bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inverse kinematics and inverse dynamics for control of a biped walking machine
Authors: Shih Ching‐Long , Gruver William A. , Lee Tsu‐Tian 
Published: July 2007

AbstractAnalytical techniques are presented for the motion planning and control of a 12 degree‐of‐freedom biped walking machine. From the Newton‐Euler equations, joint torques are obtained in terms of joint trajectories, and the inverse dynamics are developed for both the single‐support and double‐support cases. Physical admissibility of the biped trajectory is characterized in terms of the equivalent force‐moment and zero‐moment point. This methodology has been used to obtain reference inputs and implement the feedforward control of walking robots. A simulation example illustrates the application of the techniques to plan the forward‐walking trajectory of the biped robot. The implementation of a prototype mechanism and controller is also described.
Geometric analysis of antagonistic stiffness in redundantly actuated parallel mechanisms
Authors: Yi Byung‐Ju , Freeman Robert A. 
Published: July 2007

AbstractParallel closed‐chain mechanical architectures allow for redundant actuation in the force domain. Antagonistic actuation, afforded by this input force redundancy, in conjunction with nonlinear linkage geometry creates an effective stiffness directly analogous to that of a wound metal spring. A general stiffness model for such systems is derived and it is shown that the constitutive relationship between actuation effort and active stiffness is the second‐order kinematic constraint set relating the actuation sites. The extent of stiffness modulation possible is then evaluated and necessary conditions for full stiffness modulation are obtained. Configuration‐dependent, second‐order, geometric singularities affecting stiffness generation are illustrated in terms of a three‐degree‐of‐freedom parallel spherical mechanism example and discussed in relation to their more commonly investigated first‐order counterparts that affect force and velocity transmission. Finally, a load distribution methodology for simultaneous motion and stiffness generation is introduced, and it is shown that with hyperredundant actuation the internal load state of the mechanism can be controlled independent of its motion and effective stiffness. © 1993 John Wiley & Sons, Inc.
A linear complementarity approach to the articulated multifingered friction gripper
Authors: Ai‐Fahed A. M. , Panagiotopoulos P. D. 
Published: July 2007

AbstractIn this article, the problem of grasping by an articulated multifingered gripper is investigated. The fingers' joints are idealized by angular and linear springs for the revolute and prismatic joints, respectively. The method, which was developed here, considers the cases of both hard and soft fingers. The unilateral frictional contact problem for the gripper‐object system is formulated as a linear complementarity problem. Numerical examples illustrating the theory are given.
Suboptimal Robot Joint Interpolation Within User‐Specified Knot Tolerances
Authors: Simon Dan , Isik Can 
Published: July 2007

AbstractApproximation of a desired robot path can be accomplished by interpolating a curve through a sequence of joint‐space knots. A smooth interpolated trajectory can be realized by using trigonometric splines. But, sometimes the joint trajectory is not required to exactly pass through the given knots. The knots may rather be centers of tolerances near which the trajectory is required to pass. In this article, we optimize trigonometric splines through a given set of knots subject to user‐specified knot tolerances. The contribution of this article is the straightforward way in which intermediate constraints (i.e., knot angles) are incorporated into the parameter optimization problem. Another contribution is the exploitation of the decoupled nature of trigonometric splines to reduce the computational expense of the problem. The additional freedom of varying the knot angles results in a lower objective function and a higher computational expense compared to the case in which the knot angles are constrained to exact values. The specific objective functions considered are minimum jerk and minimum torque. In the minimum jerk case, the optimization problem reduces to a quadratic programming problem. Simulation results for a two‐link manipulator are presented to support the results of this article.
Force‐closed grasping with two hands
Authors: Caraza José‐Antonio N. , Yun Xiaoping 
Published: July 2007

