bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficient workspace generation for binary manipulators with many actuators
Authors: Ebert‐uphoff Imme , Chirikjian Gregory S. 
Published: July 2007

AbstractBinary actuators have only two discrete states, both of which are stable without feedback. As a result, manipulators with binary actuators have a finite number of states. Major benefits of binary actuation are that extensive feedback control is not required, task repeatability can be very high, and two‐state actuators are generally very inexpensive, thus resulting in low‐cost robotic mechanisms. Determining the workspace of a binary manipulator is of great practical importance for a variety of applications. For instance, a representation of the workspace is essential for trajectory tracking, motion planning, and the optimal design of binary manipulators. Given that the number of configurations attainable by binary manipulators grows exponentially in the number of actuated degrees of freedom, 0(2), brute force representation of binary manipulator workspaces is not feasible in the highly actuated case. This article describes an algorithm that performs recursive calculations starting at the end‐effector and terminating at the base. The implementation of these recursive calculations is based on the macroscopically serial structure and the discrete nature of the manipulator. As a result, the method is capable of approximating the workspace in linear time, O(n), where the slope depends on the acceptable error. © 1995 John Wiley b Sons, Inc.
Surgical applications of milli‐robots
Authors: Cohn Michael B. , Crawford Lara S. , Wendlandt Jeffrey M. , Sastry S. Shartkar 
Published: July 2007

AbstractMinimally invasive surgical techniques, especially endoscopy and laparoscopy, possess many advantages over conventional methods. These include accelerated patient recovery and reduced rate of complications. However, limitations of current operating instruments create difficulties for the surgeon. In this article, we present a design for an improved polypectomy snare for the endoscope, several rotary actuator designs for endoscopic tools, and a prototype endo‐platform, which provides fine motion control for endoscopic tools. We also present several prototypes of more dextrous laparo‐scopic tools based on the human hand. Finally, we present a sensory glove designed as a natural and dextrous human interface. © 2995 John Wiley & Sons, Inc.
New bounds on the number of frictionless fingers requied to immobilize
Authors: Rimon Eton , Burdick Joel W. 
Published: July 2007

AbstractUsing a novel second‐order mobility theory that was recently developed by the authors, this article develops new lower bounds on the number of frictionless fingers required to immobilize generic planar objects. We show that any generic smooth or polygonal planar object can be immobilized with three convex fingers or fixtures that have sufficiently flat curvature. Further, if it is possible to specify the fingertip curvature, then any generic smooth or polygonal object can be immobilized with two, possibly concave, fingers. © 1995 John Wiley & Sons, Inc.
Geometric optimization algorithims for robot kinematic design
Authors: Park Frank C. , Bobrow James E. 
Published: July 2007

AbstractThis article addresses the problem of designing a robotic mechanism such that its end‐effector frame comes closest to reaching a set of desired goal frames. We formulate this as an optimization problem, in which the kinematic parameters are selected to minimize the total distance between the end‐effector frame and each goal frame. The objective function is defined in terms of a class of distance metrics on the rigid body motions that are invariant with respect to choice of fixed reference frame. A main contribution of this article is an explicit expression for the gradient of this objective function with respect to the kinematic parameters. With this analytic gradient, efficient optimization algorithms can now be developed for the design of general spatial mechanisms. Our design methodology is illustrated with an example involving the base positioning of two cooperating robots. © 1995 John Wiley & Sons, Inc.
Identification and resolution of structural and algorithmic singularity in redundancy control of serial manipulations
Authors: Wang Zhaoyu , Kazerounian Kazem 
Published: July 2007

