bluuebunny/crossref_metadata_2025 huggingface dataset:
Geopolitics, Economic Freedom and Growth in China and the West
Authors: Weede Erich
Published: July 2009

Three hundred years ago China and Europe were about equally poor. Then the West forged ahead of Asian societies, thereby generating rising global income disparities until the end of the 20th century. Since 1979 the Chinese have raised per capita incomes sevenfold. This history of economic performance poses two explanatory challenges. Why did China fall behind Europe or the West? Why has China started to close the income gap recently? Here, a unitary explanatory framework is suggested for answering both questions. Because of weak property rights, lack of scarcity prices, and too little economic freedom, China grew much more slowly than the West. The West benefited from better institutions than China because of political fragmentation resulting in limited government and comparatively free markets. Similarly, China could start its attempt to catch‐up with the West only after climbing out of the socialist trap by a de facto improvement of property rights and economic freedom, by “market‐preserving federalism” and by vigorously joining the capitalist world economy. This account of Western and Chinese performance ultimately rests on geopolitics. Interstate rivalry between European states, kingdoms and principalities contributed to safe property rights and the European miracle. Competition between European states forced them to establish limited instead of absolutist government and therefore to provide space for the commercial and industrial revolutions in the West. Similarly, rivalry between the People's Republic of China on the Mainland and the Republic of China on Taiwan, the hostile competition between Communist China and the Soviet Union, the historical rivalry between China and Japan, and the geographical closeness of US troop deployments to China forced the People's Republic of China leadership in the late 1970s to consider the consequences of falling further and further behind the West, Japan, and Taiwan. Thus, geopolitical threat perception has been the midwife of Chinese economic reform policies. The current financial and economic crisis is likely to increase government interference with the economy and to reduce economic freedom in China as well as in the West.
Coexistence without Principle: Reconsidering Multicultural Policies in Japan*
Authors: Kwak Jun‐Hyeok
Published: July 2009

Multicultural coexistence (tabunka kyōse) in Japan is as complicated as its definition. On the one hand, it is regarded as a challenge to the coherence of national identity that sustains the popular image of ethnic homogeneity in Japan; on the other hand, it has been considered a retrogressive force that destabilizes civic solidarity needed for the development of responsible citizens. After describing the multicultural policies proposed by local governments in Japan that have facilitated multicultural coexistence, this article critically reviews the policies' relevance as a viable democratic practice for foreign residents and warns against the dangers of exclusion and assimilation when multicultural policies are driven by local citizens without a regulative principle. Then, this article presents “reciprocal nondomination” as a regulative principle that prevents the practice of multicultural coexistence from leading to regressive consequences and provides a ground for democratic deliberation on various ethnic differences.
What Factors Shape Korea's Future? Forces andFortunaversus Ideas and Free Will
Authors: Clemens, Jr. Walter C.
Published: July 2009

To assess the prospects for peace on the Korean peninsula we must understand the factors that have contributed to tension and to détente in recent decades. Whatever policy goals we pursue, it would be helpful to know how these factors have operated in the past. The most relevant factors can be analyzed under three headings: material hard power; fortuna, and the intangibles of ideas and free will. This essay reviews examples of how these factors have contributed to conflict and – less often – reduced tensions on the Korean peninsula. No single factor explains the ups and downs in North–South relations and the Six‐Party Talks in recent years. No single explanation accounts for developments in the past, but the record shows that ideas and determined individuals have sometimes overcome the thrust of material forces and neutered the vagaries of time and chance. In short, free will has often outweighed both forces and fortuna. Where there is a will (on all sides), paths to mutual gain can sometimes be developed.
Performance Evaluation of a Planar 3DOF Robotic Exoskeleton for Motor Assessment
Authors: Ball Stephen J. , Brown Ian E. , Scott Stephen H.
Published: July 2009

A new planar robotic exoskeleton for upper-limb motor assessment has been developed. It provides independent control of a user’s shoulder, elbow, and wrist joints in the horizontal plane. The lightweight backdriveable robot is based on a novel cable-driven curved track and carriage system that enables the entire mechanism to be located underneath the user’s arm. It has been designed to extend the assessment capabilities of an existing planar robotic exoskeleton. This paper presents the design and performance of the new robot.
The Biomechanics of Erections: Modeling the Penis as a One-Comparment Pressurized Vessel vs. Modeling it as a Two-Compartments Pressurized Vessel
Authors: Mohamed A. , Erdman A. , Timm G.
Published: July 2009

