bluuebunny/crossref_metadata_2025 huggingface dataset:
Computer-assisted visual perception in teleoperated robotics
Authors: Mallem M. , Chavand F. , Colle E.
Published: March 2009

Due to the complexity of teleoperation tasks, human operators figure in the teleoperator perception-decision-control loop. The operator needs an interactive system to handle the huge flow of data between himself and the teleoperator.

The scene represented by the robot and its environment is viewed by one or more cameras. However, the video image may be degraded in extreme environments (underwater, space, etc.) or simply inadequate (2-D image).

In this paper we describe the visual perception aids based of the scene, and more specifically how these are generated by the method we put forward. The system developed at the LRE superimposes a 3-D synthetic image onto the video picture, and animates the scene in real-time on the basis of sensor information feedback. The graphic image can be generated from models, if the objects are known, otherwise interactively, with the cooperation of the operator if the objects are completely unknown. Experiments show that these graphic aids improve the operator's performance in task execution.
Requirements for inertial sensor systems for measuring robot positions
Authors: Janocha H. , Schmidt D.
Published: March 2009

Inertial Measurement Systems (IMS) allow the position calculation of moving objects without requiring outside information. For years the inertial 3-D coordinate measuring technique has been subject to intense research in geodesy and autonomous navigation of land-, water-and airborne vehicles. Because of these areas of application inertially-based systems have been designed for long term measuring only. Here we discuss the requirements that are imposed on inertial sensors in order for them to be used for the calculation of positions of robots. The use of modern sensor technology, combined with strategies for error correction, can result in substantial advantages when calculating robot positions independently from load and environment.
Certainty Grid Representation for Robot Navigation by a Bayesian Method
Authors: Cho Dong Woo
Published: March 2009

Recent development of sensor knowledge representation by the use of a certainty grid has been extensive and shown the usefulness of the grid-based concept for robot navigation.

Yet the methodology was not perfect. This paper introduces the Bayesian formula into the certainty grid representation to overcome some difficulties ofad hocformula that has been the only way of updating the grids. The complete derivation of the proposed updating formula is given and proved to be able to accurately identify the simulated world. Also, the paper suggests two updating models: context-sensitive and context-free. Both of them were shown to be usable through simulation in real world modeling.
Real-time determination of a mobile robot's position by linear scanning of a landmark
Authors: Kim Jae H. , Cho Hyung S.
Published: March 2009

For the navigation of a mobile robot, the determination of its absolute location is one of essential tasks. This paper proposes a stripe type landmark which enables us to develop a fast algorithm to calculate the distance and orientation of a camera relative to the landmark. Exact and closed form solution of the camera location is obtained from the geometric relation between the pattern of landmark and its projected image. Since the presented algorithm requires only one row of the mark image, determination of the location can be processed in real-time. In addition, the mark can be identified using the projective invariant of the original mark pattern without any additional patterns. The effect of the error sources on the location determination is analyzed through a series of simulations and experiments. The applicability of the algorithm to mobile robots is discussed using the experimental results.
Conceptual graph-based system for assembly program synthesis
Authors: Maimon O. , Kapitanovsky A.
Published: March 2009

ISRA is a support system for robot programming. It provides a means to automatically (guided by knowledge) convert a user's request, expressed in the natural language, into the appropriate conceptual model of the required task. This model incorporates information required for the understanding, planning and sensory-guided performance of the required robotic task.

To develop this system we applied the Natural Computation method. We considered natural information processing by humans during synthesis and interpretation of robotic programs, and then constructed an approximate conceptual model of the relevant dynamically changing real world.

Such a model has to be suitable (e.g. representable and executable) for efficient computer processing. This paper presents the results of a case study which shows that methods built by formalizing human information processing in the robotic domain may be efficiently and naturally implemented in ISRA. It provides evidence that the structure and behavior of ISRA's competence representation and algorithm are comparable with the psychological behavior of humans, as required by the Natural Computation method.

The case study illustrates the use of ISRA for the first phase of an assembly program synthesis i.e. planning of all valid assembly sequences.
Ultrasonic imaging system for robots using an electronic scanning method
Authors: Kuroda Shin-ichi , Jitsumori Akio , Inari Takahiko
Published: March 2009

This paper describes a primitive environment recognition system for advanced robots. The system can recognize the location, configuration and distribution of 3-D objects in an object space (4m×4m×2.5m) using an ultrasonic imaging method. As an experiment, we have tried to develop the recognition system for the distribution of standing persons. First, this system was tested by mechanical scanning in order to obtain a satisfactory result. Next, we have investigated the electronic scanning method. A transmitter built for testing was composed of twenty-one ultrasonic transducers (40 KHz) built into a 2-D array. The characteristics supported by measurements have agreed well with the theoretical results. Therefore, it has become clear that the ultrasonic imaging system using an electronic scanning method can be applied to environment recognition.
The ‘Omnigripper’: a form of robot universal gripper
Authors: Scott Peter B.
Published: March 2009

