bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New view of the Decoupling Problem for Industrial Robots
Authors: Troch I. 
Published: March 2009

SUMMARYNonlinear couplings between the various joints of a robotic arm cause trouble in robot control. One possibility to overcome these difficulties is offered by the concept of nonlinear decoupling. The latter leads to independent linear SISO systems, each of them describing the movement of one joint. Thus, an application of control concepts for linear SISO systems is possible. However, at present such decoupling controls are computed from the mathematical model of the arm, the so-called drive equations, whereas actuator dynamics are considered only in a secondary way. In this paper the decoupling problem for robots is investigated by accounting also for the actuator dynamics from the very beginning. This results in decoupling laws requiring a complete state feedback, i.e. not only joint positions and velocities but also the states of the various actuators have to be used. Further, formulas are given which make the computation of those states unsuitable for direct measurements.
3D Shape and surface colour sensor fusion for robot vision
Authors: Jarvis R. A. 
Published: March 2009

SUMMARYThis paper argues the case for extracting as complete a set of sensory data as practicable from scenes consisting of complex assemblages of objects with the goal of completing the task of scene analysis, including placement, pose, identity and relationship amongst the components in a robust manner which supports goal directed robotic action, including collision-free trajectory planning, grip site location and manipulation of selected object classes.The emphasis of the paper is that of sensor fusion of range and surface colour data including preliminary results in proximity, surface normal directionality and colour based scene segmentation through semantic-free clustering processes. The larger context is that of imbedding the results of such analysis in a graphics world containing an articulated robotic manipulator and of carrying out experiments in that world prior to replication of safe manipulation sequences in the real world.
Artificial Intelligence: building birds out of beer cans
Authors: Yazdani Masoud , Whitby Blay 
Published: March 2009

SUMMARYJohn Searle's attack on various interpretations of Artificial Intelligence has been the most thorough challenge to the philosophical foundations of Artificial Intelligence. In this paper we attempt to contribute to a growing body of argument as to why Searle is mistaken in his attack. We propose an analogy between intelligent objects and flying objects, leading to a definition of Artificial Intelligence similar to that of aerodynamics, but one which attempts to present general laws of intelligence in man and machines alike.
Geometric modelling of boundless grasps
Authors: Xiong Y.L. , Sanger D.J. , Kerr D.R. 
Published: March 2009

SUMMARYThis paper describes the development of the topological and geometric approach to the analysis and synthesis of form-closed grasps of arbitrary objects. Concepts of wrench spaces and the relevant subsets of the positive cone, the affine hull, the convex huli, and the related polar cone are used, and applied to a representative example.
An optimal force distribution scheme for cooperating multiple robot manipulators
Authors: Shin Yong Dal , Chung Myung Jin 
Published: March 2009

SUMMARYIn this paper, we suggest an optimal force distribution scheme by weak point force minimization and we also present an efficient method to solve the problem. The concept of a weak point is a generalized one which is applicable to any points of interest, as well as joints or contact points between end-effectors and an object. The problem is formulated by a quadratic objective function of the forces exerted at weak points subject to the linear equality and inequality constraints, and its optimal solution is obtained by an efficient method. As regards the solution of the problem, the original problem is reformulated to a reduced order dual problem after the equality constraints are eliminated by force decomposition.
Optimal load distribution for two cooperating robots using a force ellipsoid
Authors: Choi Myoung Hwan , Lee Bum Hee , Ko Myoung Sam 
Published: March 2009

SUMMARYThe concept of the force ellipsoid and the manipulability ellipsoid of robotic mechanism is extended to two cooperating robot arms, and the equations of the dual arm force and manipulability ellipsoids are derived. The load distribution problem for two cooperating robots is studied using the concept of the force ellipsoid. The problem is usually underspecified mathematically and a variety of optimal solutions may exist. A new solution approach utilizing the force ellipsoid is proposed in this paper. The load distribution problem is formulated as a nonlinear optimization problem with a quadratic cost function and inequality constraints. The optimality criterion is the minimum energy, and two different cases are considered depending on the presence of the constraints on joint torques.
An Algorithm for Robust Tracking Control of Robots
Authors: Novaković Zoran R. , Z˘lajpah Leon 
Published: March 2009

SUMMARYBased on the Lyapunov theory, a new principle was developed for synthesizing robot tracking control in the presence of model uncertainties. First, a general Lyapunov-like robust tracking concept is presented. It is then used as a basis for the control algorithm derived via a quadratic Lyapunov function constructed using a sliding mode function (based on the output error). Control synthesis is made in task-space, without any need for solving the inverse kinematics problem, i.e. one does not need to inver the Jacobian matrix. It is also shown that the tracking error becomes close to zero in a settling time which is less than a prescribed finite time. Simulation results are incorporated.
Distance estimation in a system with a mobile camera
Authors: Lide Yu , Stewart N. F. 
Published: March 2009

