bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytic Modeling and Integral Control of Heterogeneous Thermostatically Controlled Load Populations
Authors: Ghaffari Azad , Moura Scott , Krstić Miroslav
Published: December 2014

Thermostatically controlled loads (TCLs) account for approximately 50% of U.S. electricity consumption. Various techniques have been developed to model TCL populations. A High-fidelity analytical model of heterogeneous TCL populations facilitates the aggregate synthesis of power control in power networks. Such a model assists the utility manager to increase the stability margin of the network. The model, also, assists the customer to schedule his/her tasks in order to reduce his/her energy cost. We present a deterministic hybrid partial differential equation (PDE) model which accounts for heterogeneous populations of TCLs, and facilitates analysis of common scenarios like cold load pick up, cycling, and daily and/or seasonal temperature changes to estimate the aggregate performance of the system. The proposed technique is flexible in terms of parameter selection and ease of changing the set-point temperature and deadband width all over the TCL units. We provide guidelines to maintain the numerical stability of the discretized model during computer simulations. Moreover, the proposed model is a close fit to design output feedback algorithms for power control purposes. Our integral output feedback control, designed using the comparison principle, guarantees fast and efficient power tracking for various real-world scenarios. We present simulation results to verify the effectiveness of the proposed modeling and control technique.
MEMS Nanopositioner for Lissajous-Scan Atomic Force Microscopy
Authors: Fowler Anthony G. , Maroufi Mohammad , Bazaei Ali , Moheimani S. O. Reza
Published: December 2014

This paper presents a new silicon-on-insulator-based MEMS nanopositioner that is designed for high-speed on-chip atomic force microscopy (AFM). The device features four electrostatic actuators in a 2-DOF configuration that allows bidirectional actuation of a central stage along two orthogonal axes with displacements greater than ±10μm. The x- and y-axis resonant modes of the stage are located at 1274Hz and 1286Hz, respectively. Integrated electrothermal sensors are used to control the system in closed loop, with a damping controller and an internal model controller being implemented for each axis. The performance of the closed-loop system is demonstrated by performing a 20μm×20μm contact-mode AFM scan via a Lissajous scan trajectory with a 410Hz sinusoidal reference.
Developing an Affordable Laboratory Kit for Undergraduate Controls Education
Authors: Reck Rebecca M. , Sreenivas Ramavarapu S.
Published: December 2014

The aim of this research is to expand the possibilities of multi-disciplinary controls education at the undergraduate and graduate levels with an affordable laboratory kit. A kit was assembled for around $130 while replicating the educational functionality of a typical laboratory station in a university controls laboratory. This kit could also replace expensive equipment with an affordable alternative that can be easily shipped anywhere in the world and used by students with any computer. This greatly enhances the accessibility of the laboratory experience to students in budget-strapped campus laboratories and those participating in distance education. The kit design consists of a Raspberry Pi, a DC motor, and various components required for the lab exercises. The first two kits allow students to complete labs that include DC motor system identification, DC motor control, inverted pendulum control, and any other project a student might want to create with a Raspberry Pi, DC motor, and a 3-D printer.
Pitch and Roll Motion Control of a Floating Wind Turbine With Hybrid Actuation
Authors: Jalili Kaveh , Li Yaoyu , Rotea Mario A.
Published: December 2014

Platform stabilization and load reduction are of great importance for the successful development of floating offshore wind turbines. The increased degrees-of-freedom (DOF) for the relevant dynamics presents the challenge of underactuation. Recently, a tuned-mass damper (TMD) and active vane have been proposed to control the pitch and roll motions of a floating turbine platform. Simulations have indicated that TMD in the fore-aft (FA) direction cannot reduce the damage equivalent load (DEQL) for the side-to-side (SS) bending moment at the tower-base across all the loading conditions. In this study, the TMD in the FA direction is combined with an active vertical vane to reduce both the FA and SS platform motions and DEQLs. We refer to this combined system of actuation as the “hybrid actuation system”. The effectiveness of this hybrid scheme is demonstrated via simulations which are carried out in accordance with the IEC 61400-3 standard design load case 1.2–fatigue load testing.
Thermoelectric Generation Using Diesel Engine Exhaust Waste Heat
Authors: Austin Kelly , She Xin (James) , Wagner John
Published: December 2014

In the transportation industry, the need to improve powertrain efficiency and provide additional power to the many amenities has encouraged research on engine waste heat recovery. Approximately one-third of the gasoline or diesel fuel energy passes through the engine’s exhaust system as heat. With ongoing developments in thermoelectric materials and module design, thermoelectric power generation has a potential use in engine heat recovery. In this study, the capability of generating usable power by thermoelectric generation from the exhaust heat of a three-cylinder, 697 cubic centimeter diesel engine was investigated. From experimental testing, the maximum power output and maximum current for a single module and four modules connected in series was 0.49W with 0.437A, and 2.81W with 0.60A, respectively. To harvest larger power magnitude from the waste heat, the modules will be configured in a co-axial manner along the pipe. Other possible applications include stationary power generation systems in which added weight does not effect overall performance.
Nonlinear Moving Horizon Observer for Estimation of States and Parameters in Under-Balanced Drilling Operations
Authors: Nikoofard Amirhossein , Johansen Tor Arne , Kaasa Glenn-Ole
Published: December 2014