Previous biomechanical models of the penis that have attempted to simulate penile erections have either been limited to two-dimensional geometry, simplified three-dimensional geometry or made inaccurate assumptions altogether. Most models designed the shaft of the penis as a one-compartment pressurized vessel fixed at one end, when in reality it is a two-compartments pressurized vessel, in which the compartments diverge as they enter the body and are fixed at two separate points. This study began by designing simplified two-dimensional and three-dimensional models of the erect penis using Finite Element Analysis (FEA) methods with varying anatomical considerations for analyzing structural stresses, axial buckling and lateral deformation. The study then validated the results by building physical models replicating the computer models. Finally a more complex and anatomically accurate model of the penis was designed and analyzed. There was a significant difference in the peak von-Mises stress distribution between the one-compartment pressurized vessel and the more anatomically correct two-compartments pressurized vessel. Furthermore, the two-compartments diverging pressurized vessel was found to have more structural integrity when subject to external lateral forces than the one-compartment pressurized vessel. This study suggests that Mother Nature has favored an anatomy of two corporal cavernosal bodies separated by a perforated septum as opposed to one corporal body, due to better structural integrity of the tunica albuginea when subject to external forces.
Design of a Catheter-Based Device for Performing Percutaneous Chordal-Cutting Procedures
Authors: Slocum A. H. , Bosworth W. R. , Mazumdar A. , Saez M. A. , Culpepper M. L. , Levine R. A.
Published: July 2009

In this paper we detail the rapid design, fabrication and testing of a percutaneous catheterbased device that is envisioned to enable externally controlled manipulation and cutting of specific chordae tendinae within the heart. The importance of this work is that it (a) provides a means that surgeons may use to alleviate problems associated with some forms of mitral valve regurgitation and (b) demonstrates how a deterministic design process may be used to drive design innovation in medical devices while lowering development cost/time/resources. In the United States alone, approximately 500,000 people develop ischemic or functional MR per year. A chordal cutting procedure and device could allow many patients, who would otherwise be unable to survive open-heart surgery, to undergo a potentially life-saving operation at reduced risk. The design process has enabled us to generate a solution to this problem in a relatively short time. A deterministic design process was used to generate several design concepts and then evaluate and compare each concept based on a set of functional requirements. A final concept to be alpha prototyped was then chosen, optimized, and fabricated. The design process made it possible to make rapid progress during the project and to achieve a device design that worked the first time. This approach is important to medical device design as it reduces engineering effort, cost, and the amount of time spent in iterative design cycles. An overview of the design process will be presented and discussed within the context of a specific case study–the rapid design/fabrication of a chordal cutting device. Experimental results will be used to assess: (i) The performance of the catheter in maneuvering into the heart and grasping various structures. (ii) The effectiveness of the catheter's RF ablation tip at cutting chordae inside of a heart. In the first experiment, the catheter was guided to the basal chordae under direct visualization, which showed that the catheter is capable of successfully grasping a chord. During the second experiment, ultrasound was shown to be a viable method of visualizing the catheter within the heart. During this experiment, once contact between the chord and RF ablator tip was confirmed, the chord was successfully ablated. We will also discuss experiments that are currently underway to visualize the catheter utilizing a Trans-Esophageal Echo probe, as well as imaging the mitral valve from the apex of the heart with a laparoscope so that video of the basal chord being grasped and cut can be acquired on a heart whose anatomical structures are intact. A brief synopsis will then be given of how the design process has been used in research and educational collaborations between MIT and local hospitals.
An Intelligent Bone Spinal Disc Implant for Asian Population
Authors: Chui C. , Jonaidi M. N. , Kuang S.
Published: July 2009

There is a high level of patient appeal and physician acceptance of motion preservation as the future treatment of symptomatic and painful degenerative disc disease. However, spinal artificial disc replacement is still in its infancy. We have been designing, developing and evaluating motor articulated implants for use in bone-spinal disc surgery for Asian population. Apart from the generally smaller built of Asian compared to the American and European, the motor articulated implant should make provisions for the difference in eastern and western lifestyles. In the eastern world, we generally sit on a lower platform. Frequent activities like squatting result in a different stress-strain profile on the lower spine of an Asian compared to that of the Westerner. Preserving the motion of flexion bending in human lumbar spine is important. The motion preservation characteristics have to be maintained without compromising device durability, bone-device interfaces and corrective intervention. A systematic approach was adapted in designing the implant. Physical size of the implant should replicate the actual Intravertebral Disc (IVD). Implant should be able to fit into vertebral body. This is aid by shaping the spine vertebral body to accommodate the implant. A motor articulated implant must have suitable spaces for the implementation of sensors to detect forces and motors to control the motion of the prototype. The device must be able to receive real-time sensory inputs which can then modulate the implant orientation in bending accordingly. A prototype of the implant device has been fabricated to study its motion preservation capabilities. The prototype comprises of a parallel manipulator mechanism where the top plate is linked to the base plate by independent kinematic chains. The mechanical structure is made of Aluminium 6061. The mechanical parts were also put through the chemical process of anodizing for a good finishing surface. In the prototype device, we used three DC micromotors (Faulhaber) for actuation. Due to the small dimension, fibre optics pressure sensors were used. Three customized sensors were developed, calibrated and deployed on the upper plate. A PIC32 microprocessor was used to compute the compliance motion of the prototype when subjected to forces during flexion bending motion. The computer simulation of the kinematics of the parallel mechanism demonstrated the implant's flexion bending capabilities. We are conducting biomechanical experiments with this prototype implant deployed between L3–L5 of an artificial spinal column. The prototype device should achieve motion preservation capabilities comparable to the existing implants. More computer simulation will also be conducted to improve the mechanical design and control mechanisms of the proposed disc implant.
A Fibre Optic System for the Detection of Dental Caries
Authors: Hughes D. , Poland S. , Girkin J. , Longbottom C. , Cochran S.
Published: July 2009

