bluuebunny/crossref_metadata_2025 huggingface dataset:
A hybrid control algorithm for robotic manipulators
Authors: Lee J. S. , Kwon W. H.
Published: March 2009

In this paper, new hybrid control laws for the position control of robotic manipulators are proposed. The proposed control laws are composed of discrete feedforward component and continuous feedback component. The open loop nominal torque about the desired trajectories is taken as the feedforward component, while a modified version of the sliding mode control is taken as the feedback component. For the three proposed control laws, we give sufficient conditions which guarantee the bounded tracking errors in spite of the modeling errors. The existence of the control gains which satisfy these conditions is shown by numerical examples. The computational burden of feedback control is analyzed, which shows that the feedback control can be used in real time digital control. The robustness and the good tracking performance of proposed algorithms are demonstrated by the numerical simulation of a manipulator position control under payloads and parameter uncertainties.
A new simulation scheme for self-tuning adaptive control of robot manipulators
Authors: Wang Q. , Broome D. R.
Published: March 2009

In most dynamic adaptive control simulation of robotic manipulators, the Langrange–Euler (L–E) dynamic equations are first piecewise linearized about the desired reference and then discretized and rewritten in a state space form. This makes things very complicated and it is easy to make errors. What is more is that with a different reference this work must be done again. A new simulation scheme – Backward Recursive Self-Tuning Adaptive (BRSTA) – as it will be called, is suggested in this paper for adaptive controller design of robot manipulators. A two degree of freedom robot manipulator is used to verify the scheme in the condition of highly nonlinear and highly coupled system. A one degree of freedom robot manipulator is used for comparing both the forward and backward methods. The main advantages of this scheme include that it can be used for evaluating the self-tuning adaptive control laws and provide the initial process parameters for real-time control. And it is concluded here that the Newton–Euler (N–E) dynamic equations are equally well qualified as the Langrange–Euler (L-E) equations for the simulation of self-tuning adaptive control of robot manipulators.
Design of an advanced robotic vehicle evaluation laboratory
Authors: Jarka Richard E. , Sabri Zeinab A. , Adams S. Keith , Liang Enju , Barnett Michael , Rodriguez Rodrigo J. , Husseiny Abdo A.
Published: March 2009

Robotic vehicles have a wide field of applications in the civilian and military industry including manufacturing, assembly lines, security, operation in hostile environment, and testing. In the defense area, robotic vehicles have the potential for force multiplication and removing the soldier from hazardous environments on the battlefield. To make such vehicles avaialable requires research, development, testing and demonstration of advanced robotics and artificial intelligence (AI) technologies and systems. A realistic effort towards that objective requires the establishment of an advanced laboratory responsible for evaluation and development of subsystems and integration of the various elements into vehicles for field tests. Hence, requirements for the laboratory are given including a layout design and link analysis of the different components. As the first part of planning the laboratory, the technology was assessed to assure inclusion of the state-of-the-art equipment. Then, equipment requirements were defined, including interactions between pieces of equipment and providing for support, recording and monitoring equipment.
Time-suboptimal quasi-continuous path generation for industrial robots
Authors: Troch I.
Published: March 2009

The problem of constructing a smooth path with respect to time throughNgiven points in configuration space is considered. Two variants of an algorithm suggested by Paul are presented and evaluated. It is shown that the algorithms suggested in this paper yield in general considerable improvements in two respects: Firstly, the deviation of the resulting path from the given points is reduced markedly and secondly, the overall time needed for the movement is reduced significantly and consequently, is closer to the true minimum-time. The price to be paid for these improvements is a moderate increase of computation time allowing still online use of the algorithm.
Robotic force control for deburring using an active end effector
Authors: Bone G. M. , Elbestawi M. A.
Published: March 2009

An active force control system for robotic deburring based on an active end effector is developed. The system utilizes a PUMA-560 six axis robot. The robot's structural dynamics, positioning errors, and the deburring cutting process are examined in detail. Based on ARMAX plant models identified using the least squares method, a discrete PID controller is designed and tested in real-time. The control system is shown to maintain the force within l N of the reference, and reduce chamfer depth errors to 0.12 mm from the 1 mm possible without closed-loop control.
Nonlinear control robot: A phenomenological approach to linearization by static feedback
Authors: Verdier M. , Rouff M. , Fontaine J. G.
Published: March 2009

This paper presents a linearization by static feedbacks in the robotic field, i.e. by feedback depending on the whole state space. A phenomenological approach is considered, which by using the derivation with respect to time, leads to the major results of the method. Simulation results are presented, and some aspects of the correction of the effect of the characteristic numbers are also discussed.
A parameter identification method for robot dynamic models using a balancing mechanism
Authors: Lim T. G. , Cho H. S. , Chung W. K.
Published: March 2009

