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  Subjects -> ENGINEERING (Total: 1955 journals)
    - CHEMICAL ENGINEERING (153 journals)
    - CIVIL ENGINEERING (148 journals)
    - ELECTRICAL ENGINEERING (81 journals)
    - ENGINEERING (1113 journals)
    - ENGINEERING MECHANICS AND MATERIALS (289 journals)
    - HYDRAULIC ENGINEERING (45 journals)
    - INDUSTRIAL ENGINEERING (52 journals)
    - MECHANICAL ENGINEERING (74 journals)

ENGINEERING (1113 journals)            First | 2 3 4 5 6 7 8 9 | Last

International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 6)
International Journal of Mathematics in Operational Research     Hybrid Journal   (Followers: 1)
International Journal of Medical Engineering and Informatics     Hybrid Journal   (Followers: 5)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 3)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Microwave Science and Technology     Open Access   (Followers: 2)
International Journal of Mobile Network Design and Innovation     Hybrid Journal   (Followers: 3)
International Journal of Multiphase Flow     Hybrid Journal   (Followers: 2)
International Journal of Nanomanufacturing     Hybrid Journal   (Followers: 1)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Navigation and Observation     Open Access   (Followers: 5)
International Journal of Network Management     Hybrid Journal  
International Journal of Nonlinear Sciences and Numerical Simulation     Full-text available via subscription   (Followers: 1)
International Journal of Numerical Methods for Heat & Fluid Flow     Hybrid Journal   (Followers: 7)
International Journal of Optics     Open Access   (Followers: 1)
International Journal of Organisational Design and Engineering     Hybrid Journal   (Followers: 8)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 6)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 2)
International Journal of Physical Modelling in Geotechnics     Hybrid Journal   (Followers: 3)
International Journal of Plasticity     Hybrid Journal   (Followers: 6)
International Journal of Plastics Technology     Hybrid Journal  
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 3)
International Journal of Polymer Science     Open Access   (Followers: 16)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 6)
International Journal of Precision Technology     Hybrid Journal  
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 2)
International Journal of Production Economics     Hybrid Journal   (Followers: 10)
International Journal of Quality and Innovation     Hybrid Journal   (Followers: 2)
International Journal of Quality Engineering and Technology     Hybrid Journal   (Followers: 2)
International Journal of Quantum Information     Hybrid Journal  
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 2)
International Journal of Reliability, Quality and Safety Engineering     Hybrid Journal   (Followers: 4)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 7)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 2)
International Journal of Science Engineering and Advance Technology     Open Access  
International Journal of Sediment Research     Full-text available via subscription   (Followers: 1)
International Journal of Self-Propagating High-Temperature Synthesis     Hybrid Journal   (Followers: 2)
International Journal of Signal and Imaging Systems Engineering     Hybrid Journal  
International Journal of Six Sigma and Competitive Advantage     Hybrid Journal  
International Journal of Social Robotics     Hybrid Journal   (Followers: 1)
International Journal of Software Engineering and Knowledge Engineering     Hybrid Journal   (Followers: 1)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 2)
International Journal of Speech Technology     Hybrid Journal   (Followers: 2)
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 5)
International Journal of Surface Engineering and Interdisciplinary Materials Science     Full-text available via subscription   (Followers: 1)
International Journal of Surface Science and Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Systems Assurance Engineering and Management     Hybrid Journal  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 4)
International Journal of Telemedicine and Applications     Open Access   (Followers: 2)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 4)
International Journal of Thermodynamics     Open Access   (Followers: 1)
International Journal of Turbo & Jet-Engines     Full-text available via subscription  
International Journal of Ultra Wideband Communications and Systems     Hybrid Journal  
International Journal of Vehicle Autonomous Systems     Hybrid Journal   (Followers: 1)