AbstractA major difficulty that has haunted most researchers in the process of optimal redundancy resolution of robotic manipulators is the instability observed in even very simple numerical simulations. This numerical instability is not related to the structurally singular configurations of the manipulators, and in the literature has been referred to as “algorithmic singularity,” “artificial singularity,” or “unavoidable singularity.” In this work, conditions on both structural and algorithmic singularities are studied based on the Singular Value Decomposition of the Jacobian matrix, and, hence, a singularity‐free control algorithm for redundant manipulators is developed and resolved as the Lagrange problem of optimal control. It is shown that many well‐known methods for optimal redundant manipulation in the literature, including the Extended Jacobian Technique, most of constraint function‐based methods, and most of the previously reported methods on global optimization techniques, are all special cases of the formulation provided here. Further, the necessary conditions of the global optimality for this general formulation are derived in explicit form and the source of “algorithmic singularity” is rigorously identified and resolved. © 2995 John Wiley & Sons, Inc.
Mobile robot path planning for fine‐grained and smooth path spcification
Authors: Shin Dong Hun , Ollero Anibal 
Published: July 2007

AbstractThis article introduces and draws a comparison on B‐splines and clothoids for generating fine‐grained, smooth path specifications as applied to mobile robot path planning. At one level, a sequence of objective points that the robot must attain to avoid obstacles and to progress toward its goal are supplied by a coarse path planner. Using B‐spline and clothoid curves, these objective points are converted into a path of finer detail, as requisite to a robot driving controller/tracker. Through experimental results with the Navlabll, a mobile robot vehicle at Carnegie Mellon University (CMU), we differentiate the advantages of this approach over conventional poly‐line fit/round corner used to date. © 2995 John Wiley & Sons, Inc.
Improved manipulator perfomance through local d‐h calibation
Authors: Everett Louis J. , Lei James 
Published: July 2007

AbstractThis article deals with the subject of increasing the positioning accuracy of a manipulator beyond what is typically obtained via Denavit‐Hartenberg (D‐H) calibration. It is commonly accepted that one method for accomplishing this requires including “extra” terms (such as static deflection) in the D‐H model. Another technique, which is experimentally verified and quantified in this article, is that of local calibration. Rather than continually introducing more and more modeling terms, we restrict the workvolume of the manipulator. One contribution of this article is an experimental investigation of local calibration. Most data indicates that local calibration offers advantages and it quantifies that the approximate improvement on one particular PUMA 560 robot is as much as four times better than global calibration. Some data indicates that it is not always true that “localizing” the calibration is an improvement. The article also discusses the problem of recognizing bad calibration data. We demonstrate a technique for identifying and removing “bad” data. Finally, the article shows that the locality of workvolume must include a consideration of the joint motions as well. For example, it presents results when data is taken with the arm in a single configuration, and in multiple configurations. © 1995 John Wiley & Sons, Inc.
Feedback linearization of robot manipulators and riemannian curvature
Authors: Bedrossian Nazareth S. , Spong Mark W. 
Published: July 2007

AbstractSeveral authors have noted that if the robot inertia matrix D(q) can be factored as NT(q)N(q) where N(q) is the Jacobian of a function Q(q), then Q and P = N(q)q define a canonical transformation relative to which the robot dynamics are linear except for gravity terms. In this article, we show that necessary and sufficient condition for the existence of such a factorization is that the Riemannian curvature of the robot inertia matrix D(q) vanish identically. We use this result to generate feedback linearization and approximate feedback linearization control laws that require fewer calculations than the usual method of computed torque. © 1995 John Wiley & Sons, Inc.
Near‐time optimal robot motion planning foe on‐line applications
Authors: Croft E. A. , Benhabib B. , Fenton R. G. 
Published: July 2007