SUMMARYWe consider the problem of distance estimation in the context of a mobile camera, as, for example, when the camera is attached to a robot arm. It is natural in this case to consider stereo motion, and we present here the theoretical basis for an axial stereo method based on cross-correlation using the Fast Fourier Transform, which is appropriate in the context considered here. Finally, we describe the state of implementation of the system in our laboratory.
Control of tracking systems by image correlation
Authors: Ciccotelli Joseph , Dufaut Michel , Husson René 
Published: March 2009

SUMMARYOwing to advances in machine vision, it is now possible to study automatic gripping of moving parts. This complex task requires a precise knowledge of the displacements of objects in a camera field.In this paper, a method to analyse the motion of parts is presented; it is based on the correlation of numerical images. The treatment of data provided by the image background makes this method quite original.The utilization of this method, often considered as rather awkward, makes it possible, in this case, to develop a position feedback operation of the robot actuators controlled in an open loop (step by step motors).
Cartesian control of robotic manipulators with joint compliance
Authors: Hill S. D. , Vaccaro R. J. 
Published: March 2009

SUMMARYAn efficient on-line scheme for computing the inverse joint solution of robotic manipulators is combined with an improved formulation of robust, non-linear feedback control in joint space to produce a realizable Cartesian control scheme. Parametric uncertainties in the robot model are highlighted by the inclusion of compliance at each joint. Simulation results for a two link, coupled manipulator demonstrate that this Cartesian control enables the tip of the arm to track the demanded trajectory with arbitrarily small error in response to realistic actuator torques.
Applications of entity-relationship model to picture description
Authors: Lee Edward T. , Chu P. , Wu C. Peng 
Published: March 2009

SUMMARYThe concepts of entity-relationship diagram have been applied to picture description. Primitive picture entities, picture relationships, and picture grammars are presented with illustrative examples. A high-level description of a two-level picture generation system is proposed using either string description or ER diagram description. Illustrative examples are also given. The advantages of ER diagram description together with its comparison to string description are also presented. The results may have useful applications in robotics, artificial intelligence, expert systems, picture processing, pattern recognition, knowledge engineering and pictorial database design.
Forces of reaction and neighbouring Hamilton's principle in the tracking control of manipulators via a sliding scheme
Authors: Jumarie Guy 
Published: March 2009

SUMMARYIt is shown that if one comes back to the formulation of the Hamilton's variational principle, it is then possible to obtain new viewpoints on the tracking control of robot manipulators. First, the Lagrange multiplier associated to the sliding surface can be interpretated in terms of control effort and/or forces of reaction of the mechanical system. Secondly, one can use the Taylor expansion of the mechanical Lagrangian, combined with a neighbour- ing Hamilton's principle, to obtain control schemes via sliding surfaces. Thirdly, a perturbation approach combined with the neighbouring Hamilton's principle provides results on the robustness of the control.
New approaches to manipulator arm solutions via unconstrained optimization theory
Authors: Sasaki Shinobu 
Published: March 2009

SUMMARYIn this study, highly practical and reliable methods are proposed to determine arm solutions for a six-link robot manipulator. Based on a typical mathematical structure of minimizing an objective function, the optimization theory is applied to solve a reduced system of kinematic equations. The performance tests show that three different approaches are superior to a conventional method and of sufficiently practical use. Especially, the use of an algorithm presented in a linear search is promising.
Fourier-based optimal design of a flexible manipulator path to reduce residual vibration of the endpoint
Authors: Park Kyung-Jo , Park Youn-Sik 
Published: March 2009

SUMMARYA method is presented for generating the path which significantly reduces residual vibration. The desired path is optimally designed so that the system completes the required move with minimum residual vibration. The dynamic model and optimal path are effectively formulated and computed by using special moving coordinates, called virtual rigid link coordinates, to represent the link flexibilities. Also joint compliances are included in the model. Characteristics of residual vibration are identified from the linearized equations of motion. From these results, the performance index is selected to reduce residual vibration effectively. The path to be designed is developed by a combined Fourier series and polynomial function to satisfy both the convergence and boundary condition matching problems. The concept of correlation coefficients is used to select the minimum number of design variables, i.e. Fourier coefficients, the only ones which have a considerable effect on the reduction of residual vibration. A two-link manipulator is used to evaluate this method. Results show that residual vibration can be drastically reduced by selecting an appropriate manipulator path.
Formulation and control of robots with link and joint flexibility
Authors: Gogate Sachin , Lin Yueh-Jaw 
Published: March 2009