International Journal of Vehicle Design     Hybrid Journal   (Followers: 6)
International Journal of Vehicle Information and Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Vehicle Noise and Vibration     Hybrid Journal   (Followers: 3)
International Journal of Vehicle Safety     Hybrid Journal   (Followers: 4)
International Journal of Vehicular Technology     Open Access   (Followers: 2)
International Journal of Virtual Technology and Multimedia     Hybrid Journal   (Followers: 4)
International Journal of Wavelets, Multiresolution and Information Processing     Hybrid Journal  
International Journal on Artificial Intelligence Tools     Hybrid Journal   (Followers: 4)
International Nano Letters     Open Access   (Followers: 6)
International Review of Applied Sciences and Engineering     Full-text available via subscription  
Inverse Problems in Science and Engineering     Hybrid Journal   (Followers: 2)
Ionics     Hybrid Journal  
IPTEK The Journal for Technology and Science     Open Access  
IRBM News     Full-text available via subscription  
Irrigation and Drainage Systems     Hybrid Journal  
ISA Transactions     Full-text available via subscription   (Followers: 1)
ISRN - International Scholarly Research Notices     Open Access   (Followers: 69)
ISRN Nanotechnology     Open Access  
ISRN Signal Processing     Open Access  
ISRN Thermodynamics     Open Access  
IT Professional     Full-text available via subscription   (Followers: 2)
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 1)
Journal of Advanced Manufacturing Systems     Hybrid Journal   (Followers: 7)
Journal of Aerosol Science     Hybrid Journal   (Followers: 2)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 124)
Journal of Alloys and Compounds     Hybrid Journal   (Followers: 7)
Journal of Analytical and Applied Pyrolysis     Hybrid Journal   (Followers: 3)
Journal of Analytical Science & Technology     Open Access   (Followers: 4)
Journal of Analytical Sciences, Methods and Instrumentation     Open Access   (Followers: 1)
Journal of Applied Analysis     Full-text available via subscription  
Journal of Applied and Industrial Sciences     Open Access  
Journal of Applied Logic     Full-text available via subscription  
Journal of Applied Physics     Hybrid Journal   (Followers: 151)
Journal of Applied Probability     Full-text available via subscription   (Followers: 6)
Journal of Applied Research and Technology     Open Access  
Journal of Applied Science and Technology     Full-text available via subscription  
Journal of Applied Sciences     Open Access   (Followers: 5)
Journal of Architectural Engineering     Full-text available via subscription   (Followers: 5)
Journal of ASTM International     Full-text available via subscription   (Followers: 3)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 6)
Journal of Biological Dynamics     Open Access   (Followers: 1)

  First | 2 3 4 5 6 7 8 9 | Last

Journal of Dynamic Systems, Measurement, and Control
   [9 followers]  Follow    
   Full-text available via subscription Subscription journal
     ISSN (Print) 1528-9028 - ISSN (Online) 0022-0434
     Published by ASME International Homepage  [25 journals]   [SJR: 0.701]   [H-I: 53]
  • ECMS Controller Robustness in Flex-Fuel Hybrid Vehicles
    • Authors: Manzie C; Grondin O, Sciarretta A, et al.
      Abstract: Control algorithms for hybrid vehicles have undergone extensive research and development leading to near-optimal techniques being employed and demonstrated in prototype vehicles over the previous decade. The use of different implementations of optimal controllers is inevitably linked through the assumed knowledge of the system being controlled. With the growing interest in alternative fuels, such as ethanol, liquified petroleum gas (LPG), and compressed natural gas (CNG) due to enhanced emissions and fuel security considerations, a natural extension is to hybridize these engines to improve fuel economy and CO2 emissions. This step is complicated by the potential variation in fuel composition seen with many gasoline and diesel alternatives, leading to uncertainty in the models used by the hybrid powertrain controller. This work investigates the robustness of one hybrid powertrain optimal control approach, the equivalent consumption minimization strategy (ECMS). Two case studies are performed involving experimentally obtained engine maps from two significantly different prototypes flex-fuel vehicles to quantify the potential impact of map error caused by incorrect fuel assumptions.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Tracking Control of Limit Cycle Oscillations in an Aero-Elastic System
    • Authors: Bialy BJ; Pasiliao CL, Dinh HT, et al.
