bluuebunny/crossref_metadata_2025 huggingface dataset:
Emission and absorption spectroscopy of X-ray-heated plastic foils
Authors: Földes I.B. , Eidmann K.
Published: March 2009

Spherical gold Hohlraums were heated by the iodine laser ASTERIX IV (200 J/0.4 ns at 440 nm) and were used to investigate radiative heating of low-Z plastic foils at temperatures up to 100 eV by time-resolved XUV emission and absorption spectroscopy. Spectra of the reemitted radiation (the albedo) for different C-, O-, F-, or Cl-containing plastic materials are presented. Depending on the material, the typical total (frequency-integrated) reemission is in the range of ≈10% of the gold reemission. By measuring the absorption spectra it was possible to follow the burnthrough in carbon from the initial solid degenerate state up to a high ionization state with absorption lines due to hydrogen-like carbon corresponding to a temperature of about 100 eV. The propagation of the heat wave into the material also has been studied by observing the emission from boron tracer layers embedded at different depths in the plastic foil. The experimental observations are compared with MULTI simulations.
Laser-supported detonation in a transverse magnetic field: A qualitative theory and direct conversion of laser radiation energy into electricity
Authors: Alferov Yuri B. , Budnik Alexander P.
Published: March 2009

This paper presents the results of a theoretical investigation of a laser-supported detonation wave (LDW) in a transverse magnetic field. A 1D problem of a steady-state wavefront structure is considered. The magnetic structure of the LDW is determined. Specific attention is focused on the stability conditions of a shock wavefront. The value of the induced (downstream) electric field strength is obtained from numerical calculations. The possibility of direct conversion of laser radiation energy into electricity in optical discharge plasma moving across an external magnetic field is considered. Such a device could be used in the energy supply systems of space vehicles.
Electronic and ionic structure of dense plasmas
Authors: Zinamon Z. , Nardi E.
Published: March 2009

Classical molecular dynamics of the ions and quantum treatment of the electrons are combined in the study of the properties of hot, dense plasmas. An effective ionic interaction potential is used in the molecular dynamics simulations. The electronic density of states is calculated using the equation of motion method. Special attention is given to the broadening of resonances in the electronic density of states, which may have important effects on the thermodynamic properties of the plasma.
Stopping power in nonideal plasmas
Authors: Morawetz K.
Published: March 2009

The stopping power of dense nonideal plasmas is calculated in different many-body approximations. The T-matrix approximation of binary collisions is compared with the random phase approximation (RPA) approximation of dielectric fluctuations. It is found that RPA contributions are more important for dense plasmas at low temperatures. Within a microscopic model, the dynamical evolution of the velocity of the projectile is calculated. It reproduces experimental values well for the stopping of fast heavy ions at times after a pinch discharge. Further improvements due to memory effects and relaxation fields are discussed. A renormalization of the effective energy transfer by memory effects is presented.
Opacity calculations of plasmas by using parametric potentials
Authors: Martel P. , Gil J.M. , Rodríguez R. , Doreste L. , Martel P. , Gil J.M. , Mínguez E.
Published: March 2009

A numerical model for opacity calculations by using a family of analytical potentials for each configuration in the plasma is presented. The obtained numerical opacity results with this model are compared with those obtained by using a self-consistent potential model.
New approximation for calculating free-free absorption in hot dense plasmas
Authors: Perrot F.
Published: March 2009

We propose a model for calculating free-free absorption (inverse bremsstrahlung) in hot dense plasmas. This model writes the total Gaunt factor as the product of a static factor and a dynamic factor. The treatment of the static part is based on a relation between the absorption cross section and the elastic scattering cross section, which is exact for very low frequencies and becomes asymptotically correct when the Born approximation is valid. Generalizing this relation provides an expression of the absorption cross section Q(k, k′), which depends on the initial and final wave vectors k and k′, as an integral of a unique function S*(k). The calculation of nondiagonal matrix elements (k ≠ k′) is thus avoided. The analytic summation of the high angular momenta in the partial wave expansion of the cross section makes possible to apply the model in the limit of weak electron screening. The collective effects are accounted for in a dynamic Gaunt factor and in an index of refraction different from unity. Numerical results for the Gaunt factor in cesium are presented and discussed. An application to the mean opacities of carbon is also shown.
Analytical wave functions in self-consistent field models for high-temperature plasma
Authors: Nikiforov A.F. , Novikov V.G. , Solomyannaya A.D.
Published: March 2009

The possibility of using the analytical wave functions in hydrogen-like and semiclassical approximations for self-consistent Hartree-Fock-Slater model is considered. The usage of analytical wave functions simplifies the obtaining of self-consistent field and yields the suitable expressions for calculation various characteristics of high-temperature plasmas—cross sections of radiative processes, Rosseland mean opacities, and equation of state.
MHD Instabilities in the dynamic model of plasma open switches
Authors: Zubkov P.I.
Published: March 2009

