategy for each node in the network to follow, where at each time-step, each node updates its internal state to be a linear combination of the states of the nodes in its neighborhood. We show that this causes the entire network to behave as a …

Adaptive Algorithms For Coverage Control And Space Partitioning In Mobile Robotic Networks, Jerome Le Ny, George J. Pappas

George J. Pappas

We consider deployment problems where a mobile robotic network must optimize its configuration in a distributed way in order to minimize a steady-state cost function that depends on the spatial distribution of certain probabilistic events of interest. Three classes of problems are discussed in detail: coverage control problems, spatial partitioning problems, and dynamic vehicle routing problems. Moreover, we assume that the event distribution is a priori unknown, and can only be progressively inferred from the observation of the location of the actual event occurrences. For each problem we present distributed stochastic gradient algorithms that optimize the performance objective. The stochastic …

Adaptive Robot Deployment Algorithms, Jerome Le Ny, George J. Pappas

George J. Pappas

In robot deployment problems, the fundamental issue is to optimize a steady state performance measure that depends on the spatial configuration of a group of robots. For static deployment problems, a classical way of designing high- level feedback motion planners is to implement a gradient descent scheme on a suitably chosen objective function. This can lead to computationally expensive deployment algorithms that may not be adaptive to uncertain dynamic environments. We address this challenge by showing that algorithms for a variety of deployment scenarios in stochastic environments and with noisy sensor measurements can be designed as stochastic gradient descent algorithms, …

The Wireless Control Network: Monitoring For Malicious Behavior, Shreyas Sundaram, Miroslav Pajic, Christoforos N. Hadjicostis, Rahul Mangharam, George J. Pappas

George J. Pappas

We consider the problem of stabilizing a plant with a network of resource constrained wireless nodes. In a companion paper, we developed a protocol where each node repeatedly transmits a linear combination of the values in its neighborhood. For certain topologies, we showed that these linear combinations can be designed so that the closed loop system is stable (i.e., the wireless network itself acts as a controller for the plant). In this paper, we design a Intrusion Detection System (IDS) for this control scheme, which observes the transmissions of certain nodes in the network and uses that information to (a) …

Topological Conditions For Wireless Control Networks, Miroslav Pajic, Shreyas Sundaram, George J. Pappas, Rahul Mangharam

George J. Pappas

We study the problem of stabilizing a linear system over a wireless control network. We propose a scheme where each wireless node maintains a scalar state, and periodically updates it as a linear combination of neighboring plant outputs and node states. We make connections to decentralized fixed modes and structured system theory to provide conditions on the network topology that allow the system to be stabilized. Our analysis provides the minimal number of feedback edges that have to be introduced to stabilize the system over a network, and shows that as long as the network connectivity is larger than the …

Network Synthesis For Dynamical System Stabilization, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam

George J. Pappas

We present our recent results in the area of distributed control over wireless networks. In our previous work, we introduced the concept of a Wireless Control Network (WCN), where the network acts as a decentralized structured controller. In this case, the network is not used only as a communication medium (as in traditional control paradigms), but instead as a fully distributed computational substrate. We show that the dynamics of the plant dictate the types of network topologies that can be used to stabilize the system. Finally, we describe how to obtain a stabilizing configuration for the WCN if the topological …

A Simple Distributed Method For Control Over Wireless Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam

George J. Pappas

We present a distributed scheme used for control over wireless networks. In our previous work, we introduced the concept of a Wireless Control Network (WCN), where the network itself, with no centralized node, acts as the controller. In this work, we show how the WCN can be modified to include observer style updates which substantially improves robustness of the closed-loop system to link failures. In addition, we analyze how the WCN simplifies extraction of the communication and computation schedules and enables system compositionality and scalability.

The Wireless Control Network: Synthesis And Robustness, Miroslav Pajic, Shreyas Sundaram, Jerome Le Ny, George J. Pappas, Rahul Mangharam

George J. Pappas

We consider the problem of stabilizing a plant with a network of resource constrained wireless nodes. Traditional networked control schemes are designed with one of the nodes in the network acting as a dedicated controller, while the other nodes simply route information to and from the controller and the plant. We introduce the concept of a Wireless Control Network (WCN) where the entire network itself acts as the controller. Specifically, at each time-step, each node updates its internal state to be a linear combination of the states of the nodes in its neighborhood. We show that this causes the entire …

The Wireless Control Network: A New Approach For Control Over Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam

George J. Pappas

We present a method to stabilize a plant with a network of resource constrained wireless nodes. As opposed to traditional networked control schemes where the nodes simply route information to and from a dedicated controller (perhaps performing some encoding along the way), our approach treats the network itself as the controller. Specifically, we formulate a strategy for each node in the network to follow, where at each time-step, each node updates its internal state to be a linear combination of the states of the nodes in its neighborhood. We show that this causes the entire network to behave as a …

Dynamic Modeling Of Solid Oxide Fuel Cell Stack Based On Local Linear Model Tree Algorithm, Hesamoddin Marzooghi, M. Raoofat, M. Dehghani, G. H. Elahi