      Abstract: Limit cycle oscillations (LCOs) affect current fighter aircraft and are expected to be present on next generation fighter aircraft. Current efforts in control systems designed to suppress LCO behavior have either used a linear model, restricting the flight regime, require exact knowledge of the system dynamics, or require uncertainties in the system dynamics to be linear-in-the-parameters and only present in the torsional stiffness. Furthermore, the aerodynamic model used in prior research efforts neglects nonlinear effects. This paper presents the development of a controller consisting of a continuous robust integral of the sign of the error (RISE) feedback term with a neural network (NN) feedforward term to achieve asymptotic tracking of uncertainties that do not satisfy the linear-in-the-parameters assumption. Simulation results are presented to validate the performance of the developed controller.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Constructive Proof of Preisach Right Inverse With Applications to Inverse
           Compensation of Smart Actuators With Hysteresis
    • Authors: Dong Y; Hu H, Zhang Z.
      Abstract: Hysteresis poses a significant challenge for control of smart material actuators. If unaccommodated, the hysteresis can result in oscillation, poor tracking performance, and potential instability when the actuators are incorporated in control design. To overcome these problems, a fundamental idea in coping with hysteresis is inverse compensation based on the Preisach model. In this paper, we address systematically the problem of Preisach model inversion and its properties, employing the technique of three-step composition mapping and geometric interpretation of the Preisach model. A Preisach right inverse is achieved via the iterative algorithm proposed, which possesses same properties with the Preisach model. Finally, comparative experiments are performed on a piezoelectric stack actuator (PEA) to test the efficacy of the compensation scheme based on the Preisach right inverse.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Transient Response Control of Two-Mass System via Polynomial Approach
    • Authors: Qiao Y; Cao J, Ma C.
      Abstract: This paper discusses the application of polynomial method in the transient response control of a benchmark two-mass system. It is shown that transient responses can be directly addressed by specifying the so-called characteristic ratios and the generalized time constant. The nominal characteristic ratio assignment (CRA) is a good starting point for controller design. And the characteristic ratios with lower indices have a more dominant influence. Two practical low-order control configurations, the integral-proportional (IP) and modified-integral-proportional-derivative (m-IPD) controllers are designed. The primary design strategy of the controllers is to guarantee the lower-index characteristic ratios to be equal to their nominal values, while the higher-index characteristic ratios are determined by the interaction with the generalized time constant and the limits imposed by zeros, a specific control configuration, etc. The demonstrated relationship between the transient responses and the assignments of characteristic ratios and generalized time constant in simulation and experiments explains the effectiveness of the polynomial-method-based controller design.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Control-Oriented Gas Exchange Model for Diesel Engines Utilizing Variable
           Intake Valve Actuation
    • Authors: Kocher L; Koeberlein E, Stricker K, et al.
      Abstract: Modeling and control of the gas exchange process in modern diesel engines is critical for the promotion and control of advanced combustion strategies. However, most modeling efforts to date use complex stand-alone simulation packages that are not easily integrated into, or amenable for the synthesis of, engine control systems. Simpler control-oriented models have been developed; however, in many cases, they do not directly capture the complete dynamic interaction of air handling system components and flows in multicylinder diesel engines with variable geometry turbocharging (VGT), high pressure exhaust gas recirculation (EGR), and flexible intake valve actuation. Flexibility in the valvetrain directly impacts the gas exchange process not only through the effect on volumetric efficiency but also through the combustion process and resulting exhaust gas enthalpy utilized to drive the turbomachinery. This paper describes a low-order, five state model of the air handling system for a multicylinder variable geometry turbocharged diesel engine with cooled EGR and flexible intake valve actuation, validated against 286 steady state and 62 transient engine operating points. The model utilizes engine speed, engine fueling, EGR valve position, VGT nozzle position, and intake valve closing (IVC) time as inputs to the model. The model outputs include calculation of the engine flows as well as the exhaust temperature exiting the cylinders. The gas exchange model captures the dynamic effects of the not only the standard air handling actuators (EGR valve position and VGT position) but also IVC timing, exercised over their useful operating ranges. The model's capabilities are enabled through the use of analytical functions to describe the performance of the turbocharger, eliminating the need to use look-up maps; a physically based control-oriented exhaust gas enthalpy submodel and a physically based volumetric efficiency submodel.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • An Iterative Learning Control Approach to Improving Fidelity in
           Internet-Distributed Hardware-in-the-Loop Simulation
    • Authors: Ersal T; Brudnak M, Salvi A, et al.