AbstractTwo‐handed grasping of rigid objects in two‐dimensional space is studied. The hands considered in this article are either flat‐surface palms or grippers with two angular‐motion fingers. Presented in this article is a condition that establishes the existence of force‐closed grasping without the knowledge of the shape of the grasped object and of the exact contact locations on the palms or fingers. Further, an algorithm is developed that determines force‐closed grasping based on the position and orientation of the two hands.
Set point trajectory and internal force control in redundant dual‐arm manipulation
Authors: Jankowski Krzysztof P. , Eimaraghy Waguih H. , Eimaraghy Hoda A. 
Published: July 2007

AbstractA nonlinear decoupling and linearizing feedback control is considered for dynamic coordination of two planar robot arms manipulating an object. A general inverse dynamics‐based method is presented that assures an exact feedback linearization for simultaneous control of the object trajectory on the plane and internal efforts transmitted from the robot end‐effectors to the object. The method takes the manipulator dynamics and object dynamics into consideration. A method for parameterizing the grip matrix null space is proposed, which has formed a basis for developing a new method for calculating the internal efforts. The procedure is invariant with respect to the change of the torque origin and units of length, and provides the force distribution without internal squeezing effects. A comparison between the approaches known so far and the new method is presented. No previously published method assures noninvariance and nonsqueezing properties for all possible contact configurations. Control algorithms are developed for a system of robotic arms that has more degrees of freedom than necessary for given tasks, exhibiting both actuation and kinematic redundancy. The implementation of this method is demonstrated for the case of a system of two planar three‐link arms with the end‐effectors manipulating an object, with different constrained task configurations. Practical aspects of discrete‐time inverse dynamics control, such as influence of the computational time delay and robustness to model imperfections, are discussed. It is demonstrated that it is possible to achieve high‐precision tracking of object position and internal force profiles, even if a system imperfect model is used for controller design. © 1993 John Wiley & Sons, Inc.
Dynamics modeling of robotic manipulators using an artificial neural network
Authors: Eskandarian Azim , Bedewi Nabih E. , Kramer Bruce M. , Barbera Anthony J. 
Published: July 2007

AbstractDynamics modeling is important for the design, analysis, simulation, and control of robotic and other computer‐controlled mechanical systems. The complete dynamic modeling of such systems involves the computationally intensive solution of a set of non‐linear, coupled differential equations. Artificial neural networks are well suited for this application due to their ability to represent complex functions and, potentially, to operate in real time. The application of an artificial neural network to dynamics modeling of robotic systems is investigated. The Cerebellar Model Arithmetic Computer (CMAC) is employed. A hybrid implementation of CMAC is proposed to allow use of the model for either simulation or control of robotic manipulators. The success of the simulated results and the accuracy of the generated outputs after a few training cycles demonstrate great promise for further development of the method and its implementation in control systems. © 1994 John Wiley & Sons, Inc.
Sensory guidance of seam tracking robots
Authors: Bahr Behnam , Haung J. T. , Ehmann K. F. 
Published: July 2007

AbstractThe primary goal of a seam tracking robot, based on sensory feedback, is to maintain a prescribed relationship between the end effector and the workpiece throughout the whole motion of the manipulator along the nominal path. The purpose of this article is to present the essential conceptual and theoretical features of a high‐speed seam tracking controller for sealant application. The general system configuration is discussed, followed by a brief account of the key aspects involved with the sensing of the seam location and subsequent correction command generation for the guidance of the robot. The theoretical considerations are followed by a detailed account of the physical implementation of the proposed system, with performance evaluation data obtained under actual working conditions. © 1994 John Wiley & Sons, Inc.
Learning control based on local linearization by using DFT
Authors: Manabe Tetsuya , Miyazaki Fumio 
Published: July 2007