The tooth is a biological entity comprising of a hard enamel layer, encasing the softer (but still hard) dentine which conceals the much softer pulp chamber. Dental caries, commonly known as tooth decay, is the localized demineralization of enamel or dentine caused by the acidic by products of bacteria. Current methods of detection and diagnosis routinely used in the dental surgery are limited to the subjective act of visual inspection (with aide of a metal probe known as an explorer) and bitewing X-ray. Neither method provides quantitative information about the state of the disease in the tooth for accurate diagnosis and subsequent treatment planning. Such methods are also poor at detecting disease in the early (and most treatable) stages. There are, however, new technologies, generally optically based, making their way into the dental clinic, including Quantitative Light Fluorescence and the DiagnoDent tool. Both methods are able to improve the detection rates of dental caries, however, the outputs from these tools are still somewhat subjective and not quantitative, in particular providing no information on the depth of a lesion. We are reporting on work carried out using the technique of Fibre Optic Confocal Microscopy (FOCOM) in order to produce a device which can record depth profiles through the tooth and allow detection and quantification of subsurface lesions. The method has been shown to detect caries lesions and this paper concentrates on the miniaturisation of the tool for use in the oral cavity within the dental clinic. Two types of miniature lenses, GRIN and aspheric, are investigated using a computer simulation followed by experimental verification. The subsequent choice of the latter is then reported in a desktop system in the near infrared to produce depth profiles through extracted teeth with these profiles showing different characteristics between sound enamel and lesioned enamel. Results with the system used to monitor the change in surface reflection from a tooth during acid erosion of the enamel surface. The results from this new diagnostic instrument thus have applicability for both detecting and following caries lesions during a planned treatment programme of remineralization as well as to monitor the effects of acid erosion a growing dental problem caused by the consumption of acidic soft drinks.
Electro-Fluid Four-Way On-Off Pneumatic Valve
Authors: Taft C. K. , Harned T. J.
Published: July 2009

The development of an electro-fluid fourway on-off pneumatic valve is described. The design utilizes two permanent magnet valving elements between ferromagnetic nozzles; coils around the nozzles are energized to cause the permanent magnets to switch from one nozzle to the other. The valve can direct fluid flow to one of two loads alternately. It consumes electrical power during switching only; once the switch has been completed no further electrical power is required. Furthermore, the first stage of the valve only consumes air during switching, no steady state fluid power is consumed by this stage.
Improved Statistical Linearization for Analysis and Control of Nonlinear Stochastic Systems: Part I: An Extended Statistical Linearization Technique
Authors: Beaman J. J. , Hedrick J. Karl
Published: July 2009

A practical method of improving the accuracy of the Gaussian statistical linearization technique is presented. The method uses a series expansion of the unknown probability density function which includes up to fourth order terms. It is shown that by the use of the Gram-Charlier expansion a simple generating function can be derived to evaluate analytically the integrals required. It is also shown how simplifying assumptions can be used to substantially reduce the required extra equations, e.g. symmetric or assymetric and single input nonlinearities. It is also shown that the eigenvalues of the statistically linearized system can be used to estimate the stability and speed of response of the nonlinear system. The reduced expansion technique is applied to first and second order nonlinear systems and the predicted mean square response is compared to the Gaussian statistical linearization and the exact solution. The prediction of the time response of the mean of a nonlinear first order system by the use of the statistically linearized eigenvalues is compared to a 300 run Monte Carlo digital solution.
Space Sampling Effects in Nonlinear Distributed System Stability
Authors: Jumarie Guy
Published: July 2009

The purpose of this paper is to determine, from a practical point of view, the effects of a space sampling on the input-output stability, and the absolute stability of distributed parameter systems with distributed control. Three models are proposed which involve, respectively, transfer functions in space and time, Laplace-Green’s functions, and distributed transfer functions. It is shown that the first model is the most pessimistic, but in contrast is the easiest to use. While the first model applies to system with constant coefficients only, the other ones can be used with constant or space dependent coefficients.
Energy-Based Modeling and Quasi Coordinates
Authors: Brown F. T.
Published: July 2009