      Abstract: One of the main challenges of cosimulating hardware-in-the-loop (HIL) systems in real-time over the Internet is the fidelity of the simulation. The dynamics of the Internet may significantly distort the dynamics of the network-integrated system. This paper presents the development and experimental validation of an iterative learning control (ILC) based approach to improve fidelity of such networked system integration. Toward this end, a new metric for characterizing coupling fidelity is proposed, which, unlike some existing metrics, enables the formulation of the problem of improving system fidelity without requiring any knowledge about the reference dynamics (i.e., dynamics that would be observed, if the system was physically connected). Next, using this metric, the problem of improving fidelity is formulated as an ILC problem. The proposed approach is illustrated on an experimental setup simulating a hybrid electric powertrain distributed across three different sites with a real engine and battery in the loop. The conclusion is that the proposed approach holds significant potential for achieving high fidelity in Internet-distributed HIL (ID-HIL) simulation setups.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Modeling and Dynamical Feedback Control of a Vehicle Diesel Engine Speed
           and Air-Path
    • Authors: Wang H; Tian Y, Bosche J, et al.
      Abstract: This paper presents a modeling and dynamical feedback stabilization control of a diesel engine which is equipped with a variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) valve. A fourth-order dimensional nonlinear model which takes into account the engine crankshaft speed dynamics and the air-path dynamics is proposed for the considered diesel engine. The difficulties for the control design are that the referred system is nonlinear, nonminimum phase unstable and coupled system. The fuel flow rate Wf which is considered as input for the engine crankshaft subsystem and acts as an external perturbation for the three-order dimensional nonminimum phase air-path subsystem. The global control objectives are to track desired values of engine speed, intake manifold pressure and compressor flow mass rate which can be suitably chosen according to low emission criterions. For the considered objectives, a dynamical feedback stabilization control with a two-loop structure of inner outer loop is proposed. The inner loop considers a control based on a Lyapunov function which realizes the desired engine speed trajectory tracking. The outer loop which is developed from a particular extended nonlinear air-path subsystem with its modified outputs concerns the coordinated EGR and VGT control and ensures both the desired intake manifold pressure and the desired compressor mass flow rate trajectory tracking. Meanwhile, this outer loop dynamical feedback stabilization control provides also the external fuel mass flow rate perturbation rejection. From the corresponding numerical simulation results, the proposed method efficiency is validated.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Real-World Robustness for Hybrid Vehicle Optimal Energy Management
           Strategies Incorporating Drivability Metrics
    • Authors: Opila DF; Wang X, McGee R, et al.
      Abstract: Hybrid vehicle fuel economy and drive quality are coupled through the “energy management” controller that regulates power flow among the various energy sources and sinks. This paper studies energy management controllers designed using shortest path stochastic dynamic programming (SP-SDP), a stochastic optimal control design method which can respect constraints on drivetrain activity while minimizing fuel consumption for an assumed distribution of driver power demand. The performance of SP-SDP controllers is evaluated through simulation on large numbers of real-world drive cycles and compared to a baseline industrial controller provided by a major auto manufacturer. On real-world driving data, the SP-SDP-based controllers yield 10% better fuel economy than the baseline industrial controller, for the same engine and gear activity. The SP-SDP controllers are further evaluated for robustness to the drive cycle statistics used in their design. Simplified drivability metrics introduced in previous work are validated on large real-world data sets.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Sensitivity Analysis and Experimental Research on Ball Bearing Early Fault
           Diagnosis Based on Testing Signal From Casing
    • Authors: Chen GG; Hao TF, Wang HF, et al.