The dynamic model of plasma open switches is proposed in this article. It is based on the initiation and development of force instabilities (pinches and necks) in spatially inhomogeneous plasma accelerated by the magnetic field pressure. The model proposed does not require the consideration of subtle effects at the pinch implosion stage. It allows one to account for main features of the operation of plasma current open switches within the framework of magnetic hydrodynamics. It also provides quantitative estimates in good agreement with experimental results.
Direct numerical simulation of turbulent mixing in shear flows
Authors: Stadnik A.L. , Statsenko V.P. , Yanilkin Yu.V. , Zhmailo V.A.
Published: March 2009

This article considers one of the simplest shear flows–ID time-dependent plane mixing layer. Under certain conditions, many more complicated flows are similar to it: timeindependent plane mixing layer, initial portion of plane and round jets, initial mixing phase in cylindrical vortex, etc. This application was previously studied in a 2D approximation. In this computation the turbulence was treated as the result of random perturbations initially applied to the interface of two flows. Numerical simulation used a 2D EGAK code. The computational results were interpreted using the version of semi-empirical turbulent theory with isotropic Reynolds tensor (model 1). This article continues the studies by Bakhrakh; in addition, a similar approach is implemented based on 3D simulation with the TREK method. The data interpretation uses the version of semi-empirical theory with and without Reynolds tensor anisotropy (models 1 and 2, respectively).
Simulation of a high-brightness, hard X-ray source based on high-intensity interaction of ultra-short laser pulses with high-Z targets
Authors: Lykov V.A. , Chernyakov V.E. , Kandiev Ya.Z. , Litvinenko I.A. , Nikolaev V.G.
Published: March 2009

The results of numerical simulations of fast electrons interaction with matter, calculated yield and angular distribution of bremsstrahlung and fluorescence K-α X-ray radiation and generation of electromagnetic fields, carried out by ERA, PM2D, and PRIZMA codes for the state of experiments on interaction of ultra-short laser pulses with high-Z targets at intensity of 1016−1018 W/cm2 are presented. Spherical targets with conical hollows and conical targets of high-Z matter are proposed for experiments with picosecond lasers to increase the brightness of hard X-ray sources.
Simulation of propagating a proton beam in a reactor
Authors: Niu K.
Published: March 2009

One of the difficulties of light ion beam fusion is to propagate the beam in the reactor cavity and to focus the beam on the target. The light ion beam has some local divergence angle because there are several causes for divergence at the diode. The ion beam propagates with a speed of one tenth of light speed. With this high speed, the leading edge of the ion beam cannot be charge-neutralized due to the delay of neutralization by the inertia of thermal electrons in the background plasma. The electrostatic force induced by this mechanism at the leading edge causes the beam divergence during propagation. To confine the beam in a small radius during propagation, the magnetic field must play a role. Here the electron beam is proposed to be launched simultaneously with the launch of a proton beam. If the electron beam has the excess current, the beam induces the magnetic field in the negative azimuthal direction, which confines the ion beam in a small radius by the electrostatic field, as well as the electron beam by the Lorentz force. The metal guide around the beam path helps the beam confinement and reduces the total amount of magnetic field energy induced by the electron current. Simulation shows that the proton beam with the comoving electron beam propagates in a small radius confined in the metal guide.
Simple 2D Model for Helical Flux-compression Generators
Authors: Novac B.M. , Enache M.C. , Smith I.R. , Enache M.C. , Stewardson H.R.
Published: March 2009

This paper presents a simple but complete 2D model for helical flux-compression generators that overcomes many of the limitations present in existing zero-dimensional models. The generator circuit is effectively decomposed into separate z and; current carrying circuits, with each of the; circuits (rings) corresponding to a different current. Use is also made of a technique by which these rings are sequentially switched out of circuit. The approach proposed opens the way to a full understanding of the behavior of cascade systems of generators inductively coupled by dynamic transformers using the so-called flux-trapping technique. In addition, the model can also yield an important insight into the phenomena that differentiates the performance of small generators when primed by a capacitor, a battery, or an externally produced magnetic field. Finally, the numerical code developed in the paper can readily be adapted to model high-energy and high-current generators in which the helical coil and the armature are of variable geometry. Valuable design information is provided on the magnetic and the electric field distributions within the generator and on the likely radial and axial movements of the stator turns.
Numerical Simulation of Radiation-driven Targets for Light-ion Inertial Confinement Fusion
Authors: Olson R.E. , Macfarlane J.J.
Published: March 2009