Accurate modeling of robot dynamics is a prerequisite for the design of model-based control schemes and enhancement of the performance of the robot. The dynamic parameters associated with a pseudo-inertia matrix are often difficult to identify accurately because the inertia torques are small in comparison to gravity loadings, thus creating signal processing problem. The identification method presented in this paper utilizes a balancing mechanism which increases the estimation accuracy of the dynamic parameters. The balancing mechanism has the effect of amplifying the inertia-related torque signal by eliminating gravity loadings acting on the robot joints. A series of motion data were experimentally obtained through sequential test steps. By incorporating the measured information about joint torques, angular positions, velocities and accelerations the least square algorithm was used to identify the dynamic parameters. The estimated values were converted to those of the original robot model to obtain its dynamic model parameters. The identified robot dynamic model was shown to be accurate enough to predict the actual robot motions.
Effect of joint stiffness on the dynamic stability of a one-link force-controlled manipulator
Authors: Chiou Bing C. , Shahinpoor M.
Published: March 2009

Studies are the effects of joint flexibility on the dynamic stability of a one-link force-controlled manipulator. The closed-loop dynamic equation with the explicit force controller and the damping force controller are first derived. Stability analysis is then carried out by computing the system eigenvalues. Results indicate a conditionally stable system. Due to the presence of discontinuous contacts with the environment during the interaction process, the system exhibits a stable limit cycle when the force feedback gain goes beyond the critical value.
Recursive formulation for the analytical or numerical application of the Gibbs-Appell method to the dynamics of robots
Authors: Desoyer K. , Lugner P.
Published: March 2009

To derive the equations of motion for a multibody system using the Gibbs-Appell calculus – the partial derivatives of the Gibbs function G = 1/2 ∫ a2 dm with respect to the generalized accelerations equal the generalized forces-shows special advantages. Describing the kinematics with Jacobi matrices and local terms, these equations can be written in such a way that the partial derivations need not be performed explicitly. Kinetic effects of fast rotating driving devices attached to the moving links can be included in a similar way. Though an analytical formulation of the equations of motion is especially desirable with respect to its application for industrial robots, such a formulation becomes too extended and susceptible to errors for systems with more than 3 or 4 bodies. Therefore an approach is developed for tree structured robots with rotational or translational joints for calculating the Jacobi matrices and the local terms without employing any differentiation process. So it is possible to use the Gibbs-Appell method numerically in a recursive way e.g. for calculating the torques of the actuators of a robot with 6 or more degrees of freedom for a given motion.
An interactive robotic device with progress monitoring
Authors: Widmer Neal S. , Nof Shimon Y. , Karlan George R.
Published: March 2009

The purpose of this paper is to describe a system which utilizes an interactive robotic device to help in the educational process of very young disabled children. Within the System the child's performance is monitored and evaluated on line, providing a current prescription for progress to more or less advanced learning levels. The robotic Systems developed at Purdue University during research on this concept are described as well as the prototype Systems to monitor progress of the students
Dynamic characteristics of balanced robotic manipulators with joints flexibility
Authors: Lee S. B. , Cho H. S.
Published: March 2009

The mass balancing of robotic manipulators has been shown to have favorable effects on their dynamic characteristics. In actual practice, however, since conventional manipulators have flexibility at their joints, the improved dynamic properties obtainable for rigid manipulators may be influenced by those joints flexibilities. This paper investigates the effects of the joints flexibility on the dynamic properties and the controlled performance of a balanced robotic manipulator. The natural frequency distribution and damping characteristics were investigated through frequency response analyses. To evaluate the dynamic performance a series of simulation studies of the open-loop dynamics were made for various trajectories, operating velocities, and joint stiffnesses. These simulations were also carried out for the balanced manipulator with a PD controller situated inside the motor control loop. The results show that, at low speed, the joints flexibility does but little influence the performance of the balanced manipulator, but at high speed it tends to render the balanced manipulator susceptible to vibratory motion and yields large joints deformation errors.
Hermies-III: A step toward autonomous mobility, manipulation and perception
Authors: Weisbin C. R. , Burks B. L. , Einstein J. R. , Feezell R. R. , Manges W. W. , Thompson D. H.
Published: March 2009

HERMIES-III is an autonomous robot comprised of a seven degree-of-freedom (DOF) manipulator designed for human scale tasks, a laser range finder, a sonar array, an omnidirectional wheel-driven chassis, multiple cameras, and a dual computer system containing a 16-node hypercube expandable to 128 nodes. The current experimental program involves performance of human-scale tasks (e.g., valve manipulation, use of tools), integration of a dexterous manipulator and platform motion in geometrically complex environments, and effective use of multiple cooperating robots (HERMIES-IIB and HERMIES-III). The environment in which the robots operate has been designed to include multiple valves, pipes, meters, obstacles on the floor, valves occluded from view, and multiple paths of differing navigation complexity. The ongoing research program supports the development of autonomous capability for HERMIES-IIB and III to perform complex navigation and manipulation under time constraints, while dealing with imprecise sensory information.
Closed loop trajectory control of walking machines
Authors: Gardner J. F. , Srinivasan K. , Waldron K. J.
Published: March 2009

