bluuebunny/crossref_metadata_2025 huggingface dataset:
Discrimination of taste qualities among mouse fungiform taste bud cells
Authors: Yoshida Ryusuke , Miyauchi Aya , Yasuo Toshiaki , Jyotaki Masafumi , Murata Yoshihiro , Yasumatsu Keiko , Shigemura Noriatsu , Yanagawa Yuchio , Obata Kunihiko , Ueno Hiroshi , Margolskee Robert F. , Ninomiya Yuzo
Published: July 2009

Multiple lines of evidence from molecular studies indicate that individual taste qualities are encoded by distinct taste receptor cells. In contrast, many physiological studies have found that a significant proportion of taste cells respond to multiple taste qualities. To reconcile this apparent discrepancy and to identify taste cells that underlie each taste quality, we investigated taste responses of individual mouse fungiform taste cells that express gustducin or GAD67, markers for specific types of taste cells. Type II taste cells respond to sweet, bitter or umami tastants, express taste receptors, gustducin and other transduction components. Type III cells possess putative sour taste receptors, and have well elaborated conventional synapses. Consistent with these findings we found that gustducin‐expressing Type II taste cells responded best to sweet (25/49), bitter (20/49) or umami (4/49) stimuli, while all GAD67 (Type III) taste cells examined (44/44) responded to sour stimuli and a portion of them showed multiple taste sensitivities, suggesting discrimination of each taste quality among taste bud cells. These results were largely consistent with those previously reported with circumvallate papillae taste cells. Bitter‐best taste cells responded to multiple bitter compounds such as quinine, denatonium and cyclohexamide. Three sour compounds, HCl, acetic acid and citric acid, elicited responses in sour‐best taste cells. These results suggest that taste cells may be capable of recognizing multiple taste compounds that elicit similar taste sensation. We did not find any NaCl‐best cells among the gustducin and GAD67 taste cells, raising the possibility that salt sensitive taste cells comprise a different population.
Fuel selection in Wistar rats exposed to cold: shivering thermogenesis diverts fatty acids from re‐esterification to oxidation
Authors: Vaillancourt Eric , Haman François , Weber Jean‐Michel
Published: July 2009

This study characterizes the effects of shivering thermogenesis on metabolic fuel selection in Wistar rats. Because lipids account for most of the heat produced, we have investigated: (1) whether the rate of appearance of non‐esterified fatty acids (Ra NEFAs) is stimulated by shivering, (2) whether mono‐unsaturated (oleate) and saturated fatty acids (palmitate) are affected similarly, and (3) whether the partitioning between fatty acid oxidation and re‐esterification is altered by cold exposure. Fuel oxidation was measured by indirect calorimetry and fatty acid mobilization by continuous infusion of 9,10‐[3H]oleate and 1‐[14C]palmitate. During steady‐state cold exposure, results show that total heat production is unequally shared by the oxidation of lipids (52% of metabolic rate), carbohydrates (35%) and proteins (13%), and that the same fuel selection pattern is observed at all shivering intensities. All previous research shows that mammals stimulate Ra NEFA to support exercise or shivering. In contrast, results reveal that the Ra NEFA of the rat remains constant during cold exposure (∼55 μmol kg−1 min−1). No preferential use of mono‐unsaturated over saturated fatty acids could be demonstrated. The rat decreases its rate of fatty acid re‐esterification from 48.4 ± 6.4 to 19.6 ± 6.3 μmol kg−1 min−1 to provide energy to shivering muscles. This study is the first to show that mammals do not only increase fatty acid availability for oxidation by stimulating Ra NEFA. Reallocation of fatty acids from re‐esterification to oxidation is a novel, alternative strategy used by the rat to support shivering.
Signal pathways regulating hyaluronan secretion into static and cycled synovial joints of rabbits
Authors: Ingram K. R. , Wann A. K. T. , Wingate R. M. , Coleman P. J. , McHale N. , Levick J. R.
Published: July 2009

Joint lubrication, synovial fluid conservation and many pathophysiological processes depend on hyaluronan (HA). Intra‐articular HA injection and exercise, which stimulates articular HA production, ameliorate osteoarthritis. We therefore investigated the pathways regulating movement‐stimulated articular HA secretion rate ()in vivo.Endogenous HA was removed from the knee joint cavity of anaesthetised rabbits by washout. Joints were then cycled passively or remained static for 5 h, with/without intra‐articular agonist/inhibitor, after which newly secreted HA was harvested for analysis. Movement almost doubled. Similar or larger increases were elicited in static joints by the intra‐articular Ca2+ionophore ionomycin, prostaglandin E2, cAMP‐raising agents, serine/threonine phosphatase inhibitor and activation of protein kinase C (PKC). PKC‐stimulated secretion was inhibited by the PKC inhibitor bisindolylmaleimide I and inhibitors of the downstream kinases MEK‐ERK (U0126, PD98059). These agents inhibited movement‐stimulated secretion of HA (MSHA) only when the parallel p38 kinase path was simultaneously inhibited by SB203580 (ineffective alone). The phospholipase C inhibitor U73122 almost fully blocked MSHA (P= 0.001,n= 10), without affecting static. The ENaC channel blocker amiloride inhibited MSHA, whereas other inhibitors of stretch‐activated channels (Gd3+, ruthenium red, SKF96365) did not. It is proposed that MSHA may be mediated by PLC activation, leading to activation of parallel PKC–MEK–ERK and p38 kinase pathways.
Regulation of apoptotic potassium currents by coordinated zinc‐dependent signalling
Authors: Redman Patrick T. , Hartnett Karen A. , Aras Mandar A. , Levitan Edwin S. , Aizenman Elias
Published: July 2009