Energy-based modeling may be appropriate for physical systems or parts thereof which are awkward to model directly. Many of these models are nonholonomic, use quasi coordinates, require unconventional coordinates, or involve energy types not conventionally modeled in this way. Confusions arising from the literature are clarified, particularly the identification of proper coordinates and other variables for discrete models. A general medium-free derivation of Lagrange’s and related equations is given, and the use of kinetic coenergy is reviewed. Examples include the incorporation of heat transfer as a nonholonomic constraint. The results are interpreted also with bond graphs.
A Fluidic, Hydraulic Servovalve
Authors: Lee D. , Wormley D. N.
Published: July 2009

This study focuses upon the analysis, design, and experimental evaluation of a hydraulic servovalve constructed from laminar proportional fluid amplifiers and resistance feedback elements. A servovalve has been developed in which the pressure/flow characteristics can be contoured to match a specific application through appropriate design of the proportional amplifiers and selection of the feedback elements. A set of design equations have been derived to select the appropriate feedback elements. Using the design procedure, two valve configurations have been constructed and tested. Experimental evaluations of the two configurations in terms of static pressure and flow gains and dynamic response have agreed closely with analyses.
Frequency Response of Blocked Annular Fluid Transmission Lines
Authors: Franke M. E. , Farney G. R. , Moore E. F.
Published: July 2009

Frequency response measurements on blocked annular pneumatic transmission lines with five different radius ratios have been obtained and compared with annular transmission line theory. The agreement between theory and experiment was good.
Active Vibration Control of a Flexible Rotor on Flexibly-Mounted Journal Bearings
Authors: Stanway R. , Burrows C. R.
Published: July 2009

Some recent experimental studies have been concerned with the stabilization of rotating machinery through control action applied at critical points on the rotor. These studies have tended to ignore fundamental constraints on the positioning of active control inputs and measurement transducers. Such constraints must be considered to ensure both a cost effective design and system integrity in the event of component failure. This paper presents the first stage of a theoretical examination of active control by investigating a mathematical model of a three-mass flexible rotor symmetrically supported on flexibly mounted journal bearings. Three questions are posed: how many control sources are required, what measurement transducers are required and what information about the system dynamics is required in order to implement active control? The multivariable nature of the model and uncertainty about the oil-film dynamics makes general solutions to these problems difficult. However some solutions are proposed based upon the structural properties of the model. It is shown that the general requirements for system identification and control are conflicting. The practical implications of this conflict are discussed.
Structure Graphs: A New Approach for Interactive Computer Modelling of Multi-Energy Domain Systems
Authors: Liebner R. , Abdullah F. , Finkelstein L.
Published: July 2009

A computer package MEDIEM (Multi-Energy Domain Interactive Element Modelling) has been developed and mounted on a minicomputer for the purpose of interactive modelling of multi-energy domain engineering systems. The basis of the package is a graphical language called “structure graphs” which allows the user to model the “structure” or essential features of a lumped parameter engineering system in close correspondence to a schematic. It is shown that structure graphs arise naturally when modelling is considered within an interactive computer-aided environment. The approach has certain advantages over those based on current techniques such as bond graphs, linear graphs, and signal flow graphs; the main ones being the ease of model construction and the ease of effecting model changes (both structural and parameter changes). The package will handle both linear and nonlinear systems. Some illustrative examples of the use of structure graphs are provided together with a detailed example of the use of MEDIEM for modelling a complex differential pressure transducer. Lastly some special causal problems reported in the bond graph literature are examined and shown not to exist when MEDIEM is used.
A Proposal for Performance Criteria for Propulsion Losses Due to Ship Steering
Authors: Reid R. E.
Published: July 2009

The problem of definition of propulsion loss related to ship steering is addressed. Performance criteria representative of propulsion losses due to steering over a range of operating conditions including operation in calm water and a seaway are considered. Criteria are derived from strict analytical considerations and from empirical assumptions based on experimentally derived hydrodynamic data. The applicability of these various criteria and the implications for both assessment of relative performance of existing ship autopilots and for the design of new steering controllers is discussed in relation to simulation results for a high-speed containership.
Software for Eight-Bit Microprocessors in Multivariable Digital Control Systems
Authors: Sweet L. M. , Gerber J. C. , Mehta R. S. , Wong E. Y.
Published: July 2009

This paper compares computer programs implementing linear multivariable digital control algorithms written in high level and assembly languages for eight-bit microprocessors. The execution speeds of the programs are compared for fixed-point and floating-point formats for controllers of increasing order, with faster speeds allowing greater achievable controller sampling rates. Methods are presented for optimizing the high level language programs using in-line assembly code in critical program modules and performing floating-point computations on a dedicated arithmetic function processor. Quantitative results are presented for achievable sampling rates as functions of the order of the controller, the number of inputs and outputs, language level used for the control program, and optimization method. Design guidelines are given for development of controller software for different applications.
The Mathematics of Supervisory Computer Control of Manipulators
Authors: Brooks T. L.
Published: July 2009