      Abstract: The ball bearings of an aero-engine are key parts that frequently fail, and it is very important to effectively carry out fault diagnosis of the ball bearings. However, in the present research work, the ball bearing faults characteristics are extracted mainly from the bearing house signals, it is well known that usually only the casing signals can be measured in practical aero-engine test, and the ball bearing faults characteristics will greatly weaken after transmitting to the casing from the bearing house, therefore, it is very important to extract the fault characteristics of ball bearings from casing vibration signals for the ball bearing fault diagnosis in the practical aero-engine. In this study, simulation experiments for ball bearing faults are conducted using two rotor experimental rigs with casings. In addition, by means of the impulse response method, the transfer characteristics from the ball bearings to casing measuring points are measured, and a sensitivity analysis is performed. Faults are created on the inner ring, outer ring, and ball of the ball bearings in the two experimental rigs. The ball bearing experiments are carried out, and the fault features are extracted by means of a wavelet envelope analysis. The experimental results indicate that, with high connection stiffness between the bearing house and the casing, there is little vibration attenuation. However, with low connection stiffness, the vibration attenuation is great. After the impulse vibrations caused by the ball bearing faults are transmitted to the casing, the casing vibration is very weak and is often submerged in other signals. However, the ball bearing fault characteristic frequencies can still be effectively extracted from the weak casing vibration signals by using a wavelet envelope analysis. The research results in this study provide an experimental basis for a ball bearing fault diagnosis based on a casing test signal from a practical aero-engine.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Stiffness Analysis and Control of a Stewart Platform-Based Manipulator
           With Decoupled Sensor–Actuator Locations for Ultrahigh Accuracy
           Positioning Under Large External Loads
    • Authors: Ding B; Cazzolato BS, Stanley RM, et al.
      Abstract: Robot frame compliance has a large negative effect on the global accuracy of the system when large external forces/torques are exerted. This phenomenon is particularly problematic in applications where the robot is required to achieve ultrahigh (micron level) accuracy under very large external loads, e.g., in biomechanical testing and high precision machining. To ensure the positioning accuracy of the robot in these applications, the authors proposed a novel Stewart platform-based manipulator with decoupled sensor–actuator locations. The unique mechanism has the sensor locations fully decoupled from the actuator locations for the purpose of passively compensating for the load frame compliance, as a result improving the effective stiffness of the manipulator in six degrees of freedom (6DOF). In this paper, the stiffness of the proposed manipulator is quantified via a simplified method, which combines both an analytical model (robot kinematics error model) and a numerical model [finite element analysis (FEA) model] in the analysis. This method can be used to design systems with specific stiffness requirements. In the control aspect, the noncollocated positions of the sensors and actuators lead to a suboptimal control structure, which is addressed in the paper using a simple Jacobian-based decoupling method under both kinematics- and dynamics-based control. Simulation results demonstrate that the proposed manipulator configuration has an effective stiffness that is increased by a factor of greater than 15 compared to a general design. Experimental results show that the Jacobian-based decoupling method effectively increases the dynamic tracking performance of the manipulator by 25% on average over a conventional method.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Optimal Control of the Heat Release Rate of an Internal Combustion Engine
           With Pressure Gradient, Maximum Pressure, and Knock Constraints
    • Authors: Zurbriggen F; Ott T, Onder C, et al.