Oxidant‐liberated intracellular Zn2+regulates neuronal apoptosis via an exocytotic membrane insertion of Kv2.1‐encoded ion channels, resulting in an enhancement of voltage‐gated K+currents and a loss of intracellular K+that is necessary for caspase‐mediated proteolysis. In the present study we show that an N‐terminal tyrosine of Kv2.1 (Y124), which is a known target of Src kinase, is critical for the apoptotic current surge. Moreover, we demonstrate that Y124 works in concert with a C‐terminal serine (S800) target of p38 mitogen‐activated protein kinase (MAPK) to regulate Kv2.1‐mediated current enhancement. While Zn2+was previously shown to activate p38, we show here that this metal inhibits cytoplasmic protein tyrosine phosphatase ɛ (Cyt‐PTPɛ), which specifically targets Y124. Importantly, a point mutation of Y124 to a non‐phosphorylatable residue or over‐expression of Cyt‐PTPɛ protects cells from injury. Kv2.1‐encoded channels thus regulate neuronal survival by providing a converging input for two Zn2+‐dependent signal transduction cascades.
Analysis of Flow Control in Alternative Manufacturing Configurations
Authors: Solberg J. J. , Nof S. Y.
Published: July 2009

A mathematical model of workflow, based on queueing network theory, is used to compare the performance of four alternative layout configurations for manufacturing systems: a product layout (or flowshop), a process layout (or job shop), and two layouts which have been used in computerized manufacturing system. It is shown that, under appropriate conditions, any one of the four layouts could be the preferred choice. The impact of part mix, process selection, and the ratio of mean process time to mean transport time on the layout design are revealed and quantified.
Dynamical Models for Multidimensional Structures Using Bond Graphs
Authors: Margolis D. L.
Published: July 2009

Bond graphs are used to construct finite mode, long wavelength models of multidimensional structures. These structures are, in some cases, either too large or constructed from so many physical pieces that complete modeling using finite element methods is prohibited. Bond graph development for this type of dynamic system is given. The technique is demonstrated for the Lawrence Livermore Laboratory Shiva-Nova laser spaceframe.
Asymptotic Theory of Freight Car Hunting
Authors: Whitman A. M.
Published: July 2009

A simple formula is derived for the hunting speed of a freight car from an 8 degree of freedom linear model using asymptotic techniques. A comparison is made between the approximation and exact (numerical) solutions. The two agree within 10 percent for parameter values typical of present designs.
Improved Statistical Linearization for Analysis and Control of Nonlinear Stochastic Systems: Part II: Application to Control System Design
Authors: Beaman J. J. , Hedrick J. K.
Published: July 2009

Using the techniques of Gaussian statistical linearization and the extension given in Part I, this paper describes the synthesis of linear feedback controllers for nonlinear stochastic systems. The method used is that of pole placement of the statistically linearized “eigenvalues”. The technique is described in terms of a design example, a position servomechanism with backlash, it is shown that for this type of system the standard Gaussian method works well for large input noise levels but can lead to an unstable design for low input levels. The extended fourth cumulant method is satisfactory for both cases studied. The results of the analysis are compared to Monte Carlo digital simulations to test their accuracy.
A Diagnosis Method for Linear Stochastic Systems With Parametric Failures
Authors: Watanabe K. , Yoshimura T. , Soeda T.
Published: July 2009

A method of failure diagnosis for discrete-time stochastic systems with some parametric failures is proposed. It is assumed that the time instances of failure occurrence and the dynamic behaviors of failure parameters cannot be estimated in advance. The idea of Two-Filters is utilized as the filter construction for the diagnosis system. The new feature of the approach is to use a modified adaptive extended Kalman filter which estimates system parameters and states simultaneously under the failure mode. The adaptive mechanism of this filter is based on hypothesis tests for the innovation and for the estimation errors of system parameters, and modifies the filter gains if the hypothesis is rejected. In addition, a discriminator, which uses the trace value of the approximate local sensitivity, is developed in order to help the operator’s tasks. Experimental results indicate that the proposed method on the failure diagnosis is effective for several numerical examples.
Payoff Sensitivity of Linear Quadratic Differential Games to Parameter Change
Authors: Leondes C. T. , Sui T. K.
Published: July 2009