This paper advances a mathematical formulation which, when combined with appropriate operator and sensor inputs, can be used to generate the control functions necessary for short, autonomous periods of remote manipulation under human supervision. It is shown that all manipulation tasks belong to one of four basic categories which are a function of the spatial variability of the task and its dynamic state. Techniques for both describing and executing tasks in each category are given and the relation between these techniques and previous efforts are discussed. Additionally, methods for measuring and tracking the task motion as a function of position, velocity and acceleration are considered.
Stochastic Artificial Aeration Control for Regional Drainage Basins
Authors: Olgac N. M. , Longman R. W. , Cooper C. A.
Published: July 2009

Regional planning for the abatement of pollution in a river drainage basin can profitably include artificial in-stream aeration as a key component in a coordinated abatement effort. This technique compares very favorably, on a capital expense basis, with more traditional abatement methods. A general drainage basin structure containing a river, or rivers, with tributaries in a graphical tree structure is considered. The mathematical mode developed is a general formulation which deals with the arbitrary number of confluences in the basin, tributaries entering the controlled section, the spacially discrete nature of the feedback water quality measurements and of the treatment sites, and the stochastic nature of the measurements and pollution sources. An optimal aeration strategy is determined for each aerator as a function of measurement data throughout the basin, and examples are given to illustrate the results.
Identification and Control of Rotating Disk Vibration
Authors: Radcliffe C. J. , Mote C. D.
Published: July 2009

Small amplitude, transverse vibration of a circular disk can be viewed as a superposition of travelling waves each wave corresponding to a particular vibration mode. When the plate damping is small, the transverse motion of the plate is often dominated by response in one mode [1]. The active control method discussed here used an on-line FFT analysis of the rotating disk displacement to periodically identify the dominant mode of the disk response in a changing operating environment. Active control forces were applied electromagnetically to the disk to suppress the amplitude of that particular mode. In laboratory tests, the prototype controller reduced the modal amplitude to less than 15 percent of the uncontrolled value. Analytical predictions correlated well with these laboratory observations.
Analysis of Dynamic Systems Using Heuristic Optimization
Authors: Langrana N. A. , Lee T. W.
Published: July 2009

In certain dynamic problems, the determination of the applied torques at the joints from the measured displacement-time history is of interest, and is known as the inverse dynamic problem. A general purpose algorithm, “Heuristic Combinatorial Optimization Technique”, [1] has been shown to produce fast and improved solutions in the kinematic and the dynamic design of mechanical systems compared to conventional techniques. In the present study, a new approach to the inverse dynamic problem is introduced. An effective algorithm is developed by combining the Heuristic Optimization Technique with the Automated Assembly Program [2]. Two problems are investigated. The first deals with a man-machine interaction system; the second deals with the spatial motion of a manipulator. The investigation demonstrates the potential application of the procedure in the analysis of dynamic systems of realistic complexity.
Experimental Investigation of Freight Car Lateral Dynamics
Authors: Fries R. H. , Cooperrider N. K. , Law E. H.
Published: July 2009

Field tests and accompanying data analysis to characterize the stable and hunting behavior of freight cars are discussed. These tests confirmed the fundamentally nonlinear nature of the conventional freight car. The hunting performance of an open hopper car is described by speed ranges in which intermittent hunting occurs. At speeds above the intermittent hunting speed ranges, hunting always occurs, and at speeds below these ranges, hunting does not occur. Results of evaluating the stability of the freight car in terms of the natural frequency and damping ratio of the least-damped vibration mode are presented. Anomalies in these results indicate that the damping ratio may not be an adequate stability measure for this nonlinear system. Root-mean-square values of significant vehicle motions are presented for the entire range of vehicle test speeds.
Influence of Wheel/Rail Contact Geometry on Large Amplitude Wheelset Equations of Motion
Authors: Burton T. D.
Published: July 2009

The nonlinear equations of motion and velocities of creep of a simply restrained wheelset on tangent track are derived for the case of large amplitude motion including flange contact. The nonlinearities considered are those arising from the wheel/rail contact geometry. It is shown that during flange contact the lateral creep velocity may differ by as much as 30-40 percent when compared to that calculated using the usual creep velocity models. Furthermore, the use of the equations of rolling and vertical motion as a means of defining the wheel/rail normal constraint forces results in the inclusion in the dynamic model of several effects not usually included. The equations of motion which result for the lateral translation and yaw of the wheelset contain substantially different loadings than those used in most models. The attendant effect on wheelset stability may be significant.
Optimum Vehicle Suspensions Minimizing RMS Rattlespace, Sprung-Mass Acceleration and Jerk
Authors: Hrovat D. , Hubbard M.
Published: July 2009

