bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intemal correction of dead‐reckoning errors with a dual‐drive compliant linkage mobil robot
Authors: Borenstein Johann 
Published: July 2007

AbstractThis paper presents internalposition error correction(IPEC)—a new method for accurate and reliable dead‐reckoning with mobile robots. The IPEC method has been implemented on our recently developedmulti‐degree‐of‐freedom(MDOF) mobile platform, a vehicle in which two differential‐drive mobile robots (called trucks) are physically connected through acompliant linkage.In addition to its four wheel encoders, the MDOF platform has one linear and two rotaryinternalencoders, which allow measurement of the relative distance and bearing between the two trucks. During operation, both trucks perform conventional dead‐reckoning with their wheel encoders. But, in addition, the IPEC method uses information from the internal encoders to detect and correct dead‐reckoning errors as soon as they occur.Our system, calledcompliant linkage autonomous platform with position error recovery(CLAPPER), requires neither external references (such as navigation beacons, artificial landmarks, known floorplans, or satellite signals), nor inertial navigation aids (such as accelerometers or gyros). Nonetheless, the experimental results included in this article show one to two orders of magnitude better positioning accuracy than systems based on conventional dead‐reckoning. The CLAPPER corrects not only systematic errors, such as different wheel diameters, but also non‐systematic errors, such as those caused by floor roughness, bumps, or cracks in the floor.These features are made possible by exploiting the newgrowth‐rate conceptfor dead‐reckoning errors that is introduced in this article for the first time. The growth‐rate concept distinguishes between certain dead‐reckoning errors that develop slowly and other dead‐reckoning errors that develop quickly. Based on this concept, truck A frequently measures a property withslow‐growingerror characteristics on reference truck B (thus admitting a small error) to detect afast‐growingerror on truck A (thus correcting a large error), and vice versa. ©1995 John Wiley & Sons, Inc.
Sliding mode force, motion control, and stabilization of elastic manipulator in the presence of uncertainties
Authors: Vim Woosoon , Singh Sahjendra N. 
Published: July 2007

AbstractThis article considers the question of position and force control of three‐link elastic robotic systems on a constraint surface in the presence of robot parameter and environmental constraint geometry uncertainties. The approach of this article is applicable to any multi‐link elastic robot. A sliding mode control law is derived for the position and force trajectory control of manipulator. Unlike the rigid robots, sliding mode control of an end point gives rise to unstable zero dynamics. Instability of the zero dynamics is avoided by Controlling a point that lies in the neighborhood of the actual end point position. The sliding mode controller accomplishes tracking of the end‐effector and force trajectories on the constrained surface; however, the maneuver of the arm causes elastic mode excitation. For point‐to‐point control on the constraint surface, a stabilizer is designed for the final capture of the terminal state and vibration suppression. Numerical results are presented to show that in the closed‐loop system position and force control is accomplished in spite of payload and constraint surface geometry uncertainty. © 1995 John Wiley & Sons, Inc.
Vibration‐free handing of deformable beams by robot end‐effectors
Authors: Chen Ming Z. , Zheng Yuan F. 
Published: July 2007

AbstractPassive approaches for vibration‐free handling of deformable beams are investigated in this article. Dynamic equations of a flexible beam handled by robot end‐effectors are formulated and analyzed first. From the analysis, it is revealed that the inertia forces caused by the beam motion may affect the vibration of the beam in certain motion patterns. Motion trajectories of the end‐effector that lead to a small or no vibration of the beam in these motion patterns are then specified. Because vibrations cannot be totally eliminated even if the vibration‐free motion trajectory is employed, another passive approach is further suggested. The approach employs a rubber pad in parallel with a spring installed on the fingers of the end‐effector. To understand the effectiveness of this passive approach, damped vibration and optimal damping are investigated. Experiments and simulations are conducted to verify the above two methods. The experiments display the vibration‐free motion of the beam using the proposed motion planning strategy. The simulation results demonstrate the effects of the vibration‐free trajectory and the passive damping. © 1995 John Wiley & Sons, Inc.
Collision detection for multiple robot manipulatyors by using orthogonal neural networks
Authors: Tsens Ching‐Shiow , Wu Chen‐Chun 
Published: July 2007