At Imperial College, the author has invented a form of universal gripper comprising two slightly separated ‘fingers’, each consisting of an array of 8 by 16 closely spaced pins which can ride vertically up and down independently of each other. Lowering the gripper over an object pushes some pins out of the way, so creating ‘customised’ fingers which mould round and fit the part. To grasp objects, either the two (slightly separated) fingers can be brought together to grip an object externally, or else they can be moved slightly apart (from a ‘closed’ position) for an internal grip. In addition, feedback from each pin of the gripper can provide tactile information about an object.
Some comments on the national conference on ‘The economic, social, financial and technical effects of automation (November 27–28, 1984; University of Salford, U.K.) … conference closure
Authors: Chilver F. R. S. Henry
Published: March 2009

After reviewing the conference topics, the author discusses the technical potential of automation in the wider aspects of technical innovation. The next topic is concerned with automation and the world economy in general, and that in developed countries in particular. Some comments are then made about the manufacturing prospects in the U.K. and their relationships with education and training in the relevant fields. Finally, the inauguration of the Advanced Manufacturing Technology Chair at the University of Salford is described in the context of industry-education problems.
Change and the nature of work. Some employment and organisational problems of advanced manufacturing technology
Authors: Tynan Oliver
Published: March 2009

Some changes have uncomfortable characteristics. Change is inevitable, large, penetrating, unpredictable. There is thus the need to create ‘learning’ organisations capable of coping with change. The following topics are considered:

1. Changes in organisational shape – transition from hierarchical triangular shaped to ‘heterarchical’ diamond shaped organisations – the breakdown hierarchy.

2. Changes in the role of people in manufacturing and services including the public service.

3. ‘Managers’ and new technology – management role enhanced co-ordinating and creating motivation.

4. Three models for change.

5. The productivity of automation is essential. ‘Working’ years are shortening, ‘dependent’ years are lengthening.

6. People as assets.

7. Technology, Human Aspects, Process of change = TRAP.
Manipulator motion along a constraint
Authors: Lensky A. V. , Lizunov A. B. , Formal'sky A. M. , Shneider A. Yu.
Published: March 2009

This paper is concerned with the problem of keeping contact with a fixed object during the motion of a manipulator gripper along the contour of an object, i.e. along a constraint. The theory of the existence and the stability of stationary regimes of motion along a straight line and a circle is studied.
Concurrent Pascal as a robot level language – a suggestion
Authors: Steiger-Carçao Adolfo , Camarinha-Matos L. M.
Published: March 2009

This paper briefly describes actual robot level programming languages, focusing on their intrinsic limitations when compared with traditional concurrent programming languages or when used for robotic systems/flexible production workshops programming, and not only for an isolated manipulator control.

To reduce such limitations, a suggestion is made to base the development of robotic programming systems on already existing concurrent languages (Concurrent Pascal, Modula-2), taking into account their built-in extension facilities for fastening the incorporation of (or easy interfacing with) existing packages or products already developed in robotics (robot models, CAD systems, vision systems, etc).

Using such languages as a support base for a robotic station programming environment, with access to different components developed separately, will allow a better understanding of the inter-relations among components and their limitations when faced with an integration perspective.
Manufacturing of a Scara Type Direct-Drive Robot with Graphite Fiber Epoxy Composite Material
Authors: Lee Dai Gil , Kim Ki Soo , Kwak Yoon Keun
Published: March 2009

A SCARA type direct-drive robot which can be used in the assembly operation of printed circuit boards was designed and manufactured with graphite fiber epoxy composite material. The optimum stacking angle of the graphite fiber which gives the minimum deflection of the composite robot arm was calculated by the energy method and the manufacturing method of the box-type cross section of the robot arm with composite materials was developed.

In order to compare the dynamic characteristics of the composite material robot arm with a conventional material robot arm, an aluminum robot arm which has the same dimensions and thickness of the composite robot arm was manufactured.