Both maximizing and minimizing players are concerned with the change in payoff due to small variation of system parameters. A technique is developed to derive linear algebraic matrix equations which can be used to determine the payoff sensitivity of all the parameters in linear zero- sum differential games with constant feedback. Above all, this technique is applicable for determining both the optimal strategy and payoff.
Use of Lead/Lag Approximations in Modeling Thermal Regenerator Systems
Authors: Burns A. , Jeffreson C. P. , Willmott A. J.
Published: July 2009

A method of building simple low order lead/lag approximations to a “heat exchanger” model of regenerator systems is described. The method involves extraction of successive real poles and zeros of the system transfer functions for temperature or flow forcing. The first moments of the system provide a-useful guide to the number of such real poles and zeros required for a particular combination of system parameters.
A Note on Avoidance Control
Authors: Barmish B. R. , Schmitendorf W. E. , Leitmann G.
Published: July 2009

This note points out some technical difficulties which can arise when attempting to determine the existence of a control which guarantees avoidance of a given set in the state space. It is concluded that the hypotheses of the existence theorem in [1] require strengthening.
On the Inverse of a Special Class of Bilinear Systems
Authors: Hsu C. S. , Mohler R. R.
Published: July 2009

In this paper, the design of inverse system for a special class of bilinear control processes is examined. It is shown that if the rank of the input matrix B is unity, then the inverse system of a bilinear process is a completely controllable linear time-invariant system. A simplified model of immune response is used as an example to illustrate the design procedure and its biomedical significance. Result of computer simulation is also presented.
A New Feedback Method for Dynamic Control of Manipulators
Authors: Takegaki Morikazu , Arimoto Suguru
Published: July 2009

A new approach to the dynamic control of manipulators is developed from the viewpoint of mechanics. It is first shown that a linear feedback of generalized coordinates and their derivatives are effective for motion control in the large. Next, we propose a method for task-oriented coordinate control which can be easily implemented by a micro-computer and is suited to sensor feedback control. The proposed method is applicable even when holonomic constraints are added to the system. Effectiveness of the proposed method is verified by computer simulation.
Optimum Path Planning for Mechanical Manipulators
Authors: Luh J. Y. S. , Lin C. S.
Published: July 2009

To assure a successful completion of an assigned task without interruption, such as the collision with fixtures, the hand of a mechanical manipulator often travels along a preplanned path. An advantage of requiring the path to be composed of straight-line segments in Cartesian coordinates is to provide a capability for controlled interaction with objects on a moving conveyor. This paper presents a method of obtaining a time schedule of velocities and accelerations along the path that the manipulator may adopt to obtain a minimum traveling time, under the constraints of composite Cartesian limit on linear and angular velocities and accelerations. Because of the involvement of a linear performance index and a large number of nonlinear inequality constraints, which are generated from physical limitations, the “method of approximate programming (MAP)” is applied. Depending on the initial choice of a feasible solution, the iterated feasible solution, however, does not converge to the optimum feasible point, but is often entrapped at some other point of the boundary of the constraint set. To overcome the obstacle, MAP is modified so that the feasible solution of each of the iterated linear programming problems is shifted to the boundaries corresponding to the original, linear inequality constraints. To reduce the computing time, a “direct approximate programming algorithm (DAPA)” is developed, implemented and shown to converge to optimum feasible solution for the path planning problem. Programs in FORTRAN language have been written for both the modified MAP and DAPA, and are illustrated by a numerical example for the purpose of comparison.
A Mathematical Model of Hand Transfer Motion for Application to Manipulator Control
Authors: Totani Takayoshi , Miyakawa Shohei
Published: July 2009

The hand motions which are observed when one holds an object and transfers it to a specified position are analyzed and a proposed mathematical model is compared with the real movements. The functions of time of which the space trajectories of the hand are constructed are classified into five modes and are expressed as a group of stationary functions in a variational problem in which a quadratic integral cost function is to be minimized. Some relations between the model parameters and the kinematic features of the motion patterns are shown. A way of designating the desired inputs for the joint angle servosystems of a manipulator is also shown.
Application of Model Reference Adaptive Techniques to a Class of Nonlinear Systems
Authors: Yoshimura Toshio , Tomizuka Masayoshi
Published: July 2009

This paper is concerned with the convergence analysis of an identification algorithm for a class of nonlinear dynamic systems. The class includes systems that can be separated into symmetric zero-memory nonlinear gain parts and linear dynamic parts. A model reference adaptive technique is applied to the identification of such a nonlinear dynamic system after taking the following three points into consideration: 1) approximation of the nonlinear characteristics by a set of functions, 2) introduction of a set of parameters to obtain a multi-input, single-output system which is equivalent to the nonlinear system and 3) selection of an appropriate input signal. The convergence analysis of the proposed identifier is investigated from the stochastic view-point. A numerical example is presented to illustrate the effectiveness of the proposed identifier.
Nonlinear State Estimation and Feedback Control of Nonlinear and Bilinear Distributed Parameter Systems
Authors: Balas M. J.
Published: July 2009

