bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal motion coordination of two robots—a polynomial parameterization approach to trajectory resolution
Authors: Tabarah E. , Benhabib B. , Fenton R. G. 
Published: July 2007

AbstractA novel approach is presented for the optimal coordination of two robots performing continuous‐path manufacturing tasks. Two types of operations are considered: contact operations, such as deburring, which require the tool to maintain contact with the workpiece during the operation execution, or non‐contact operations, such as arc‐welding, where the tool moves relative to the workpiece without contact. In both cases, the required tool‐path is specified with respect to the workpiece. A task is performed by mounting the tool on a robot, while a second robot grips the workpiece; the two robots are then coordinated to move simultaneously relative to one another so that the tool follows its prescribed trajectory at a constant speed relative to the workpiece, and provides sufficient contact force in the case of contact operations. The original tool‐trajectory is thus resolved into a pair of conjugate trajectories, specified in task space relative to an inertial frame, describing the motion of the two robots. In cases where the two robots form a kinematically redundant system, the trajectory resolution process can yield an infinity of conjugate‐trajectory pairs corresponding to a given original tool‐trajectory, of which one pair may be chosen based on a specific choice of cost function. This article presents a technique whereby the robot's conjugate trajectories are parameterized using polynomial functions. A method is then developed for optimizing the robot's motion by selecting the optimal pair of conjugate trajectories. The proposed optimal trajectory‐resolution technique is further enhanced by coupling it to a procedure for selecting the optimal relative placement of the two robots, resulting in the best achievable solution. This method of coordinating two robots yields lower cycle‐time values than the corresponding single‐robot operation, as well as reduces the need for complex jigs and fixtures. Numerical simulations are presented to illustrate the proposed technique. © 1994 John Wiley & Sons, Inc.
Workspace analysis of stewart platforms via vertex space
Authors: Ji Zhiming 
Published: July 2007

AbstractThis article introduces the concept of “vertex space” for the study of the workspace of Stewart platforms. It shows that the vertex space has potential to link the dimensional parameters to the characteristics of the workspace of a platform. A method for constructing vertex spaces is developed. An example is provided to illustrate the influence of dimensional parameters on the vertex space. © 1994 John Wiley & Sons, Inc.
Robot guidance using ultrasonic arrays
Authors: Webb P. , Gibson I. , Wykes C. 
Published: July 2007

AbstractThe flexibility of robots can be considerably increased by having sensors that can detect the location and orientation of the components that are being manipulated by the robots. Vision systems have been widely applied to this problem, but there has been very little reported work on the use of ultrasonic sensors. This article reports the use of novel ultrasonic sensors that have been manufactured in‐house to measure the range and bearing of a target and guide the robot in a pick and place operation. The configuration of the transducer is described as well as the signal processing method employed. Experimental results are given and future developments and applications of the system are described. © 1994 John Wiley & Sons, Inc.
Inverse dynamics of a parallel manipulator
Authors: Pang Hyunsok , Shahinpoor Mohsen 
Published: July 2007

AbstractPresented is an analysis of the kinematics and the inverse dynamics of a proposed three degree of freedom (dof) parallel manipulator resembling the Stewart platform in a general form. In the kinematic analysis, the inverse kinematics, velocity, and acceleration analyses are performed, respectively, using vector analysis and general homogeneous transformations. An algorithm to solve the inverse dynamics of the proposed parallel manipulator is then presented using a Lagrangian technique. In this case, it is found that one should introduce and subsequently eliminate Lagrange multipliers to arrive at the governing equations. Numerical examples are finally carried out to examine the validity of the approach and the accuracy of the numerical technique employed. The trajectory of motion of the manipulator is also performed using a cubic spline. © 1994 John Wiley & Sons, Inc.
Collision avoidance by fuzzy logic control for automated guided vehicle navigation
Authors: Lee Pai‐Shih , Wang Ling‐Ling 
Published: July 2007

AbstractA fuzzy approach to collision avoidance for automated guided vehicle (AGV) navigation is proposed. Static obstacles with no a priori position information as well as moving obstacles with unknown trajectories are considered in this study. Intuitive and subjective human ideas of collision avoidance are modeled into fuzzy rules. Fuzzy logic is applied in the inference procedure for AGV navigation, such that the AGV is guided from the starting point toward the target without colliding with obstacles. Furthermore, the proposed method can also be used for the navigation of multiple AGVs, where each AGV must avoid other AGVs as well as obstacles in the environment. Simulation results are presented to show the feasibility of the proposed fuzzy approach. © 1994 John Wiley & Sons, Inc.
Control of a two‐degree‐of‐freedom lightweight flexible arm with friction in the joints
Authors: Feliu Vincente , Rattan Kuldip S. , Brown H. Benjamin 
Published: July 2007