AbstractSolving current formulations of the time‐optimal point‐to‐point motion problem for robotic manipulators is a computationally intensive task. Thus, most existing solutions are not suitable for on‐line motion planning applications, such as the interception of moving targets, where time‐optimality of the motion is advantageous. A novel technique is proposed in this article that separates the time‐optimal point‐to‐point motion problem into the following two sub‐problems: (1) selection of a near‐time‐optimal path between the two endpoints, and (2) generation of time‐optimal motion along the selected path (i.e., constrained continuous path motion). Although our approach uses known path‐constrained time‐optimal‐motion algorithms for the second sub‐problem, a new method is proposed for the selection of near‐time‐optimal paths. Based on a study of the characteristics of global‐time‐optimal paths, the near‐optimal path is selected as a minimum‐curvature joint spline, tangent to one of the manipulator's acceleration directions at the start point, and tangent to the required manipulator velocity direction at the end point. The algorithm for determining the overall near‐optimal path is described herein, along with an example. Simulation test results and computation‐time studies indicate that the proposed method is suitable for on‐line motion planning applications. © 1995 John Wiley & Sons, Inc.
Generation of discontinuous gaits for quadruped walking vehicles
Authors: Santos Pablo Gonzalez De , Jimenez Maria A. 
Published: July 2007

AbstractDiscontinuous gaits for walking machines have not yet been properly studied. Research has focused on the investigation, comprehension, and mathematical formulation of natural gaits. These gaits feature the fact that the body is in constant motion. The results have been significant, but they seem more adequate for animals than machines. On the other hand, discontinuous gaits, executed by animals under extreme conditions, exhibit excellent attributes for implementation in walking machines. This article presents a comparative study of continuous and discontinuous gaits with regard to their maximum achievable velocity and stability. Other aspects such as implementation in real machines, power requirements, and control under terrain difficulties are mentioned briefly. An elemental discontinuous gait is stated, and some variations on deriving crab and turning gaits are performed. Different methods for enlarging the achievable crab angle and improving stability are discussed for discontinuous crab gaits. A similar study is also done for turning gaits. (c) 1995 John Wiley & Sons, Inc.
Simulation of an open chain of flexible links in a mixed formalism
Authors: Boyer FréDéric , Coiffet Philippe 
Published: July 2007

AbstractThis article presents the second part of a research work devoted to modeling and control of robots with flexible links. First, we recall the generalization of the Newton Euler equations for an open chain of flexible links. These equations constitute an original dynamic model because they represent the dynamic behavior of the chain with a mixed formalism, because it is both Lagrangian and Eulerian. This formalism allows us to find the linear intrinsic dynamic model of links. Second, we exhibit the constrained nature of these equations. We use a numerical integration method for a constrained system, and an updating procedure well suited to our particular formalism. Finally, simulation results on spatial kinematics involving up to three links are reported. (c)1995 John Wiley & Sons, Inc.
Path planning for robobt manipulators in polyhhedral objects environment
Authors: Tseng Ching‐Shiow , Lue Tsun‐Sun 
Published: July 2007

AbstractA recent development in robotics is the increase of intelligence in robots. One of the research fields is to enable robots to autonomously avoid collisions with surrounding objects. This article presents an efficient method for planning collision‐free paths for an articulated robot that is surrounded by polyhedral objects. The algorithm plans a hypothetical Archimedes's spiral path from the initial position to the goal position. When a collision among the arms and obstacles is detected, the hypothetical path will be modified to avoid the collision. The algorithm applies geometric methods to determine the upper and lower bounds of the reachable area of the wrist and then determines a collision‐free path point on that reachable area. Because the equations, which represent the upper and lower bounds, are simple, the algorithm can rapidly determine a collision‐free path. Moreover, with minor modifications, this path planning algorithm can also be applied to other robots such as spherical, cylindrical, and Cartesian types of robots. ©1995 John Wiley & Sons, Inc.
Cad‐based off‐line planning for active vision
Authors: He Xiaoyu , Benhabib Beno , Smith Kenneth C. 
Published: July 2007

AbstractA novel active‐vision system for 3‐D object recognition was developed. The vision system combines object pre‐marking and active sensing. Therein, an object is modeled by a few of its 2‐D perspective (standard) views, each with a corresponding viewing axis defined by a marker placed on the object. The operation of the active‐vision system is characterized by its off‐line planning and on‐line recognition phases. The primary objective of this article is to address two issues in regard to the former: optimal object pre‐marking and optimal camera placement. The optimal object pre‐marking problem is defined as the determination of the minimum number of markers, and their best locations on a given set of objects to yield maximum “distinctiveness” for the 2‐D standard‐views defined by these markers. The optimal camera‐placement problem targets minimization of camera movements in detecting the markers. Following a brief description of the proposed on‐line recognition process, the techniques developed for the off‐line planning stage are described in this article. For experimental verification purposes, a prototype of the proposed active‐vision system was also implemented and is described herein. ©1995 John Wiley & Sons, Inc.
A dynamic coupling index for underactuated manipulators
Authors: Bergerman Marcel , Lee Christopher , Xu Yangsheng 
Published: July 2007