SUMMARYPresent study on industrial manipulator control either completely neglects structural flexibility or only considers manipulator link flexibility. Ignoring joint flexibility may cause significant errors in gross motion control if the joint elastic effect is predominant. This paper presents an effective control scheme which can compensate for the motion errors generated by simultaneous existence of both link and joint flexibility. The manipulator dynamics is formulated comprehensively by a superposition of two models, namely, an assumed modes of vibration model for links and a torsional spring model.for joints. Then, a nonlinear feedback rate servo control system is developed that compensates for the gross motion errors introduced by both joint elasticity and link flexibility. Motion simulation results show that the proposed formulation can effectively describe the dynamic behavior of a flexible-link, elastic-joint robot. They also verify that the proposed controller is robust in that it can satisfactorily suppress the manipulator end oscillations and yield an accurate gross motion.
Computer simulation of sensor-based robot collision avoidance in an unknown environment
Authors: Sun K. , Lumelsky V. 
Published: March 2009

SUMMARYComputer simulation is a major tool in validation of robot motion planning systems, since, on the one hand, underlying theory of algorithms typically requires questionable assumptions and simplifications, and, on the other hand, experiments with hardware are necessarily limited by available resources and time. This is especially true when the motion planning system in question is based on sensor feedback and the generated trajectory is, therefore, unpredictable. This paper describes a simulation system ROPAS (for RObot PAth Simulation) for testing one approach — called Dynmic Path Planning (DPP) — to sensor-based robot collision avoidance in an environment with unknown obstacles. Using real time graphics animation of the motion planning system, the user can simulate the behavior of an autonomous vehicle or a robot arm manipulator with a fixed base. The overall structure of the system is described, and examples are presented.
An approach to robot motion planning for time-varying obstacle avoidance using the view-time concept
Authors: Ko Nak Yong , Leet Bum Hee , Kot Myoung Sam 
Published: March 2009

SUMMARYAn analytic solution approach to the time-varying obstacle avoidance problem is adopted. The problem considers the collision between any link of the robotic manipulator and the time-varying obstacle. The information on the motion and shape change of the obstacle is given prior to robot motion planning. To facilitate the problem, we analyze and formulate it mathematically in a robot joint space. We then introduce the view-time concept and analyze its properties. Using the properties of the view-time, a view-time based motion planning method is proposed. The view-time based method plans the robot motion by units of the view-time. In every view-time, it uses a stationary obstacle avoidance scheme. The proposed method is applied to the motion planning of a 2 DOF robotic manipulator in an environment with a polyhedral moving obstacle.
Robust and adaptive position/force stabilization of robotic manipulators in contact tasks
Authors: Ekalo Y. , Vukobratović M. 
Published: March 2009

SUMMARYControl laws are described for solving the task of stabilization of motion and force of interaction of a robot with its environment with a prescribed quality of transient processes with respect to position and in the presence of control, motion, and interaction force constraints. The robustness of these laws to parametric perturbations and their stability with respect to initial and external perturbations and measuring sensor errors have been proven.
Design and implementation of an inductive learning control system for a manipulator gripper
Authors: Fontaine D. , Bidaud P. 
Published: March 2009

SUMMARYThis paper presents an advanced control system for an active compliant device. This device, a manipulator-gripper, was designed to achieve stable grasp of objects with various shapes and to impart compliant fine motions to the grasped object. In the control system of this end-effector, we introduced autonomous reasoning capabilities. Fine motion strategies, needed for mating or grasping, use inductive learning from experiments to achieve uncertainty and error recovery. An overview of the articulated gripper's structure is provided for a better understanding of the programming environment we propose. For solving the problem of synthesis programs for fine motion planning we introduce declarative programming facilities in the controller through a time-sensitive mini-prolog. The paper gives some details on the implementation of this mini-prolog. We develop a heuristic procedure to obtain an implicit local model of contacts in complex assembly tasks. Finally, a specific example of this approach – a peg-in-hole operation– –is outlined.
Navigation of mobile robots using a fuzzy behaviorist approach and custom-designed fuzzy inferencing boards
Authors: Pin François G. , Watanabe Yutaka 
Published: March 2009

SummaryTwo types of computer boards incorporating recently developed VLSI fuzzy inferencing chips have been developed to support the addition of qualitative reasoning capabilities to the real-time control of robotic systems. The design and operation of these boards are first reviewed and their use, in conjunction with our proposed Fuzzy Behaviorist approach, is discussed. This approach uses superposition of elemental sensor-based behaviors expressed in the Fuzzy Sets theoretic framework, to emulate "human-like" reasoning inrobotic systems.
A discrete-time virtual passive control algorithm for large space systems
Authors: Lee Gordon K. F. , Clark Eric 
Published: March 2009