Light ion beam inertial confinement fusion (ICF) is a concept in which intense beams of low atomic number ions would be used to drive ICF targets to ignition and gain. Here, results from numerical simulations are presented describing the operation of an indirect-drive light-ion ICF target designed for a commercial power plant application. The simulations indicate that the ICF target, consisting of an X-ray-driven capsule embedded in a spherical foam-filled hohlraum, will produce a fusion energy output of over 500 MJ when driven with lithium ion beams containing a total input energy of 8 MJ.
Solids in Strong Magnetic Fields at High Pressures: Static Properties and Lattice Dynamics
Authors: Petrov Yu.V.
Published: March 2009

The equation of state and other thermodynamic functions of solids consisting of many electron atoms in strong magnetic fields arising in some laser experiments and astrophysical objects are calculated within the Kadomtzev's approach up to the high-pressure range. All static thermo-dynamic functions under consideration are obtained from the two-parametric scaling relations on the atomic number and magnetic field from the universal functions of the specific volume. At this high-pressure region, lattice dynamics of monoatomic solids in strong magnetic fields are considered. Vibrational spectra of face-centered cubic lattice of neon are obtained, which do not satisfy any scaling law and differ from that one in the absence of the magnetic field, especially in the long wave region.
Optimum design of gripper jaws for tapered components
Authors: Pham D.T. , Nategh M.J.
Published: March 2009

For ease of manufacture, axisymmetric components produced by processes such as forging, casting and moulding are often designed with a taper angle. This paper presents a family of devices for handling such components by their tapered portion. The devices are essentially finger tips, or jaws, to be fitted to standard scissor-type robot grippers. The jaws possess a three-dimensional profile constructed as a stack ofv-shaped planar curves. The special jaw profile enables components of different diameters and taper angles to be gripped concentrically without calling for complex movements to reposition the gripper. The equations describing two categories of profile are derived and the optimum selection of profile parameters to yield compact jaws to grip components of a wide range of dimensions is discussed in the paper.
Towards a theory of sensory robotics
Authors: Pinkava Jan
Published: March 2009

A partial review of some efforts in robotics research is presented. We identify two broad categories of work: one characterised by application-driven experimental engineering, the other by a more ‘scientific’ approach based on testing theoretical models through implementation. We argue that although the former represents some of the best practical results obtained to-date, this experiment-first-theory-later approach does not contribute to a homogeneous body of knowledge. If robotics is to make measured progress, sound theoretical ground is needed. We argue for a task-specific paradigm for future theoretical work founded on formal models. To this end, we present a general analysis of a sensory robotic system, and identify key elements that must be defined in any formal model before we can decide what sensory information is useful for a given task.
Modeling and adaptive control of a flexible one-link manipulator
Authors: Chen Jian-Shiang , Menq Chia-Hsiang
Published: March 2009

The dynamics modeling and payload adaptability of a light-weight flexible one-link manipulator are studied. Using the FEM (Finite-Element Method) model of a flexible manipulator, a lower order Linear Quadratic Gaussian compensator can provide satisfactory performance without controller/observer spillover. Moreover, the payload can be separated from the beam model, therefore, it is expected that the identification algorithm should have better robustness than the other schemes. The simulation results have shown that the proposed payload-adaptation synthesizer, which synthesizes a payload identifier and a nominal regulator/estimator interpolator to obtain a near-optimal compensator, has good adaptability with varying payload. And the resulting synthesizer also provides a near-optimal damping for this sensor-actuator noncolocated system.
A direct approach to modeling an industrial robot from samples of input-output data
Authors: Karnik Ajit M. , Sinha Naresh K.
Published: March 2009

The increased demand on the performance and efficiency of industrial robots, has led to the design of sophisticated control systems. Such control systems require an accurate dynamic model of the system. A commonly used method of modeling an industrial robot, involves the description of a set of dynamic equations, relating actuator torques to loads and accelerations. These equations are generally quite complex and inconvenient for implementation on digital computers.

Another method often used for identification, is the ‘indirect method’, in which the transfer function is obtained in two steps. The discrete time model is first derived from samples of the input and output measurements, which is then transformed to the continuous-time model. A limitation of this method is that it requires the excitation to be of the ‘persistently exciting’ type, thus precluding the application of simple inputs like the step signal.

This paper describes a ‘direct’ method for identification of an ‘industrial robot’ from samples of input and output observations. Results of modeling an industrial robot and two simulations are presented. One of the simulations, and the industrial robot uses the step input as excitation. The other example was excited with an exponential input.
Expedient range enhanced 3-D robot colour vision
Authors: Jarvis R. A.
Published: March 2009

Robotic vision is concerned with providing, primarily through image sensory data acquisition and analysis, the basis for planning robotic manipulator actions upon and within a restricted world of solid objects. Ideally, its function should correspond to the human visual system's capacity to guide hand/eye coordination or body/eye navigation tasks. Fundamental to the notion of functionality in a 3D space partially filled with solid objects, is the requirement to appreciate the depth dimension, from a particular viewpoint. Human vision abounds with depth cues derivable from imagery and many of these have been the subjects of study for robotic vision application. However, direct range recovery using time-of-flight methods (ultrasonic or light) has distinct advantages for robotics and it is easy to justify these alternative approaches despite (and maybe even because of) their independence from visual cues.