The static and dynamic characteristics of the composite material robot arm such as static deflection, natural frequency and damping as well as weight saving were considerably improved compared to those of the aluminum robot arm.
An inverse kinematics algorithm for robot manipulators using incremental unit computation method
Authors: Park Seo W. , Oh Jun H.
Published: March 2009

This paper presents a new method for solving the inverse kinematics of robot manipulators. The method defines incremental units in joint and Cartesian spaces, which represent the position resolutions in each space. Based on these units, the incremental computation of the DDA integrator is used to solve the direct kinematics. The repetitive calculation of the inverse Jacobian matrix is replaced by a simple look-up table. By using an iterative procedure with convergence rules, the inverse kinematics algorithm is established. A 3 DOF robot is considered as the combination of two types of a 2 DOF robot. Simulation and experiment are performed to test the algorithm.
Artificial intelligence for production engineering: a historical approach
Authors: Aleksander Igor
Published: March 2009

This paper describes the principles of the advanced programming techniques often dubbed Artificial Intelligence involved in decision making as may be of some value in matters related to production engineering. Automated decision making in the context of production can adopt many aspects. At the most obvious level, a robot may have to plan a sequence of actions on the basis of signals obtained from changing conditions in its environment. These signals may, indeed, be quite complex, for example the input of visual information from a television camera.

At another level, automated planning may be required to schedule the entire work cycle of a plant that includes many robots as well as other types of automated machinery. The often-quoted dark factory is an example of this, where not only some of the operations (such as welding) are done by robots, but also the transport of part-completed assemblies is automatically scheduled as a set of actions for autonomic transporters and cranes. It is common practice for this activity to be preprogrammed to the greatest detail. Automated decision making is aimed at adding flexibility to the process so that it can absolve the system designer from having to forsee every eventuality at the design stage.

Frequent reference is made in this context to artificial intelligence (AI), knowledge-based and expert systems. Although these topics are more readily associated with computer science, it is the automated factory, in general, and the robot, in particular, that will benefit from success in these fields. In this part of the paper we try to sharpen up this perspective, while in part II we aim to discuss the history of artificial intelligence in this context. In part III we discuss the industrial prospects for the field.
Automatic generation of salient features for the recognition of partially occluded parts
Authors: Mudge T.N. , Turney J.L. , Volz R.A.
Published: March 2009

A method for solving the recognition of partially occluded parts is presented. It is based on the automatic generation of features from a set of primitive features which are configurations of pairs of fixed length segments of boundary edges of the parts. The procedure that creates the recognition features assigns a number in the range (0,1) that indicates the importance of the feature in the recognition strategy. This number is referred to as the feature's saliency. The method assumes that the parts that can occur in a scene come from a known set of parts. An example illustrates how automatically generated features can be used to count the number of identical parts in a heap.
Computational requirements for a discrete Kalman filter in robot dynamics algorithms
Authors: Kozłowski Krzysztof
Published: March 2009

In standard classical kinematic and dynamic considerations the equations of motion for ann-link manipulator can be obtained as recursive Newton-Euler equations. Another approach to finding the inverse dynamics equations is to formulate the system dynamics and kinematics as a two-point boundary-value problem. The equivalence between these two approaches has been proved in this paper. Solution to the two-point boundary-value problem leads to the forward dynamics equations which are similar to the equations of Kalman filtering and Bryson-Frazier fixed time-interval smoothing. The extensive numerical studies conducted by the author on the new inverse and forward dynamics algorithms derived from the two-point boundary-value problem establish the same level of confidence as exists for current methods. In order to obtain the algorithms with the smallest coefficients of the polynomial of orderO(n), the categorization procedure has been implemented in this work.
Robotic Assembly by Slight Random Movements
Authors: Badano F. , Betemps M. , Redarce T. , Jutard A.
Published: March 2009

In this paper we develop a compilant system that permits robotic assembly of chamferless pieces. The idea is to absorb the positioning error between parts to be inserted by giving one of them a planar random movement. An actuator consisting of two axes (X and y) operated by an electromagnetic System is fitted to the work table; when its inputs are pseudo-random binary signais (P.R.B.S.) random motion is obtained. The trajectories of the actuator are analysed depending upon the P.R.B.S. parameters and a peg-in-a-hole assembly task is carried out. Experimental results show that large positioning errors can be compensated for chamferless insertions.
The future of robot programming
Authors: Gini Maria
Published: March 2009

This paper presents current trends in robot programming. The open problems with current robot programming systems are outlined and indications for solutions are given. Since computer controlled robots have been introduced, the methodology of robot programming has seen a great deal of development. Two completely different approaches to robot programming have been considered in the past. On the one hand within the Artificial Intelligence community a lot of research has been done to provide robots with autonomous reasoning capabilities. On the other hand, the need to control industrial robots has pushed the development of simple but effective methods for robot programming. To put it simply, Artificial Intelligence researchers have taken a top-down approach trying to solve the difficult problem of reasoning and have assumed that all the rest was easy. Others have taken a bottom-up approach first trying to control robots and only later trying to incorporate intelligence. The complexity of industrial automation tasks requires programming systems more sophisticated that those in use today. Artificial Intelligence is the best candidate to create the next generation of robot programming systems.
Work-space robot controllers
Authors: Vibet C.
Published: March 2009