The global trajectory control of walking machines is addressed here with particular attention paid to the consequences of actuator redundancy for control and to the inclusion of actuator dynamics in trajectory controller design. Redundancy of actuation, typical of walking machines, results in the trajectory control problem being formulated perforce in a global coordinate frame, instead of the joint space, as in nonredundant manipulators. This lack of one-to-one correspondence between the degrees of freedom of motion in the global coordinate frame and the actuators results in coupling between the different trajectory control loops. A mechanism for reducing this coupling effect is proposed here, along with a procedure to take into account approximately the effect of actuator dynamics in designing the trajectory controllers. The proposed methods are evaluated by simulation for an example problem in legged locomotion and are shown to be effective.
Formulation of manipulator Jacobian using the velocity similarity principle
Authors: Gupta K. C. , Ma R.
Published: March 2009

Velocity similarity principle V(θ.,ṡ, ub, Qb) = DabV (θ.,ṡ, ua, Qa)Dab–1is presented and used to derive several useful forms of the Jacobian matrix for the manipulator from its basic kinematic equations in 4 X 4 matrix form. The zero reference position representation is used and, therefore, the base system is the only coordinate system utilized in the derivations. For manipulators with a spherical wrist, a modified form of the Jacobian is presented in which the Jacobian columns corresponding to the regional structure are completely decoupled from those corresponding to the wrist structure.
Derivation of optimal walking motions for a bipedal walking robot
Authors: Channon P. H. , Hopkins S. H. , Pham D. T.
Published: March 2009

The problem of determining energy optimal walking motions for a bipedal walking robot is considered. A full dynamic model of a planar seven-link biped with feet is derived including the effects of impact of the feet with the ground. Motions of the hip and feet during a regular step are then modelled by 3rd order polynomials, the coefficients of which are obtained by numerically minimising an energy cost function. Results are given in the form of walking profiles and energy curves for the specific cases of motion over level ground, motion up and down an incline, and varying payload.
Compliant robotic devices, and electroadhesion
Authors: Monkman G. J.
Published: March 2009

This paper illustrates means by which the techniques of compliance and electroadhesion can, using electror-heological, and other fluids, be combined to provide very effective shape adaptive robot end-effectors and similar holding surface.
DELTA: a simple and efficient parallel robot
Authors: Pierrot F. , Reynaud C. , Fournier A.
Published: March 2009

The DELTA parallel robot, designed by an EPFL (Ecole Polytechnique Fédérale de Lausanne) research team, is a mechanical structure which has the advantage of parallel robots and ease of serial robots modeling. This paper presents solutions for a complete modeling of the DELTA parallel robot (direct and inverse kinematics, inverse statics, inverse dynamics), with few arithmetic and trigonometric operations. Our method is based on a satisfactory choice of kinematic parameters and on a few restricting hypotheses for the static and dynamic models. We give some details of each model, we present some computation results and we put the emphasis on some particular points, showing the capabilities of this mechanical structure.
Payload capacity of balanced robotic manipulators
Authors: Lim T. G. , Cho H. S. , Chung W. K.
Published: March 2009

The payload capacity of a conventional robot is usually limited as compared to the mass of the robot body. This is because a payload adds additional gravity loadings to the robot joints resulting in large input joint torques. To reduce the required input joint torques, the authors have proposed a mechanical balancing mechanism. Basically, the mechanism was designed to exactly balance the first three links of an articulated robot by adjusting the positions of counter-balancing masses so as to eliminate the gravity loading terms. Since the input joint torques are greatly reduced by adopting balancing mechanisms, a balanced robot is expected to carry heavier payload and move with higher speed and acceleration. This paper further investigates the possibilities of improving the payload capacity as well as speed and acceleration capabilities. These features were investigated under various operating conditions involving payload, maximum angular velocity, and acceleration period. Based upon the simulation results, the performances of the balanced robot are compared in detail with those of a unbalanced conventional robot.
An approach to the modeling of the highest control level of flexible manufacturing cell
Authors: Jocković M. , Vukobratović M. , Ognjanović Z.
Published: March 2009

The paper considers the highest control level organization of a flexible manufacturing cell (FMS). The indeterminancy problem in Petri nets is discussed as well as a method for overcoming it by two control levels. The net is decomposed into individual robot nets and machines. A simple language for defining robot activation conditions is developed and used for defining knowledge base contents. A method for linking it with other control modules is given. Also, the solution performance is analysed.
Trajectory planning of redundant robots by maximizing the moving acceleration radius
Authors: Kim Ki-Kap , Yoon Yong-San
Published: March 2009

The moving acceleration radius (MAR) is proposed as a local performance index quantifying the dynamic uniformity of a redundant robot. MAR can be calculated by a simple sequential algorithm, and the resolution of the redundant joint angles is obtained by maximizing MAR locally. In addition, the reduction of the joint torques is achieved by maximizing the acceleration bound in the direction of work path, while MAR is being kept at a maximum. Also a new differentiation algorithm for angular acceleration is suggested for numerical efficiency as well as accuracy, using a null space operator.