AbstractLearning control is one of the most interesting subjects in robotics field, and several works on this topic were extensively investigated. Learning control is necessary for high‐speed and high‐precision trajectory control in cases where an objective system includes uncertain parameters and/or has practical limitations on the feedback control. Conventional learning control methods, however, have a problem concerning how to determine a learning operator that guarantees the convergence of the scheme without a priori knowledge of an objective system. For instance, designing learning controllers that will work for complex robot systems, such as pneumatic robots with complicated dynamics or robots with complex sensory feedback, is extremely difficult.This article provides a new type of learning control scheme for a class of discrete‐time nonlinear systems. The algorithm of proposed learning control utilizes local linearization techniques by usingDiscrete Fourier Transform(DFT) to design the learning operator and the numerical function iterative techniques. In our case, thesecant methodis used, which can find the bestlearning operatorby itself at each learning step, in other words, at each calculation step of iteration. This proposed learning algorithm has been extensively tested by simulation on the computer. © 1994 John Wiley & Sons, Inc.
Robot calibration by mobile camera systems
Authors: Zhuang Hanqi , Roth Zvi S. , Wang Kuanchih 
Published: July 2007

AbstractA measurement technique for kinematic calibration of robot manipulators, which uses a stereo hand‐eye system with moving camera coordinates, is presented in this article. The calibration system consists of a pair of cameras rigidly mounted on the robot end‐effector, a camera calibration board, and a robot calibration fixture. The stereo cameras are precalibrated using the camera calibration board so that the 3D coordinates of any object point seen by the stereo cameras can be computed with respect to the camera coordinate frame [C] defined by the calibration board. Because [C] is fixed with respect to the tool frame [T] of the robot, it moves with the robot hand from one calibration measurement configuration to another. On each face of the robot calibration fixture that defines the world coordinate frame [W], there are evenly spaced dot patterns of uniform shape. Each pattern defines a coordinate frame [Ei], whose pose is known in [W]. The dot pattern is designed in such a way that from a pair of images of the pattern, the pose of [Ei] can be estimated with respect to [C] in each robot calibration measurement. By that means the pose of [C] becomes known in [W] at each robot measurement configuration. For a sufficient number of measurement configurations, the homogeneous transformation from [W] to [C] (or equivalently to [T]), and thus the link parameters of the robot, can be identified using the least‐squares techniques. Because the cameras perform local measurements only, the field‐of‐view of the camera system can be as small as 50 × 50 mm2, resulting in an overall accuracy of the measurement system as high as 0.05 mm. This is at least 20 times better than the accuracy provided by vision‐based measurement systems with a fixed camera coordinate frame using common off‐the‐shelf cameras. © 1994 John Wiley & Sons, Inc.
Feedback control of decoupled bending and torsional vibrations of flexible beams
Authors: Matsuno Fumitoshi , Murachi Toshihiko , Sakawa Yoshiyuki 
Published: July 2007

AbstractIn this article, we consider a flexible beam with a rigid body, of which the bending vibration and the torsional vibration are decoupled. Therefore we need two control motors to suppress the vibrations. Each set of dynamic equations is treated in the form of an appropriate Hilbert space. A stabilizing feedback control law of each rotation motor will be established on the basis of modal analysis. A set of experiments has been carried out, and the results demonstrate the effectiveness of the dynamic model and the proposed control law. © 1994 John Wiley & Sons, Inc.
Decentralized adaptive control of manipulators
Authors: Colbaugh Richard , Seraji Homayoun , Glass Kristin 
Published: July 2007

AbstractThis article presents two new adaptive schemes for motion control of robot manipulators. The first controller possesses a partially decentralized structure in which the control input for each task variable is computed based on information concerning only that variable and on two “scaling factors” that depend on the other task variables. The need for these scaling factors is eliminated in the second controller by exploiting the underlying topology of the robot configuration space, and this refinement permits the development of a completely decentralized adaptive control strategy. The proposed controllers are computationally efficient, do not require knowledge of either the mathematical model or the parameter values of the robot dynamics, and are shown to be globally stable in the presence of bounded disturbances. Furthermore, the control strategies are general and can be implemented for either position regulation or trajectory tracking in joint‐space or task‐space. Computer simulation results are given for a PUMA 762 manipulator, and these demonstrate that accurate and robust trajectory tracking is achievable using the proposed controllers. Experimental results are presented for a PUMA 560 manipulator and confirm that the proposed schemes provide simple and effective real‐time controllers for accomplishing high‐performance trajectory tracking. © 1994 John Wiley & Sons, Inc.
Stability and traction control of an actively actuated micro‐rover
Authors: Sreenivasan S. V. , Wilcox B. H. 
Published: July 2007