It is not possible to directly measure the total mass of gas and liquid in the annulus and geological properties of the reservoir during petroleum exploration and production drilling. Therefore, these parameters and states must be estimated by online estimators with proper measurements. This paper describes a nonlinear Moving Horizon Observer to estimate the annular mass of gas and liquid, and production constants of gas and liquid from the reservoir into the well during Under-Balanced Drilling with measuring the choke pressure and the bottom-hole pressure. This observer algorithm based on a low-order lumped model is evaluated against Joint Unscented Kalman filter for two different simulations with low and high measurement noise covariance. The results show that both algorithms are capable of identifying the production constants of gas and liquid from the reservoir into the well, while the nonlinear Moving Horizon Observer achieves better performance than the Unscented Kalman filter.
Electrochemical-Thermal Modeling of Li-Ion Battery Packs
Authors: Fan Guodong , Pan Ke , Bartlett Alexander , Canova Marcello , Rizzoni Giorgio
Published: December 2014

Lithium-ion batteries for automotive applications are subject to aging with usage and environmental conditions, leading to the reduction of the performance, reliability and life span of the battery pack. To this extent, the ability of simulating the dynamic behavior of a battery pack using high-fidelity electrochemical and thermal models could provide very useful information for the design of Battery Management Systems (BMS). For instance such models could be used to predict the impact of cell-to-cell variations in the electrical and thermal properties on the overall performance of the pack, as well as on the propagation of degradation from one cell to another.

This paper presents a method for fast simulation of an integrated electrochemical-thermal battery pack model based on first-principles. First, a coupled electrochemical and thermal model is developed for a single cell, based upon the data of a composite LiNi1/3Mn1/3Co1/3O2 – LiMn2O4 (LMO-NMC) Li-ion battery, and validated on experimental data. Then, the cell model is extended to a reconfigurable and parametric model of a complete battery pack. The proposed modeling approach is completely general and applicable to characterize any pack topology, varying electrical connections and thermal boundary conditions. Finally, simulation results are shown to illustrate the effects of parameter variability on the pack performance.
Study of a Non-Circular Gear Infinitely Variable Transmission
Authors: Hebbale Kumar , Li Dongxu , Zhou Jing , Duan Chengwu , Kao Chi-Kuan , Samie Farzad , Lee Chunhao , Gonzales Robert
Published: December 2014

Improving automobile fuel efficiency is an important research and development effort in the automotive industry. In the transmission area, it is generally understood that optimum fuel economy can be achieved via a combination of highly efficient power transfer (gears, for example) and an ability to transmit power at an infinite number of ratios (CVT, for example). In this paper, a geared infinitely variable transmission (IVT) is analyzed for efficiency through static analysis. This IVT is based on a non-circular gear concept described in [1, 2]. This IVT consists of multiple function generators with each function generator comprising two sets of non-circular gear sets whose outputs are combined with a summing planetary gear set. Each function generator provides the desired gear ratio for only a part of the driving rotation. So, multiple function generators are combined along with multiple one-way clutches to provide an infinitely variable transmission.

This paper first explains the operating principle of the geared IVT. A static analysis of the IVT powerflow is derived and it is shown that this powerflow exhibits a torque recirculation phenomenon, which is not desired. This recirculation phenomenon is expected to be present in all similarly arranged IVTs where two inputs are combined using a planetary gear set to provide infinite gear ratio capability. The efficiency of the IVT is calculated based on assumed individual component efficiency and it is shown that, owing to torque recirculation, the efficiency of this transmission may not compare well with that of current automatic transmissions for a passenger car application.
Location-Aware Adaptive Vehicle Dynamics System: Linear Chassis Predictions
Authors: Bandy Rebecca Anne , Cho Sukhwan , Ferris John B. , Schlinkheider Joerg , Wimmershoff Marc
Published: December 2014

A Location-Aware Adaptive Vehicle Dynamics System (LAAVDS) is currently being developed to predict and maintain vehicle handling capabilities through upcoming maneuvers. This system depends heavily on an understanding of the interplay between the vehicle’s longitudinal, lateral, and vertical forces, as well as their resulting moments. These vehicle dynamics impact the Performance Margin metric and ultimately the point at which the Intervention Strategy will modulate the throttle and brake controls. Real-time implementation requires the development of computationally efficient predictive models of the vehicle dynamics. A method for predicting future vehicle states for smooth but tortuous roads is developed in this work using perturbation theory. An analytical relationship between the change in these forces and the resulting change in the Performance Margin is also derived. This model is implemented in the predictor-corrector algorithm of the Intervention Strategy. Corrections to the predicted states are made at each time step using a detailed, full, non-linear vehicle model; this full vehicle model is a precursor to incorporation of the LAAVDS in a real vehicle. Eventually, this work will be expanded to include the impact of rough terrain.
A Computationally Efficient Predictive Controller for Lane Keeping of Semi-Autonomous Vehicles
Authors: Liu Changchun , Lee Chankyu , Hansen Andreas , Hedrick J. Karl , Ding Jieyun
Published: December 2014