A three degrees of freedom planar robot with one degree of redundancy, simulated using these algorithms for various situations, showed a marked improvement in dynamic characteristics.
A Real-time Algorithm for Obstacle Avoidance of Autonomous Mobile Robots
Authors: Han-Pang Huang , Pei-Chien Lee
Published: March 2009

A real-time obstacle avoidance algorithm is proposed for autonomous mobile robots. The algorithm is sensor-based and consists of a H-mode and T-mode. The algorithm can deal with a complicated obstacle environment, such as multiple concave and convex obstacles. It will be shown that the algorithm is more efficient and more robust than other sensor-based algorithms. In addition, the algorithm will guarantee a solution for the obstacle avoidance problem. Since the algorithm only takes up a small computational time, it can be implemented in real time.
Application-oriented robotic vision – a review
Authors: Jarvis R. A.
Published: March 2009

Computer Vision is essentially concerned with emulating the process of seeing, naturally manifested in various higher biological systems,1–4 on a computational apparatus, and is consequently part of the Artificial Intelligence field within the sub-category of Machine perception. Seeing has to do with making sense of image data acquired through an optical system and subsequently dealt with at increasing levels of abstraction and association with known facts about the world. The spectrum of interest in Computer Vision ranges from attempting to answer basic questions concerning the functionality of biological vision systems, particularly human, at one end, all the way to enhancing the reliability, speed and cost effectiveness of specific industrial operations, particularly component inspection and vision driven robotic manipulation. The main bulk of interest is in the middle, where the quest for generality pushes interest towards biological vision systems with their demonstrated effectiveness in a wide range of environments, some hostile, whilst the need for economic viability and timeliness in relation to particular application pushes interest towards finding workable algorithms which function reliably at high speed on affordable apparatus.

This paper is addressed, in somewhat tutorial style, at clarifying, by examples of work in the area, the issues surrounding application oriented robotic vision systems, their assumptions, strengths, weaknesses and degree of generality, and at the same time putting them in the context of the overall field of Computer Vision. In addition, the paper points to directions of development which promise to provide powerful industrial vision tools at an acceptable price.
Special computer architectures for image analysis
Authors: Fu K. S.
Published: March 2009

With the recent advances of VLSI technology, it has become possible to realize parallel architectures for image processing which are more efficient than the customary sequential processors. The paper discusses general architectural requirements for parallel processing and then the existing systems architectures. This is followed by a description of VLSI devices for image processing in three examples. The paper emphasizes VLSI architectures for image feature extraction, classification and structure (syntax) analysis.
Parallel processing in machine vision
Authors: Sternberg Stanley R.
Published: March 2009

Machine vision systems incorporating highly parallel processor architectures are reviewed. A new processor architecture, the image flow computer, is presented in detail. An interactive image processing programming language based on mathematical morphology is then presented. A detailed example of the use of the system for the inspection of a particular industrial part concludes the presentation.
Automated assembly by reference measurement
Authors: Francois C. , Artigue F.
Published: March 2009

This paper describes an automatic assembly method by reference searching followed by workpiece repositioning. In such a case, the adjustment of the piece to be assembled to its relative location is obtained before the final insertion phase.

The efficiency of the method is shown in the case of the automatic fitting of a car suspension triangle. The main elements of the prototype designed for this task are described and their principles are developed. Considerations regarding less specific devices lead to a possible improvement of the flexibility of the assembly method.
Inference of Automata by dialectic learning
Authors: Richetin M. , Naranjo M.
Published: March 2009

An algorithm for the inference of the external behaviour model of an automaton is given. It uses a sequential learning procedure based on induction-contradiction-correction concepts. The induction is a generalization of relationships between automaton state properties, and the correction consists in a more and more accurate discrimination of the automaton state properties. These properties are defined from the input/output contradictory sequences which are discovered after the observed contradictions between successive predictions and observations.
International cooperation and trends in the field of industrial robots
Authors: Yonemoto Kanji
Published: March 2009

After discussing the advent of the Age of Automation, the author considers the number of robots in operation throughout the world and the forecasts of their manufacture for each country. Attention is then drawn to the international exchange of research and technological information, in particular to the frequent symposia on industrial robots (ISIR). In addition to ISIR, international conferences on advanced robotics are also envisaged (ICAR). Finally, some details are given of international cooperation in the realm of industrial research.
Robot vision as a problem of picture analysis optimization
Authors: Bereznaya I. Y. , Granovskaya R. M.
Published: March 2009