This paper presents work in progress in the Computer Vision and Robotics Laboratory at The Australian National University towards implementing a robotic hand/eye coordination system with applicability in the scene domain of brightly coloured, simply shaped objects with relatively untextured surfaces in arbitrary 3 dimensional configurations. The advantages of using directly acquired range data (via a laser time-of-flight range scanner) in enhancing the scene segmentation phase of analysis is emphasised and fairly convincing results presented. Actual vision-driven manipulation has not yet been developed but plans towards this end are included.
Robot planning with fuzzy sets
Authors: Yager Ronald R.
Published: March 2009

We discuss the use of fuzzy set based methodologies as a tool for helping robots develop and implement plans. We are particularly concerned with matching fuzzily described states with fuzzy antecedents in production rules.
Real-time cooperative interaction between structured-light and reflectance ranging for robot guidance
Authors: Kent Ernest W. , Wheatley Thomas , Nashman Marilyn
Published: March 2009

When applied to rapidly moving objects with complex trajectories, the information-rate limitation imposed by video-camera frame rates impairs the effectiveness of structured-light techniques in real-time robot servoing. To improve the performance of such systems, the use of fast infra-red proximity detectors to augment visual guidance in the final phase of target acquisition was explored. It was found that this approach was limited by the necessity of employing a different range/intensity calibration curve for the proximity detectors for every object and for every angle of approach to complex objects. Consideration of the physics of the detector process suggested that a single log-linear parametric family could describe all such calibration curves, and this was confirmed by experiment. From this result, a technique was devised for cooperative interaction between modalities, in which the vision sense provided on-the-fly determination of calibration parameters for the proximity detectors, for every approach to a target, before passing control of the system to the other modality. This technique provided a three hundred percent increase in useful manipulator velocity, and improved performance during the transition of control from one modality to the other.
An efficient numerical approach for calculating the inverse kinematics for robot manipulators
Authors: Lenarčič Jadran
Published: March 2009

This paper compares three numerical methods for obtaining the joint trajectory of a robot manipulator, which causes movement along the desired Cartesian path. The first solves the kinematic equations, which are given in the Jacobian form, while the other two solve the nonlinear kinematic equations directly by using an iterative computational procedure based on the conjugate gradient technique. The computational efficiency of the proposed methods is estimated in terms of the execution time on a VAX 11/750 minicomputer. It is shown that by using the capacity of microcomputers, these methods could be well used in real-time computation.
A fuzzy model for learning in automata
Authors: Datta Ashoke Kumar
Published: March 2009

A simple general model for learning, using a fuzzy set theoretic approach and fuzzy decision in an automaton which has nonfuzzy input/output, is proposed. The process has been modelled somewhat in the fashion of general biological systems, which may be viewed as a fuzzy decision process where learning consists in taking a tentative action and reinforcing the membership values on the basis of the results of that action. The model is tested on an automaton whose sole purpose is to follow the boundary on an object with which it makes contact during its movements. The automaton is simulated by a computer. it has standard 8–neighbourhood configuration with binary sense capability and three action capabilities. The automaton has been found to learn to take correct action in a large number of possible input situations within only a few thousand moves.
Control of a biped locomotion system in a double support phase
Authors: Narikiyo Tatsuo , Ito Masami
Published: March 2009

This paper considers theoretically and experimentally the control problem of the biped locomotion system on the double support phase. The motion on the double support phase is described by the constrained dynamic system with two static constraints. The reduced order equations are derived by eliminating Lagrange's multiplier from the constrained equations, and a control algorithm for stabilizing the motion is obtained in reduced space. Finally, this algorithm is applied to an actual robot constructed in our laboratory and its usefulness is shown.
Employment skills for the robot age
Authors: Bell D.A.
Published: March 2009

Increasing productivity in manufacturing industry leads to a continuing shift in the balance between employment in ‘productive’ and in ‘service’ industries, the latter providing more employment at present in a ratio of about 70:30. This paper is primarily concerned with employment in manufacturing industry. Some have seen automation as a means of de-skilling jobs, but there is evidence of a gradual ‘upward’ shift of skill requirements in manufacturing industry: the unskilled workers are being eliminated and the skilled manual workers replaced by technicians with mental skills. This introduces the need for re-training and raises the question whether one can have a society in which there are no unskilled persons.
The three robot worlds — a view point (A Review of the different goals of robotics research)
Authors: Lee Mark H.
Published: March 2009

This paper deals with the motivation behind robotics. It surveys the different goals of robotics research and analyses the ways in which robotics could help in various domains. After discussing the task specifications, emphasis is placed on three research sub-cultures that form separate robot “worlds”, viz. the Model World, the Industrial World and the Human World. The paper concludes with a case study to illustrate the need to reduce rash predictions and stimulate better science.
Japan's robotics research for the next generation
Authors: Umetani Yoji , Yonemoto Kanji
Published: March 2009

This paper discusses those study themes considered essential in responding to the expectations that are mostly likely to be generated by Japanese society in regard to robots in the coming one or two decades.