Model predictive control (MPC) is a popular technique for the development of active safety systems. However, its high computational cost prevents it from being implemented on lower-cost hardware. This paper presents a computationally efficient predictive controller for lane keeping assistance systems. The controller shares control with the driver, and applies a correction steering when there is a potential lane departure. Using the explicit feedback MPC, a multi-parametric nonlinear programming problem with a human-in-the-loop model and safety constraints is formulated. The cost function is chosen as the difference between the linear state feedback function to be determined and the resultant optimal control sequence of the MPC problem solved off-line given the current state. The piecewise linear feedback function is obtained by solving the parametric programming with an approximation approach. The effectiveness of the controller is evaluated through numerical simulations.
A Motor Point Identification Technique Based on Dempster Shafer Theory
Authors: Anugolu Madhavi , Potluri Chandrasekhar , Urfer Alex , Schoen Marco P.
Published: December 2014

The objective of this work is to identify the motor point location from the obtained sEMG signals using Dempster Shafer theory (DST). The proposed technique is applied on data obtained from a male test subject. In particular, the sEMG signals and its corresponding skeletal muscle force signals from the Flexor Digitorum Superficialis are acquired at a sampling rate of 2000 Hz using a Delsys Bangnoli- 16 EMG system. The acquired sEMG signals are rectified and filtered using a Discrete Wavelet Transforms (DWT) with a Daubechies 44 mother wavelet. For the system identification, an Output Error (OE) model structure is assumed to obtain the dynamic relation between the sEMG signal and the corresponding finger force signals. Subsequently, model based probabilities and fuzzy inference based probabilities are obtained for discrete sensor locations of a sEMG sensor array. Considering these evidences, a DST based motor point location identification method is proposed. The results based on one subject show the potential of the proposed theory and approach for affectively identifying motor point locations using an array sEMG sensor.
Implementation of a Large-Scale Actuator Network for Distributed Manipulation
Authors: Sinclair Martin , Raptis Ioannis
Published: December 2014

A class of cyber-physical systems that is gradually attracting increased scientific attention is Large-Scale Actuator Networks (LSAN). A prospective application of actuator networks is distributed manipulation. Distributed manipulation has the potential to become a game-changing technology in the area of industrial automation. To examine this class of systems, this paper presents a reactive elastic surface that autonomously morphs its shape by using a grid of linear actuators to transport an object into a target location. The combined action of the actuator grid overcomes the limitations of individual actuators, resulting in a system with multiple degrees-of-freedom. Experimental results illustrate the applicability of the platform.
Visual Feedback Based Droplet Size Regulation in Electrohydrodynamic Jet Printing
Authors: Altın Berk , Tse Lai Yu Leo , Barton Kira
Published: December 2014

Electrohydrodynamic jet (e-jet) printing is a recent micro-manufacturing technique that uses electrostatic force to draw out ink from a conductive nozzle onto a conductive substrate. While the advantages (high speed and resolution, flexibility) of e-jet printing over ink jet printing and other microfabrication methods are abundant, precise control of the process is necessary for successful commercialization of the technology. This paper shows how visual feedback through image processing may be used to regulate the volume of printed droplets for increased manufacturing precision.
Effects of Non-Proportional Damping on the Residual Vibrations of Mode-Coupled Ultra-Precision Manufacturing Machines
Authors: Lee Jihyun , Okwudire Chinedum
Published: December 2014

Ultra-precision manufacturing (UPM) machines are used to fabricate and measure complex parts having micrometer-level features and nanometer-level tolerances/surface finishes. Therefore, low-frequency residual vibrations that occur during the motion of the machines’ axes must be minimized. Recent work by the authors has revealed that coupling vibration modes of passively-isolated UPM machines can provide conditions for drastic reduction of residual vibrations vis-a-vis the recommended practice of modal decoupling. This paper presents an investigation into the effects of non-proportional (NP) damping on the conclusions reached in the authors’ prior work. With NP damping added, the conditions under which mode coupling is beneficial relative to decoupling are seen to remain largely the same. However, NP damping is shown to significantly influence the conditions under which the system’s response is most sensitive to mode coupling. Design guidelines for maximally exploiting the benefits of mode coupling are presented and demonstrated experimentally on a UPM machine.
Stability of Blade-Casing Interference in Turbomachinery and the Design Alternatives on Damping Characteristics
Authors: Olgac Nejat , Zalluhoglu Umut , Kammer Ayhan S.
Published: December 2014