The optimal suspension structure for a simple one-degree-of-freedom vehicle model is derived using Linear-Quadratic regulator theory. In addition to rms rattlespace and acceleration, rms jerk is included in the performance index. The suspension structure contains a skyhook spring as well as the more well known skyhook damper to inertial ground and must be mechanized actively except for the shock isolation problem with no ground motion. When jerk weighting is predominant, the damping ratio ζ of the complex roots shifts from 0.707 to 0.5. Charts are presented which enable preliminary design calculations to be done graphically. Using frequency response and time response techniques, performance is compared to that of optimal suspensions disregarding jerk.
Nonstationary Response of Vehicles on Rough Ground—A State Space Approach
Authors: Hammond J. K. , Harrison R. F.
Published: July 2009

The motion of vehicles traveling over rough ground at variable speed is non-stationary. In this paper, a method for the computation of response variance is presented which uses the concept of a “spatial” shaping filter to represent the uneven ground, leading to a state space form for the combination of vehicle and excitation. The formulation is for linear systems of arbitrary order and allows any deterministic velocity history to be accommodated easily. An example is discussed in detail.
Stable Linear Systems Simplification Via Pade´ Approximations to Hurwitz Polynomials
Authors: Bistritz Y. , Shaked U.
Published: July 2009

In many problems of control and simulation of a high order system, it is often advantageous to have an appropriate lower order model for approximate design. Introducing the concept of (mixed) Pade´ approximations to Hurwitz polynomials, a novel method for linear time invariant system simplification is established. The method offers many models of the same order that are stable for a stable system, approximate a desired number of the system eigenvalues near to and far from the origin, and emphasize differently the approximation of the low frequency/steady-state and high frequency/transient responses of the system. The presented method is based entirely on a simple unified Pade´ technique.
A Geometrical Representation of Manipulator Dynamics and Its Application to Arm Design
Authors: Asada Haruhiko
Published: July 2009

A new approach to the geometrical representation of manipulator dynamics is presented. The inertia ellipsoid, which is used to represent dynamic characteristics of a single rigid body, is extended to a general ellipsoid for a series of rigid bodies in order to represent the manipulator dynamics. The geometrical configuration of the generalized inertia ellipsoid (GIE) represents the characteristics of the manipulator as a whole. One can understand the complicated inertial effect and nonlinearity of multi-degree-of-freedom motion by simply investigating the GIE configuration. In the latter half of the paper, this method is applied to aid the design of a mechanical arm, in which dimensions of an arm structure and its mass distribution are optimized through the evaluation and graphical representation of the arm dynamics.
Development of Measuring Equipment for Location and Direction (MELODI) Using Ultrasonic Waves
Authors: Arai Tatsuo , Nakano Eiji
Published: July 2009

In this paper we will introduce the Measuring Equipment for Location and Direction, which uses ultrasonic waves. Its basic charactersitics and the method for calculating the position and the direction will be explained. The direction of three points fixed in the plane should be measured at the same time in order to control the movement of the robot in real time. For this purpose, each point has a speaker that transmits an ultrasonic wave of a different frequency. The measuring equipment is provided with three sensors that can receive the corresponding ultrasonic wave and follow the corresponding point independently. From the experiment, where the three points are set in the vertexes of the regular triangle with a 400 cm side, the positional error is less than 5 cm.
Computationally Convenient State Variables for Bond Graph Two-Phase Accumulators
Authors: Tylee J. Louis
Published: July 2009

New state variables for the bond graph two-phase accumulator are proposed. The usual accumulator states, total fluid mass and total fluid energy, require an iterative solution procedure to obtain accumulator pressure. The newly proposed states, fluid quality and pressure, eliminate these iterations.
Impact Force Prediction Using Measured Frequency Response Functions
Authors: Thornhill R. J. , Smith C. C.
Published: July 2009

A method is presented for predicting impact forces using measured frequency response functions when an ideal mass elastically impacts a stationary structure. It is shown that a frequency response function measured at the point of impact on the structure together with the impactor’s mass and velocity can be used to form a function which, after inverse Fourier transformation yields the predicted force. After the basic equation is developed, predicted and measured force pulses are compared for a steel missile impacting an aluminum casting. The limitations of the method due to hardware and experimental technique are also discussed.
Model Reduction Via Laguerre Polynomial Technique
Authors: Hwang Chyi , Shih Yen-Ping
Published: July 2009

In this paper, a recursive algorithm is derived for computing the Laguerre spectra of a truncated Laguerre series which approximately represents the response of a system characterized by a transfer function model. Based on the minimization of the sum squared-error of a set of Laguerre spectrum equations of the model parameters, a model reduction method is proposed. The method is computationally attractive. An illustrative example is given. The method is also applied to design a model-reference feedback control system.
Static Shape Determination and Control for Large Space Structures: I. The Flexible Beam
Authors: Weeks Connie J.
Published: July 2009