This paper presents a theory of nonlinear state observers for nonlinear and bilinear distributed parameter systems. Convergence results are proved for these observers. Linear feedback control derived from such state observers is applied to the distributed parameter system and conditions are presented for closed-loop stability. The emphasis is on finite dimensional state observers and controllers (which can be implemented with on-line computers) and conditions for their successful operation with infinite dimensional distributed parameter systems.
On the Efficacy of Nonlinear Control in Uncertain Linear Systems
Authors: Leitmann G.
Published: July 2009

We consider a class of linear dynamical systems containing uncertain elements and subject to uncertain inputs, and for which either uncertain state or output is available. We construct a feedback control, utilizing measured state or estimated state, which guarantees that every system response is ultimately bounded within a certain neighborhood of the zero state. Performance resulting from use of this control is compared with that due to the use of purely linear feedback control.
Fabrication, Testing, and Evaluation of Prototype Fluidic Capillary Pyrometer Systems
Authors: Negas T. , Parker H. S. , Phillippi R. M. , Drzewiecki T. M. , Domingues L. P.
Published: July 2009

Protype fluidic capillary pyrometers (FCP) were designed and fabricated to measure elevated temperatures for several field applications. The device utilizes a viscosity and, hence, temperature-sensitive fluid resistor or capillary tube as the sensing probe combined with a simple fluid resistor bridge. Small pressure changes due to temperature are then amplified to a useable level with fluidic laminar amplifier circuitry. Monolithic FCP sensors for low thermal stress applications were constructed from several refractory oxides. Other sensors, for high thermal shock duty, were constructed from molybdenum protected with ceramic oxide coatings. This demonstrated that fabrication is feasbile and permitted the evaluation of performance at elevated temperature. Two monolithic sensors were installed at the Scranton Army Ammo Plant and have, to date, successfully operated for over 5000 hr. A coated molybdenum sensor was tested in various environments which included rapid immersion in an inductively heat molten gray iron bath. This sensor accumulated over 48 hr at temperatures up to 1550°C and made measurements for 6 hr in the molten iron. Materials and design options for high temperature probes are outlined and pertinent fluid circuitry is detailed.
Flood Protection by Vortex Valves
Authors: Brombach H.
Published: July 2009

The flow control function of a flood retention reservoir is taken care of by two double-controlled conical vortex valves. The nozzle diameters of these valves are 900 mm, the diameter of the vortex chamber being 2700 mm. The rate of the outflow to be controlled is up to 8 m3/s. The valves were installed in the spring of 1980 and will be put into service in 1981. Their purpose is to protect a town from floods caused by bad weather.
Measurements and Observations on Wheelset Lateral Dynamics of Locomotives on Tangent Track
Authors: Kummrow R.
Published: July 2009

Field tests with an electric Re 6/6 locomotive are summarized in this paper. The test objectives included the assessment of the lateral wheel-rail dynamics on tangent track. A method is presented which measures continuously the wheelset’s lateral and yaw displacement from track centerline and local rail deflections. The data are obtained on a spatial base through track side marks in conjunction with wheelset rotary trigger pulses. These measurements give a vivid description of the nature of wheelset motion on real track. They allow to scrutinize some of the assumptions inherent to linear rail vehicle modelling. Linearization of the creep force laws and the contact geometry is found to be questionable particularly in the presence of tractive effort, and generally for near critical speed. The results should be of interest primarily to theoretical and experimental rail vehicle dynamicists.
Motion of a Bored Sphere in a Spinning Spherical Cavity
Authors: Nunn R. H. , Bloomer J. W.
Published: July 2009

Theory and experiment are combined to develop a predictive model for the motion of a bored sphere within a spinning spherical cavity. The motion is gyroscopic in nature with the sphere eventually aligning its hole with the axis of spin of the cavity. Analytical expressions are derived for the applied moments on the sphere due to its motion relative to that of the cavity, and the resulting equations of motion are solved by numerical methods. An approximate closed-form solution is also obtained. Experiments are described in which the measured nutation of the sphere substantiates the analytical predictions.
Model Reference Adaptive Controllers and Stochastic Self-Tuning Regulators—A Unified Approach
Authors: Landau I. D.
Published: July 2009

The control objectives for Model Reference Adaptive Control Systems (MRAC) are specified in terms of a reference model. The control objectives for Stochastic Self-Tuning Regulators (S-STURE) are specified in terms of an ARMA model. These two types of adaptive control systems share a common characteristic (duality). This duality extends the one existing in the linear case with known parameters between modal control (pole-placement) and minimum variance control. Based on the duality properties, a unified presentation of the two techniques is possible; the S-STURE being interpreted as a stochastic MRAC. The underlying concepts and the structure of these adaptive control systems are described. The available theoretical results concerning the analysis of these systems are briefly reviewed. The primary domain of application of these techniques are indicated. An overview of the unsolved problems concludes the paper.
Solution of Finite-Time LQP Optimal Control Problems for Discrete-Time Systems
Authors: Grimble M. J. , Fotakis J.
Published: July 2009