In regard to work-space controller design, a derivation of the relationships between the operational approach and the decoupling method is introduced. The given generating rules, which are valid for nonredundant robots, permit the design of a Position-Speed-Acceleration controller or hybrid Force-PSA controllers.
Elastostatic contact imaging for a mechanoreceptive tactile device
Authors: Mehdian M. , Johns-Rahnejat P.M. , Rahnejat H.
Published: March 2009

This paper presents a sensory gripper, consisting of two tactile sensing matrices which acquire three dimensional images of objects of interest. The image processing algorithm uses elastostatic contact information to discriminate among a host of parts made of different materials. The algorithm also enables the assessment of orientation of parts without the pre-requisite of having to recognise them. The positions of stable holdsites and a safe gripping force are also evaluated.
Automatic inference on stable robotic assembly sequences based upon the evaluation of base assembly motion instability
Authors: Cho D.Y. , Shinf C.K. , Chot H.S.
Published: March 2009

The consideration of part motion instability is crucial to the determination of assembly sequence since this affects the complexity of fixtures and dexterity of robots. This paper presents a new approach to the inference of robotic assembly sequences, taking into consideration the instability of base assembly motions. Based upon the evaluation of motion instability, the method generates stable assembly sequences by use of the precedence constraint inference method previously developed by the authors. An example assembly of a 10-part electrical relay is given to illustrate the concepts and procedure of the proposed scheme. The results show that the proposed method can be effectively utilized to generate stable assembly sequences, thus providing crucial information on the fixture design and selection of types of assembly robots.
Introduction to the special issue: Intelligent control for manipulation
Authors: Gershon David
Published: March 2009

This special issue is concerned with the intelligent control of robots in the performance of manipulation tasks. First we will try to define what we mean byintelligent controland bymanipulation tasks.

Unfortunately, intelligent control is a somewhat imprecise term, just like the word control itself, so that its meaning can vary widely depending on the application and on the writer's scientific discipline. In general terms, we can say that intelligent control implies some degree of autonomy in performing a task while accommodating uncertainty. In the control of sensor-based robot systems, we could characterize an intelligent controller as one with the following capabilities;
Neuro-adaptive control of robotic manipulators
Authors: Khemaissia S. , Morris A.S.
Published: March 2009

The need to meet demanding control requirements in increasingly complex dynamical control systems under significant uncertainties makes neural networks very attractive, because of their ability to learn, to approximate functions, to classify patterns and because of their potential for massively parallel hardware implementation. This paper proposes the use of artificial neural networks (ANN) as a novel approach to the control of robot manipulators. These are part of the general class of non-linear dynamic systems where non-linear compensators are required in the controller.
A stereo vision-based obstacle detecting method for mobile robot navigation
Authors: Cho Yong C. , Cho Hyung S.
Published: March 2009

This paper presents a computationally simple stereo vision method for detecting useful features of obstacles on the ground relevant to a mobile robot's navigation in an indoor environment. Enhanced time efficiency and reliability is achieved by introducing a geometrical image transformation and a frame-wise iterative edge image comparison scheme. The image transformation used in this paper relates each constant disparity value to an oblique plane at an elevation from the floor. The stereo correspondence method is devised by implementing a frame-wise AND operation based upon edge orientation and a subsequent pixel wise intensity correlation checking. This method is efficient in terms of computation time and capable of identifying isodisparity points, so that the height information of all the obstacle points above the floor can be determined. The obtained disparities are recorded on a local map to give complete obstacle features for mobile robot's path planning. Through a series of experiments performed under various environmental conditions, it is found that the proposed method can effectively be applied for locating obstacles of various heights in indoor navigation of mobile robots.
Piecewise smooth and safe trajectory planning
Authors: Elnagar Ashraf , Basu Anup
Published: March 2009

A new approach to generating smooth piecewise local trajectories for mobile robots is proposed in this paper. Given the configurations (position and direction) of two points, we search for the trajectory that minimizes the integral of acceleration (tangential and normal). The resulting trajectory should not only be smooth but also safe in order to be applicable in real-life situations. Therefore, we investigate two different obstacle-avoidance constraints that satisfy the minimization problem. Unfortunately, in this case the problem becomes more complex and not suitable for real time implementations. Therefore, we introduce two simple solutions, based on the idea of polynomial fitting, to generate safe trajectories once a collision is detected with the original smooth trajectory. Simulation results of the different algorithms are presented.
A novel and practical strategy for the precise chamferless robotic peg hole insertion
Authors: Qiao H. , Dalay B. S. , Parkin R. M.
Published: March 2009