AbstractIn recent years, researchers have been dedicated to the study of underactuated manipulators, which have more joints than control actuators. In previous work, researchers always assumed that there was enough dynamic coupling between the active and the passive joints of the manipulator for it to be possible to control the position of the passive joints via the dynamic coupling. In this work, the authors aim to develop an index to measure the dynamic coupling, so as to address when control of the under‐actuated system is possible, and how the motion and robot configuration can be designed. We discuss extensively the nature of the dynamic coupling and of the proposed coupling index, and their applications in the analysis and design of underactuated systems, through a detailed mathematical analysis and several illustrative examples. ©1995 John Wiley & Sons, Inc.
Robust contorl of a mamipulator pefoming constrained motion with uncertainties in the constraint
Authors: Ho Yeons Khing , Wang Danwei , Son Yens Chai 
Published: July 2007

AbstractThis article deals with the control of a robot manipulator performing constrained motion in an environment where the constraint function contains uncertainties. The uncertainties are appropriately modeled, and a controller consisting two components, one for positional and velocity tracking, and the other for force regulation, is proposed. The controller contains a nonlinear term that takes the form of a polynomial in the norms of the trajectory and force errors. The coefficients of the nonlinear function are chosen in relation to the bounds on the dynamic parameters of the robot system and an estimate of the bound on the uncertainty in the constraint function. Simulation results show that the modeling is appropriate and the controller is robust against parameter uncertainties ©1995 John Wiley & Sons, Inc.
Optimization of a leg design
Authors: Eltze JÜRgen , Pfeiffer Friedrich 
Published: July 2007

AbstractA crucial point in developing walking machines is the load to weight ratio. Leg design and in it the drives essentially determine the leg's weight. Therefore it makes sense to optimize the design as well as the best motor‐gear‐combination with respect to power density. Some typical principles of legs have been derived from biological findings, especially for insects. The technical solution was adapted to these principles in an optimal way. The resulting leg achieves a load to weight ratio of approximately six. © 1995 John Wiley & Sons, Inc.
Reducing flexible base vibrations through local redundancy resolution
Authors: Hanson Mark L. , Tolson Robert H. 
Published: July 2007

AbstractFuture space systems will use teleoperated robotic systems mounted on flexible bases such as the Shuttle Remote Manipulator System. Due to dynamic coupling, a major control issue associated with these systems is the effect of flexible base vibrations on the performance of the robot. If uncompensated, flexible vibrations can lead to inertial tracking errors and an overall degradation in system performance. One way to overcome this problem is to use kinematically redundant robots. Thus, this article presents research results obtained from locally resolving kinematic redundancies to reduce or damp flexible vibrations. Using a planar, three‐link rigid robot example, numerical simulations were performed to evaluate the feasibility of three vibration damping redundancy control algorithms. Results showed that compared to a zero redundancy baseline, the three controllers were able to reduce base vibration by as much as 90% in addition to decreasing the required amount of joint torque. However, similar to locally optimizing joint torques, excessive joint velocities often occurred. To improve stability, fixed weight, multi‐criteria optimizations were performed. ©1995 John Wiley & Sons, Inc.
The Isotropic Design of Two General Classes of Planar Parallel Manipulators
Authors: Mohammadi H. R. , Zsombor‐murray P. J. Daniali , Angeles J. 
Published: July 2007