A shape control or determination problem for a large space structure involves a linear partial differential equation representing shape displacements with respect to space and time, together with spatially discrete forcing functions or observations which represent the placement of actuators or sensors at discrete points along the structure. The use of Green’s functions to convert boundary value problems into integral equations provides a convenient treatment of this mixture of continuous and discrete mathematics. Static shape control and determination algorithms are developed for one dimensional models, and illustrated with simulations of flexible beam examples. Solutions reduce to the solution of systems of linear equations of dimension less than or equal to the number of observations, or control forces. Approximations to solution elements in terms of modal expansions are presented.
Forced Vibration of a Base-Excited Single-Degree-of-Freedom System With Coulomb Friction
Authors: Marui Etsuo , Kato Shinobu
Published: July 2009

Using the “stopping region of motion” concept, a brief analytical technique is worked out for the behavior of the linear forced vibratory system under the influence of a Coulomb friction force. The following points are clarified by the above technique: 1. The behavior of the system is completely determined by the three non-dimensional parameters of nondimensional friction force, frequency ratio and damping ratio. 2. The vibratory system undergoes a periodic vibration with stopping periods when the mass cannot move. These stopping periods increase at lower exciting frequencies, owing to Coulomb friction. 3. The relation between the kind of motion occurring in the system and the above three parameters can be obtained theoretically and verified experimentally.
Minimal Pade´ Model Reduction for Multivariable Systems
Authors: Bistritz Y. , Shaked U.
Published: July 2009

The approximation of high order linear multivariable systems in the Pade´ sense is considered. A unified treatment is presented by which various models of minimal order are found which match given sequences of time moments and Markov matrices. The uniqueness of these models is investigated and in cases where there exist more than one minimal model for a given sequence the set of all the distinct models is characterized by a minimal set of independent parameters which can be assigned arbitrary values. The possible instability of Pade´ reduced models for stable systems is considered and a method is suggested which yields stable models that approximate the high order system, or at least its magnitude, in the Pade´ sense.
Adaptive State Variable Estimation Using Robust Smoothing
Authors: Groutage F. D. , Jacquot R. G. , Smith D. E.
Published: July 2009

The development of a conventional Kalman filter is based on full knowledge of system parameters, noise statistics, and deterministic forcing functions. This work addresses the problem of known system parameters and unknown noise statistics and deterministic forcing functions. A robust estimation technique for weighting certain elements of the Kalman gain and covariance matrices is given. These weights are functions of sample means and variances of the residual (innovations) sequence. Robust statistical procedures are employed to smooth the estimates given by the adaptive Kalman filter. An application to a simple linear system is given, however, primary application would be to the estimation of position, velocity, and acceleration for a maneuvering body in three dimensional space based on observed data collected by a remote sensor tracking the maneuvering body.
Mixed Method of Routh and ISE Criterion Approaches for Reduced-Order Modeling of Continuous-Time Systems
Authors: Hwang Chyi
Published: July 2009

A mixed method using the advantages of Routh approximation method and integral-squared-error criterion is proposed for obtaining stable reduced-order models for high-order continuous-time systems. The reduced-order model tends to approximate the transient portion of the system response in the sense of minimum mean-squared-error, while the steady-state portion is matched exactly. Instead of actually evaluating time responses of the system and the reduced-order model, a matrix formula is used to calculate the integral-squared-error from the error transfer function.
A Generalized Solution to the Inverse Kinematics of Robotic Manipulators
Authors: Goldenberg A. A. , Lawrence D. L.
Published: July 2009

In the context of kinematic control of a robotic manipulator if a certain set of task space coordinates (end effector position and orientation) are commanded then the corresponding configuration space coordinates (joint variables) must be provided. The joint variables are obtained by solving the “inverse kinematics problem.” Typically a solution to the problem can be obtained in closed-form; however, such a solution is inherently manipulator-dependent. The paper presents an approach for providing a generalized inverse kinematics solution which is manipulator-independent. The solution is based on an iterative procedure. An algorithm was developed and demonstrated using the PUMA-560 and Stanford manipulator models.
Decentralized Adaptive Stabilization of a Class of Large-Scale Interconnected Discrete Systems
Authors: Lyou J. , Bien Z.
Published: July 2009

This paper considers the problem of stabilizing a class of discrete-time large-scale interconnected systems subject to system parameter uncertainties and bounded deterministic disturbances. An adaptive scheme is devised, based on the adaptive feedback concept for stabilization of the interconnected system with uncertain system parameters and the adaptive feed-forward concept for compensation of bounded deterministic disturbances with unknown magnitudes. A condition of stability is given under which the overall adaptive system is assured to be stable. Also, a numerical example is illustrated via comptuer simulation.
Impedance Control: An Approach to Manipulation: Part I—Theory
Authors: Hogan Neville
Published: July 2009