AbstractThis article discusses the application of orthogonal neural networks to detect collisions between multiple robot manipulators that work in an overlapped space. By applying an expansion/shrinkage algorithm, the problem of collision detection between arms is transformed into that among cylinders (or rectangular solids) and line segments. This mapping simplifies the collision detection problem and thus neural networks can be applied to solve it. The property of parallel processing enables neural networks to detect collisions rapidly. A single‐layer orthogonal neural network is developed to avert the problems of conventional multilayer feedforward neural networks such as initial weights and the number of layers and processing elements. This orthogonal neural network can approximate various functions and is used to calculate forward solution and to detect collisions. An efficient neural network system for collision detection is also developed. © 1995 John Wiley & Sons, Inc.
Optimal trajectory planning for a space robot docking with a moving target via homotopy algorithms
Authors: Chen Y. , Watson L. T. 
Published: July 2007

AbstractThe mathematical formulation of optimal trajectory planning for a space robot docking with a moving target is derived. The calculus of variations is applied to the problem so that the optimal robot trajectory can be obtained directly from the target information without first planning the trajectory of the end‐effector. The nonlinear two‐point boundary value problem resulting from the problem formulation is solved numerically by a globally convergent homotopy algorithm. The algorithm guarantees convergence to a solution for an arbitrarily chosen initial guess. Numerical simulation for three examples demonstrates the approach. © 3995 John Wiley & Sons, Inc.
Inverse dynamics of redundant manipulators using a minimum number of control forces
Authors: Ider S. Kemal 
Published: July 2007

AbstractThe number of the control actuators used by the inverse kinematics and dynamics algorithms that have been developed in the literature for generating redundant robot joint trajectories is equal to the number of the degrees of freedom of the manipulator. In this article, an inverse dynamics algorithm that performs the tasks using only a minimum number of actuators is proposed. The number of actuators is equal to the dimension of the task space, and the control forces are solved simultaneously with the corresponding system motion. It is shown that because all degrees of freedom are not actuated, the control forces may lose the ability to make an instantaneous effect on the end‐effector acceleration at certain configurations, yielding the dynamical equation set of the system to be singular. The dynamical equations are modified in the neighborhood of the singular configurations by utilizing higher‐order derivative information, so that the singularities in the numerical procedure are avoided. Asymptotically stable inverse dynamics closed‐loop control in the presence of perturbations is also discussed. The algorithm is further generalized to closed chain manipulators. Three‐link and two‐link redundant planar manipulators are analyzed to illustrate the validity of the approach. © 2995 John Wiley & Sons, Inc.
Task reliability assessment in robotic systems
Authors: Musto Joseph C. , Saridis George N. 
Published: July 2007

AbstractA new method for assessing the performance of a robotic system performing a high‐precision task has been developed. The method utilizes an entropy‐based formulation to provide a measure of the reliability of a robotic system with respect to a task specification. The derivation of the proposed technique is presented, including two alternative formulations that differ in terms of their complexity and level of approximation. Methods for combining these measures for complex robotic tasks are detailed. The new method is demonstrated in a case study involving a robotic assembly system, in which the entropy formulation is used to select an optimal system design from a set of alternatives. (c)1995 John Wiley & Sons, Inc.
A smart robot's geometric model inverting system
Authors: Zhou J. , Coiffet P. 
Published: July 2007

AbstractThis article deals with a real‐time model inverting system. The mathematical inverting problem is no longer solved with a mathematical algorithm but through the design of the system control itself. The control algorithm is issued from human knowledge. The stability of this system is proved, and the properties are discussed. This system can be used where a geometric model should be inverted in real time, especially for redundant robots. (c)1995 John Wiley & Sons, Inc.
Dynamic control of a robot manipulator for high‐performance conveyor tracking
Authors: Park Tae Hyoung , Lee Beom Hee 
Published: July 2007

