bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficient PUMA manipulator jacobian calculation and inversion
Authors: Leahy M. B. , Nugent L. M. , Saridis G. N. , Valavanis K. P. 
Published: July 2007

AbstractAn efficient Jacobian calculation and inversion for a PUMA manipulator permits the real‐time implementation of modern Cartesian space manipulator control techniques. Efficient exact computational formulations for the Jacobian and its inverse have been developed by symbolic reduction techniques. Jacobian computational requirements have been reduced to 66 multiplications and 30 additions. The inverse Jacobian requires only 103 multiplications, 5 divisions, and 70 additions. These computational requirements are easily satisfied in real‐time by modern microprocessor‐based manipulator control systems.
Robot manipulator kinematic compensation using a generalized jacobian formulation
Authors: Driels Morris R. , Pathre Uday S. 
Published: July 2007

AbstractThe kinematic error compensation of robot manipulators is at present being attempted by improving the precision of the nominal robot kinematic parameters. This paper addresses the problem of kinematic compensation using a new mathematical joint model proposed to account for shortcomings in existing methods. The corrected manipulator transformation is formulated in terms of “generalized Jacobians”: relating differential errors at the joints to the differential change in the manipulator transformation. The details of application are discussed for a particular industrial manipulator.
Kinematic modeling of wheeled mobile robots
Authors: Muir Patrick F. , Neuman Charles P. 
Published: July 2007

AbstractWe formulate the kinematic equations of motion of wheeled mobile robots incorporating conventional, omnidirectional, and ball wheels.1 We extend the kinematic modeling of stationary manipulators to accommodate such special characteristics of wheeled mobile robots as multiple closed‐link chains, higher‐pair contact points between a wheel and a surface, and unactuated and unsensed wheel degrees of freedom. We apply the Sheth‐Uicker convention to assign coordinate axes and develop a matrix coordinate transformation algebra to derive the equations of motion. We introduce a wheel Jacobian matrix to relate the motions of each wheel to the motions of the robot. We then combine the individual wheel equations to obtain the composite robot equation of motion. We interpret the properties of the composite robot equation to characterize the mobility of a wheeled mobile robot according to a mobility characterization tree. Similarly, we apply actuation and sensing characterization trees to delineate the robot motions producible by the wheel actuators and discernible by the wheel sensors, respectively. We calculate the sensed forward and actuated inverse solutions and interpret the physical conditions which guarantee their existence. To illustrate the development, we formulate and interpret the kinematic equations of motion of Uranus, a wheeled mobile robot being constructed in the CMU Mobile Robot Laboratory.
Decentralized variable structure control of a two‐arm robotic system
Authors: Özgüner Ü. , Yurkovich S. , Ai‐Abbass F. 
Published: July 2007

AbstractThe control problem for a two‐arm robotic system in coordinated motion is addressed. A hierarchical framework, employing two levels of control hierarchy, is utilized, and the decentralized model reference adaptive control approach using variable structure controllers (DMRA‐VSC) is applied. Within the control hierarchy, the DMRA‐VSC strategy is accomplished at the lower level, where control is responsible for the servoing of each joint. These local controllers are coordinated by the high‐level, central controller, whose task is to provide the local controllers with the upper bound on the dynamical interactions with other subsystems. The local controllers are responsible for making each link follow the prescribed local reference subsystem in moving from one position to another. This is done using the local measurements and the information provided by the central controller. Advantages of the DMRA‐VSC approach for multiple manipulator control include the inherent robustness properties to nonlinearities and interaction effects, the decentralization structure facilitating ease in multiple manipulator system programming and implementation, and the general structure of the controller which allows further extensions such as force feedback.
Object identification using automated decision tree construction approach for robotics applications
Authors: Luo Ren C. , Scherp Ralph S. , Lanzo Mark 
Published: July 2007

AbstractThe objective of this article is to present a novel approach to object recognition and classification for robotic applications using the automated decision tree generation technique. The method developed relies upon simple statistical measurements extracted from object classes and represented in the form of a distance matrix ‘D’ to form a decision tree. The algorithms presented here are computationally efficient and simple to implement. The effectiveness of the features are automatically assessed, allowing for the automatic selection of only those features needed to accomplish object recognition and classification. The performance of the algorithms are successfully tested and demonstrated.
Adaptive force and position control of manipulators
Authors: Seraji H. 
Published: July 2007