Some principles of information processing in the right and left cerebral hemispheres are used to construct effective algorithms for the recognition of handwritten characters and for processing complex grey-level pictures, viz, photographs of human faces. These algorithms reduce to a considerable extent the exhaustive search for pixels being analysed. A quantitative estimate of the thus obtained gain is given.
A method for the generation and recording of industrial robots continuous trajectories
Authors: Couderc Robert , Fannechère Georges , Poiraudeau Jean-François , Roux Serge
Published: March 2009

The need to store the trajectory information required by industrial robots, so that they may carry out tasks such as painting, has led to various data compression methods. The method proposed, simple to implement and adaptable to low cost systems, enables a best compromise to be reached for a given application between the detailed description of a complex movement and the use of as little memory as possible. This method was first used on a hydraulic prototype for the French Master-Slave firm PHAREMME.
Extended kinematic path control of robot arms
Authors: Krustev Evgeny , Lilov Ljubomir
Published: March 2009

Path planning a robot arm motion essentially requires that the constraints of the joint variables and the vector of the joint motion rates are taken into account. In order to satisfy the constraints of the joint variables a sliding mode is being employed together with the developed kinematic path control method. The extended form of the kinematic path control method, here proposed, treats simultaneously the constraints of the joint variables and the vector of joint motion rates in path planning a robot arm motion.
Dynamics of redundant robots – inverse solutions
Authors: Huston Ronald L. , King Timothy P.
Published: March 2009

The dynamics of “simple, redundant robots” are developed. A “redundant” robot is a robot whose degrees of freedom are greater than those needed to perform a given kinetmatic task. A “simple” robot is a robot with all joints being revolute joints with axes perpendicular or parallel to the arm segments. A general formulation, and a solution algorithm, for the “inverse kinematics problem” for such systems, is presented. The solution is obtained using orthogonal complement arrays which in turn are obtained from a “zero-eigenvalues” algorithm. The paper concludes with an assertion that this solution, called the “natural dynamics solution,” is optimal in that it requires the least energy to drive the robot.
Time-optimal Trajectories for Robot Manipulators
Authors: Dissanayake M. W. M. G. , Goh C. J. , Phan-Thien N.
Published: March 2009

A computational technique for obtaining minimum-time trajectories for robot manipulators is described in this paper. In the analysis, limitations to link movements due to design constraints are taken into consideration. Numerical examples based on a two-link planar robot arm shows the feasibility of the technique proposed. A physical explanation for the general characteristics of the observed trajectories is also presented. The importance of appreciating optimal control issues in designing robot manipulators and in planning robot workstation layouts is emphasised.
Constrained Motion Control of Manipulation Robots – A Contribution
Authors: Stokić Dragan M.
Published: March 2009

The problems concerning the control of constrained motion of manipulation robots are discussed in the paper. Two general problems of hybrid position/force control are considered: the problem of interaction between position and force control and the problem of contact between a robot and an environment. Some promising solutions to these problems are identified. It is shown that adaptive control is necessary to solve these problems. A new control scheme is proposed and results of computer simulations are presented
Task-Driven Extraction of Object Contour by Human Haptics: Part 2
Authors: Lederman Susan J. , Klatzky Roberta L. , Balakrishnan J. D.
Published: March 2009

The extraction of contour information from subjects is essential for purposes of grasping and manipulation. We proposed that human haptic exploration of contours, in the absence of vision, would reveal specialized patterns, or “contour exploration procedures,” that are directly related to task goals and intrinsic system capacities. Our general assumptions, method, and initial results were described in Part 1. Part 2 provides an analysis of the relation between contour extraction procedures and processing constraints. These theoretical assumptions are supported by empirical findings, and implications are discussed for issues of importance to robotic exploration and manipulation.
Assembly Strategies for Parts with a Plane of Symmetry
Authors: Aspragathos N. A.
Published: March 2009

This paper describes the development of assembly strategies based on hybrid force/position control. The assembly strategies developed are confined to the large class of assembly tasks defined as a peg-in-the-hole assembly having a plane of symmetry passing through the axis of insertion.

The basic idea to develop a robotic system for programmable assembly is presented. This system can currently operate controlled manipulators with minor modifications, i.e. if a force/torque sensor and proper software for hybrid control are provided.