AbstractA new robot control scheme for the specific application to conveyor tracking is presented. To improve the performance of conveyor tracking, the robot arm dynamics is incorporated into the control scheme. The tracking problem for the workpiece on a variable‐speed conveyor is formulated as a stochastic optimal tracking problem with specified criteria. Dividing the conveyor speed into the nominal term and the perturbed term, a two‐stage control strategy is employed to cope with the nonlinearity and uncertainty of the robot‐conveyor system. Simulation results are given to verify the good tracking performance with fast cycle time and high accuracy obtained in a robotic workcell. ©1995 John Wiley & Sons, Inc.
The jacodian matrix for a flexble manipulator
Authors: Piedboeuf Jean‐Claude 
Published: July 2007

AbstractThis article develops the exact first‐order endpoint Jacobian matrix for a general n‐degrees of freedom tree‐like robot with flexible links. The Jacobian is developed in terms of the joint axes, the link deformations, and the relative position vectors using cross products. To have the correct first‐order endpoint Jacobian matrix, the second‐order kinematics is used to describe a flexible link. Using two local Jacobian matrices enables to write the endpoint Jacobian sub‐matrix associated to a flexible link, which is similar to the column of the Jacobian associated to a joint. An example with a one‐link flexible arm rotating in a vertical plane illustrates the usefulness of the endpoint Jacobian in calculating the torque required to apply an endpoint force and the link deformation resulting from this force. An experimental verification proves the validity of the developed Jacobian and suggests that using only first‐order kinematics results in serious errors in the prediction of the beam's curvatures and deformations © 1995John Wiley & Sons, Inc.
A partial state feedback controller for tajectory tracking of rigid‐link fiexible‐joint robot using an observed backstepping approach
Authors: Urn S. Y. , Hu J. , Dawson D. M. , Queiroz M. 
Published: July 2007

AbstractThis article presents a partial state feedback controller for a rigid‐link flexible‐joint (RLFJ) robot using an observed integrator backstepping approach. The robot controller requires only link position and actuator position measurements, and eliminates the need for measuring link velocity and actuator velocity. The controller uses two exact knowledge, second‐order nonlinear observers to estimate the link and actuator velocities. The overall control system achieves a semiglobal exponential stability result for the link position and velocity tracking errors as well as the velocity observation errors. A stability proof and simulation results for the proposed partial state feedback controller are included in the article. © 1995John Wiley & Sons, Inc.
A Study of Reactional Force Compensation Based on Three‐Degree‐of Freedom Parallel Platforms
Authors: Song Shin‐Min , Zhang Ming‐Dons 
Published: July 2007

AbstractReaction compensation is necessary for space robot applications because reactional forces/torques will cause undesired movement of the spacecraft. Because the reactional torques can be compensated by the existing torque balancing device in the spacecraft, an additional reaction compensating device is necessary to compensate the reactional forces. In this article we study two types of reactional force compensating devices based on three‐degree‐of freedom, parallel platforms. The first type has three R‐P‐S legs while the second type has three R‐R‐P‐S leg and a passive R‐R‐P leg. A three‐degree of freedom serial manipulator is used to generate reactional forces, which are to be compensated by the paralle platforms. The kinematics and dynamics of both platforms are analyzed and closed form inverse kinematics solutions are derived. We then design a reactional force compensating device that satisfies the strict volume constraint in a spacecraft. The first type of parallel platform is found to require very long legs due to large orientational motion at certain positions. The second type has smooth motion in both position and orientation, and therefore its size can be very compact. It is concluded that the second type of parallel platform has great potential to be used as a compact reactional force compensating device. © 1995 John Wiley & Sons, Inc.
Real‐time direct kinematics of general six‐degree‐of‐freedom parallel manipulators with minimum‐sensor data
Authors: Etemadi‐zanganeh Kourosh , Angeles Jorge 
Published: July 2007