Bladed disks in turbomachinery are commonly designed to operate within a very small clearance from the stationary shroud (casing). For variety of reasons, however, they interfere with each other during routine operation which results in undesirable vibrations. The novel idea in this paper originates from the claim that this dynamics is inherently akin to internal machining operation which uses compliant cutters (blades) with relatively rigid workpiece (casing). It is known that machining processes suffer from a phenomenon called chatter, which has been studied over decades to a considerable extend. We propose a new perspective to investigate the stability of blade-casing contact vibrations by a modeling approach borrowed from chatter literature. The mathematical model arises with a signature time-delayed dynamics for which we utilize a recent analytical tool called the Cluster Treatment of Characteristic Roots (CTCR). We present an exhaustive stability analysis and study the effects of altering damping characteristics in the casing structure.
Autonomous Lighting Audits: Part 1 — Building Navigation and Mapping
Authors: Bay Christopher J. , Terrill Trevor J. , Rasmussen Bryan P.
Published: December 2014

Buildings represent a large portion, approximately 40%, of all US energy use and carbon emissions. Significant savings can be found by conducting energy audits of the buildings, but the extensive training and cost of the audits prevent more widespread use. Automating the audit process with robots can greatly reduce the cost and provide more information to give better recommendations. This paper is the first in a series that proposes a system of autonomous robots that can conduct energy audits.

Specifically, this paper presents an overview of the autonomous system and details an unmanned aerial vehicle (UAV) platform which is used to perform automated lighting audits. Also, modifications to an existing exploration algorithm are proposed that will allow autonomous exploration of an unknown, GPS-denied environment while identifying and navigating to targets in real-time. This new algorithm is called SRT-Target. The UAV navigates to the lights, the target objects, in order to take additional measurements so that the light type can be determined. Movement of the UAV can be limited by a calibration factor β to account for sensor capabilities of the target sensor. Simulations of the algorithm show the exploration of the unknown area and the UAV moving to targets as they are identified.
Autonomous Lighting Audits: Part 2 — Light Identification and Analysis
Authors: Terrill Trevor J. , Bay Christopher J. , Rasmussen Bryan P.
Published: December 2014

Buildings are responsible for approximately 40% of all US energy use and carbon emissions. There exists large potential to improve building efficiency through retro-commissioning, but expense and required expertise of building auditors limit current implementation. Autonomous robotic assessments have the potential to provide consistent building energy audits with reduced cost and enhanced capabilities. As a first step in automating building audits, this paper presents work on automating the lighting analysis of a building.

As an aerial vehicle navigates and explores a room, the prototype system captures images and collects spectrometer readings. These data are used to quantify and classify lighting in a room. Additionally, images acquired from the optical camera are merged to form a composite image of the area. This composite image is used for navigation to lights to record spectrometer readings. Lighting type is then classified from these spectrometer readings. The combined lighting quantification and classification is used to create a topology map of light levels. The combined data are used to perform a thorough analysis of lighting and make lighting recommendations.
Linear Quadratic Design of Passive Vibration Isolators
Authors: Bağdatlı S. Murat , Okwudire Chinedum E. , Ulsoy A. Galip
Published: December 2014

Design of passive vibration isolators using the popular Linear Quadratic (LQ) control design method is discussed. A single degree of freedom (DOF) example is used to illustrate the main concepts (i.e., skyhook damping, tradeoff between response to base excitation and external disturbances). The LQ design results are also presented for two DOF isolators to investigate two alternative approximate solution strategies, selection of weights, and location of isolators. The LQ approach is shown to be a suitable and convenient approximate design method for locating and tuning passive vibration isolators that approximate skyhook damping.
Minimum-Time Cornering for Manufacturing Machines Using Optimal Control
Authors: Duan Molong , Okwudire Chinedum E.
Published: December 2014

When traversing sharp corners, manufacturing machines are forced to tradeoff speed and accuracy. The most common way of reducing this tradeoff is to smooth the sharp corner using a pre-specified curve (e.g., a circular arc or spline). However, pre-specified curves cannot guarantee optimal performance. This paper presents a preliminary investigation into the potential of using methods from optimal control to minimize this tradeoff. First, a useful simplification is made to the exact cornering problem to make it tractable. Dynamic programming is then used to determine the best free-form curve that minimizes corner traversal time while adhering to path tolerance and machine kinematic constraints. Significant improvements in cornering time are demonstrated compared to two methods that use pre-specified curves. However, dynamic programming is found to be too computationally costly, thus impractical. Less computationally intensive techniques in optimal control are considered for future work.
Caretaker-Machine Collaborative Manipulation With an Advanced Hydraulically Actuated Patient Transfer Assist Device
Authors: Humphreys Heather C. , Book Wayne J. , Huggins James D. , Jimerson Brittney
Published: December 2014