First, for the purpose of understanding the current structure and status of research and development concerning robotics, statistical data based on the responses obtained from universities and national and public research institutes will be shown together with an illustration of the recent patent trends related to industrial robots. Then, an overview on the results of forecasts regarding robot technology by governmental bodies will be presented in an effort to predict the technological as well as social needs surrounding robots. Lastly, tasks of high contribution value for society requiring large-scale research and development systems will be both identified and clarified.
Vibration due to motion discontinuities in hydraulically actuated robots
Authors: Jones J. Rees
Published: March 2009

Vibrations in robot action, both in the arm control system and arm itself, and in the transported load, are a serious problem in the development of high speed systems. The paper discusses the typical causes of vibration resulting from the motion command in path controlled robots and those due to the failure of a system to meet the specified command through power and performance limitations. Experimental results illustrating such phenomena are presented. Methods of reducing the magnitude or occurrence of such vibrations through the improved design of motion commands, which take account of the vibratory nature of the system and load, are presented.
Robot vision implementation by high-speed image processor TOSPIX: Battery inspection
Authors: Kuno Yoshinori , Numagami Hideo , Ishikawa Minoru , Hoshino Hiroshi , Nakamura Yasushi , Kidode Masatsugu
Published: March 2009

This paper presents an intelligent robot vision system using TOSPIX which has been newly developed to realize frequently-used and time-consuming image processing functions at low-cost and high-speed. The vision system has been studied for use in observing surface information about electric parts (dry batteries), inspecting them and then placing good ones into a given box. Three major robot vision functions are implemented here: object recognition, inspection and position determination by binary and gray-scale image processing techniques. While binary image techniques are used in battery terminal inspection and box position determination gray-scale image processing functions are performed in a label pattern check on a battery surface, front or rear surface determination, and surface defect inspection.
Introduction to the special FMS issue
Authors: Ranky Paul G.
Published: March 2009

It is pleasant to realise that every leading institution and manufacturing company in the world is dealing with some aspects of flexible automation, because many researchers and managers in industry have found that the concept of designing and making goods and products on order, rather than for stock, is the key issue in order to cut down manufacturing costs and lead time, and eventually to stay in business in the future.
The application of a flexible tooling system in a flexible manufacturing system
Authors: Carter Norman
Published: March 2009

The introduction of Flexible Manufacturing Systems, Cell Technology, and Automated Machining Techniques with the related reduction in manning levels has resulted in the development of tooling systems, tool management systems, and, independent tool magazines to service TURNING MACHINES where a high number of tools are required to cover one shift or unmanned operation.

Actual cutting time (production time) represents a value between 5% and 20% of average machine utilisation time, and developments in cutting materials and geometries have largely exhausted rationalisation possibilities in this area.
VAL-II, a language for hierarchical control of a robot-based automated factory
Authors: Braganca C. A. J. , Sholl P.
Published: March 2009

The goal of manufacturing system development today is the integration of basic production elements to suit a variety of industrial and shop floor requirements. This may seem an awesome goal, but the authors suggest that careful assessment of requirement at each level and an appreciation of the true level of complexity needed at each level for control purposes, systematic integration will be possible as products become commercially available.

Six levels of integration can be defined for robot-based
applications:
Level 1 - the single robot application level
Level 2 - the system with robots working in teams
Level 3 - the combination of different robot systems
Level 4 - the combination of feeding work automatically to islands of automation from fully automated warehouses.
Level 5 - the integration of planning and control functions
Level 6 - the integration of CAD based design functions.

The approach to integration and the level to which it extends will to a large extent be determined by a company's objective, present computer capacity, general production capability and availability of appropriate flexible automation products and systems for use in a given industrial environment. This paper examines the global needs of hierarchical integration, the level of control needed and the implication of VAL-II to this end.
Contribution to a computer-aided choice of D.C. motors for manipulation robots
Authors: Potkonjak V. , Jakšić N.
Published: March 2009

This paper presents a method for a computer-aided choice of D.C. motors for manipulation robots. The method takes into account the complete dynamics of the manipulator mechanism. The discussion is concerned with the complexity of the actuator mathematical model. The necessary order of the model is found.
Some principles for robotics based on general automata
Authors: Koenig Eldo C.
Published: March 2009