AbstractWe present a formulation of the direct kinematics of a general six‐degree‐of‐freedom parallel manipulator, sometimes referred to as the generalized Steward platform, whereby the positioning and orientation problems are decoupled by introducing two auxiliary coordinates in the forms of either two angles or two lengths. This is in accordance with the type of extra sensors, i.e., rotary or translational, that are collocated on a leg of the manipulator. Moreover, a real‐time implementation of extra‐sensor data, with a unique direct kinematics solution, is proposed by resorting to an eigenvalue problem. The parallelism in the proposed formulation enables the user to benefit from a parallel computing environment. Hence, we introduce a parallel computing algorithm that highly increases the robustness of the computational algorithm. © 1995 John Wiley & Sons, Inc.
On the stiffnes of a novel six‐degree‐freedom parallel minimanipulator
Authors: Tahmasebi Farhad , Tsai Lung‐Wen 
Published: July 2007

AbstractThe dimensionally uniform Jacobian matrix of a novel three‐limbed, six degree‐of‐freedom (DOF) minimanipulator is used to derive its dimensionally uniform stiffness matrix. The minimanipulator limbs are inextensible and its actuators are base‐mounted. The lower ends of the limbs are connected to bidirectional linear stepper motors that are constrained to move on a base plane. The minimanipulator is capable of providing high positional resolution and high stiffness. It is shown that, at a central configuration, the stiffness matrix of the minimanipulator can be decoupled (diagona‐lized), if proper design parameters are chosen. It is also shown that the stiffness of the minimanipulator is higher than that of the Stewart platform. Guidelines for obtaining large minimanipulator stiffness values are established. © 1995 John Wiley & Sons, Inc.
Simulation and computer‐aided kinematic design of three‐degree‐of‐freedom spherical parallel manipulators
Authors: Gosselin Clement M. 
Published: July 2007

AbstractParallel robotic manipulators are complex mechanical systems that lead to involved kinematic and dynamic equations. Hence, the design of such systems is in general not intuitive, and advanced simulation and design tools specialized for this type of architecture are highly desirable. This article discusses the kinematic simulation and computer‐aided design of three‐degree‐of‐freedom spherical parallel manipulators with either prismatic or revolute actuators. The kinematic analysis of spherical parallel manipulators is first reviewed. Solutions for the direct and inverse kinematic problems are given, and the expressions for the singularity loci are then introduced. The determination of the workspace of this type of manipulator is also addressed. Finally, a computer package developed specifically for the CAD of spherical parallel manipulators is presented. This package allows the interactive analysis of manipulators of arbitrary architecture including the representation of the workspace, the representation of singularities, and the graphic animation of trajectories specified either by the direct or the inverse kinematic module. It can be used for the design of any spherical parallel three‐degree‐of‐freedom actuated mechanism, which can find many applications in high‐performance robotic systems. © 3995 John Wiley & Sons, Inc.
A robotically assisted munition loading system
Authors: Nguyen Charles C. , Zhou Zhen‐Lei , Bryfogle Mark D. 
Published: July 2007

AbstractDue to the reliance upon manual operations, conventional loading of munitions on tactical arcraft has several deficiencies including inefficient manpower and time utilization; accident potential; exposure of crew members to chemical, biological, and nuclear agents; and visual obstruction. This article reports on the research and development of a full‐scale prototype robotic system called Robotically Assisted Munition Loading System (RAMLS) comprising a fine motion mechanism (FIMOM), a pose acquisition device (PAD), a manual controller, and a data acquisition and computing system. The FIMOM is a six‐degree‐of‐freedom (DOF) parallel mechanism driven by six hydraulic actuators and the PAD is a passive open kinematic chain mechanism having 6 DOF. The article describes the design and functions of the RAMLS components and presents results of experiments conducted to evaluate the RAMLS's performance. © 3995 John Wiley & Sons, Inc.
Low earth orbit satellite systems for communications
Authors: Maral Gérard , de Ridder Jean‐Jacques , Evans Barry G. , Richharia Madhavendra 
Published: July 2007

