bluuebunny/crossref_metadata_2025 huggingface dataset:
A transputer-based system for locating parts and controlling an industrial robot
Authors: Pham D. T. , Hu Huosheng , Pote J.
Published: March 2009

A parallel-processing system for locating parts and controlling an industrial robot is proposed. The system employs Transputers and Occam to achieve parallelism. In conjunction with a novel vibratory sensor, the system enables a robot to determine the exact location of parts which have been picked up from a semi-ordered work place. A new algorithm for obtaining the coordinates of the parts using the sensed vibration and deflection signals is described. The algorithm dispenses with the lengthy and complex equation-solving procedures previously required. Instead, it only involves looking up a data table and performing simple two-dimensional interpolation calculations. The design of the algorithm to ensure efficient parallel operation is described. Experimental results showing the successful implementation of the algorithm on the proposed system are presented.
Continuous path planning via a non-inverting parallel algorithm
Authors: Voliotis S. D. , Christodoulou M. A.
Published: March 2009

The problem of path tracking in robotic manipulators applications is studied in this paper. The path is generated as a sequence of elementary motions. The characteristic feature of our algorithm is that it avoids singularities, because there is no need to use inverse kinematics. Direction and proximity criteria are introduced.

The application of parallel processing methods to path tracking according to the previous algorithm is presented. The algorithm is implemented in the Alliant FX/80 parallel machine.
Computing a Manipulator Regressor Without Acceleration Feedback
Authors: Yuan Jing , Stepenanko Yury
Published: March 2009

A manipulator regressor is an n x l matrix function in the dynamic expression τ = Y r or τ = Wr, which linearizes the robotic dynamics with respect to a properly defined inertia parameter vector ζr є R1. Many modern adaptive controllers require on-line computation of a regressor to estimate the unknown inertia parameters and ensure robustness of the closed-loop system.

While the computation of Y is studied by Atkeson, An and Hollerbach1 and Khosla and Kanade,2 the computation of W for a general n–link robot has not been reported in the literature. This paper presents an algorithm to compute W for a general n–link robotic manipulator. The variables used to construct the regressor matrix are directly available from the outward iteration of a Newton-Euler algorithm; some additional arithmetic operations and first-order, low-pass filtering are needed. The identification of unknown inertia parameters is also discussed.
A vibratory sensor for locating parts
Authors: Pham D. T. , Dissanayake M. W. M. G.
Published: March 2009

A vibratory sensor capable of locating parts by measuring their inertial properties is described in this paper. The sensor is designed to be fitted to the wrist of a robot and used to acquire parts from a stack or a tray. The initial coordinates of the parts need only be approximately known (say to ±25 mm and ±45°). The robot is thus said to operate in a “semi-ordered” environment which can be realised inexpensively as accurate pallets, fixtures or other parts presentation equipment are not required. Furthermore, the absence of complete disorder, as would exist with a “bin-picking” approach where parts are allowed to lie at random in a bin, reduces the degree of sophistication demanded of the sensor system. Consequently, the cost of the latter can also be kept low.

The proposed sensor has a circular platform mounted on the shaft of a motor such that the shaft is normal to the platform. The part whose location is to be determined is held on the platform by magnetic or other means. The assembly consisting of the part, platform and motor is constrained to vibrate about an axis parallel to the platform. Two methods for computing the location of the part relative to the platform are described. Both methods require the natural frequencies of vibration of the part-platform-motor assembly for various angular positions of the platform. A simulation study to examine the effect of various design and operational parameters (inertias of the platform and part, stiffness of the spring restraining the movements of the vibrating assembly, location of part on platform, accuracy of frequency measurements) on the accuracy of the location computed is presented. The simulation results clearly demonstrate the feasibility of the sensor.
Semi-automatic calibration procedure for the vision-robot interface applied to scale model decoration
Authors: Trabasso Luis Gonzaga , Zielinski Cezary
Published: March 2009

A semi-automatic method for calibrating a robot-vision interface is presented. It puts a small work-load on the operator, requires a simple calibration jig and a solution of a very simple system of equations. It has been extensively used in an experimental robotic cell set up at Loughborough University of Technology, where various aspects of the manufacturing and the decoration of scale models are being investigated. As an extension of the calibration procedure, the paper also shows practical solutions for the problem of dealing with three dimensional objects using a single camera.
Real-time path planning procedure for a whole-sensitive robot arm manipulator
Authors: Cheung Edward , Lumelsky Vladimir
Published: March 2009