      Abstract: In this paper, we present an analysis of the optimal burn rate in an internal combustion engine (ICE) considering pressure gradient, maximum pressure, and knocking. A zero-dimensional model with heat losses is used for that purpose. The working fluids are assumed to behave like ideal gases with temperature dependent gas properties. In the first part, it is assumed that the burn rate can be arbitrarily chosen at every time instance in order to maximize the mechanical work. This leads to an optimal control problem with constraints. In the second part, a Vibe type burn rate is assumed, where the center of combustion, the duration and the form factor can be chosen in order to maximize the mechanical work. This Vibe type burn rate is finally compared with the arbitrary combustion as the benchmark in order to evaluate the potential of the more realistic burn shape.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Power Conserving Bond Graph Based Modal Representations and Model
           Reduction of Lumped Parameter Systems
    • Authors: Louca LS.
      Abstract: Dynamic analysis is extensively used to study the behavior of continuous and lumped parameter linear systems. In addition to the physical space, analyses can also be performed in the modal space where very useful frequency information of the system can be extracted. More specifically, modal analysis can be used for the analysis and controller design of dynamic systems, where reduction of model complexity without degrading its accuracy is often required. The reduction of modal models has been extensively studied and many reduction techniques are available. The majority of these techniques use frequency as the metric to determine the reduced model. This paper describes a new method for calculating modal decompositions of lumped parameter systems with the use of the bond graph formulation. The modal decomposition is developed through a power conserving coordinate transformation. The generated modal decomposition model is then used as the basis for reducing its size and complexity. The model reduction approach is based on the previously developed model order reduction algorithm (MORA), which uses the energy-based activity metric in order to generate a series of reduced models. The activity metric was originally developed for the generic case of nonlinear systems; however, in this work, the activity metric is adapted for the case of linear systems with single harmonic excitation. In this case closed form expressions are derived for the calculation of activity. An example is provided to demonstrate the power conserving transformation, calculation of the modal power and the elimination of unimportant modes or modal elements.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Onset of Oscillations in Traveling Wave Thermo-Acoustic-Piezo-electric
           Harvesters Using Circuit Analogy and SPICE Modeling
    • Authors: Nouh MM; Aldraihem OO, Baz AA.
      Abstract: Equations governing different physical fields such as mechanical, acoustical, and electrical are inherently similar. This enables mechanical, thermal, and acoustical networks to be fully described with analogous electric networks. For thermo-acoustic-piezo-electric (TAP) harvesters, such a modeling approach allows the whole system to be characterized in the electrical domain and facilitates the understanding of the underlying physics. In this paper, a traveling wave thermo-acoustic-piezoelectric (TWTAP) energy harvester is considered which converts thermal energy, such as solar or waste heat energy, directly into electrical energy without the need for any moving components. The input thermal energy generates a steep temperature gradient along a porous regenerator. At a critical threshold of the temperature gradient, self-sustained acoustic waves are developed inside an acoustic resonator. The associated pressure fluctuations impinge on a piezo-electric diaphragm, placed at the end of the resonator, to generate electricity. The acoustic pressure oscillations are amplified by a specially designed acoustic feedback loop that introduces appropriate phasing to make the pulsations take the form of traveling waves. The behavior of this TWTAP is modeled using electrical circuit analogy. The developed model combines the descriptions of the acoustic resonator, feedback loop, and the regenerator with the characteristics of the piezo-electric diaphragm. With the help of a simulation program with integrated circuit emphasis (SPICE) code, the developed electric circuit is used to analyze the system’s stability with regard to the input heat and hence predict the necessary temperature ratio required to establish the onset of self-sustained oscillations inside the harvester’s resonator. The predictions are compared with published results obtained using root locus and numerical methods and validated against experiments. This approach provides a very practical approach to the design of TAP energy harvesters both in the time and frequency domain. Such capabilities do not exist presently in the well-known design tool design environment for low-amplitude thermo-acoustic energy conversion (DeltaEC) developed at Los Almos National Laboratory which is limited to steady-state analysis. This is in contrast to the present approach which can be applicable to both steady as well as transient analysis.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Output-Feedback Stabilization for a Special Class of Stochastic Nonlinear
           Time-Delay System With More General Growth Conditions
    • Authors: Guo L; Liu J, Zuo X, et al.