The influence of the angle between the axes of the peg and hole (angular error) and the contact surface defects on the measurement of deviation (lateral error) have been carefully analysed. It has been shown that they would influence the measurement of the magnitude of deviation and even its direction. This phenomenon causes severe difficulty in the assembly operations. A novel strategy for the high-precision chamferless peg hold insertion with a wrist force sensor is presented. This strategy is constructed: (1) to obtain the relationship between the peg and hole from the force sensor signal when an angle between the axes of the peg and hole exists and defects of the contact surfaces are present, (2) to reduce the angular and lateral errors, (3) to achieve the precise chamferless robotic peg hole insertion. In this paper, the insertion can be obtained with a reasonably large range of initial conditions. The principle is to move and rotate the peg from an area having many geometric uncertainties to a new area, where the deviation of the peg and hole can be obtained.
Spline-based micro accuracy joint interpolation
Authors: Choi P. J. , Rice J. A.
Published: March 2009

The concept of tension is introduced and applied to a robot's trajectories, then new joint interpolation strategies are implemented. A joint interpolation strategy is proposed which uses joint variable reference data calculated from inverse kinematics, along with a polynomial equation or quintic equation as the parametric equation of the joint variables. This method can use any polynomial equation which has the C2 continuity property and has intermediate points which pass through the reference data. For the time variable, first order linear equations can be used where the number of equations is n – 1, n being the number of points in the reference data. Due to large reductions in computational burden resulting from this form, this method may be suited for real time applications.
A comparative model-based analysis and design for multi-robot systems
Authors: Lee Ki Dong , Lee Bum Hee , Ko Myoung Sam
Published: March 2009

For a robotic workcell with multiple robots, several interconnection methods are presented in terms of a processor-based architecture. The concept of the multiple processor system (MPS) or multiple computer system (MCS) is used to formulate and analyze the multi-robot interconnection system (MRIS). The MRIS is modelled as a queueing network, and mathematical analysis is done on the basis of modelling. Performance evaluation is achieved for the MRIS through the mean value analysis with the response time and the probability of service failure under different workloads. The results together with some comments suggest a useful guideline for a selecting an appropriate interconnection method for the MRIS subject to the system environment and application.
Tactile recognition of solid objects
Authors: Mehdian M. , Thomas D.
Published: March 2009

An algorithm is presented for the recognition of a set of prototype, solid objects. Cost estimate and simulation results suggest that the algorithm would provide rapid recognition of the objects over a greater range of horizontal, vertical and rotational errors, in the position of the object than is likely to be encountered in practice.
Near minimum-time trajectory for two coordinated manipulators
Authors: Lee K. Y. , Dissanayake M. W. M. G.
Published: March 2009

This paper presents a method to obtain near minimum-time trajectories for two coordinated manipulators handling a rigid object. A piece-wise constant function is used to approximate the second derivatives of the generalised coordinates of the manipulators of the system. This transforms the time optimal control problem into a non-linearly constrained optimisation problem. The transformed problem is then solved by the sequential quadratic programming technique. A numerical example involving two SCARA type manipulators handling a long beam is used to illustrate the proposed scheme.
Robust estimation and control of robotic manipulators
Authors: Qu Zhihua , Dawson Darren M. , Dorsey John F. , Duffie John D.
Published: March 2009

For the trajectory following problem of a robot manipulator, a robust estimation and control scheme which requires only position measurements is proposed to guarantee uniform ultimate bounded stability under significant uncertainties and disturbances in the robot dynamics. The scheme combines a class of robust control laws with a robust estimator where the robust control law can be chosen to be either a modification of the standard computed torque control law or simply a linear and decentralized “PD” control law. The proposed robust estimator is also linear and decentralized for easy implementation. Constructive choices of the gains in the control law and estimator are proposed which depend only on the coefficients of a polynomial bounding function of the unknown dynamics. The asymptotic stability of the tracking errors and the estimation error is also investigated. Experimentation results verify the theoretical analysis.
Vibration reduction in flexible systems using a time-varying impulse sequence
Authors: Cho Jung-Keun , Park Youn-Sik
Published: March 2009

An input shaping technique using a time-varying impulse sequence is presented to reduce the motion-induced vibration of flexible systems in a feedforward way.

The decoupled modal responses for a general linear time-varying system are firstly approximated. Upon this approximation, the time-varying impulse sequences to suppress the vibrational modes are found. The reference inputs to the systems are shaped by convolving with the time-varying impulse sequence to suppress the multimode vibrations. This technique can be also applied to suppress the vibration of nonlinear time-varying systems.