We consider the problem of sensor-based motion planning for a three-dimensional robot arm manipulator operating among unknown obstacles. When every point of the robot body is subject to potential collision. The corresponding planning system must include these four basic components: sensor hardware; real-time signal/sensory data processing hardware/software; a local step planning subsystem that works at the basic sample rate of the arm; and finally, a subsystem for global planning. The arm sensor system developed at Yale University presents a proximity sensitive skin that covers the whole body of the arm and consists of an array of discrete active infrared sensors that detect obstacles by processing reflected light. The sensor data then undergoes low level processing via a step planning procedure, which converts sensor information into local normals at the contact points in the configuration space of the robot. This paper presents preliminary results on the fourth component, a real-time algorithm that realizes the upper, global level of planning. Based on the current collection of local normals, the algorithm generates preferable directions of motion around obstacles, so as to guarantee reaching the target position if it is reachable. Experimental results from testing the developed system are also discussed.
Harmonic drive transmissions: the effects of their elasticity, clearance and irregularity on the dynamic behaviour of an actual SCARA robot
Authors: Legnani Giovanni , Faglia Rodolfo
Published: March 2009

This paper deals with the study of the effects of Harmonic Drives characteristics on the dynamic behaviour of industrial robots. These components are firstly analyzed on the basis of the technical literature and, as a result, a mechanical model with concentrated parameters is obtained. Finally, the influence of these parameters on the dynamic behaviour of an actual SCARA robot in our department is investigated by means of experimental tests and by a computer simulation program purposely written.
Algorithms for simple object reconstruction using the largest possible object approach
Authors: Lee Edward T. , Wu Fred Y.
Published: March 2009

Recently, three-dimensional motion analysis and shape recovery have attracted growing attention as promising avenues of approach to image understanding, object reconstruction as well as computer vision for robotic Systems. The image generation problem and the model generation problem are presented. More specifically, the inputs to the image generator are an old image, object model, motion specification, and hidden line and hidden surface algorithms. The output is a new image. Since the object model is given, the top-down approach is usually used. On the other hand, for the model generation problem, the input is an image sequence while the output is an object model. Since the object model is not given, and bottom-up approach is usually used.

In this paper, the largest possible object approach is proposed and the advantages of this approach are stated. They are:

1. This approach may be applicable to objects with planar surfaces as well as nonplanar surfaces.

2. This approach may be applicable to the case that there are more than one face change per frame.

3. This approach may be applicable when the camera is moving.

4. This approach may be applicable when the object is measured by several measuring stations.

By using this approach, algorithms for simple object reconstruction given a sequence of pictures are presented together with illustrative examples. The relevance and importance of this work are discussed.

The results of this paper may have useful applications in object reconstruction, pictorial data reduction and computer vision for robotic Systems.
Robot navigation algorithms using learned spatial graphs
Authors: Iyengar S. S. , Jorgensen C. C. , Rao S. V. N. , Weisbin C. R.
Published: March 2009

Finding optimal paths for robot navigation in a known terrain has been studied for some time but, in many important situations, a robot would be required to navigate in completely new or partially explored terrain. We propose a method of robot navigation which requires no pre-learned model, makes maximal use of available information, records and synthesizes information from multiple journeys, and contains concepts of learning that allow for continuous transition from local to global path optimality. The model of the terrain consists of a spatial graph and a Voronoi diagram. Using acquired sensor data, polygonal boundaries containing perceived obstacles shrink to approximate the actual obstacles surfaces, free space for transit is correspondingly enlarged, and additional nodes and edges are recorded based on path intersections and stop points. Navigation planning is gradually accelerated with experience since improved global map information minimizes the need for further sensor data acquisition. Our method currently assumes obstacle locations are unchanging, navigation can be successfully conducted using two-dimensional projections, and sensor information is precise.
On the use of time-varying inertia links to increase the versatility of manipulators
Authors: Jumarie Guy
Published: March 2009

For a manipulator which works in a given fixed environment, like in manufacturing plants for instance, the control system may be designed in a fixed definite way. But when the characteristics of this environment is subject to variations, e.g. change in the mass of the object to be moved, it is necessary to endow the manipulator with some versatility which allows it to adapt itself to the new working conditions. The purpose of the paper is to show that the use of links with varying inertia is a possible way to achieve this flexibility.
Robotics: the strategic issues
Authors: Owen Tony
Published: March 2009

Increasing domestic and international competition is forcing the adoption of robotics. The advantages of robotics can be measured objectively at both a national and company level. The rate of adoption is slower than was predicted in the late 70's; and Computer Integrated Manufacturing has yet to appear. Generally, the UK's manufacturing industry is reluctant to adopt robotics, though changes in managerial attitude, strategic objectives, and the training of future staff is overcoming this reluctance.
Servoed world models as interfaces between robot control systems and sensory data
Authors: Kent Ernest W. , Albus James S.
Published: March 2009