AbstractThe article presents simple methods for the design of adaptive force and position controllers for robot manipulators within the hybrid control architecture. The force controller is composed of an adaptive PID feedback controller, an auxiliary signal, and a force feedforward term, and achieves tracking of desired force setpoints in the constraint directions. The position controller consists of adaptive feedback and feedforward controllers as well as an auxiliary signal, and accomplishes tracking of desired position trajectories in the free directions. The controllers are capable of compensating for dynamic cross‐couplings that exist between the position and force control loops in the hybrid control architecture. The adaptive controllers do not require knowledge of the complex dynamic model or parameter values of the manipulator or the environment. The proposed control schemes are computationally fast and suitable for implementation in online control with high sampling rates. The methods are applied to a two‐link manipulator for simultaneous force and position control. Simulation results confirm that the adaptive controllers perform remarkably well under different conditions.
Robot trajectory planning using the convolution operator
Authors: Mirman C. R. , Gupta K. C. 
Published: July 2007

AbstractAn automatic trajectory planning technique is presented to produce smooth joint displacement‐time functions. One can start with few approximately specified joint displacement values, or from a joint displacement‐time function which is not entirely satisfactory. The final joint displacement‐time function passes through the initial and final points, and lies in the vicinity of the intermediate approximate points; it also passes through some points which are in the joint dwell ranges. It is important that the final trajectory exhibit little deviation from the desired displacement values. One would also want to obtain a smooth joint acceleration function, and a rapidly declining envelope for the harmonic spectrum. This new method of trajectory planning is based upon the use of the mathematical operation of convolution. It was found that the use of convolution on a given joint displacement time function tended to decrease the peak acceleration amplitudes, while producing a smooth acceleration function. Convolution also reduced the frequency spectrum amplitudes associated with the joint functions, thus reducing the severity of vibrations which can be induced by the joint motion. While there are some drawbacks to this method, such as increased deviations at intermediate points after convolution, it will be shown that these may be reduced by using techniques described in this article.
Application of discrete‐time model reference adaptive control to a flexible single‐link robot
Authors: Yuh J. 
Published: July 2007

AbstractThis article addresses the feasibility of applying discrete‐time model reference adaptive control techniques to the flexible link of robot mechanisms. The method of separation of variables is used to represent the deflection of the link. A nonlinear model is obtained using a Lagrangian equation, and the candidate frequencies and the associated mode functions are obtained using Bernoulli‐Euler beam theory. By considering the effect of flexibility as an internal disturbance torque acting on the rigid body motion of the system, a discrete‐time MRAC is determined for a single non‐rigid link. The control algorithm is implemented for a collocated sensor and actuator system, and for a noncollocated end‐point sensor and actuator system. Results of computer simulation show the feasibility of this approach and the advantage of using an end‐point sensing system.
Static grip selection for robot‐based automated assembly systems
Authors: Ahmad Shaheen , Feddema John T. 
Published: July 2007

AbstractIn this article we present an algorithmic approach to determine the suitable grasp of an object in an automated assembly environment. The algorithm is based on the available object surfaces and the initial and final task constraints and gripper characteristics. If the imposed task and gripper constraints do not allow a possible grasp, intermediate motions may need to be made to reorient the part. Once a set of possible grasps which statisfy task and gripper constraints are found, the stability of each grasp is analyzed using screw theory. An optimal grasp is one which minimizes the grasping forces over the possible set of grasps. Results utilizing our methodology are presented. Our method can be interfaced with CAD database such as a solid modelling system based on boundary representation for automatic selection of grasping configurations.
Formulation of the kinematic model of a general (6 DOF) robot manipulator using a screw operator
Authors: Payandeh S. , Goldenberg A. A. 
Published: July 2007

AbstractIn general, the manipulator's end‐effector can be located in a desired position and orientation in its work‐space through angular and/or linear displacements of its joints. These joint coordinates can be obtained by solving the loop‐closure equation of the manipulator's kinematic model. The most common method for obtaining this equation is based on the point coordinates 4×4 homogeneous transformation matrix. This method uses a special set of frames which are adapted to the manipulator's configuration. Within the last few years there has been some interest in the use of screw operators (line transformations) to model the kinematic configuration of manipulators and to form the loop‐closure equation. In this article, a kinematic model of a general (6 DOF) manipulator is obtained through the application of a screw operator (dual‐unit quaternion) to represent the screw displacements of the line coordinates of the manipulator link and joint axes. The loop‐closure equation of the closed kinematic chain is obtained by introducing a hypothetical link/joint at the manipulator's end‐effector location. The resultant non‐linear loop‐closure equation is then solved for the joint coordinates using a numerical technique. The method is illustrated with an example.
An extensible ball bar for evaluation of robots' positioning performance
Authors: Vira N. , Lau K. 
Published: July 2007