The principles of writing assembly strategies are analysed and examples of more complex assembly tasks than the classic round peg-in-the-hole are discussed in detail.
Concepts of Augmented Image Space and Transformed Feature Space for Efficient Visual Servoing of an “Eye-in-Hand Robot”
Authors: Jang Won , Kim Kyungjin , Chung Myungjin , Bien Zeungnam
Published: March 2009

For efficient visual servoing of an “eye-in-hand” robot, the concepts of Augmented Image Space and Transformed Feature Space are presented in the paper. A formal definition of image features as functionals is given along with a technique to use defined image features for visual servoing. Compared with other known methods, the proposed concepts reduce the computational burden for visual feedback, and enhance the flexibility in describing the vision-based task. Simulations and real experiments demonstrate that the proposed concepts are useful and versatile tools for the industrial robot vision tasks, and thus the visual servoing problem can be dealt with more systematically.
A Distributed PC-Based Control System for Education in Robotics
Authors: Kirćanski N. , Leković Dj. , Borić M. , Vukobratović M. , Djurović M. , Djurović N. , Petrović T. , Karan B. , Urosević D.
Published: March 2009

The paper presents an educational system for teaching and research in robotics which consists of a manipulator, controller and a PC compatible host computer. The advanced design of host-computer user-interface software makes the system very suitable for teaching. It allows the user not only to follow the system states but also to change the control structure on-line. In the first part of this paper the architecture of the system, window-oriented user interface, specially designed robot language and several build-in students lessons will be described as well as the data acquisition system and advanced graphical capabilities.

In the second part of this paper the executive controller architecture is described. Besides the manipulator control function and IO operations, the controller supports communication with the host-computer. The controller is programmable, i.e. it executes various tasks within user-defined and build-in students lessons. By the use of simple host-computer commands the controller can execute various algorithms both for trajectory generation and dynamically compensated digital servo control. The dynamic model components in the feed-forward and feed-back control loop can be selectively included and changed during the manipulator's motion. Experimental results with a 4-link educational robot are presented.
Application of redundant robots to constrained-motion tasks
Authors: Potkonjak Veljko
Published: March 2009

The problem of the constrained motion of robot end-effector is discussed. The redundant robot is considered, redundancy being added in order to improve robot working characteristics. In the phase of free motion towards the constraint the errors of basic non-redundant configuration are corrected by means of redundancy. During the constrained motion redundancy plays the role either of active or passive compliance. Between these two phases, the collision with the constraint occurs, and the impact can be absorbed by using redundancy.
Virtual reality and telepresence
Authors: Stone Robert
Published: March 2009

The UK Advanced Robotics Research Centre's VERDEX Project (Virtual Environment demote Driving Experiment) is an experimental test bed for investigating telepresence and virtual reality technologies in the design of human-system interfaces for telerobots. The achievements of the Project to date include the transformation of scanning laser rangefinder output to stereo virtual imagery (viewed using the VPL EyePhoneTM), the Teletact® Tactile Feedback Glove (for use with the VPL DataGloveTM), a high-speed, head-slaved stereo TV system, and a T800/i860 SuperVisionTM graphics/video parallel processing system.
AI and Robotics; Flexibility and Integration
Authors: Mowforth Peter , Bratko Ivan
Published: March 2009

This paper reviews some current research problems in Artificial Intelligence applied to robotics, in particular the processing of sensory information and robot programming. It is perceived that much progress has been made in applying AI techniques to particular isolated tasks, but the important theme at the leading edge of the AI-based robotics technology seems to be the interfacing of the subsystems into an integrated environment. This requires flexibility of the subsystems themselves. But on the other hand it also increases the flexibility of the integrated system in that it broadens the variety of ways for solving problems through functional combination of the subsystems. The presentation in this paper is illustrated by examples from the hardware and software environment of the advanced robotics research at the Turing Institute.
How robotics expands A.I.
Authors: Andrew Alex M.
Published: March 2009

Artificial Intelligence clearly influences Robotics, but the advent of the latter alters the character of A.I. itself, bringing it closer to natural intelligence. This is partly due to greater attention to processes depending on continuous variables, and the combination of these with concept-based or “logical” processes. Some fundamental A.I. principles, notably Minsky's heuristic connection, involve continuity, and the advent ofRobotics should stimulate developments which take them into account. A scheme for a robot which can increase its speed of operation by a learning process is outlined.
Robotic assembly: a synthesizing overview
Authors: Cho H. S. , Warnecke H. J. , Gweon D. G.
Published: March 2009

Robotic assembly systems offer tremendous promise for the flexible assembly automation but present a variety ofcomplexresearch issues due to the positioning inaccuracy of the manipulator, dimensional variation of mating parts and their physical interactions. This paper provides an up-to-date survey of researches in robotic assembly with emphasis on parts mating technology. Depending upon the mating strategy, presently available methods of performing precision assembly operations are classified and their advantages and limitations are discussed from the view points of the system complexity, adaptability and reliability. The performance variables such as the mating speed, positioning error absorbing capability and applicability are compared in some details for various assembly methods.
Parallel computation of symbolic robot models of pipelined processor architectures
Authors: Kirćanski N. , Petović T. , Vukobratović M.
Published: March 2009