AbstractIt may be that we are now entering the era of LEO constellation satellite communications after thirty years of domination by the GEO systems. This paper heralds the coming of the new era with a tutorial approach to the system design and trade‐offs of LEO constellation system design. It discusses orbital configurations, network topologies and routeing considerations, multiple access schemes and link performance design. In so doing it brings out the major design parameters and how they interact with each other. Also considered are the service applications for the LEO constellation systems, and the important difference between real‐time and delayed communication systems is highlighted. Examples of single and multi‐beam (cellular) coverage system link designs are presented for L‐Ka frequency bands. Future papers will consider aspects of the LEO spacecraft and launchers.
A promising application for broadband ISDN: Hypermedia teleconference
Authors: Shimamura Kazunori , Masaki Shigeki , Tanigawa Hiroya 
Published: July 2007

AbstractThe optimum BISDN teleconference service for business, calledhypermedia teleconference, is designed based on research into typical business activities and ATM, the most promising BISDN architecture. Service characteristics are determined by analysing the daily work practices of a large set of businessmen. It is shown that communication tasks occupy 44 per cent of the working day. The analysis further shows that some 60 per cent of all communication tasks could be performed through an advanced digital teleconference service. Hypermedia teleconference is designed to satisfy the needs of business through personal communication terminals and ATM public networks. The terminals effectively allocate the BISDN's high‐speed transmission capability between a number of subchannels that realize distributed multipoint connection links and multimedia paths. The terminals use a new variable‐bit‐rate ATM codec created to realize high quality video. Users can easily create full featured teleconferences without a centralized connection facility. Terminals allow the synergistic combination of video, voice, telewriting, telepointing and document transmission services.
Required protection ratios for co‐frequency pal fm tv transmissions
Authors: Harverson M. , Dutronc J. , Dobbie W. , Court B. 
Published: July 2007

AbstractThis paper contains the results of a measurement campaign to determine the protection ratio requirements for PAL FM TV satellite transmissions in a form suitable for direct application in satellite planning exercises.The following cases were considered in the study:

the mutual interference between two co‐frequency PAL TV signals frequency modulated using a deviation sensitivity of either 16 MHz/V or 25 MHz/V
the interference effects created by two independent co‐frequency PAL TV carriers interfering with the same victim PAL TV carrier, with all signals frequency modulated using a deviation sensitivity of 25 MHz/V.
Protection ratios were assessed with a wide variety of different conditions assumed for the wanted and interfering signals, such as the target picture quality and the operating carrier to noise ratio. The analysis of the results indicates that the required protection ratio is dependent upon some of the study parameters such as the picture content of the wanted signal. Protection ratio guidelines are derived on the basis of this analysis for co‐frequency interference into PAL FM TV signals. The results also confirm that, for planning purposes, multiple interfering signals can be treated by addition on a power basis.
Fault tolerance of on‐board digital signal processing circuits
Authors: Raghunandan K. , Coakley F. P. , Evans B. G. 
Published: July 2007

AbstractThe paper is organized in four sections. The first section introduces the nature of faults as well as their causes. The methods used to identify faults and the actions necessary to correct the situation are outlined. The second section identifies the different fault tolerance approaches to conventional computational circuits and the DSP circuits. Current research work in the area of fault tolerance of FFT, signal processing and VLSI circuits involving systolic arrays is reviewed. Since some of the techniques do not involve error correction, reconfiguration of the circuit after error detection becomes necessary and a brief look at the relevant reconfiguration strategies is appropriate. Software fault tolerance is introduced and some work applicable to computations in general is reviewed. The implementation of the methods and its consequences are described in the third section. Concluding remarks form the final section.