The performance of this method is demonstrated with two practical examples: a moving overhead crane and a two-link robot manipulator. Consequently, this study provides an input shaping technique applicable to the vibration suppression of broader classes of flexible systems.
A position estimation system for mobile robots using a monocular image of a 3-D landmark
Authors: Koh Kyoung C. , Kim Jae S. , Cho Hyung S.
Published: March 2009

This paper presents an absolute position estimation system for a mobile robot moving on a flat surface. In this system, a 3-D landmark with four coplanar points and a non-coplanar point is utilized to improve the accuracy of position estimation and to guide the robot during navigation. Applying theoretical analysis, we investigate the image sensitivity of the proposed 3-D landmark compared with the conventional 2-D landmark. In the camera calibration stage of the experiments, we employ a neural network as a computational tool. The neural network is trained from a set of learning data collected at various points around the mark so that the extrinsic and intrinsic parameters of the camera system can be resolved. The overall estimation algorithm from the mark identification to the position determination is implemented in a 32-bit personal computer with an image digitizer and an arithmetic accelerator. To demonstrate the effectiveness of the proposed 3-D landmark and the neural network-based calibration scheme, a series of navigation experiments were performed on a wheeled mobile robot (LCAR) in an indoor environment. The results show the feasibility of the position estimation system applicable to mobile robot's real-time navigation.
Automated inverse-kinematics for robot off-line programming
Authors: Red W.Edward , Gongt Shao-Wei
Published: March 2009

Automated methods are developed to classify a robot's kinematic type and select an appropriate library inverse-kinematic solution based on this classification. These methods automatically generate DenavitHartenberg joint frame parameters, given any frame representation that can mathematically be represented as a homogeneous transformation.

To reduce the number of closed-form inverse-kinematics solutions required for a broad class of serial robots, additional methods account for differences in robot zero state, base frame location, and joint polarity. Further generalization results from using joint frame decoupling to map lower degree-of-freedom robots into the inverse-kinematics solutions of higher degree-offreedom robots.
Geometric and algebraic approach to the inverse kinematics of four-link manipulators
Authors: Uzmay I. , Yildirim S.
Published: March 2009

This paper presents an example of the application of geometric and algebraic approaches to the inverse kinematics problem of four-link robot manipulators. A special arm configuration of the robot manipulator is employed for solving the inverse kinematics problem by using the geometric approach. The obtained joint variables as angular positions are defined in the form of cubic polynomials. The other kinematic parameters of the joints, such as angular velocities and angular accelerations, are the time derivatives of these polynomials. It is evident that there is no definite difference between the results of the two approaches. Consequently, if an appropriate arm configuration for the geometric approach can be established, the inverse kinematics can be solved in a simpler and shorter way.
Decentralized adaptive compliance control of robot manipulators
Authors: Colbaugh R. , Glass K.
Published: March 2009

This paper presents two adaptive schemes for controlling the end-effector compliance of robot manipulators. Each controller possesses a decentralized structure, in which the control input for each configuration degree-offreedom (DOF) is computed based on information concerning only that DOF. The first scheme is developed using anadaptive impedancecontrol approach and consists of two subsystems: a simple “filter” which modifies the end-effector position trajectory based on the sensed contact force and the desired dynamic relationship between the position and force, and an adaptive controller that produces the joint torques required to track this modified trajectory. The second compliant motion control strategy is anadaptive admittance controllerfor position-controlled manipulators. In this scheme a desired contact force is specified and then position setpoints for the “inner-loop” position controller are generated which ensure that this desired force is achieved. The proposed controllers are extremely simple computationally, do not require knowledge of the manipulator dynamic model or parameter values of the manipulator or the environment, and are implemented in decentralized form.
Contribution of internal forces to the dynamics of closed chain mechanisms
Authors: Adli Mehmet Arif , Hanafusa Hideo
Published: March 2009

The kinematic structure of closed chain mechanisms is suitable for putting an excess number of inputs in addition to the required number to control their position and orientation. With the addition of these excess inputs, it is possible to generate and control the internal forces within the mechanisms by simultaneously activating joints whose action opposes each other. The internal forces balance inside the structure of mechanisms and do not create any resultant force. However, at the static or quasi-static cases they change the stiffness of the mechanisms. In dynamic cases, in addition to the change in stiffness, they may also generate a damping effect. As a result of these effects, the dynamic behavior of closed chain mechanisms changes. This study analyzes the dynamics of the closed chain mechanisms under the effect of internal forces through the simulation and experimental results using a planar closed chain mechanism.
A new on-line method to avoid collisions with links of redundant articulated robots
Authors: Rahmanian-Shahri N. , Troch I.
Published: March 2009