Increased speed of inverse dynamics computation is essential for improving the characteristics of robot control systems. This is achieved by reducing the numerical complexity of the models and by introducing parallelism in model computation. In this paper customized symbolic models with a near minimum numerical complexity will be used as a basis for the examination of parallelism in inverse dynamic robot models. A scheduling algorithm for the distribution of computational load onto an arbitrary linear array of pipelined processors will be developed. The proposed algorithm is experimentally evaluated on a transputer network.
R & D Profile Jet Propulsion Laboratory Robotic Facilities and Associated Research
Authors: Weisbin C. , Perillard D.
Published: March 2009

This paper describes the robotics facilities and associated research program of the Jet Propulsion Laboratory, lead center in telerobotics for the United States National Aeronautics and Space Administration. Emphasis is placed on evolution from teleoperation to remote System automation. Research is described in manipulator modelling and control, real-time planning and monitoring, navigation in outdoor terrain, real-time sensing and perception, human-machine interface, and overall System architectures. Applications to NASA missions emphasize robotic spacecraft for solar System exploration, satellite servicing and retrieval, assembly of structures, and surveillance. Applications to military missions include battlefield navigation, surveillance, logistics, command and control.
Task–Driven Extraction of Object Contour by Human Haptics: Part 1
Authors: Klatzky Roberta L. , Lederman Susan J. , Balakrishnan J. D.
Published: March 2009

The extraction of contour information from objects is essential for purposes of grasping and manipulation. We proposed that human haptic exploration of contours, in the absence of vision, would reveal specialized patterns. Task goals and intrinsic system capacities were assumed to constrain the breadth of processing and the precision with which contour is encoded, thus determining parameters of exploration and ultimately producing movement synergies or “contour exploration procedures.” A methodology for testing these assumptions is described, and the most frequently observed procedures are documented in Part 1. Part 2 will further analyze the procedures, test predictions, and develop implications of the research. The paper (2 parts) is novel in its study of human manipulative behavior from a robotic standpoint; it is thus of interest to robotics research workers interested in the long-term goals of robot manipulation and those interested in an anthropomorphic approach to robotics studies.
Identifiable Parameters and Optimum Configurations for Robots Calibration
Authors: Khalil W. , Gautier M. , Enguehard Ch.
Published: March 2009

This paper presents a general method to identify the geometric parameters of robots. An algorithm is given to calculate the identifiable geometric parameters. The robot location and the tool location parameters are taken into account. The algorithm is generalized to tree structure robots. The problem of selecting the optimum robot configurations to be used during the identification is discussed and a solution is proposed.
Iterative Generation of Virtual Reference for a Manipulator
Authors: Yamakita M. , Furuta K.
Published: March 2009

Virtual reference is defined as the signal for a closed-loop System so that the response tracks the desired path perfectly. It is proposed to obtain a virtual reference signal suitable for a manipulator to track a predetermined trajectory using repetitive operations. Thus the algorithm ensures that the difference between the desired and the manipulator trajectories will become negligible as the number of operations approaches infinity if the manipulator is compensated for properly by local feedback. This algorithm uses a dual System to recursively improve the reference signal. Such a System has the advantage of being simple to design. The derivation of this algorithm is based on functional analysis. The effectiveness is confirmed by two experimental results.
Structured Motion Planning in the Local Configuration Space
Authors: Zalzala A. M. S. , Morris A. S.
Published: March 2009

The minimum-time motion of robot manipulators is solved by defining a suitable time history for the arm end-effector to traverse. As the planning is performed in the configuration space, the uniqueness of the proposed algorithm emerges from the combination of both cubic and quadratic polynomial splines. Furthermore, the highly efficient time optimisation procedure could be applied to local segments of each joint trajectory, leading to a significant reduction of the travelling time. In addition, the ability to perform a search in the work space is granted, exploiting all possible options for an optimum motion. The method proposed considers all realistic physical limitations inherent in the manipulator design, in addition to any geometric constraints imposed on the path. Simulation programs have been written, and results are reported for the Unimation PUMA 560 robot manipulator.
On the Dynamic Characteristics of a Redesigned Robot
Authors: Park H. S. , Cho H. S.
Published: March 2009

A robotic manipulator is usually a very complicated system whose dynamics is too complicated time consuming for real-time control. The authors propose general criteria for designing an ideal robot whose dynamics is very much simpler than that of the conventional one. In this paper, dynamic characteristics of an ideally designed robot are investigated. The design guidelines were applied to a 6-degree-of-freedom PUMA 560 robot. Based upon the design concept dynamic equations of the redesigned robot were derived. Utilizing these equations, dynamic characteristics of the redesigned robot are investigated with respect to the computation efforts required, variation of the inertia matrix, joint input torque chracteristics, and couplings between the joints. A detailed comparison study is also made between the redesigned and conventional robots.
Identification and Compensation of a Robot Kinematic Parameter for Positioning Accuracy Improvement
Authors: Kim D. H. , Cook K. H. , Oh J. H.
Published: March 2009