Hesamoddin Marzooghi

This paper presents a dynamic model for Solid Oxide Fuel Cell (SOFC) stack using Local Linear Model Tree (LOLIMOT) algorithm which is useful for both dynamic and steady-state studies. Most of conventional SOFC models require a large number of parameters and factors, which are difficult to be determined or estimated. In this paper, a LOLIMOT-based model, which does not require the parameters of fuel cell, is proposed for each operation mode of SOFC. In these models, decision tree-based feature selection approach is exploited to select inputs of the LOLIMOT. The proposed models are trained in a short time and they …

Fadec Advances Allow Better Engine Performance, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Application Of Modern Control Theory For The Power-System Analysis And Control, Mulukutla S. Sarma, Earl D. Eyman

Sarma Mulukutla

With the current rise in the demand of electrical energy, present-day power systems which are large and complex, will continue to grow both in size and complexity. Also, our dependence on electrical energy is so great that it is essential to have uninterrupted supply of electrical power within set limits of frequency and voltage levels, and that it becomes a dire necessity to develop methods for effective control and operation of power systems. Modern control theory concepts have been effectively used and will continue to be utilized for the power system analysis and control. This paper attempts in assessing the …

Polar Field Oriented Control With 3rd Harmonic Injection, Martin Todd Hess

Master's Theses

Abstract

POLAR FIELD-ORIENTED CONTROL

with

3^RD HARMONIC INJECTION

Martin Todd Hess

Field Oriented Control (FOC), also known as vector control, is a widely used and well documented method for controlling Permanent-Magnet Synchronous Motors (PMSM) and induction motors. Almost invariably the orientation of the stator and rotor (field) fluxes are described in rectangular coordinates. In this thesis we explore the practicality of using polar coordinates.

Third harmonic injection is also a well-known technique that allows full utilization of the bus (DC-link), thus allowing the motor to run to full base speed without the use of field weakening. This technique potentially …

Root Locus Techniques With Nonlinear Gain Parameterization, Brandon Wellman

Theses and Dissertations--Mechanical Engineering

This thesis presents rules that characterize the root locus for polynomials that are nonlinear in the root-locus parameter k. Classical root locus applies to polynomials that are affine in k. In contrast, this thesis considers polynomials that are quadratic or cubic in k. In particular, we focus on constructing the root locus for linear feedback control systems, where the closed-loop denominator polynomial is quadratic or cubic in k. First, we present quadratic root-locus rules for a controller class that yields a closed-loop denominator polynomial that is quadratic in k. Next, we develop cubic root-locus rules …

Modeling And Simulation Of Z-Source Inverter, Suresh L

suresh L

Z – source inverters have been recently proposed as an alternative power conversion concept as they have both voltage buck and boost capabilities. These inverters use a unique impedance network, coupled between the power source and converter circuit, to provide both voltage buck and boost properties, which cannot be achieved with conventional voltage source and current source inverters. To facilitate understanding of Z – source inverter, this paper presents a detailed analysis, showing design of impedance network, implementation of simple Boost control PWM technique and simulation of Z – source inverter for different values of modulation indices.

Adaptive Kriging Controller Design For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu

Bin Xu

No abstract provided.

Direct Neural Discrete Control Of Hypersonic Flight Vehicle, Bin Xu

Bin Xu

No abstract provided.

A Teaching Practice Review Of The Use Of Multiple-Choice Questions For Formative And Summative Assessment Of Student Work On Advanced Undergraduate And Postgraduate Modules In Engineering, Aidan O'Dwyer

Articles

This paper reflects on, reports on and evaluates the use of multiple-choice questions, in both formative and summative assessment modes, on control engineering modules taken by advanced undergraduate and postgraduate engineering students, over four academic years. The material covered by the modules is analytical in nature. The rationale for examining the assessment strategy was the poor performance by students in a closed book traditional terminal examination on one of the advanced undergraduate modules over some years. The change in assessment strategy has improved student learning, as measured by assessment data; student feedback on the assessment methods is broadly positive. The …

Feedback Control For Electron Beam Lithography, Yugu Yang

Theses and Dissertations--Electrical and Computer Engineering

Scanning-electron-beam lithography (SEBL) is the primary technology to generate arbitrary features at the nano-scale. However, pattern placement accuracy still remains poor compared to its resolution due to the open-loop nature of SEBL systems. Vibration, stray electromagnetic fields, deflection distortion and hysteresis, substrate charging, and other factors prevent the electron-beam from reaching its target position and one has no way to determine the actual beam position during patterning with conventional systems. To improve the pattern placement accuracy, spatial-phase-locked electron-beam lithography (SPLEBL) provides feedback control of electron-beam position by monitoring the secondary electron signal from electron-transparent fiducial grids on the substrate. While …

An Adaptive Utility Interactive Photovoltaic System Based On A Flexible Switch Matrix To Optimize Performance In Real-Time, Mahmoud Alahmad, Mohamed Amer Chaaban, Siu Kit Lau, Jonathan Shi, Jill Neal

Durham School of Architectural Engineering and Construction: Faculty Publications

Reconfigurable architectures are of great interest to system designers to improve the system’s operation and efficiency. In this paper, we propose an adaptive utility interactive photovoltaic (PV) system based on a novel Flexible Switch array Matrix topology. This proposed system maximizes the generated power in real-time in response to operational conditions such as shading, soiling, mismatches, and module failure among others. The proposed system is a compromise in the utilization of power conditioning equipment to maximize energy capture and system efficiency. Simulation results demonstrate an average 13% improvement in efficiency when compared with the central inverter topology performance. A prototype …