AbstractThis article addresses the issue of enhancing mobility of actively actuated vehicles by the use of optimal force distribution, and by actively controlling the location of the center of mass of the vehicle body. Force distribution in actively actuated vehicles is an underspecified problem, and optimal force distribution leads to improved contact conditions. Actively actuated vehicles also possess the ability to vary their configuration. This capability can be used to locate the center of mass of the system to further enhance mobility by providing sufficient traction, and ensuring vehicle stability, during difficult vehicle maneuvers. In this work, the general idea of control of the location of the center of mass, followed by optimal force distribution, is addressed first. This is followed by an application of these ideas to Gofor, a simple actively actuated wheeled micro‐rover system, that has been designed and fabricated at the Jet Propulsion Laboratory. An algorithm to achieve desired traction and stability has been developed. Simulation studies were performed to investigate negotiation of a vertical surface. It was found that one set of wheels readily climbed the vertical surface with the use of active mass and force distribution. This is a significant improvement over traditional wheeled vehicle systems. © 1994 John Wiley & Sons, Inc.
The dynamic effects and compensation of load transitions in robotic systems
Authors: Song Y. D. , Anderson J. N. 
Published: July 2007

AbstractThe problem of a robot handling a payload typically involves pre‐load, load, and post‐load stages, and payload transitions between these stages. Although considerable work has focused on the control of robots carrying payloads, few consider the problem of load transitions—one of the most important effects on system performance. This article studies these transitions and presents a compensation method. It is shown that load transitions lead to abrupt (jump) parameters and uncertain transition times in the robot/payload model. A control strategy is proposed that takes the load transitions into account and guarantees the stable path tracking of robots in the face of these transitions. The effectiveness of the proposed control strategy is verified via simulation. © 1994 John Wiley & Sons, Inc.
Unconstrained and constrained motion control of a planar two‐link structurally flexible robotic manipulator
Authors: Choi B.‐O. , Krishnamurthy K. 
Published: July 2007

AbstractUnconstrained and constrained motion control of a planar two‐link structurally‐flexible robotic manipulator are considered in this study. The dynamic model is obtained by using the extended Hamilton's principle and the Galerkin criterion. A method is presented to obtain the linearized equations of motion in Cartesian space for use in designing the control system. The approach to solving the control problem is to use feedforward and feedback control torques. The feedforward torques maneuver the flexible manipulator along a nominal trajectory and the feedback torques minimize any deviations from the nominal trajectory. The feedforward and feedback torques are obtained by solving the inverse dynamics problem for the rigid manipulator and designing linear quadratic Gaussian with loop transfer recovery (LQG/LTR) compensators, respectively. The LQG/LTR design methodology is exploited to design a robust feedback control system that can handle modeling errors and sensor noise, and operate on Cartesian space trajectory errors. Computer simulated results are presented for an example planar, two‐link, structurally flexible robotic manipulator. © 1994 John Wiley & Sons, Inc.
No‐overshoot control of robotic manipulators in the presence of obstacles
Authors: Denker A. , Atherton D. P. 
Published: July 2007