Manipulation fundamentally requires the manipulator to be mechanically coupled to the object being manipulated; the manipulator may not be treated as an isolated system. This three-part paper presents an approach to the control of dynamic interaction between a manipulator and its environment. In Part I this approach is developed by considering the mechanics of interaction between physical systems. Control of position or force alone is inadequate; control of dynamic behavior is also required. It is shown that as manipulation is a fundamentally nonlinear problem, the distinction between impedance and admittance is essential, and given the environment contains inertial objects, the manipulator must be an impedance. A generalization of a Norton equivalent network is defined for a broad class of nonlinear manipulators which separates the control of motion from the control of impedance while preserving the superposition properties of the Norton network. It is shown that components of the manipulator impedance may be combined by superposition even when they are nonlinear.
Dynamic Interaction Between Freight Train and Steel Bridge
Authors: Bhatti M. H. , Garg V. K. , Chu K. H.
Published: July 2009

The dynamic responses of a railway steel bridge due to vehicle-track-bridge interaction were investigated for the effects of vertical and lateral track irregularities, approach track quality, vehicle weight and type, and train speed. It was found that (1) greater approach irregularities produce higher impact factors and dynamic forces in bridge members; (2) light weight and empty cars produce higher impact factors but small dynamic forces; and (3) impact factors depend on such parameters as axle spacing, suspension system stiffness, truck center distances, etc.
Bond Graph Models for Fluid Networks Using Modal Approximation
Authors: Margolis D. L. , Yang W. C.
Published: July 2009

Modal bond graph representations of the dissipative model of rigid, cylindrical fluid transmission lines with laminar flow are developed. Modal approximation techniques are used for both hydraulic and pneumatic lines. The modeling and simulation procedures for fluid networks coupled with nonlinear and dynamic systems are greatly facilitated using bond graphs. The physical interpretation of the model is preserved in this approach. Simulation results for hydraulic single lines are compared with results derived by the quasi-method of characteristics. The simulation results for fluid networds for various line and termination configurations are illustrated.
Modeling and Control of a Rotary Crane
Authors: Sakawa Y. , Nakazumi A.
Published: July 2009

In this paper we first derive a dynamical model for the control of a rotary crane, which makes three kinds of motion (rotation, load hoisting, and boom hoisting) simultaneously. The goal is to transfer a load to a desired place in such a way that at the end of transfer the swing of the load decays as quickly as possible. We first apply an open-loop control input to the system such that the state of the system can be transferred to a neighborhood of the equilibrium state. Then we apply a feedback control signal so that the state of the system approaches the equilibrium state as quickly as possible. The results of computer simulation prove that the open-loop plus feedback control scheme works well.
Multivariable Direct Adaptive Control of Thermal Mixing Processes
Authors: Zhang Qiusheng , Tomizuka Masayoshi
Published: July 2009

Multivariable direct adaptive control is tested on a nonlinear thermal mixing process and is compared with state space based nonadaptive controllers. The linear quadratic optimal control approach is used to design two nonadaptive controllers: one without integral action (ordinary LQ) and the other with integral action (LQI). The operating point is changed over a wide region in the experiment. The adaptive controller is verified to perform most consistently under the tested conditions.
Heuristic Optimization in the Balancing of High Speed Rotors
Authors: Yang J. L. , Chu F. H. , Lee Ting W.
Published: July 2009

This paper presents a new approach to the dynamic balancing of flexible rotors. The unbalance of a rotor is treated as a combination of a number of discrete unbalancing components, which are identified and subsequently removed using an effective heuristic optimization technique. The method allows the treatment of nonlinear rotor response and design constraints. A specific example is used to illustrate the approach and the results are compared with the ones obtained using another optimum balancing technique.
Analytical and Experimental Investigation of Flow-Reversible Heat Exchangers Using Temperature-Entropy Bond Graphs
Authors: Shoureshi Rahmatallah , McLaughlin Kevin M.
Published: July 2009

Modeling of heat exchangers using true bond graphs with temperature and rate of change of entropy as power variables is presented. Techniques used for modeling of irreversabilities and compressible flows are shown. The results of two and three lump models are compared with experimental results, with the agreement between those low order models and the experimental results being good. This paper shows how well a three lump model (6th order) can predict the dynamics of an actual reversal of flow. Heat exchanger response to mass flow rate oscillation is presented.
Journal Bearing Identification Under Operating Conditions
Authors: Stanway Roger
Published: July 2009

This note describes an approach to the problem of identifying linearized journal bearing dynamics using data acquired under normal operating conditions. The basic problem is reformulated so that an existing algorithm for state estimation in noisy nonlinear dynamical systems can be applied. The results of some numerical experiments are presented to demonstrate the feasibility of the approach.