This paper presents a simple identification method of the actual kinematic parameters for a robot with parallel joints. It is known that Denavit–Hartenberg's coordinate System is not useful for nearly parallel joints. In this paper, the coordinate frames are reassigned to model the kinematic parameter between nearly parallel joints by four parameters. The proposed identification method uses a straight ruler about 1 m long. A robot hand is placed by using a teaching pendant at the prescribed points on the ruler, and the corresponding error function is defined. The identified kinematic parameters, which make the error function zero, are obtained by the iterative least square method based on the singular value decomposition. In the compensation of joint angles, only the position is considered because the usual applications of robot do not require a precise orientation control.
On the problem of translating an elliptic object through a workspace of elliptic obstacles
Authors: Oommen B. John , Reichstein Irwin
Published: March 2009

Two algorithms are presented which deal with translating an elliptic object, A, without collision amidst elliptic obstacles. These are:

(i) An exact algorithm, of complexity O(N log N), where N is the number of obstacles, yielding all directions along which the object is separable from the obstacles by a single translation.

(ii) An algorithm quadratic in N, which yields, with a degree of approximation determined by the user, a path of the object from its initial to its final position.
A fast tracking error control method for an autonomous mobile robot
Authors: Lee S.S. , Williams J.H.
Published: March 2009

This paper proposes a fast tracking error control method for a mobile robot with two differentially driven wheels. The tracking error between reference state and current state is transformed to the required displacement changes of each drive wheel by a wheel Jacobian. The major objective of this paper is to propose a control method for eliminating the tracking error quickly by controlling two independent driving wheels at the same time. To avoid long computational requirements of a Cartesian-based control, a kinematic model of the vehicle and co-ordinate system are introduced. Several simulation results are presented using this method. The fast tracking error control method proposed is mainly hardware-independent and Hence can be applied to various kinds of mobile robots which have two differentially driven wheels. The method was implemented on an experimental vehicle, WCVS, The experimentation shows a performance suitable for practical applications.
A modeling method for collision detection and motion planning of robots
Authors: Wu Chia-Ju
Published: March 2009

A modeling method for robots is proposed, in which a convex polyhedron is represented as a set of inequalities and a robot is represented as a union of convex polyhedrons. With this method, collision between robots can be detected by solving a set of linear programming problems at every sampling instant. By detecting possible collision at every sampling instant, a directed graph for robots is created. The motion planning problem of robots is then transformed into a path searching problem in the directed graph and can be solved by exisiting searching algorithms.
On-line polynomial path planning in Cartesian space for robot manipulators
Authors: Froissart Cyrille , Mechler† Pierre
Published: March 2009

A method is presented to perform path planning in the Cartesian space. The motion velocity and acceleration are continuous. This is the first polynomial path planning algorithm in the Cartesian space working in real-time; it does not need an advanced knowledge of the trajectory and can be used when knot points are provided on-line by a sensor. The Bézier representation is used to compute a fifth degree polynomial path. It has been tested on an industrial robot controller.
Avoidance of obstacles with unknown trajectories: locally optimal paths and path complexity, Part I
Authors: Gil de Lamadrid James , Zimmerman† Jill
Published: March 2009

We consider the problem of moving a point robot through a two dimensional workspace containing polygonal obstacles moving on unknown trajectories. We propose to use sensor information to predict the trajectories of the obstacles, and interleave path planning and execution. In this paper, we present preliminary work in which we propose our basic algorithm and define a locally minimum velocity path as an optimal robot trajectory, given only local information about obstacle trajectories. In the sequel (part II) to this paper we will show that the complexity of a path planning problem can be characterized by how frequently the robot must change directions to approximate the locally minimum velocity path.
An automatic Guidance system of an autonomous vehicle —the trajectory generation and the control algorithm
Authors: Lee S.S. , Williams J.H. , Rayment P.J.
Published: March 2009

This paper presents a trajectory generation method using smooth functions for an automatic guidance system of an autonomous vehicle with two differentially driven wheels within structured environments. A control algorithm based on an incrementally generated smooth trajectory gives a good performance when implemented on an experimental vehicle.
Human posture modelisation as a problem of inverse kinematic of redundant robots
Authors: Lepoutre F.X.
Published: March 2009

Human posture is the co-operation of parts of the body to perform a task. This organization is self optimised by the operator to minimize strain and pain and maximize efficiency. This problem is formulated as a problem of inverse kinematic of a redundant robot. Constraints are imposed by the visual and manual task, and criteria may be modified in relation to operator motivation and tiredness. An interactive graphical software is designed to teach the postural problem and as an ergonomic aid.