Twelve equations are presented for describing how robots move through their environments receiving information and producing required results. There is a total of 16 variables, and the sets of independent and dependent variable for the system of equations are presented. Graphs and example uses are also presented.
Thermal sensor for object shape and material constitution
Authors: Russell R. Andrew
Published: March 2009

This paper describes a novel tactile sensor array designed to provide information about the material constitution and shape of objects held by a robot manipulator. The sensor is modeled on the thermal touch sense which enables humans to distinguish between different materials based on how warm or cold they feel. Some results are presented and methods of analysing the sensor data are discussed.
Synthesis of a minimum-time manipulator trajectories with geometric path constraints using time scaling
Authors: Ozaki H. , Mohri A.
Published: March 2009

The minimum-time and subminimum-time joint trajectories of manipulators with geometric path constraints are planned in consideration of physical constraints based on kinematics and dynamics. The idea of time scaling is introduced, i.e. a time scale factor k(t) and a set of joint trajectories, called reference trajectories, are used to describe all the sets of trajectories tracing the specified geometric path. The desirable factor k(t) which makes the travelling time as short as possible is obtained by two proposed methods: the first one is an iteratively improving method using B spline, and the second one is a directly minimizing method. These two methods are preferably applied to a geometric collision-free path of a manipulator.
Contribution to the dynamics and control of robots having elastic transmissions
Authors: Potkonjak V.
Published: March 2009

This paper discusses one problem of robot dynamics rarely mentioned in papers relevent to this field. It is the problem of torsional effects in torque transmissions (reducers, shafts, transmission chains, etc.). The problem is significant since oscillations can appear to be due to these effects. The complete dynamic model, which includes these effects, is derived and the possible simplifications considered. The position of feedback transducers is discussed since it appears as an important problem when it is intended to minimize the influence of these elastic vibrations. The discussion is based on eigenvalues and simulation results.
Prospects for introducing computer-integrated manufacturing in the USSR – a viewpoint
Authors: Baranson Jack
Published: March 2009

Intensified automation related to computer integrated manufacturing (CIM) is viewed by Soviet planning authorities as a major means for increased productivity in Soviet industry. But efforts to increase automation are conditioned by the political–economic environment in which industrial production Systems are engineered and managed. The forces driving Soviet automation efforts are examined, and some tentative judgments are made on the proposed prospects for implementing changes aimed at enhancing the potential contribution of CIM to increased productivity in Soviet industry. The article is based on author's chapters in a forthcoming book, Soviet Automation: Perspectives and Prospects, edited by Jack Baranson (Mt. Airy, Md.: Lomond Publications, 1987).
Planning of manipulator joint trajectories by an iterative method
Authors: Yamamoto M. , Ozaki H. , Mohri A.
Published: March 2009

Manipulator joint trajectories are planned to make an arbitrary cost function as good as possible in consideration of physical constraints based on kinematics and dynamics of a manipulator system. An algorithm presented in this paper is an iteratively improving method using the local controllability of B spline. It can be also applied to the case that some points are specified and joint trajectories must pass through those points. This algorithm is applied to an example of trajectory planning of a manipulator with two links and two degrees of freedom.
Admissible trajectory determination for two cooperating robot arms
Authors: Lim Joonhong , Chyung Dong H.
Published: March 2009

The problem of finding an allowable object trajectory for a cooperating two-robot system is investigated. The purpose is to move an object from one point to another by firmly grasping it at two different points using two robotic hands. The major difficulty is caused by the fact that, unless the robots have true six degrees of freedom, the trajectories the object can follow are severely limited and, in general, are difficult to find. The method proposed in the paper is based on reformulating the problem as a nonlinear optimization problem with equality constraints in terms of the joint variables. The optimization problem is then solved numerically on a computer. The solution automatically gives the corresponding joint variable trajectories as well, thus eliminating the need for solving the inverse kinematic problem. The method has been successfully applied to a real experimental system.
On-line robot trajectory control in joint coordinates by means of imposed acceleration profiles
Authors: Aken Ir. L. Van , Brussel H. Van
Published: March 2009

A method for trajectory control in the joint space is presented. An acceleration profile is proposed for each segment of the trajectory. After a twofold integration a position trajectory is obtained with advantageous characteristics. The position trajectory is completely dynamically balanced; it exhibits continuity up to the third derivative of the position. This way, minimum requirements are imposed on the actuators. The technique delivers predictable results since the trajectory deviates only slightly from a straight line connection between successive joint coordinates. Very limited computational effort is required.
Trajectory control of manipulators with time varying inertia links
Authors: Jumarie Guy
Published: March 2009