A hierarchical robot sensory system being developed for industrial robotics is described. At each level of the hierarchy, sensory interpretative processes are guided by expectancy-generating modeling processes. The modeling processes are driven by a priori knowledge (object prototypes), by knowledge of the robot's movements (feed-forward from the control system), and by feedback from the interpretative processes (prior state of the sensory world). At the lowest level, the senses (vision, proximity, tactile, force, joint angle, etc.) are handled separately; above this level, they are integrated into a multi-model world model. At successively higher levels, the interpretative and modeling processes describe the world with successively higher order constructs, and over successively longer time periods. Each level of the modeling hierarchy provides output, in parallel, to guide the corresponding levels of a hierarchical robot control system.
Simulation of human judgement in a robot-based adjustment system
Authors: Naghdy Fazel , Billingsley John , Harrison David
Published: March 2009

A robot-based automatic system for adjusting energy regulators in electric cookers is described in this paper. It is claimed that this system improves the quality of the regulators and increases productivity. First, the operator's intuitive judgement and decision-making are simulated on a microcomputer; the structure and performance variables of the regulator are then described. A discussion of computer modelling of the regulator then follows, leading to the development of an algorithm for the adjustment procedure and overall strategy of the system. Experiments on 2,000 regulators showed that this automated operation was superior to the manual procedure as regards consistency and accuracy. This technique based on a robot may be applied to quality control and manufacture of a variety of similar products.
Separation of two monotone polygons in linear time
Authors: Toussaint Godfried T. , El Gindy Hossam A.
Published: March 2009

Let P= (p1, p2, …, pn) and Q= (q1, q2, …, qm) be two simple polygons monotonic in directions θs and φ respectively. It is shown that P and Q are separable with a single translation in at least one of the directions: ,. Furthermore, a direction for carrying out such a translation can be determined in O(m + n) time. This procedure is of use in solving the FIND-PATH problem in robotics.
FMS and the main car industry
Authors: Nicolò V.
Published: March 2009

The attainment of a breakeven for lower outputs, the diversification of models in order to meet market demand and the improvement of quality are accepted as strategic objectives for the automotive industry. The role of flexible manufacturing with reference to these objectives is illustrated. The steps, through which the new technology is introduced, are discussed and some production systems already installed are described within the given framework.
An efficient procedure for generating dynamic manipulator models
Authors: Vukobratović M. , Li Shi-Gang , Kirćanski N.
Published: March 2009

An iterative procedure for obtaining dynamic model of manipulator has been proposed in this paper. The high efficiency of the procedure is reached on the basis of iterative relations of dynamic parameters. For general six revolute joint manipulator, the complete dynamic model i.e. matrices H(q), C(q), G(q) and vector of joint torques 13. requires 992 multiplications and 776 additions. When the complete dynamic model is given by 13. the number of operations reduces to 863 multiplications and 773 additions.
On synchronized proportional motion of multi-robot systems with stepper motors and shared controller
Authors: Lirov Yuval
Published: March 2009

The synchronized action of robots is important in many applications, especially in the manufacturing processes. An algorithm to obtain a smooth synchronized movement of the multiple-robot system is presented for the case when only one processor is available to control all of the robots that incorporate stepper motors. The origin of this algorithm stems from the digital differential analyzer used in machine tool control.
Dynamic direct subspaces for robot path planning
Authors: Red W. E. , Kim K. H.
Published: March 2009

A direct subspace of a dynamic three-dimensional joint space is found to be useful for robot path planning in workspaces comprised of both static and dynamic objects. Dynamic descriptions permit positioning tables, automated guided vehicles, conveyors and cycling machine tools to be modeled by elements which translate or cycle along rectilinear paths. Graphical path planning procedures use cursor indicators to move the robot configuration point between the desired starting and final configurations while avoiding both the static and dynamic joint space obstacles.
Design of a mechanical proximity sensor
Authors: Schiebel Edward N. , Busby Henry R. , Waldron Kenneth J.
Published: March 2009

A proximity sensor using a mechanical contact principle is under development for robotic applications. Good discrimination between contact loads and inertial windage loads is essential. Rugged design and easy replacement of sensing elements is also necessary. The sensor is under consideration for use on the feet of the Adaptive Suspension Vehicle.
Combined flexural-joint stiffness matrix and the elastic deformation of a servo-controlled two-link robot manipulator
Authors: Shahinpoor M. , Meghdari A.
Published: March 2009

An expression is derived for the combined flexural-joint stiffness matrix and the elastic deformation field of a servo-controlled two-link robot manipulator. Such expressions are needed in dealing with light weight high-speed flexible robot manipulators. The approach employs a strain energy invariance principle with respect to the elemental and the system reference coordinate frames to derive the desired 9 × 9 combined flexural joint stiffness matrix.
Learning Control for Autonomous Machines
Authors: Shoureshi R. , Swedes D. , Evans R.
Published: March 2009