A new mathematical formulation of robot and obstacles is presented such that for on-line collision recognition only robot joint positions in workspace are required. This reduces calculation time essentially because joint positions in workspace can be computed every time from the joint variable through robot geometry. It is supposed that the obstacles in the workspace of the manipulator are represented by convex polygons. For every link of the redundant robot and every obstacle a boundary ellipse in 2D is defined in workspace such that there is no collision if the robot joints are outside these ellipses. First, some methods are presented for the automatic determination of these ellipse functions from the obstacle and robot data. Then, the boundary ellipse functions are used as optimization criterion in a collision-avoidance method. The method permits the tip of the hand to follow a given path in the free space while the kinematic control algorithm maximizes the boundary ellipse function of the critical link. The effectiveness of the proposed methods is discussed by theoretical considerations and illustrated by simulations of the motion of three- and four-link manipulators between obstacles.
A model and strategy analysis of the peg-hole system in the search process associated with robotic assembly operations without chamfers
Authors: Qiao Hong , Moore Philip , Knight Jeff
Published: March 2009

Robotic peg-hole insertion operations can play a very important role in manufacturing industry because it is a common requirement in the manufacturing process and, it requires high precision and high speed.

In general, this operation can be divided into two processes: Search process to engage the peg and the hole and, insertion process.

The search process is critical in the assembly operation. It can be defined as a process where the angular.and the translational errors between the peg and the hole are reduced until insertion can occur.
A study of neural network control of robot manipulators
Authors: Jung Seul , Hsia T. C.
Published: March 2009

The basic robot control technique is the model based computer-torque control which is known to suffer performance degradation due to model uncertainties. Adding a neural network (NN) controller in the control system is one effective way to compensate for the ill effects of these uncertainties. In this paper a systematic study of NN controller for a robot manipulator under a unified computed-torque control framework is presented. Both feedforward and feedback NN control schemes are studied and compared using a common back-propagation training algorithm. Effects on system performance for different choices of NN input types, hidden neurons, weight update rates, and initial weight values are also investigated. Extensive simulation studies for trajectory tracking are carried out and compared with other established robot control schemes.
Hybrid force/position control for robot manipulators based on a D-type learning law
Authors: Pandian Shunmugham R. , Kawamura Sadao
Published: March 2009

A learning control algorithm is proposed for hybrid force/position tracking of a manipulator in contact with a hard surface. The algorithm utilizes acceleration errors and force errors for learning the inputs required to perform repetitive tasks. We prove the convergence of both force and position tracking errors theoretically. The speed of convergence of the tracking errors is shown to be improved by proper choice of learning gains. The method is compared with PI and PID learning, and similarities with the free-space case are outlined. The robustness of the new scheme to uncertainties in surface geometry and link parameters is discussed. Results of simulation studies and experimental implementation on 3-link robot manipulators are presented to illustrate the effectiveness of the proposed learning controller.
An approach to time-optimal, smooth and collision-free path planning in a two robot arm environment
Authors: Cao Bailin , Dodds Gordon I. , Irwin George W.
Published: March 2009

An approach to time-optimal smooth and collision-free path planning for two industrial robot arms is presented, where path planning and joint trajectory generation are integrated. A suitable objective function, combining the requirements of time optimality and path smoothness, is proposed, which is subject to the continuity of joint trajectories, limits on their rates of change and collision-free constraints. Fast and effective collision detection for the arms is achieved using the Kuhn- Tucker conditions along with the convexity of the distance function and relying on geometrical relationships between cylinders. Nonlinear optimization is used to solve this path planning problem. The feasibility of this method is illustrated both by simulation and by experimental results.
Modeling of robot manipulators working under the sea and the design of a robust controller
Authors: Hyeung-Sik Choi
Published: March 2009

This paper presents a study of the dynamics of undersea robot manipulators in an unstructured sea water environment and a control scheme appropriate for manipulating them. Under the sea, the buoyancy and the added mass should be considered in modeling the dynamics of the robot manipulators. However, due to the complexity of the modeling of the added mass, the dynamics of the robot manipulators are treated as an unmodeled dynamics in this paper. In addition to the buoyancy and added mass/moment of inertia, disturbing forces due to drag, and current affecting the dynamics of the robot manipulators should be considered. In this paper, the forces due to the drag are defined as disturbance forces in addition to the frictional force of manipulator joints. In order to control the manipulator, a robust control scheme is devised to achieve trajectory tracking while regulating disturbance forces. A numerical example is shown.
Workspaces of a walking machine and their graphical representation. Part II: static workspaces
Authors: Zhang S.J. , Howard D. , Sanger D.J.
Published: March 2009

Part I of this paper was concerned with kinematic workspaces of walking machines, while this paper addresses the static workspaces of a walking machine and their graphical representation. The results of static analysis are presented; the static workspace constraints are established; an algorithm for investigation of static workspaces is presented; and the position static workspaces are analysed and graphically represented for an example walking machine design.
An autonomous robot navigation system - integrating environmental mapping, path planning, localisation and motion control
Authors: Badcock J. M. , Dun J. A. , jay K. , Kleeman L. , Jarvisb R. A.
Published: March 2009