One way to increase the flexibility (or versatility) of manipulators is to use links with time varying inertia. One can then control both the joint torques and the inertias of the links therefore more pliancy in the practical utilisation of the arm. The paper deals with the Lagrangian formulation of the corresponding inertia control problem which can be considered either in open loop or in closed loop form. The general equations are derived and it is shown that one so obtains a set of uncoupled Ricatti differential equations which define the dynamics of the structural inertias. Problems related to stabilization and to structural parameter uncertainty are also considered.
Three-dimensional flexural-joint stiffness analysis of flexible manipulator arms
Authors: Meghdari A. , Shahinpoor M.
Published: March 2009

This paper presents a complete derivation of the combined flexural-joint stiffness matrix and the elastic deformation field of flexible manipulator arms treated in a three-dimensional fashion. The stiffness properties are derived directly from the differential equations used in the engineering beam theory. The expressions developed here can readily be used in the modeling, control and design of light weight flexible robot manipulators. A two-link arm is used to formulate these expressions and the results can be generalized to n–link manipulators. The stiffness matrix for a robotic link element in 3-D is of the order of 12 X 12, and for an n–link robotic arm the total elemental and system stiffness matrices will be of the order of the (12n X 12n) and 6(n + 1) X 6(n + 1), respectively.
Les apports respectifs des langages symboliques et de la cao en programmation des robots
Authors: Laugier C.
Published: March 2009

A high-level robot programming language constitutes a general purpose interface for accessing the basic functional capabilities of a robot. On the other hand, CAD facilities give the possibility of using a subset of these capabilities in an easier fashion. In this paper, we show how a robot programming language and CAD facilities can be combined to obtain a robot programming system satisfying the need for generality, and allowing an easy connection with the basic robot programming functions. Such a connection is based on a “complete” simulator providing facilities for executing robot control programs on a graphic display, for describing manipulation tasks using interactive graphic tools, for simulating the physical world and its perception through sensors, and for displaying three-dimensional scenes as shaded pictures.
A new program package for the generation of efficient manipulator kinematic and dynamic equations in symbolic form
Authors: Kirćanski M. , Vukobratović M. , Kirćanski N. , Timčenko A.
Published: March 2009

This paper presents a new program package for the generation of efficient manipulator kinematic and dynamic equations in symbolic form.

The basic algorithm belongs to the class of customized algorithms that reduce the computational burden by taking into account the specific characteristics of the manipulator to be modelled. The output of the package is high-level computer program code for evaluation of various kinematic and dynamic variables: the homogeneous transformation matrix between the hand and base coordinate frame, Jacobian matrices, driving torques and the elements of dynamic model matrices. The dynamic model is based on the recursive Newton-Euler equations. The application of recursive symbolic relations yields nearly minimal numerical complexity. Further improvement of computational efficiency is achieved by introducing different computational rates for the terms depending on joint angles, velocities and accelerations. A comparative study of numerical complexity for several typical industrial robots is presented.
Navigational path planning for a vision-based mobile robot
Authors: Arkin Ronald C.
Published: March 2009

The Autonomous Robot Architecture (AuRA) provides multi-level representation and planning capabilities. This paper addresses the task of navigational path-planning, which provides the robot with a path guaranteed to be free of collisions with any modeled obstacles. Knowledge supporting visual perception can also be embedded, facilitating the actual path traversal by the vehicle.

A multi-level representation and architecture to support multi-sensor navigation (predominantly visual) are described. A hybrid vertex-graph free-space representation based upon the decomposition of free space into convex regions capable for use in both indoor and limited outdoor navigation is discussed. This “meadow map” is produced via the recursive decomposition of the initial bounding area of traversability and its associated modeled obstacles. Of particular interest is the ability to handle diverse terrain types (sidewalks, grass, gravel, etc.) “Transition zones” ease the passage of the robot from one terrain type to another.

The navigational planner that utilizes the data available in the above representational scheme is described. An A* search algorithm incorporates appropriate cost functions for multi-terrain navigation. Consideration is given to just what constitutes an “optimal” path in this context.
Specific computation of inverse kinematics in a robot off-line programming environment
Authors: Cassar Jean - Philippe , Vanheeghe Philippe
Published: March 2009

An off-line programming station for a robotised welding cell is presented. In this context the choice of a kinematic inversion method applied to the simulation of robots is discussed.