AbstractThis article describes the development of a one‐dimensional extensible ball bar designed to measure the positioning accuracy and repeatability of industrial robots. The ball bar has a linear travel of 5 cm (2 in) that is monitored by a built‐in electronic transducer having a resolution of 2.5 μm (0.0001 in). At each end of the bar is a precision steel sphere, one of which is attached to an universal joint mounted on a robot's wrist. The other steel ball is magnetically attached to a socket which is firmly located within the work zone of the robot. During the measuring process the robot wrist is programmed to move in an arc whose radius is the nominal length of the bar. The variation of the length of the bar is recorded from the linear transducer and used to obtain a one‐dimensional measurement of the positioning poerformance of the robot. Linear displacement and sag tests indicate that the ball bar has an accuracy of 32 μm (0.0013 in) and a repeatability of 20 μm (0.0008 in). Test procedures to evaluate a robot's performance are also presented.
Tactile array sensor for object identification using complex moments
Authors: Luo Ren C. , Loh Horng‐Hai 
Published: July 2007

AbstractThis article explores object identification by complex moment features obtained using a tactile array sensor. Some complex moment invariants have been derived and implemented eliminating the effects of lateral displacement and rotation from the tactile images. The generation of a decision tree and use of the complex moment features, allow easy identification of object shapes from the tactile array sensor.
Hypersurfaces of special configurations of serial manipulators and related concepts. part III: Measures for the position and orientation space of 6 dof manipulators
Authors: Soylu Resit , Duffy Joseph 
Published: July 2007

AbstractIn this article two alternatives are introduced as measures for the position and orientation space of 6 DOF manipulators which include considerations of joint limitations and scale. The cumulative freedom of the end effector, considered as a rigid body in 3D space, can thus be quantified. These alternative measures are shown to be equivalent for manipulators with spherical wrists. Applications are presented and the new concepts are illustrated by an example.
An experimental investigation of an articulating robotic manipulator with a graphite‐epoxy composite arm
Authors: Choi S. B. , Gandhi M. V. , Thompson B. S. , Lee C. Y. 
Published: July 2007

AbstractAn experimental program was undertaken to investigate the elastodynamic response characteristics of a General Electric P50 robot retrofitted with a prototype graphite‐epoxy forearm. The retrofitted robot with this high‐strength, high‐stiffness lightweight arm was then programmed to execute a variety of maneuvers and the attendant elastodynamic deflections were measured. These experimental data were then compared with the results of complementary studies of the original robot which featured an aluminum arm. The preliminary experimental results from this proof‐of‐concept study clearly demonstrate the superior performance characteristics of the robot retrofitted with the composite arm.
A feasibility study of ic chip wire bond inspection
Authors: Pal A. L. , Patel K. U. , Lai K. K. 
Published: July 2007

AbstractProduct inspection, which is an important step in industrial manufacturing, has depended on human inspectors whose performance is generally inadequate and variable. In the past few years, automated machines for wire bonding have been developed and integrated in the production of quality IC chips for the electronic industry. However, inspection of the wire bonds has not been automated as yet. This article describes a feasibility study for the automated visual inspection of IC chip wire bonds conducted in the Computer Vision Research Laboratory at Arizona State University. Both the system setup and algorithms for detecting some of the typical wire bonding defects such as ball bond, stitch bond placement, and size defects, and connecting wire defects such as missing and shorted wires using two‐dimensional digital images are described.
A miniature robotic boundary layer data acquisition system
Authors: Wilkinson Stuart 
Published: July 2007

AbstractA sophisticated, highly miniaturized, mobile robot has been developed to collect boundary layer velocity profile data over the surfaces of wind tunnel models. To reduce aerodynamic interference effects the robot was built with dimensions of only 150mm tall X 70mm long X 35mm wide, yet it contained a substantial number of electro‐mechanical and electronic systems for accurately positioning small pressure probes, and for transducing their pressure data. The robot system, which could be controlled in a tele‐operator mode from outside the wind tunnel, was capable of traversing a pressure probe normal to the model surface at two speeds, and was able to stop the probe at any desired location with a positional accuracy of 0.022mm. The robot also included systems that enabled it to move over the model surfaces in a chordwise sense, and to rotate the probe through 180° for use in reversed flow regions. When used operationally during actual wind tunnel testing, the robot functioned flawlessly, and returned high quality boundary layer data.
Redundant robot control using task based performance measures
Authors: Dubey Rajiv , Luh John Y. S. 
Published: July 2007