The deterministic discrete-time optimal control problem for a finite optimization interval is considered. A solution is obtained in the z-domain by embedding the problem within a equivalent infinite time problem. The optimal controller is time-invariant and may be easily implemented. The controller is related to the solution of the usual infinite time optimal control problem due to Wiener. This new controller should be of value in self-tuning control laws where a finite interval controller is particularly important.
Longitudinal Control for Automated Highway Vehicles
Authors: Caudill R. J. , Di Matteo P. , Thomas S. P.
Published: July 2009

The problem of designing longitudinal control systems for automated highway vehicles powered by internal combustion engines is examined. Careful controller design is required so that the movement of freight and people may be achieved in the same roadway while maintaining stringent safety and operational standards. Individual vehicle control is achieved utilizing a modified proportional-error controller with switching boundaries. Longitudinal control of vehicle strings is based upon the model reference control concept. Analytical and computer simulation results indicate it is feasible to operate mixed vehicle strings.
Dynamic Modeling of Serial Manipulator Arms
Authors: Thomas M. , Tesar D.
Published: July 2009

To design and precisely control a manipulator requires a representative dynamic model of the system. This paper presents the derivation of a rigid-link model for the serial manipulator, which reduces all of the arm’s dynamic properties to their effective values at the generalized inputs. The component terms of the model are readily calculated from the dynamic influence coefficients, which are based only on the geometry of the system. All necessary influence coefficients for serial manipulators are given in a particularly simple form. The model formulation keeps the system parameters and the input dynamics explicit in the controlling equations of motion, such that analysis and dynamic response results can be obtained in the most direct manner. Dynamic analysis results for an industrial manipulator are presented.
Comparison of Optimal Linear Regulators Applied to Minimization of Steering Losses of a Containership in a Seaway Using Frequency Domain Representations
Authors: Reid R. E. , Parent P. F.
Published: July 2009

Linear Quadratic Gaussian (LQG) techniques are applied to the design of a steering controller for minimization of propulsion losses due to steering of a high-speed containership in a seaway. Alternate performance criteria are used deriving from the evaluation of the nonlinear force derivatives of the surge equation related to steering. The sensitivities of the various resulting LQG controllers to the seaway environment are compared using frequency domain representations of the seaway disturbances which are shown to be far from white Gaussian noise. The implications for optimal linear regulator design in this environment are discussed on the basis of the results presented.
Magnetic Guidance of Conventional Railroad Vehicles
Authors: Caudill R. J. , Sweet L. M. , Oda K.
Published: July 2009

The potential for improved dynamic performance of conventional rail vehicles through control of linear induction or synchronous motors is explored. Improvements in vehicle stability, ride quality, traction capability, track loading, derailment safety, and curving performance result from use of controllable lateral and normal forces present in the motor. Recent advances in technology originally developed for high-speed levitated vehicles are applied to conventional railroad systems which have a greater potential for near-term implementation. The dynamic performance of alternate configurations, consisting of several generic motor types mounted either on trucks or carbodies, are evaluated. Significant improvements in both lateral dynamic stability and curving performance may be realized through magnetic guidance of the trucks using force levels well within the capability of existing linear motor technology.
Nonlinear Stability and Tracking of Rail Passenger Trucks
Authors: Horak D. , Wormley D. N.
Published: July 2009

An analysis of a rail passenger truck which includes nonlinear wheel/rail geometry and creep forces is formulated for determining truck stability and response to rail alignment irregularities. Digital simulation studies using the analysis have illustrated the large amplitude flange to flange response which occurs in operation of a truck below critical speed on a track with significant alignment irregularity, of a truck near critical speed and excited by irregularities and of a truck operated above critical speed. The variations in temporal waveform, probability density, and power spectral density of vehicle motions for these conditions are described. The influence of vehicle suspension parameters and wheel/rail geometry on truck stability and tracking ability is discussed and related to operating conditions.
A Modified Recursive Identifier Not Requiring Initial Condition Estimates
Authors: Mocenigo J. M. , Pearson A. E.
Published: July 2009

A recursive least-squares estimator is developed in an identification observer format with the property that the need for estimating initial conditions is eliminated for time limited data. Estimators are developed that work with observed input/output data corrupted by deterministic, piecewise deterministic, or stochastic noise.
Conventional Versus Self-Steering Radial Trucks for High-Speed Passenger Trains
Authors: Doyle G. R.
Published: July 2009

The performance of self-steering, articulated, and nonarticulated trucks for high-speed passenger trains was compared to a conventional passenger truck. Lateral stability and steady state curving analyses were used to evaluate a design speed of 200 km/h (125 mi/h), and a wheel tread/rail head wear index in curves. Based on the results of this analytical study, the self-steering articulated truck would reduce the wear index in curves by a factor of two. However, the use of a “relaxation” device in the secondary yaw suspension of the conventional nonarticulated truck would reduce the wear index in curves by a factor of four.
Constrained Inverted Pendulum Model For Evaluating Upright Postural Stability
Authors: Hemami H. , Katbab A.
Published: July 2009