A significant market need has been identified for an improved assist device for transferring mobility limited patients, particularly those who are heavier or bariatric. This paper discusses our needs assessment for a new patient transfer assist device (PTAD), an initial design for a multiple degree of freedom hydraulically actuated device, and possible solutions for the caretaker interface design. The relevant patient population includes those with spinal cord injuries, neuromuscular disorders, and the elderly; most patients are wheelchair users and unable to perform independent transfers. The caretaker interface design for the PTAD presents a unique challenge in terms of human-machine collaborative manipulation, as well as control of a powerful and intrinsically stiff machine in a delicate environment with both the caretaker and patient in the workspace. This paper presents a needs assessment to determine the specific problems with the antiquated current market patient lifts, as well as user input on proposed improvements. It also presents the design of a functional first prototype PTAD, a mechanical simulation, preliminary simulation results on an impedance control approach, and next steps toward design and implementation of a caretaker- and patient-friendly operator interface and control system.
PEM Fuel Cell Flooding Diagnostics Based on an Unscented Kalman Filter Approach
Authors: Zhang Xian , Pisu Pierluigi
Published: December 2014

This paper proposes a model-based approach for the fuel cell flooding diagnostics problem. The cathode channel flooding and the GDL flooding diagnostic problems are decoupled and formulated as standard joint state and parameter estimation problems, with the amounts of the liquid water treated as varying system parameters to be identified. The unscented Kalman Filter technique has been applied to solve these problems. Simulation results prove the applicability of the cascading unscented Kalman filter design for flooding diagnostics.
Optimization of Fuel Economy of Hybrid Electric Vehicles Using Set Based Dynamic Programming
Authors: Ramaswamy Nikhil , Sadegh Nader
Published: December 2014

Dynamic Programming (DP) technique is an effective algorithm to find the global optimum. However when applying DP for finite state problems, if the state variables are discretized, it increases the cumulative errors and leads to suboptimal results. In this paper we develop and present a new DP algorithm that overcomes the above problem by eliminating the need to discretize the state space by the use of sets. We show that the proposed DP leads to a globally optimal solution for a discrete time system by minimizing a cost function at each time step. To show the efficacy of the proposed DP, we apply it to optimize the fuel economy of the series and parallel Hybrid Electric Vehicle (HEV) architectures and the case study of Chevrolet Volt 2012 and the Honda Civic 2012 for the series and parallel HEV’s respectively are considered. Simulations are performed over predefined drive cycles and the results of the proposed DP are compared to previous DP algorithm (DPdis). The proposed DP showed an average improvement of 2.45% and 21.29% over the DPdis algorithm for the series and the parallel HEV case respectively over the drive cycles considered. We also propose a real time control strategy (RTCS) for online implementation based on the concept of Preview Control. The RTCS proposed is applied for the series and parallel HEV’s over the drive cycles and the results obtained are discussed.
Entropy Coefficient and Thermal Time Constant Estimation From Dynamic Thermal Cycling of a Cylindrical LiFePO4 Battery Cell
Authors: Mendoza Sergio , Fathy Hosam K.
Published: December 2014

This paper presents a method for estimating (i) the reciprocal of the thermal time constant of a lithium-ion battery cell and (ii) the cell’s entropy coefficients for different states of charge. The method utilizes dynamic battery temperature cycling for parameter estimation. The paper demonstrates this method specifically for a cylindrical lithium iron phosphate (LiFePO4) cell. Identifying battery thermal parameters is important for accurate thermo-electrochemical modeling and model-based battery management. Entropy coefficients have been identified in previous research for various battery chemistries using calorimetric and potentiometric measurements requiring quasi-equilibrium conditions. This work, in contrast, fits the entropy coefficients and the reciprocal of the thermal time constant of a first-order thermal model to datasets collected in a noninvasive, dynamic experiment. This reduces the time required for parameter identification by a factor of 3 compared to traditional quasi-equilibrium experiments.
Shoe-Floor Interactions During Human Slip and Fall: Modeling and Experiments
Authors: Trkov Mitja , Yi Jingang , Liu Tao , Li Kang
Published: December 2014

Shoe-floor interactions such as friction force and deformation/local slip distributions are among the critical factors to determine the risk for potential slip and fall. In this paper, we present modeling, analysis, and experiments to understand the slip and force distributions between the shoe sole and floor surface during the normal gait and the slip and fall gait. The computational results for the slip and friction force distribution are based on the spring-beam networks model. The experiments are conducted with several new sensing techniques. The in-situ contour footprint is accurately measured by a set of laser line generators and image processing algorithms. The force distributions are obtained by combining two types of force sensor measurements: implanted conductive rubber-based force sensor arrays in the shoe sole and six degree-of-freedom (6-DOF) insole force/torque sensors. We demonstrate the sensing system development through extensive experiments. Finally, the new sensing system and modeling framework confirm that the use of required coefficient of friction and the deformation measurements can real-time predict the slip occurrence.
An Investigation of Eddy-Current Effects on Parameter Monitoring for Duplex Lathe Machining of Thin-Wall Components
Authors: Lee Kok-Meng , Li Min , Bai Kun
Published: December 2014