AbstractThe joint velocities required to move the end‐effector of a redundant robot with a desired linear and angular velocity depend on its configuration. Similarly, the joint torques produced due to the force and moment at the end‐effector also depend on its configuration. When the robot is near a singular configuration, the joint velocities required to attain the end‐effector velocity in certain directions are extremely high. Similarly, in some configurations the joint torque produced at certain joints may be high for a relatively small magnitude of external force. An infinite number of trajectories in the joint space can be used to achieve a desired end‐effector trajectory for redundant robots. However, a joint trajectory resulting in robot configurations requiring lower joint velocities or joint torques is desired. This may be achieved through a proper utilization of redundancy. Local performance measures for redundant robots are defined in this article as indicators of their ability to follow a desired end‐effector trajectory and their ability to apply desired forces at the end‐effector. Thus, these performance measures depend on the task to be performed. Control algorithms which can be efficiently applied to redundant robots to improve these performance measures are presented. These control algorithms are based on the gradient projection method. Gradients of the performance measures used in the control schemes result in simple symbolic expressions for “real world” robots'. Feasibility and effectiveness of these control schemes is demonstrated through the simulation of a seven‐degree‐of‐freedom redundant robot derived from the PUMA geometry.
Dynamic stability analysis of a one‐link force‐controlled flexible manipulator
Authors: Chiou Bing C. , Shahinpoor M. 
Published: July 2007

AbstractThis study analyzes the effects of link flexibility on the dynamic stability of a force‐controlled flexible manipulator. The closed‐loop dynamic equation for a l‐link manipulator is first derived explicitly using the modal representation technique. Stability analysis is then carried out by computing the system eigenvalues. Results show that the link flexibility is one of the causes of dynamic instability of motion of the flexible robotic arm.
Robustness of decentralized robot controller to payload variation
Authors: Stokić D. , Vukobratović M. 
Published: July 2007

AbstractThe decentralized controller for manipulation robot is tested for its robustness to payload variation. First the local controllers are synthesized to withstand variation of inertia round the joints and then the global stability of the robotic system is examined. Three various situations are discussed: a) when actuator inertia is large in comparison to mechanism inertia, b) if the variation of payload is small in comparison to mechanism inertia, and c) if the large variation of payload parameters are expected. An algorithm for testing the robustness of the robot control to parameter variation is established, too. The purpose of the algorithm is to determine the allowable variation of the payload parameters which can be withstood by the simple decentralized controller. On the other hand, by this algorithm the local servosystems can be synthesized which are capable to withstand assumed parameter variation. This synthesis is demonstrated on an example of particular robotic system.
Collision‐avoidance trajectory planning using tube concept: Analysis and simulation
Authors: Suh Suk‐Hwan , Bishop Albert B. 
Published: July 2007

AbstractThe concept of a tube is introduced and is applied to the solving of the collision‐avoidance, minimum‐time trajectory planning problem. A collision‐free space is represented by an articulated tube with parameters of reference points and path tolerances. For obstacle avoidance, the end effector is constrained to move inside of the tube. An algorithm which will find suboptimal solutions for optimizing both path and velocity history of the trajectory by the use of piecewise joint‐space polynomials is presented. This algorithm exploits the robot arm dynamics in realistic environments where obstacles are present and the minimization of task time is desired with smooth motion. Experimental results show that as the path tolerance increases the new algorithm takes advantage of the spatial freedom to provide solutions superior to conventional approaches and to methods based on predefined paths.
Measuring learning progress in intelligent autonomous robots
Authors: Mohamed Ahmed S. , Armstrong William W. 
Published: July 2007

AbstractAI researchers claim to understand some aspect of human intelligence when their model is able to “emulate” it. In the contexts of mobile robots, the ability to go from teleoperation to autonomy should accordingly be treated not simply as a trick for robotics hackers but as an important epistemological and methodological goal. In this article the experience derived from designing locomotion control systems for both teleoperated and autonomous multi‐legged articulated robots is described.
Completing the forward kinematic calibration of open loop manipulators when single point position sensors are used
Authors: Everett Louis J. 
Published: July 2007

AbstractSingle point sensors can measure the position of one point fixed to a manipulator's end effector. When single point sensors have been used for calibration, it has not been possible to calibrate the orientation of the tool. Furthermore, it can be difficult to calibrate the sensor system. Results in the literature seldom provide a complete kinematic calibration of the manipulator. Presented here is a technique that enables single point sensors to gather sufficient information to complete kinematic calibration. In addition, the method can reduce the burden of calibrating the sensor system.
Distribution of dynamic loads for multiple cooperating robot manipulators
Authors: Walker Ian D. , Marcus Steven I. , Freeman Robert A. 
Published: July 2007

AbstractFor the situation of multiple cooperating manipulators handling a single object, a formulation is presented which allows load distribution of the combined system to be made while taking manipulator dynamics into account. First, object dynamics are used to transform the motion task. An integrated procedure for modeling arm dynamics is detailed. Then a method is introduced which transforms the object load to the joint level. At this level, various methods of load distribution that allow subtask performance are proposed. These methods allow desired object motion while selecting loads desirable to alleviate manipulator dynamic loads.