The human torso motion about its upright position is analyzed and modeled by a feedback system where the ground reaction forces and constraint torques are explicitly computed. Further, Euler angles and body angular velocities are selected as state variables to simplify the dynamics. The general stability of this system is considered via Lyapunov’s second method. Two methods of preventing self rotation are discussed: Linear feedback law and holonomic torque constraints. The stability solution is verified by digital computer simulation.
Disturbance Decoupling by Feedforward and Preview Control
Authors: Imai H. , Shinozuka M. , Yamaki T. , Li D. , Kuwana M.
Published: July 2009

The problem of disturbance decoupling is formulated and solved for continuous-time linear systems in which feedforward of disturbance input and its derivatives is allowed. The problem of disturbance decoupling by preview control is also formulated for discrete-time linear systems and it is shown that these two problems are algebraically equivalent. The result is applied to the design of a disturbance absorber for an open bottom floating structure and a simulation study is carried out to demonstrate the effectiveness of the result.
The Vibro-Mass Gyroscope
Authors: Burdess J. S.
Published: July 2009

The paper examines the performance of a new two axis dynamically tuned gyroscope. Two types of feedback loop are described. In the first design the control force maintains the sensitive element in a near null position and provides a direct measure of the applied rate. Errors arising because of mistuning and damping are evaluated. The second design is constructed using regulator theory and the performance of the gyro is shown to be robust with respect to the parameters defining the gyro and its control system.
A Fast Computational Approach in Optimal Distributed-Parameter State Estimation
Authors: Watanabe K. , Iwasaki M.
Published: July 2009

A fast computational approach is considered for solving of a time-invariant operator Riccati equation accompanied with the optimal steady-state filtering problem of a distributed-parameter system. The partitioned filter with the effective initialization is briefly explained and some relationships between its filter and the well-known Kalman-type filter are shown in terms of the Meditch-type fixed-point smoother in Hilbert spaces. Then, with the aid of these results the time doubling algorithm is proposed to solve the steady-state solution of the operator Riccati equation. Some numerical examples are included and a comparison of the computation time required by the proposed method is made with other algorithms—the distributed partitioned numerical algorithm, and the Runge-Kutta method. It is found that the proposed algorithm is approximately from 40 to 50 times faster than the classical Runge-Kutta method with constant step-size for the case of 9th order mode Fourier expansion.
Model Reduction and Control System Design by Shifted Legendre Polynomial Functions
Authors: Chang Rong-Yeu , Wang Maw-Ling
Published: July 2009

A method of model reduction for reducing a higher order transfer function to its lower order model is developed based on the shifted Legendre function approximation. The expansion coefficients of the shifted Legendre series which represents the approximate responses of transfer functions are computed by the recursive formula, via operational matrix approach. The significances of applying shifted Legendre function to model reduction problem are that the method is simple, straightforward and the computational results obtained are accurate as well as the final time of the control system can be adjustable without any restriction. Based on the model reduction technique, a new algebraic method is proposed for the design of a feedback control system to satisfy specifications. Illustrative examples are given and satisfactory results are obtained.
Design and Application of Controllers and Observers for Disturbance Minimization and Pole Assignment
Authors: Shah S. L. , Seborg D. E. , Fisher D. Grant
Published: July 2009

A new design method for state feedback controllers which minimizes the effects of arbitrary disturbances on selected outputs is presented. The design procedure permits arbitrary assignment of closed-loop eigenvalues and is based on the minimization of a quadratic performance index which includes a term for disturbance transmittances. Two numerical examples and an experimental application to a pilot scale, double effect evaporator are included to show that the resulting control systems are practical and robust. This design method can also be used to design robust observers for systems with unknown and unmeasured disturbances.
Acceleration Profiles for Minimizing Residual Response
Authors: Aspinwall D. M.
Published: July 2009

A pulse-shaping technique based on a short, finite Fourier series expression for the forcing function is shown to attenuate residual dynamic response in elastic systems by several orders of magnitude. The approach is based on selecting the Fourier coefficients to depress the envelope of the residual response spectrum in desired regions. Response spectra comparisons are made for the rectangular, double versine, and shaped pulses.
The Elimination of Positivity Condition For Continuous System Identification
Authors: Hang C. C.
Published: July 2009

The positivity condition for discrete model reference system identification systems can be eliminated by adapting the parameters of the series compensator. The extension to continuous system identification is presented in this article and the properties of the resultant adaptive system are analysed.
On the Simplification of Transfer Functions of Linear Dynamical Systems
Authors: Yahagi Takashi
Published: July 2009