AbstractThis article describes the design and control of a two‐joint, two‐link flexible arm. This flexible arm was built with very light links, has most of its mass concentrated at the tip and uses a special mechanical configuration to approximately decouple radial tip motions from angular tip motions. The lightweight design and decoupling maximize the efficiency of power transmitted to the load. An important problem when controlling lightweight flexible arms is the large Coulomb friction of the motors. A two‐nested‐loop multivariable controller is used to control the lightweight flexible arm with friction in the joints. The inner loop controls the position of the motors while the outer loop controls the tip position. The resolved acceleration method is generalized to control this flexible arm. The compliance matrix is used to model the oscillations of the structure and is included in the decoupling/linearizing term of this controller. Experimental results are presented. © 1995 John Wiley & Sons, Inc.
Control of a single‐link flexibe manipulator fabricated form composite laminates
Authors: Choi Seung‐Bok , Thompson Brian S. , Gandhi Mukesh V. 
Published: July 2007

AbstractAn experimental investigation on the control performances of a single‐link flexible manipulator fabricated from composite laminates is presented. The dynamic modeling of the flexible manipulator is accomplished by employing Hamilton's principle, prior to developing a finite element formulation. An output feedback controller associated with two collocated angular position and velocity sensors is designed and experimentally implemented. Comparative works are undertaken to demonstrate some of the advantages to be accrued from this proposed methodology. It is shown that the manipulator fabricated from composite laminates has superior performance characteristics, such as smaller tip deflections and a smaller input torque relative to the manipulator fabricated from aluminum. © 1995 John Wiley & Sons, Inc.
Two‐arm kinematic posture optimization for fixtureless assembly
Authors: Ro Paul I. , Lee Byung R. , Seelhammer Mark A. 
Published: July 2007

AbstractThis article focuses on finding optimal kinematic postures for two robot arms performing various assembly tasks without the aid of jigs and fixtures. The goal of the work is to identify the manipulator postures that would result in some optimum kinematic conditions for initiating a typical male‐female assembly. Specifically, the article addresses issues related to the following question: In the absence of preset jigs and fixtures, where are the optimum location in the 3‐dimensional work space and the optimum orientations of the assembly parts (therefore, the postures of the manipulators holding the parts) to perform a fixtureless assembly? First, using velocity and force ellipsoids a performance criterion is developed for the optimal kinematic posture based on constraints that are imposed by the kinematic coupling of the two robot arms as well as the environment. Next, an algorithm based on a null‐space search technique is formulated to “search” for the posture of the two‐arm system that maximizes the performance criterion within the set of postures that satisfy given constraints. Finally, the algorithm is demonstrated numerically for two planar robots performing typical fixtureless assembly operations. ©1995 John Wiley & Sons, Inc.
Control and simulation for a closed‐chain dual redundant ' manipulator system
Authors: Cheng Fan‐Tien , Lee Jou‐Jye , Tsing‐hua  , Kung Chen Fan‐Chu 
Published: July 2007

AbstractThe two‐level hierarchical control scheme is adopted to solve a dual‐chain robotic system formed by two redundant manipulators grasping a common object with hard point contacts. The upper‐level coordinator gathers all the necessary information to resolve the force distribution problem so as to generate all the desired contact forces With all the desired contact forces being specified, the dynamics of each chain are decoupled. Therefore, the lower‐level local control problem can be treated as a general open‐chain redundant manipulator problem. Furthermore, the Compact‐Dual LP method is applied to resolve the upper‐level coordination problem; while the Compact QP method associated with the computed torque control method is adopted to solve the redundant manipulator problem. To obtain proper simulation results, the simulated actual contact forces are formulated and the corresponding simulation problem of the closed‐chain robotic system is also completely solved in the article. Simulation results show that the two‐level hierarchical control scheme is an effective and efficient algorithm for resolving the large‐scale control problem of multiple‐chain robotic systems. © 1995 John Wiley & Sons, Inc.
A fast approach for the robust trajectory planning of redunant robot manipulators
Authors: Mayorga R. V. , Janabi‐sharifi F. , Wong A. K. C. 
Published: July 2007

AbstractIn this article, a fast approach for robust trajectory planning, in the task space, of redundant robot manipulators is presented. The approach is based on combining an original method for obstacle avoidance by the manipulator configuration with the traditional potential field approach for the motion planning of the end‐effector. This novel method is based on formulating an inverse kinematics problem under an inexact context. This procedure permits dealing with the avoidance of obstacles with an appropriate and easy to compute null space vector; whereas the avoidance of singularities is attained by the proper pseudoinverse perturbation. Furthermore, it is also shown that this formulation allows one to deal effectively with the local minimum problem frequently associated with the potential field approaches. The computation of the inverse kinematics problem is accomplished by numerically solving a linear system, which includes the vector for obstacle avoidance and a scheme for the proper pseudoinverse perturbation to deal with the singularities and/or the potential function local minima. These properties make the proposed approach suitable for redundant robots operating in real time in a sensor‐based environment. The developed algorithm is tested on the simulation of a planar redundant manipulator. From the results obtained it is observed that the proposed approach compares favorably with the other approaches that have recently been proposed. © 1995 John Wiley & Sons, Inc.
Deadlock avoidance schemes in a distributed robotic system: Petri net modeling and analysis
Authors: Zhou Mengchu 
Published: July 2007