AbstractThe long standing problem of guiding robotic manipulators in cluttered workspaces is treated here by a unified approach, taking into account both motion planning and control aspects. Planning the collision‐free operation is based on the notion of roadmaps. To reduce the complexity of the roadmaps, the real problem is approximated by a simplified but still realistic graph structure. Motion planning relies on the robot closely following the defined collison‐free path, so the errors in robot control must be contained within bounded regions. Satisfying this assumption ideally requires no‐overshoot control. Overshooting demands special attention in tasks that require high speed operations of robots in the presence of obstacles. To stabilize at the specified collision‐free trajectory, before going actually beyond it, joint control schemes demand slow movements through a number of intermediate subgoals. This significantly delays the completion of the task. By using ideas from variable structure control (VSC), a control policy is suggested here that switches between PD+ and CEA+ (constant error acceleration) schemes, where the CEA + scheme applies a “constant error acceleration” of the largest possible magnitude in the appropriate direction. The performance of the path planning and the control algorithms is presented through simulations of a four‐link SCARA robot in various cluttered workspaces. © 1994 John Wiley & Sons, Inc.
Closed form solution for the sensor registration problem using only position information
Authors: Ong Liang Eng , Everett Louis J. 
Published: July 2007

AbstractSensors, mounted on the dexterous end of a robot, can be used for feedback control or calibration. When you mount a sensor on a robot it becomes necessary to find the pose (orientation and position) of the sensor relative to the robot. This is the sensor registration problem. Many researchers have provided closed‐form solutions to the sensor registration problem; however, the published solutions apply only to sensors that can measure a complete pose (three positions and three orientations). Many sensors, however, can provide only position information; they cannot measure the orientation of an object. This article provides a closed‐form solution to the sensor registration problem applicable when: (1) the sensor can provide only position information and (2) the robot can move along and rotate about straight lines. © 1994 John Wiley & Sons, Inc.
Compliance control safety: An architecture‐independent analysis
Authors: Lawrence Dale A. , Chapel Jim D. 
Published: July 2007

AbstractSafe manipulator/task interaction is defined and quantified based on interaction forces resulting from manipulator motion commands.H1andH***safety bounds are introduced for evaluation of compliance control designs deriving from any control architecture or design method. Compliance control design examples are presented to demonstrate the use of these bounds, and to demonstrate the need to consider safety bounds of the type proposed. © 1994 John Wiley & Sons, Inc.
Fuzzy logic and position sensing for precision assembly
Authors: Gürocak H. B. , De A. , Lazaro Sam 
Published: July 2007

AbstractThe problem of part mating and assembly with close tolerances has been addressed in the past by active or passive compliance and by force/position control. With ambient sensor and transmission noise and with imprecise measurements it is often difficult to attain high precision in manipulator positioning. In this article, a position‐sensing wrist using simple strain gauges is described. A fuzzy logic algorithm to ascertain the positional error during an unsuccessful assembly attempt is explained. The results obtained by using this wrist and the fuzzy logic algorithm to reposition a manipulator for precision assembly are presented and discussed. © 1995 John Wiley & Sons, Inc.
Optimal assignment of robot tasks with precedence for muliti‐robot coordination by disjunctive graphs and state‐space search
Authors: Lin Chi‐Fang , Tsai Wen‐Hsiang 
Published: July 2007

AbstractAn approach to optimal assignment of tasks with precedence relationships to multiple robots is proposed. The robots are assumed to share a common workspace and work cooperatively to accomplish a given process plan consisting of a set of tasks. The optimal task assignment is defined to be the one that results in spending the least amount of time to complete the plan under the criterion that no robot collision will occur when the assigned tasks are performed. The ordering of the tasks in the process plan is described by a topological tree, which is then expanded to form a larger state‐space tree without redundant tree paths. Each path in the expanded tree represents a partially developed assignment of the tasks to the robots, and a graph formulation scheme is presented for estimating the cost of the assignment. A collision‐free motion schedule for each robot based on each task assignment can be obtained by finding the minimaximal path in a disjunctive graph formulated by the scheme. By using the A* algorithm, a search method for finding the optimal assignment with the minimum cost is presented. Some heuristic rules are also proposed to speed up the search process. Simulation results are illustrated to show the effectiveness of the proposed approach. © 1995 John Wiley & Sons, Inc.