A method for the simplification of transfer functions of linear dynamical systems is presented. The sampled input and output data of the original system are used, and the least squares fit is applied to obtain a low-order model. When the order of a simplified model is equal to m, it is necessary to compute 2m × 2m matrices in the usual methods. However, if the impulse response of the original system is used, the simplified model can be obtained by computing m × m matrices. Since the computational procedures are simple, this method is useful for obtaining a numerical solution on a digital computer.
Control Systems for Automotive Vehicle Fuel Economy: A Literature Review
Authors: Sweet L. M.
Published: July 2009

This paper is a review of current research on applications of control systems and theory to achieve energy conservation in automotive vehicles. The development of internal combustion engine control systems that modulate fuel flow, air flow, ignition timing and duration, and exhaust gas recirculation is discussed. The relative advantages of physical and empirical models for engine performance are reviewed. Control strategies presented include optimized open-loop schedule type systems, closed-loop feedback systems, and adaptive controllers. The development of power train and hybrid vehicle control systems is presented, including controllers for both conventional transmissions and those employing flywheel energy storage.
Evaluation of Time-Duration Dependent Wheel Load Criteria for Wheelclimb Derailment
Authors: Sweet L. M. , Karmel A.
Published: July 2009

The most widely accepted criterion for wheelclimb derailment defines an upper limit for safe operation on wheel/rail contact forces on the climbing wheel, with the limit varying with time duration of the forces. For dynamic wheelclimb processes with significant lateral velocities, lateral forces may be measured for short time durations that are larger than those that may be sustained without derailment in steady state. This paper shows, however, that the JNR and other time-duration dependent criteria based on wheel load measurements alone are unsuccessful in predicting derailment safety. For wheelclimb processes involving negligible lateral velocities, the derailment limit can be estimated from quasisteady analysis of wheel/rail forces. The evaluation of criteria is based on experiments with a single wheelset and a nonlinear theory for dynamic wheelclimb.
Guideway-Suspension Tradeoffs in Rail Vehicle Systems
Authors: White R. C. , Cooperrider N. K.
Published: July 2009

This study addresses the question of whether rail passenger vehicles with more sophisticated (and more expensive) suspensions can operate on rougher (and less expensive) track with an overall lower net cost for the guideway-vehicle system. Four suspensions, representing a range of performance and cost, are optimized for operation on the roughest possible track. The cost of each suspension and its guideway is estimated. Two of the advanced guideway-vehicle systems appear to result in an overall cost savings. However, because of uncertainties in the estimates of guideway maintenance cost, these conclusions are regarded as illustrative of our methodology rather than quantitatively reliable.
Modeling and Dynamic Response of Maglev Vehicles Subjected to Crosswind Gusts
Authors: Garg D. P. , Barrows T. M.
Published: July 2009

This paper presents a two-degree-of-freedom model for magnetically levitated finite-length vehicles incorporating sway and yaw dynamics. Aerodynamic lateral forces and yawing moments on the vehicle resulting from constant speed wind gusts are computed using analytical techniques. Computer simulations are run for three vehicle speeds and three apparent mass factors. It is shown that higher apparent mass factors can be instrumental in reducing peak displacements and acceleration levels. The guidance-to-lift ratio is not as much affected by an increase in apparent mass factor as are the displacements and accelerations.
A Discrete-Time Adaptive Filter for Stochastic Distributed Parameter Systems
Authors: Watanabe K. , Yoshimura T. , Soeda T.
Published: July 2009

A discrete-time adaptive filter is derived for a distributed system described by a linear partial differential equation with some unknown random constants whose a priori probabilities are known. The system concerned contains the Gaussian white noise in time, and its measurement system is treated as a so-called pointwise observation in which the measurement is taken at the finite discrete subdomains in the coordinate spaces. The use is conceptually made of an adaptive technique based on the Bayesian method and it is shown that the optimal distributed filter proposed here can be partitioned into two parts, a linear nonadaptive part that consists of a bank of distributed Kalman-Bucy type filters and a nonlinear part that incorporates the learning nature of the estimator. For the derivation of each “elemental filter”, the discrete-time innovation theory is utilized. The eigenfunction expanding method in a complete orthonormal system is applied for the numerical procedure of the proposed filter. From the simulation of the estimation problem for the neutron flux distribution in a slab type nuclear reactor, the proposed adaptive filter is shown to have attractive characteristics and therefore can be recommended for practical online adaptive estimation of distributed parameter systems.
Model Following Control of Gas Turbine Engines
Authors: Monopoli R. V.
Published: July 2009

As gas turbine engines become more complex, they also become more difficult to control. Classical control techniques and modern control theory such as multivariable optimal control have been used for design of engine control systems. Since these methods apply to linear time invariant systems, they suffer certain shortcomings when applied to the highly nonlinear gas turbine engine. In this paper, Liapunov’s direct method is used as the basis for a different approach to this problem. It is a technique specifically intended to deal with nonlinear systems. The resulting control system forces specified engine variables to track the corresponding variables generated in an ideal model of the engine. Results presented include a description of the design approach, its application to a generalized gas turbine engine with fuel flow and exhaust nozzle area as inputs, and data indicating the performance achieved when the control algorithm was tested on a detailed nonlinear digital simulation of the engine.
Control of a Direct-Drive Arm
Authors: Asada H. , Kanade T. , Takeyama I.
Published: July 2009