This paper presents a novel design of an eddy-current sensing system with an array of high-accuracy solid magnetic sensors for duplex lathe machining of thin-wall compressor disks. By controlling the penetration depth of the eddy current, the dual-frequency sensing system based on measured magnetic flux density simultaneously measures the in-feed cutting depth and workpiece thickness in real-time. Specifically, this paper provides the design concept and operational principle of the eddy-current sensing system along with the theory for designing the sensor and analyzing its performance. As eddy current cannot be measured directly, results of a numerical investigation based on finite-element analyses are presented with illustrative examples offering new physical insights into the effects of optimal design parameters on the magnetic and electric field distributions of the induced eddy-current. The effectiveness of a dual-frequency eddy-current sensor has been numerically evaluated and compared against experimental data of a commercial eddy-current sensor operated at 1MHz.
A Review of Target Pursuit Strategies in Aerial Species
Authors: Pal Sudeshna
Published: December 2014

Aerial pursuit in nature is a complex task that involves interaction with targets in motion. To date, many researchers have analyzed aerial predation strategies used by different flying species for the pursuit and interception of targets such as a prey or a conspecific. In this article, we provide a brief review of these different predation strategies with the focus primarily on insects and bats that rely on different sensory variables (vision and sonar) for navigation. The Knowledge gained from studying these strategies can guide the development of bio-inspired approaches for navigation of engineered systems.
Adaptive Multi-Loop Mode Atomic Force Microscope Imaging
Authors: Ren Juan , Zou Qingze , Li Bo , Lin Zhiqun
Published: December 2014

An adaptive multi-loop mode (AMLM) imaging of atomic force microscope (AFM) is proposed. Due to its superior image quality and less sample disturbances, tapping mode (TM) imaging is currently the de facto most widely used imaging technique. However, the speed of TM-imaging is substantially limited, and becoming the major bottleneck of this technique. The proposed AMLM-imaging overcomes the limits of TM-imaging by utilizing control techniques to substantially increase the speed of TM-imaging while preserving the advantages of TM-imaging. The AMLM-imaging is tested and demonstrated through imaging a PtBA sample in experiments, and the experiment results demonstrated that the image quality over large-size imaging (50 μm by 25 μm) achieved at the scan rate of 25 Hz is at the same level of that when using TM-imaging at 1 Hz, while the probe-sample interaction force is smaller than that of the TM-imaging at 2.5 Hz.
A Switched-System Approach to Shared Robust Control and Obstacle Avoidance for Mobile Robots
Authors: Jin Jingfu , Gans Nicholas , Kim Yoon-Gu , Wee Sung-Gil
Published: December 2014

We propose a shared control structure for nonholonomic mobile robots, in which a human operator can command motions that override autonomous operation, and the robot overrides either the teleoperation or autonomous controller if it encounters an obstacle. We divide the whole configuration, including orientation, space into an obstacle avoidance and an obstacle-free region. This enables a switched-system approach to switch between autonomous and teleoperation mode, or the obstacle avoidance and the obstacle-free region. To reject disturbances or noise present in the error dynamics, two different robust control laws are proposed using a high gain and a variable structure approach. Lyapunov-based stability analysis is provided. To rigorously test the approach under different circumstances, experiments have been conducted by two different research groups. The results from two groups show that the shared control approach works effectively both in the teleoperation mode and autonomous mode with different system settings and environments.
Impedance Control Based on a Position Sensor in a Rehabilitation Robot
Authors: Kim Bongsu , Rodot Aurelien , Deshpande Ashish D.
Published: December 2014

We examine the implementation of impedance control based on a position sensor in a wearable robot designed for rehabilitation. The first goal is to achieve the lowest possible impedance for the robot, with only a position sensor and an ON/OFF type pressure sensor, so that it is dynamically transparent to the user. We built a wearable robot for controlling the user’s arm with a brushless DC motor and a two-stage gearing system involving a planetary gearbox and a Capstan drive. We designed and implemented a controller to compensate for the inherent friction and reflected inertia using joint angle feedback from the robot, and for the stiction using the user’s intended direction detected by a pressure sensor. Stability conditions are analyzed first for the robotic system alone and then for the coupled human-robot system. Experiments with the robot show that the apparent impedance was significantly reduced with compensation. Experiments involving free motions driven by a user proved that the user’s physical effort to move the robot is dramatically decreased with compensation, thus making the robot feel lighter to the user.
Robust Adaptive Synchronization of Dynamic Networks With Varying Time Delay Coupling Using Variable Structure Control
Authors: Ojleska Vesna M. , Tükel Dilek (Bilgin) , Dimirovski Georgi M.
Published: December 2014