      Abstract: This paper focuses on a special class of stochastic nonlinear time-delay system with more weak conditions in which the drift and diffusion vectors depend on all the states, including the unmeasurable states for the first time. By introducing a high-gain observer, finding the maximum value interval of high-gain for the desired performance and choosing an appropriate Lyapunov-Krasoviskii function, an output-feedback controller is designed to ensure the equilibrium at the origin of the closed-loop system is globally asymptotically stable in probability and the output can be almost regulated to the origin surely. A practice example of mechanical movement system is provided to demonstrate the efficiency of the output-feedback controller.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Performance-Adaptive Generalized Predictive Control-Based
           Proportional-Integral-Derivative Control System and Its Application
    • Authors: Sato T; Yamamoto T, Araki N, et al.
      Abstract: In the present paper, we discuss a new design method for a proportional-integral-derivative (PID) control system using a model predictive approach. The PID compensator is designed based on generalized predictive control (GPC). The PID parameters are adaptively updated such that the control performance is improved because the design parameters of GPC are selected automatically in order to attain a user-specified control performance. In the proposed scheme, the estimated plant parameters are updated only when the prediction error increases. Therefore, the control system is not updated frequently. The control system is updated only when the control performance is sufficiently improved. The effectiveness of the proposed method is demonstrated numerically. Finally, the proposed method is applied to a weigh feeder, and experimental results are presented.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Propagation of Longitudinal Deformation Wave Along a Hoisting Rope
           Carrying an Intermediate Concentrated Load
    • Authors: Razdolsky AG.
      Abstract: Motion of the hoisting rope carrying an intermediate concentrated load is described by the one-dimensional wave equation in the region consisting of two sections separated by a moving boundary condition. The system is moved by the driving force acting at the upper cross section of the rope. Position of the intermediate load and consequently the lengths of the rope sections vary in the time depending on the magnitude of driving force. Solution of the wave equation is represented as a sum of integrals with variable limits of integration. The problem is reduced to solving the sequence of ordinary differential equations which describe a motion of the load in the fixed coordinate system and the paths of the rope ends in the moving coordinate system connected with the load. The argument of functions involved in the right-hand side of these equations lag behind the argument of the derivatives in the left-hand side of equations by a short time interval. A description of the unknown functions in a parametric form makes possible to eliminate retarded arguments from the equations. The problem is solved by using a technique of the sequential continuation of solution for time intervals corresponding to propagation of the deformation wave in the opposite directions. A computer program has been developed for solving the problem. Results of the numerical solution are presented in the case that the driving force is a piecewise linear function of time and is discontinuous at the peak point.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
  • Numerical Solution of Stiff Multibody Dynamic Systems Based on Kinematic
           Derivatives
    • Authors: Milenkovic P.
      Abstract: The Hermite–Obreshkov–Padé (HOP) method of numerical integration is applicable to stiff systems of differential equations, where the linearization has large range of eigenvalues. A practical implementation of HOP requires the ability to determine high-order time derivatives of the system variables. In the case of a constrained multibody dynamical system, the power series solution for the kinematic differential equation is the foundation for an algorithmic differentiation (AD) procedure determining those derivatives. The AD procedure is extended in this paper to determine rates of change in the time derivatives with respect to variation in the position and velocity state variables of the multibody system. The coefficients of this variation form the Jacobian matrix required for Newton–Raphson iteration. That procedure solves the implicit relations for the state variables at the end of each integration time step. The resulting numerical method is applied to the rotation of a dynamically unbalanced constant-velocity (CV) shaft coupling, where the deflection angle of the output shaft is constrained to low levels by springs of high rate and damping.
      PubDate: Fri, 08 Aug 2014 00:00:00 GMT
       
 
 
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