A direct inversion method is developed in the case of 5-axes robots of plane geometry and for a task presenting a symmetry of revolution. It uses the geometry of the tool and of the robot and vectorial calculations very well adapted to this particular case. The results presented validate the choice of this method for a specialised programming environment.
An iterative method for generating kinematically feasible interference-free robot trajectories
Authors: Buchai R. O. , Cherchas D. B.
Published: March 2009

This paper proposes a method for finding an optimal geometric robot trajectory to perform a specified point-to-point motion without violating joint displacement limits or interference constraints. The problem is discretised, and a quantitative measure of interference is proposed. Constraint violations are represented by exterior penalty functions, and the problem is solved by iteratively improving an initial estimate of the trajectory. This is accomplished by numerically minimizing a cost functional using a modified Newton–Raphson method.
Strategies of searching for collision-free manipulator motions: automata theory approach
Authors: Jacak Witold
Published: March 2009

The paper present a model of the kinematics of a rotary, redundant manipulator, in the form of a Finite State Machine, this is in fact, an example ofAIproduction systems. This model is able to supply us with succesive configurations, calculated immediately in Cartesian space and allowing at the same time to considerably simplify the computations engaged in the graph searching. For an automaton-type model of the manipulator kinematics, diverse strategies of searching for a collision-free trajectory, reduced to a search of an appropriate path in the state-transition graph of FSM, are analyzed.
Dynamic Characteristics of Balanced Robotic Manipulators with Joint Flexibility
Authors: Lee S.B. , Cho H.S.
Published: March 2009

The mass balancing of robotic manipulators has been shown to have favorable effects on the dynamic characteristics. In actual practice, however, since conventional manipulators have flexibility at their joints, the improved dynamic properties obtainable for rigid manipulators may be influenced by those joint flexibilities. This paper investigates the effects of the joint flexibility on the dynamic properties and the controlled performance of a balanced robotic manipulator. The natural frequency distribution and damping characteristics were investigated through frequency response analyses. To evaluate the dynamic performance a series of simulation studies of the open loop dynamics were made for various trajectories, operating velocities, and joint stiffnesses. These simulations were also carried out for the balanced manipulator with a PD controller built-in inside motor control loop. The results show that, at low speed, the joint flexibility nearly does not influence the performance of the balanced manipulator, but at high speed it tends to render the balanced manipulator susceptible to vibratory motion and yields large joint deformation error.
Collision–Free Trajectory Planning for Two Robot Arms
Authors: Shin Youshik , Bien Zeungnam
Published: March 2009

An approach for collision–free trajectory planning along designated paths of two robots in a common workspace is presented. Specifically, in order to describe potential collision between the links of two robots along the designated paths, explicit forms of virtual obstacle are adopted, according to which links of one robot are made to grow while the other robot is forced to shrink as a point on the path. Then, a notion of virtual coordination space is introduced to visualize all the collision–free coordinations of two trajectories. Assuming that a collision–free coordination curve between the two robots is given via a virtual coordination space, the minimum time collision–free trajectory pair for the two robots is sought considering dynamic constraints of torque and velocity bounds of actuators of the two robots.
Recognition of Unreliable Ultrasonic Range Data in a Robotic Environment
Authors: Parnis P.J. , Drazan P.J.
Published: March 2009

The use of ultrasonic range transducers is an inexpensive method of obtaining information about the environment surrounding a robotic System. However, ultrasonic ranging suffers from various shortcomings, one of the major being the production of unreliable data caused by specular reflection.

This work presents an original approach to overcoming the problem of unreliable ultrasonic range data which is caused by specular reflection of the ultrasonic beam. The approach is shown to discriminate between reliable and unreliable data, thus enhancing the role of the ultrasonic range transducer in robotic applications.
A novel tactile sensor for robot applications
Authors: Eghtedari F. , Morgan C.
Published: March 2009

This paper examines a tactile slip sensor based on photoelastic effects. Photoelastic patterns are obtained using a Dynamic Ram with a resolution of 256 by 128 pixels. Software is developed to detect changes in the stress patterns when an object moves relative to the surface of the sensor. It is suggested that the stress patterns can be used to detect slippage at the object/gripper interface.
Combined time/location optimization of robotic motions with specified paths and velocity profiles
Authors: Beiner L.
Published: March 2009

A parameter optimization approach to the time-minimization of robotic motions along specified paths is presented for the case when: (i) the velocity profile is a prescribed sequence of constant acceleration/deceleration segments with unspecified, but bounded vertex velocities at given path stations; (ii) the relative robot/path location can be varied. Such optimizations occur when technological requirements impose a certain velocity profile along the path due to velocity and acceleration constraints. Full nonlinear manipulator dynamics and path parameterization are used to determine the optimal velocity profile and robot location consistent with the actuator/configuration limitations. No numerical integration or search for switching curve are involved in the solution. Examples of time-and-location optimized robotic motions with specified velocity profile are presented.
Joint velocity uniformity in redundant robot manipulators
Authors: Hemami A.
Published: March 2009

A redundant robot manipulator has several certain or expected advantages over a nonredundant one. It is expected, among other capabilities, that the joints vary with constant velocities during the execution of those tasks which in a nonredundant manipulator require variable joint velocities. In this way, motion becomes more precise because of the elimination of errors associated with velocity change in joints. In this paper, it is shown that this expected advantage is not possible for all the joints, and that only as many joints as the degree of redundancy can have constant velocities.