The synchronization problem for a class of delayed complex dynamical networks via employing variable structure control has been explored and a solution proposed. The synchronization controller guarantees the state of the dynamical network is globally asymptotically synchronized to arbitrary state. The switching surface has been designed via the left eigenvector function of the system, and assures the synchronization sliding mode possesses stability. The hitting condition and the adaptive law for estimating the unknown network parameters have been used for designing the controller hence the network state hits the switching manifold in finite time. Two illustrative examples along with the respective simulation results are given, which employ the designed variable structure controllers.
An Initial Comparison of Energy Use Between Crane Control Methods
Authors: Vaughan Joshua
Published: December 2014

Cranes have been used for transport of material since antiquity. Modern cranes still share some characteristics with the ancients, namely payload oscillation. As such, there has an extensive research effort to control crane payload vibration, resulting in the development of many effective methods. This paper compares two popular methods of crane vibration control, feedback control and input shaping. In addition to showing that both of these methods can dramatically reduce payload oscillation, one primary measure used in this comparison is energy use. The differing nature of the control methods is shown to result in different energy use profiles. This is shown to be true even for when the payload responses for the two controllers are similar.
Linear Parameter-Varying Control of a Wing-Section Stall Flutter
Authors: Fan Wen , Liu Hugh H. T. , Kwong Raymond H. S.
Published: December 2014

This paper presents an active flutter suppression design using linear parameter-varying (LPV) control method for a nonlinear aeroservoelastic model that captures wing-section stall flutter. The loss-of-effectiveness fault is considered for the control surface. The resulting model is a function of speed as well as effectiveness factor of the control surface. These two parameters are treated as the varying parameters to formulate an LPV representation of the wing-section model using Jacobian linearization. An H2 gain-scheduled controller based on a parameter-dependent Lyapunov function is designed for the LPV system. The simulation shows that it can suppress limit cycle oscillations over a range of speed and work under a certain range of control surface effectiveness loss.
The Virtual Wheel Concept for Supportive Steering Feedback During Active Steering Interventions
Authors: Balachandran Avinash , Erlien Stephen M. , Gerdes J. Christian
Published: December 2014

Active steering systems allow for improved vehicle safety and stability through steering interventions that augment a driver’s steering command. In a conventional steering system, steering feedback torque depends on the tire forces and corresponding moments that act on the roadwheels. During active steering interventions, there are differences between the driver’s command and the actual roadwheel angle. The steering feedback can now be based on either the moments acting on the actual roadwheels or the moments acting on a virtual wheel following the driver’s intended steering command. With small interventions, the difference between these two approaches is negligible. However, when the intervention is large (e.g. obstacle avoidance maneuvers), basing handwheel moments on the actual roadwheel position results in a handwheel torque that acts in opposition to the intervention. The virtual wheel concept produces a more supportive, and potentially more intuitive, handwheel torque. This reduces the discrepancy between the driver command and the active steering system in simulation and experiments.
Prediction of Periventricular Leukomalacia Occurrence in Neonates Using a Novel Unsupervised Learning Method
Authors: Bender Dieter , Jalali Ali , Nataraj C.
Published: December 2014

Prior work has documented that Support Vector Machine (SVM) classifiers can be powerful tools in predicting clinical outcomes of complex diseases such as Periventricular Leukomalacia (PVL). A preceding study indicated that SVM performance can be improved significantly by optimizing the supervised training set used during the learning stage of the overall SVM algorithm. This preliminary work, as well as the complex nature of the PVL data suggested integration of the active learning algorithm into the overall SVM framework. The present study supports this initial hypothesis and shows that active learning SVM type classifier performs considerably well and outperforms normal SVM type classifiers when dealing with clinical data of high dimensionality.
Uniform Ultimate Boundedness of Probe-to-Probe Dynamics in Dual Probe Atomic Force Microscopy
Authors: Al-Ogaidi Ayad , Bristow Douglas
Published: December 2014

Atomic force microscopes use a probe to interface with matter at the nanoscale through a variety of imaging or manipulation methods. A dual-probe atomic force microscope (DP-AFM) has been proposed for simultaneous imaging and manipulation. One challenge of DP-AFM is probe-to-probe contact, which may occur intentionally such as when locating one probe with the other. This work studies the stability for such interactions where the 1st probe is in the tapping mode (typically used for imaging) and 2nd probe is in the contact mode (typically used for manipulation). A state dependent switched model is proposed for DP-AFM. A theorem is proposed for uniformly ultimately bounded (UUB) stability of switched systems under a sequence nonincreasing condition and applied to the DP-AFM problem.
Control of a Dual-Stage Magnetostrictive Actuator-Based Micromachining System for Optimal High-Speed Microforming Process
Authors: Wang Zhihua , Witthauer Adam , Zou Qingze , Kim Gap-Yong , Faidley LeAnn
Published: December 2014