AbstractThis article presents a Petri net‐based approach to modeling and evaluating four different deadlock avoidance schemes for a distributed robotic system, i.e., a five‐robot‐five‐assembly‐line system. Among these four schemes are the conventional, full synchronization, global semaphore, and partial synchronization schemes. To explore such issues as the system performance and control structure complexity, this article conducts detailed Petri net modeling for this system and evaluates performance of the deadlock avoidance schemes using stochastic Petri nets. The interesting results presented include that: (1) any possible system deadlock can seriously degrade the system performance even if effective deadlock resolution techniques are available; (2) conservative use of resources is likely to be the best policy; and (3) higher resource utilization may not necessarily imply higher system production rate in a resource‐sharing environment. The related results need to be further explored for the larger resource‐sharing discrete event systems. ©1995 John Wiley & Sons, Inc.
Path tracking with the links of a planar hyper‐ redundant robotic manipulator
Authors: Schilling R. J. , Read R. , Lovass‐nagy V. , Walker G. 
Published: July 2007

AbstractA technique for path tracking with the links of a planar hyper‐redundant robotic manipulator is presented. It is a joint‐space trajectory planning method that can be used for obstacle avoidance by ensuring that the links of the manipulator closely follow a collision‐free path planned for the tool. A closed‐form formulation of resolved‐motion rate control equations is developed that decomposes the manipulator into proximal and distal parts. The joint velocities are constrained to ensure that the far distal links remain tangent to the tool path, while the near distal links and the proximal links assume a compressed configuration near the base. Path tracking is illustrated with several examples that examine the effects of controller gain, link length, and number of links. ©1995 John Wiley & Sons, Inc.
Contril of rigid‐link, flexible‐joint robots:a survey of backstepping approaches
Authors: Bridges M. M. , Dawson D. M. , Abdallah C. T. 
Published: July 2007

AbstractThe purpose of this article is to show how the design procedure commonly referred to as integrator backstepping can be used to design globally stable trajectory tracking controllers for Rigid‐Link Flexible‐Joint (RLFJ) robot manipulators. Three different types of controllers are developed: (1) an exact model knowledge‐based controller, (2) an adaptive controller that compensates for parametric uncertainty, and (3) a robust controller that compensates for parametric uncertainty and unknown bounded disturbances. All three controllers are based on previously published work but are presented here in a unifying framework. ©1995 John Wiley & Sons, Inc.
Toeard a formulation of the human grasping quality sense
Authors: Hershkovitz M. , Tasch U. , Teboulle M. 
Published: July 2007

AbstractThis article examines the grasping quality problem and suggests a formulation that can capture the major mechanisms that generate the human grasping quality sense. Here, the quality of a grasp is examined from the gripper, object, and grasping‐configuration perspectives. These perspectives are incorporated into the formulation by selecting an appropriate objective function that is minimized subject to constraints that represent the geometry, friction, and force‐balance conditions of a grasp. The quality of a grasp is depicted as a polar plot that demonstrates the dependency of grasping quality on the external‐loading direction. The suggested grasping quality measures possess characteristics that are in agreement with basic human intuition. In particular this article proves that the three proposed quality measures are improved when the number of contact points is increased. In summary, the suggested grasping quality formulation captures some of the physical mechanisms that characterize a human grasp, and therefore it may lead to a powerful mathematical model of the human grasping quality sense. ©1995 John Wiley & Sons, Inc.
Geometry‐based efficient rata coordination for manipulators with kinematic redundancy
Authors: Hareendra Varma K. R. , Huang Ming Z. 
Published: July 2007

AbstractThe redundancy resolution problem for kinematically redundant serial chain manipulators is addressed. In this article we present a generalization of the geometry‐based rate allocation algorithm, developed initially for only a minimum norm solution, to obtain the optimal joint rate solution for any specified objective function, with or without weightage. This generalization is made possible through a physial interpretation of the common pseudoinverse‐based gradient solution scheme, and by developing a modified formulation for the objective function as a minimum criterion not with respect to the origin of the joint rate space, but with respect to another point in the joint rate space represented by the gradient of the specified objective. Application examples of the algorithm including procedures of solution are demonstrated using 7R manipulators with two generic types of geometry. Moreover, a closed form optimal solution for the class of 7R anthropomorphic arms is also given. ©1995 John Wiley & Sons, Inc.
Joint space trajectory planning for flexible manipulators
Authors: Yao Chih‐Min , Cheng Wen‐Hon 
Published: July 2007