Today's industrial machines and manipulators have no capability to learn by experience. Performance and productivity could be greatly enhanced if a machine could modify its operation based on previous actions. This paper presents a learning control scheme that provides the ability for machines to utilize their past experiences. The objective is to have machines mimic the human learning process as closely as possible. A data base is formulated to provide the machine with experience. An optical infrared distance sensor is developed to inform the machine about objects in its working space. A learning control scheme is presented that utilizes the sensory information to enhance machine performance in the next trial. An adaptive scheme is proposed for the modification of learning gain matrices, and is implemented on an industrial robot. Experimental results verify the potentials of the proposed adaptive learning scheme, and illustrate how it can be used for improvement of different manufacturing processes.
A New view of the Decoupling Problem for Industrial Robots
Authors: Troch I.
Published: March 2009

Nonlinear 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

This 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

John 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

This 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

In 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

The 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

Based 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

We 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

Owing 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

An 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

The 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

It 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

In 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

A 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

Present 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

Computer 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

An 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

Control 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.
Integrated control for interpreting and manipulating the robot environment
Authors: Grupen Roderic A. , Weiss Richard S.
Published: March 2009

We examine the properties of an integrated, intelligent controller for multifingered manipulators. The discussion addresses the dynamic constraints on computation and resource allocation in systems which must continually adjust objectives and the set of behaviors employed to attain them. We present a means of specifying general force domain tasks and include techniques for reflexive, sensor-based control and for optimal combinatoric grasp synthesis as alternative grasp formation mechanisms. Examples are presented to illustrate the acquisition of information, the incremental refinement of models, the use of uncertain information in reflexive grasp formation, and the use of complete geometric information in optimal grasping.
Design and implementation of an inductive learning control system for a manipulator gripper
Authors: Fontaine D. , Bidaud P.
Published: March 2009

This 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

Two 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

The 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

Navigation 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

This 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

Fluid 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

The 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

In 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

The 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.
Fundamental problems of robot control: Part II A nonlinear circuit theory towards an understanding of dexterous motions
Authors: Arimoto Suguru
Published: March 2009

Part II continues to develop a hyper-stability framework for presenting physical interpretations of dexterous motion controls, such as hybrid position/force, impedance, model-based adaptive, learning control and coordination. In all cases passivity induced by introduction of a quasi-natural potential plays a key role. In view of these considerations, the final section discusses the possibility of development of a nonlinear circuit theory based on feedback connections of hyper-stable blocks, which may give rise to a physical understanding of dexterous and skilled motions for nonlinear mechanical systems and, eventually lead to the design of intelligent functions implementable in robotic machines.
Vibratory assembly of prismatic parts using neural networkbased positioning error estimation
Authors: Kang E. S. , Cho H. S.
Published: March 2009

Despite its known effectiveness, a typical vibratory assembly method tends to generate adverse impact forces between mating parts commensurate with the relatively large vibratory motion required for reliably compensating positioning errors of arbitrary magnitude. To this end, this paper presents a neural network-based vibratory assembly method with its emphasis on reducing the mating forces for chamferless prismatic parts. In this method, the interactive force is effectively suppressed by reducing the amplitude of vibratory motion, while the greater part of the relative positioning error is estimated and compensated by a neural network. The estimation performance of the neural network and the overall performance of the assembly method are evaluated experimentally. Experimental results show that the assembly is efficiently accomplished with small reaction forces, and the possible insertion error range is also expanded
Feasibility studies of kinematics problems in the case of a class of redundant manipulators
Authors: Sasaki Shinobu
Published: March 2009

Lately, there have been numerous applications of computer algebra to special functions used in the various field of science and engineering. In this paper, we consider an efficient algorithm which generates velocity Jacobians for any class of general serial link manipulators in a compact form throughout the effective use of frame transformations. Compared with conventional techniques, a marked improvement of that capability is found in computer algebra applications to one class of a seven-joint manipulator. Together with finding of explicit solutions for joint rates, closed form arm solutions for the desired position of the hand are presented by relating the rotational motion of the elbow to a geometry problem.
State Matrix Representation of Assembly and Robot Planning
Authors: Noorhosseini S. M. , Malowany A. S.
Published: March 2009

A new approach to represent assembly called state matrix representation and an algorithm for automatic robot assembly planning based on this representation is proposed. The state matrix representation of assembly is configured by considering the inter-relationships of parts and objects involved in the initial and the goal structures. Thanks to this new representation, the planning lgorithm is straightforward and can be easily and efficiently implemented with simple matrix manipulation. Unlike other planning methods, the actions involved in the assembly process are not defined in advance but are generated at planning time. The syntax of actions are designed so that while directly reflecting the semantics of actions, they can be easily manipulated by the planner. Two examples of how to plan an assembly based on this representation are given in the paper.