In this paper, the process control of a magnetostrictive-actuator-based dual-stage microforming system is studied. Microforming has recently become an emerging advanced manufacturing technique for fabricating miniaturized products. Particularly, miniaturized desktop microforming system based on unconventional actuators possesses great potential in attaining both high productivity and low cost. Process control of such miniaturized microforming systems, however, is challenging and still at its early stage. The challenge arises from the complicated behaviors of the actuators used, the switching and transition of the actuation/motion, and the uncertainty of the system dynamics during the entire microforming process. During the microforming process, the dynamics and the hysteresis effects of magnetostrictive actuator can be excited, resulting in positioning errors of the workpieces in both trajectory tracking and output transition. Rapid transition between tracking and transition is also accompanied with substantial variation of the system dynamics. Additional challenges exist due to the use of multi-stage actuators and the augmentation of ultrasonic vibrations to the microforming process. In this paper, a control framework integrating iterative learning control and optimal transition trajectory design along with feedforward-feedback control is proposed to achieve high speed and high quality in microforming. The efficacy of the proposed control strategies is demonstrated through experimental implementation.
Parameterization and Validation of a Distributed Coupled Electro-Thermal Model for Prismatic Cells
Authors: Samad Nassim A. , Siegel Jason B. , Stefanopoulou Anna G.
Published: December 2014

The temperature distribution in a prismatic Li-ion battery cell can be described using a spatially distributed equivalent circuit electrical model coupled to a 3D thermal model. The model represents a middle ground between simple one or two state models (generally used for cylindrical cells) and complex finite element models. A lumped parameter approach for the thermal properties of the lithium-ion jelly roll is used. The battery is divided into (m × n) nodes in 2-dimensions, and each node is represented by an equivalent circuit and 3 temperatures in the through plane direction to capture the electrical and thermal dynamics respectively. The thermal model is coupled to the electrical through heat generation. The parameters of the equivalent circuit electrical model are temperature and state of charge dependent. Parameterization of the distributed resistances in the equivalent circuit model is demonstrated using lumped parameter measurements, and are a function of local temperature. The model is parameterized and validated with data collected from a 3-cell fixture which replicates pack cooling conditions. Pulsing current experiments are used for validation over a wide range of operating conditions (ambient temperature, state of charge, current amplitude and pulse width). The model is shown to match experimental results with good accuracy.
Experimental PID Controller Design: A New Frequency Domain Approach Based on Desired Performance
Authors: Diaz-Rodriguez Ivan , Mohsenizadeh Daniel N. , Bhattacharyya Shankar P.
Published: December 2014

This paper presents an alternative approach to design PID controllers based on frequency response measurements. The proposed method does not require any mathematical model of the system and can handle the design process directly from a small set of frequency domain data. It is shown that for the class of Linear Time-Invariant (LTI) control systems, there exists a rational multilinear function for the frequency response between any two arbitrary breaking points in terms of the design controller. This function can be determined by conducting a small set of frequency response measurements and then will be used to synthesize a controller that guarantee a set of desired frequency-domain specifications. In this paper, we use this result to design a PID controller for a servomechanism control system. In particular, we show that such desirable PID controller can be calculated by solving an optimization problem.
Temperature Estimation in a Battery String Under Frugal Sensor Allocation
Authors: Lin Xinfan , Stefanopoulou Anna G. , Siegel Jason B. , Mohan Shankar
Published: December 2014

In electric vehicle applications, batteries are usually packed in modules to satisfy the energy and power demand. To facilitate the thermal management of a battery pack, a model-based observer could be designed to estimate the temperature distribution across the pack. Nevertheless, cost target in industry practice drives the number of temperature sensors in a pack to a number that is not sufficient to yield observability of all the temperature states. This paper focuses on formulating the observer design and sensor deployment strategy that could achieve the optimal observer performance under the frugal sensor allocation. The considered observer performance is the estimation errors induced by model and sensor uncertainty. The observer aims at minimizing the worst-case estimation errors under bounded model and sensor uncertainty.
Fuel Consumption Optimization of Heavy-Duty Vehicles: An Analytical Approach
Authors: He Chaozhe R. , Orosz Gábor
Published: December 2014

In this paper, we establish a mathematical framework that allows us to optimize the speed profile and select the optimal gears for heavy-duty vehicles. The key idea is to solve the analogous boundary value problem analytically for a simple scenario (linear damped system with quadratic elevation profile) and use this result to initialize a numerical continuation algorithm. Then the numerical algorithm can be used to gradually introduce nonlinearities (air resistance, engine saturation), implement data-based elevation profiles, and incorporate external perturbations (wind, traffic). This approach enables real-time optimization in dynamic traffic conditions, therefore may be implemented on board.
Classification of Complex Machine Data to be Used for Structural Health Monitoring Purposes
Authors: Schiffer S. , Söffker D.
Published: December 2014

In this contribution a recently developed new modeling and classification approach to be used with streamed measurement data of industrial processes is applied.

This briefly repeated approach can be used for fault classification and diagnostic purposes. The approach is based on a fuzzy-like modeling using statistical features from training data. Based on the trained model classification can be realized allowing to distinguish unknown data sets to the given number of data classes each related to states.

Beside the brief introduction to the proposed approach, experimental data are used to demonstrate the approach and the complex example distinguishing different wear states of machine components during operation.