This paper describes an autonomous robot vehicle which can navigate through an initially unknown obstacle field to a nominated goal or systematically map its working environment. The navigation system uses combined ultrasonic beacon/odometry based localisation, optical range finders for environmental mapping, an A path planning procedure and continuous motion control. The computational support is divided between a graphics workstation 'home base' and a PC hosted transputer array on-board. The integration of all the subsystems cited above has been achieved and many successful navigation experiments completed. Possible further developments which would enhance the capabilities of the system are also discussed.
Multi-criteria optimal placement of robots in constrained environments
Authors: Zeghloul S. , Pamanes-Garcia J.A.
Published: March 2009

A general method is presented to automatically determine the placement of manipulators which allows one to optimize multiple kinematic performances indices during the execution of their tasks. It considers the presence of obstacles in the workstation and constraints on the motion of the manipulator's joints. The complete formulation is included, and an example with a six-degree-of-freedom manipulator in a cluttered environment es solved that demonstrates the improvements achieved for the manipulator performances by applying the method.
Inference on robotic assembly precedence constraints using a part contact level graph
Authors: Cho D. Y. , Cho H. S.
Published: March 2009

This paper describes a new approach to the automatic generation of assembly precedence constraints for robotic assembly, using a part contact level graph. Since inference of precedence constraints is a prerequisite to generate assembly sequences of a product, much work has been done in this field. However, most of it has some limitations in that they use a cumbersome user query or time-consuming geometric reasoning. To cope with these problems, this paper utilizes three directional part contact level graphs which, in three orthogonal directions, contain the information on directional connections for each pair of mating parts. By using these graphs, an assembly precedence constraint is inferred in two steps: The first step infers a precedence constraint for each directional connection by applying the path-finding algorithm. Utilizing the precedence constraints thus obtained, the next step infers the precedence constraint for each part to be assembled with its base assembly. Examples are given to illustrate the concepts and procedure of the proposed scheme.
Geometric modelling of bounded and frictional grasps
Authors: Xiong Y. L. , Sanger D. J. , Kerr D. R.
Published: March 2009

This paper, as an extension of an earlier paper, presents a geometrical representation and theoretical foundation of robot grasping that is affected by friction and by the magnitudes of normal contact forces. Grasp analysis and synthesis are based on the concepts of constraint cone (region), restraint cone and freedom cone in the force screw-space and location screw-space. In fact, the freedom cone is the aggregate of all the screws repelling and reciprocal to the grasp geometry (denoted by the restraint cone). Moreover, the constraint cone and the constraint region describe the effect of friction and the influence of the amplitudes of normal forces. The conditions of equilibrium grasp, stable grasp, form closure, force closure, and relative form closure are derived from the geometrical representation, and approaches are suggested for the design of adaptable fixtures, and for automatic grasp planning. It is shown that relative form closure is of great significance for frictional grasp, since it is possible to generate enough internal forces in the subspace spanned by the contacts and consequently produce corresponding friction forces in the reciprocal subspace.
Binocular vision planning with anthropomorphic features for grasping parts by robots
Authors: Chung Jae-Moon , Nagata Tadashi
Published: March 2009

Planning of an active vision having anthropomorphic features, such as binocularity, foveas and gaze control, is proposed. The aim of the vision is to provide robots with the pose informaton of an adequate object to be grasped by the robots. For this, the paper describes a viewer-oriented fixation point frame and its calibration, active motion and gaze control of the vision, disparity filtering, zoom control, and estimation of the pose of a specific portion of a selected object. On the basis of the importance of the contour information and the scheme of stereo vision in recognizing objects by humans, the occluding contour pairs of objects are used as inputs in order to show the proposed visual planning.
Design and evaluation of a high-performance haptic interface
Authors: Ellis R.E. , Ismaeil O.M. , Lipsett M.G.
Published: March 2009

A haptic interface is a computer-controlled mechanism designed to detect motion of a human operator without impeding that motion, and to feed back forces from a teleoperated robot or virtual environment. Design of such a device is not trivial, because of the many conflicting constraints the designer must face.

As part of our research into haptics, we have developed a prototype planar mechanism. It has low apparent mass and damping, high structural stiffness, high force bandwidth, high force dynamic range, and an absence of mechanical singularities within its workspace. We present an analysis of the human-operator and mechanical constraints that apply to any such device, and propose methods for the evaluation of haptic interfaces. Our evaluation criteria are derived from the original task analysis, and are a first step towards a replicable methodology for comparing the performance of different devices.