A direct-drive arm is a mechanical arm in which the shafts of articulated joints are directly coupled to the rotors of motors with high torque. Since the arm does not contain transmission mechanisms between the motors and their loads, the drive system has no backlash, small friction, and high mechanical stiffness, all of which are desirable for fast, accurate, and versatile robots. First, the prototype robot is described, and basic feedback controllers for single-link drive systems are designed. Second, feedforward compensation is discussed. This compensation significantly reduces the effect of interactions among multiple joints and nonlinear forces. The experiments showed the excellent performance of the direct-drive arm in terms of speed and accuracy.
An Adaptive Model Following Control for Robotic Manipulators
Authors: Balestrino A. , De Maria G. , Sciavicco L.
Published: July 2009

The increased demand on robotic manipulator performances leads to the use of advanced control structures. An adaptive model following control system for robotic manipulators is developed via hyperstability theory. A new control algorithm is proposed that produces a discontinuous control signal, similar to a pulse amplitude signal, so that particular trajectories, referred as sliding modes, occur. The design procedure is simple and effective and always assures the asymptotic stability in the large. The decoupling properties can be achieved by a suitable choice of the reference model. A case study is developed by numerical simulation.
A Control System to Improve the Accuracy of Finished Surfaces in Milling
Authors: Watanabe T. , Iwai S.
Published: July 2009

Adaptive control to keep the accuracy of the shape of a workpiece within acceptable levels by altering the numerical control commands according to variations of manufacturing process parameters is called “geometric adaptive control.” In this paper, a geometric adaptive control system to compensate for errors in the finished surface due to tool deflection generated by milling operations is presented. The effects of cutting forces upon the shape of the finished surface are analyzed, and the composition of the system is discussed. In the system, the location error and the waviness error at the finished surface are evaluated from the sensed bending moments in the tool. These two errors are compensated for by shifting the tool path and by adjusting the feedrate, respectively. It is verified by experiments that the accuracy of the finished surface is improved significantly by using the system described in cases where the depth of cut varies. Geometric adaptive control is useful even when a workpiece is machined by both rough and finish cuts.
Digital Simulation of a Coulomb-Damped Hydraulic Servosystem
Authors: Shearer J. L.
Published: July 2009

A valve-controlled ram-type servosystem employing position feedback with an electrohydraulic servovalve and servoamplifier is modeled to simulate with a digital computer all of the possibly significant physical characteristics of such a system, including turbulent flow in certain connecting passages, distributed-parameter supply line dynamics, and Coulomb-type dryfriction in the ram and mass load. The simulated responses are compared with corresponding measured responses of the real system for the case of a single-period sawtooth wave input. It is shown how system stability can become marginal when small amplitude inputs are used, with the system barely moving at low speed, due to lack of damping from dry friction, and minimal valve damping at small flowrates.
Controller Design for Flexible, Distributed Parameter Mechanical Arms Via Combined State Space and Frequency Domain Techniques
Authors: Book W. J. , Majette M.
Published: July 2009

The potential benefits of the ability to control more flexible mechanical arms are discussed. A justification is made in terms of speed of movement. A new controller design procedure is then developed to provide this capability. It uses both a frequency domain representation and a state variable representation of the arm model. The frequency domain model is used to update the modal state variable model to insure decoupled states. The technique is applied to a simple example with encouraging results.
Efficient Use of Directional-Control Valves in Fluid-Logic Circuits
Authors: Pessen D. W.
Published: July 2009

Various types of directional-control valves have been systematically analyzed to determine the logic output functions obtained for different input-signal combinations. It was found that a surprisingly large variety of fairly complex logic functions can be obtained with a single valve. The results are summarized in five tables, which include 186 (i.e., all the significant) input-signal combinations. Several examples are presented, illustrating how the tables can be used to implement given fluid-logic functions with a minimum number of valves. It thus becomes possible to exploit the logic capacity of these valves to their fullest extent, which can result in considerable reduction in number of valves.
A Modular Dynamic Simulation Approach to the Reconstruction of Automobile Accidents
Authors: Olson B. D. , Smith C. C.
Published: July 2009

Dynamic computer simulation of automobile accidents can play a significant role in reconstructing vehicular motion. A modular approach, where individual computer modules are used interactively by an investigator to reconstruct the physical events of an accident in separate phases is proposed. This approach presents an opportunity for widespread application and therefore influence on automobile safety due to its simplicity, costs, accuracy, and ability to meet size limitations on small computers. Modular algorithms to analyze trajectory and impact phases of accidents and a series of nondimensional graphs applicable to the impact phase are developed and applied to two different accidents. The example reconstructions and comparisons with results from trying to reconstruct the accidents using a large “general purpose” program indicate the utility, viability, and promise of a modular algorithm reconstruction approach.