SummaryThe virtual passive control approach has recently been shown to be an effective technique for robust compensation of linear as well as nonlinear systems, when the system is open-loop stable and behaves as a block second-order plant. Mechanical systems as well as current space structure designs possess this property whereby inertia, damping and stiffness parameters characterize the dynamics.Implementation of such controllers using digital systems may lead to instability, however, unless discretization issues are addressed. This paper presents a discrete-time representation of the Virtual Passive Approach and develops the robust controller structure for linear systems. The algorithm is then applied to a model of an actual experimental testbed; the test article is a ten-bay truss structure located at NASA Langley's Spacecraft Dynamics Branch. Results illustrate the robustness properties of the algorithm and expose issues which need to be addressed in future research activities.
Fuzzy logic based collision avoidance for a mobile robot
Authors: Martinez Angelo , Tunstel Eddie , Jamshidi Mo 
Published: March 2009

SummaryNavigation and collision avoidance are major areas of research in mobile robotics that involve varying degrees of uncertainty. In general, the problem consists of achieving sensor based motion control of a mobile robot among obstacles in structured and/or unstructured environments with collision-free motion as the priority. A fuzzy logic based intelligent control strategy has been developed here to computationally implement the approximate reasoning necessary for handling the uncertainty inherent in the collision avoidance problem. The fuzzy controller was tested on a mobile robot system in an indoor environment and found to perform satisfactorily despite having crude sensors and minimal sensory feedback.
Contribution to the modelling of impact with robotic systems
Authors: Drenovac Vojin , Potkonjak Veljko 
Published: March 2009

SUMMARYThis paper discusses the problem of impact with robotic systems. The original method for the solution of impact is presented. The main idea is the replacement of impact with a singularity and hence the approach is called the IVSA (Impact-Via-Singularity-Analysis) Method. This goal is achieved by considering the obstacle as a unilateral constraint and introducing the new set of generalized coordinates so as to incorporate the constraint in the dynamic model. Using the IVSA Method the impact is not described by algebraic equations but by a reduced set of differential equations resulting directly from the initial dynamic model. The integration of dynamic equations over the impact points is thus possible. A numerical example is presented.
A practical application of fluid power systems in manufacturing
Authors: Billatos Samir B. 
Published: March 2009

SUMMARYFluid power is one of the vast fields and its applications in manufacturing are not used for many real-time problems though its capabilities are known. One such application is fluid power for robotic systems. More specifically, in this study, a new hydraulic system is developed for use in actuating a robotic gripper. Electric motors were found unsatisfactory due to their poor power to weight ratio. Hydraulics were attempted using a master slave hydraulic system. Powering and positioning was done on the master cylinder, while the remote slave cylinder followed the motion. The control of the master cylinder was done with a ground based stepping motor and lead screw mechanism. Small hoses ran to the gripper based slave cylinder, which copied the motions.
An approach to automatic robots programming in the flexible manufacturing cell
Authors: Rogalinski Paweł 
Published: March 2009

SUMMARYThe paper presents an approach to automatic synthesis of program for robots in a flexible manufacturing cell (FMC). The system of program generation consists of two layers: Task-Level Programming Layer and Program Interpretation and Verification Layer. The first layer uses robot-independent planning techniques to create a work plan for robots (set of elementary actions) and program for each elementary action. The second layer uses robot-dependent planning methods to plan robot's trajectories and calculate the robot's motion times. A simulation model of whole FMC, which is created based on a description of FMC and program for robots, makes possible evaluation of efficiency of FMC work.
Control strategy for a redundant PUMA manipulator
Authors: Allgeuer Helmut 
Published: March 2009

SUMMARYIn this paper a control strategy for a redundant PUMA robot is presented. This robot is obtained from the conventional PUMA robot by addition of a joint parallel to the elbow joint. For redundancy resolution the following approach is chosen. From the position and pointing direction of the end effector of the PUMA robot the position and orientation of the fourth link of a 4R-manipulato? is calculated and the redundancy is resolved for this manipulator. This is done by adding an equation to the relationship between the joint angles and position and orientation of the fourth link. By this approach a control strategy is derived that allows motions of the end effector of the PUMA robot in a large part of its work space and shows repeatable behaviour. Furthermore, the redundancy is utilized so that the fiexture of the wrist is kept small.
Performance of generalized predictive control with on-line model order determination for a hydraulic robotic manipulator
Authors: Kotzev A. , Cherchas D. B. , Lawrence P. D. 
Published: March 2009

SummaryThe research results described present the performance of the Generalized Predictive Control (GPC) algorithm with a changing estimator and predictor model order for a specific application. The application is a hydraulically actuated heavy duty manipulator. Hydraulically actuated robotic manipulators, used in the large resource based industries, have a complex dynamic response in which, primarily due to the hydraulic actuator subsystems, the order of the dynamic model is not initially known and can change as the manipulator is operated. A nonlinear simulation model of the manipulator system is utilized in the work and the GPC controller is implemented with a CARIMA estimator together with an on-line, gradient based estimator model order determination technique. The results given show that with proper use of the order determination technique cost function and tuning of the GPC parameters, good performance and stability can be achieved.