bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robotic Assembly by Slight Random Movements
Authors: Badano F. , Betemps M. , Redarce T. , Jutard A. 
Published: March 2009

SUMMARYIn 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

SUMMARYThis 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.
Elastostatic contact imaging for a mechanoreceptive tactile device
Authors: Mehdian M. , Johns-Rahnejat P.M. , Rahnejat H. 
Published: March 2009

SUMMARYThis 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

SUMMARYThe 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

SUMMARYThe 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

SUMMARYThis 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

SUMMARYA 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

SummaryThe 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

SummaryThe 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

SummaryFor 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.
Near minimum-time trajectory for two coordinated manipulators
Authors: Lee K. Y. , Dissanayake M. W. M. G. 
Published: March 2009

SummaryThis 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

SummaryFor 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

SummaryAn 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

SUMMARYThis 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.
Decentralized adaptive compliance control of robot manipulators
Authors: Colbaugh R. , Glass K. 
Published: March 2009

SummaryThis 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

SummaryThe 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 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

SummaryThe 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

SummaryA 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

SummaryAn 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

SUMMARYThis 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

SUMMARYPart 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

SUMMARYThis 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.