AbstractA trajectory planning approach for controlling flexible manipulators is proposed. It is demonstrated that choosing actual joint angles as the generalized rigid coordinates is the key to applying the proposed approach. From the observation of the special structure of the input matrix, the concepts of motion‐induced vibration and inverse dynamics under a specified motion history of the joints are formed naturally. Based on the above concepts, trajectory planning in joint space is proposed by using the optimization technique to determine the motion of joints along a specified path in joint space or work space and for general point‐to‐point motion. The motion for each joint is assumed to be in a class consisting of a fifth‐order polynomial and a finite terms of Fourier series. This parameterization of motion allows the optimal trajectory planning to be formulated as a standard nonlinear programming problem, which avoids the necessity of solving a two‐point‐boundary‐value problem and using dynamic programming. Setting the accelerations to zero at the initial and the final times is used to obtain smoother motion to reduce the spillover energy into unmodeled high‐frequency dynamics. A penalty term on vibration energy contained in the performance index is used to minimize the vibration of the system modeled by lower frequency only. The final simulation results show the effectiveness of the proposed approach and the advantage for proper trajectory planning. © 2995 John Wiley & Sons, Inc.
Impact reduction for redundant manipulators using augmented impedance control
Authors: Lin Z. C. , Patel R. V. , Balafoutis C. A. 
Published: July 2007

AbstractIn this article, the problem of controlling redundant manipulators to reduce collision impact effects is considered, and an augmented kinematics and impedance control scheme is proposed for its solution. The proposed scheme achieves satisfactory performance by minimizing the magnitudes of impulsive forces as well as reducing rebound effects of the end‐effector. In the proposed control scheme, kinematic redundancy is resolved using an augmented kinematics approach where the augmentation of the Jacobian matrix is based on an impact model derived using the Cartesian‐space dynamic model of the manipulator. The proposed impact controller uses a simplified impedance control scheme aimed at reducing impulsive forces as well as rebound effects. The performance of the proposed controller is illustrated by computer simulations. © 2995 John Wiley & Sons, Inc.
A risc approach to sensing and manipulation
Authors: Canny John F. , Goldberg Kenneth V. 
Published: July 2007

AbstractThis article describes sensing and manipulation strategies that use simple, modular robot hardware. To bridge the gap between automation and robotic technologies, we suggest that traditional automation hardware, such as parallel‐jaw grippers and optical beam sensors, can be combined with geometric planning and sensing algorithms. The resulting systems should be cost‐effective, reliable, and easy to set up and reconfigure. They should also be flexible enough to support small batch sizes and rapid changes in part design needed in forthcoming flexible/agile manufacturing systems. The RISC acronym, borrowed from computer architecture, suggests the parallels between the two technologies. RISC robots perform complex operations by composing simple elements. The elements may be individual light beam sensors, grouped together to form an array for recognition. Or a complex manipulation task may be performed via a sequence of grasp steps by different grippers specialized for acquisition and placement. This article emphasizes three areas: (i) RISC sensing, primarily optical beam sensing, (ii) RISC manipulation using simple parallel‐jaw grippers or minimal configurations of fingers, and (iii) Computer‐aided design of RISC workcells. © 1995 John Wiley & Sons, Inc.
Friction and part curvature in parallel‐ jaw grasping
Authors: Rao Anil S. , Goldberg Kenneth Y. 
Published: July 2007

AbstractWhen grasping a part with a parallel‐jaw gripper, the part will generally rotate due to kinematic constraints. Predicting the part's final orientation is useful for grasping and for planning sequences of gripper motions to orient parts. For a given part geometry, the grasp function maps initial orientations to final orientations. Previously, we studied polygonal and algebraic parts in the absence of friction. This article considers how Coulomb friction affects the grasp function.We consider two models of Coulomb friction. For a deterministic model, we show that the grasp function of any polygonal part can be represented with a piecewise linear function that we call a step‐ramp function. We then show that any step‐ramp function is the grasp function of a curved part operating under zero friction. Both contain ranges of orientations where the part does not rotate when grasped. This yields our primary result, that any part with deterministic friction has equivalent grasp mechanics to a “dual” part under zero friction. We then apply previous results to derive grasp plans that orient parts in the presence of friction. We also give an algorithm for planning under a non‐deterministic model of Coulomb friction, and give bounds on the friction coefficient needed to insure the existence of such plans. © 1995 John Wiley & Sons, Inc.