AbstractManipulator designs with isotropic architectures have a number of advantages, including high servo accuracy and dexterity. Using the isotropy criterion, isotropic designs of two general classes of planar, three‐degree‐of‐freedom, parallel manipulators with three legs are produced. One of these classes comprises 20 manipulators, while the other, 4. As special cases for each class, the complete set of isotropic designs of 2 manipulators is found. The parameter space of isotropic design of these manipulators is a continuum of at least one dimension. © 2995 John Wiley & Sons, Inc.
The ISDN U interface and transceiver
Authors: Borns Robert J. 
Published: July 2007

AbstractThis paper describes the integrated services digital network (ISDN) basic rate interface (BRI) two‐wire U interface and the transceiver necessary for the digital transmission of 160 kb/s of information over unshielded twisted pair transmission media. Topics discussed include the U interface structure and framing as described in the American National Standards Institute (ANSI) T1.601 specification, and the VLSI implementation of the ISDN U transceiver. Pertinent transceiver design issues addressed include the type of line code used, such as 2B1Q or 4B3T, echo cancellation, near end crosstalk, equalization and sampling rates.
Survey of switching techniques in high‐speed networks and their performance
Authors: Oie Yuji , Suda Tatsuya , Murata Masayuki , Miyahara Hideo 
Published: July 2007

AbstractOne of the most promising approaches for high speed networks for integrated service applications is fast packet switching, or ATM (asynchronous transfer mode). ATM can be characterized by very high speed transmission links and simple, hard‐wired protocols within a network. To match the transmission speed of the network links, and to minimize the overhead due to the processing of network protocols, the switching of cells is done in hardware switching fabrics in ATM networks.A number of designs have been proposed for implementing ATM switches. Although many differences exist among the proposals, the vast majority of them are based on self‐routeing multistage interconnection networks. This is because of the desirable features of multi‐stage interconnection networks such as self‐routeing capability and suitability for VLSI implementation.Existing ATM switch architectures can be classified into two major classes: blocking switches, where blockings of cells may occur within a switch when more than one cell contends for the same internal link, and non‐blocking switches, where no internal blocking occurs. A large number of techniques have also been proposed to improve the performance of blocking and non‐blocking switches. In this paper, we present an extensive survey of the existing proposals for ATM switch architectures, focusing on their performance issues.
The INTELSAT VII/VIIA generation of global communications satellites
Authors: Thompson P. T. , Silk R. , Herridge A. 
Published: July 2007

AbstractDeveloped primarily to provide continuation of services from the INTELSAT V satellites in the Pacific Ocean Region, this latest generation of satellites also has utility for operation in other roles. Several new technologies are combined to give cost‐effective international satellite communications on a global, regional and domestic basis. This new higher power satellite will form a fundamental part of the INTELSAT global network, having been designed to match the projected traffic demands and future service requirements.
Personal communications via iNTELSAT Ku‐band transponders
Authors: Fang R. J. F. 
Published: July 2007

AbstractThe concept of a fully meshed network of very small terminals is presented for personal communications over Ku‐band satellite transponders. In this concept, undesirable double‐hop delays are avoided for voice communications between these terminals. The bandwidth and power resources of the transponder are efficiently shared by users in a simple demand‐assigned manner via code‐division multiple access (CDMA).1,2 Voice, data and facsimile are statistically multiplexed at each terminal. In order to minamize terminal costs, frequency‐precorrected and level‐preadjusted continuous wave (CW) tones are sent from the central network control station in each beam. The terminals in each down‐link beam can use these pilots as references for antenna acquisition and tracking, as reliable frequency sources, and as indicators of signal fade for up‐link power control (ULPC). The potential CDMA ‘near‐far’ problem due to up‐link fades is mitigated by using ULPC. Quasi‐burst‐mode transmission is employed to minimize the potential loss of clock and pseudorandom number code synchronization. When these terminals are used only to interconnect into the public switched telephony networks (PSTNs) through large, hub‐like gateway stations, they can employ flat‐plate antenna technology. The complete terminal can thereby be packaged into a briefcase so that it is easily transportable for personal use.