bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intelligent manipulator system with nonsymmetric and redundant master‐slave
Authors: Sato Katsuhiko , Kimura Motohiko , Abe Akira 
Published: July 2007

AbstractSome work is so complicated and unsteady that it is not possible to use automatic robots, such as FA robots. In such a case, a teleoperated manipulation system is applied. In this research, the authors aim at a reduction in the operator's physical and mental burdens.An artificially intelligent manipulator system has been developed with nonsymmetric and redundant master‐slave. This system has five features: (1) a polar coordinates master arm; (2) a highly operational articulated slave arm with 7 degrees of freedom; (3) a nonsymmetric configuration and different degrees of freedom master‐slave control; (4) an expert system; and (5) a new master‐slave control motion, which makes the operator's task easier with automatic force/position control.The system was experimentally produced and its performance tested and evaluated. A qualitative evaluation was carried out by conducting a comparative test on the conventional master‐slave control and the new master‐slave control. It was found to be effective in reducing operating time, as well as work‐induced fatigue.
Nonlinear ultimate boundedness control and stabilization of a flexible robotic arm
Authors: Nathan P. J. , Singh Sahjendra N. 
Published: July 2007

AbstractWe treat the question of control of an elastic robotic arm of two links. Of course, this approach can be extended to other elastic arms. A nonlinear ultimate boundedness controller (UBC) is synthesized such that in the closed‐loop system the joint angle tracking error is uniformly bounded and tends to a certain small neighborhood of the origin. The controller includes a reference joint angle trajectory generator and integral error feedback. Although the joint angles are controlled using the UBC, elastic modes are excited. A feedback stabilizer is designed for the linearized model including the UBC about the terminal state that is switched only in the vicinity of the equilibrium state for stabilization. Simulation results are presented to show that in the closed‐loop system including the UBC and the stabilizer accurate joint angle trajectory following and elastic mode stabilization are accomplished in the presence of uncertainty.
Accuracy of finite dimensional dynamic models of flexible manipulators for controller design
Authors: Cetinkunt Sabri , Yu Wen‐Lung 
Published: July 2007

AbstractThe dynamics of mechanical systems with distributed flexibility are described by infinite dimensional mathematical models, yet a real controller must be finite dimensional due to the limited bandwidth capabilities of the sensor‐actuator system and real‐time control computer hardware. Therefore, simplified finite dimensional dynamic models must be obtained for the purpose of controller design. This article addresses the issue of selecting the shape and number of mode functions in developing finite order models using a flexible robot arm as an example. The results of this work have consistently shown that the clamped‐free mode shape predicts the closed‐loop system dynamics under a feedback controller much more accurately than pinned‐free mode shapes. However, as the hub inertia increases relative to the flexible beam inertia the difference between the clamped‐free and pinned‐free mode shape model predictions becomes smaller.
Computer generation of symbolic kinematics for robot manipulators
Authors: Mu Eduardo , Cain James T. , Herrera‐Bendezú Luis G. 
Published: July 2007

AbstractComputer generation of symbolic solutions for the direct and inverse robot kinematics is a desired capability not previously available to robotics engineers. In this article, we present a methodology for the design of a software system capable of solving the direct and inverse kinematics forndegree of freedom (dof) manipulators in symbolic form. The inputs to the system are the Denavit‐Hartenberg parameters of the manipulator. The outputs of the system are the direct and inverse kinematics solutions in symbolic form. The system consists of a symbolic processor to perform matrix and algebraic manipulations and an expert system to solve the class of nonlinear equations involved in the solution of the inverse kinematics problem. The system can be used to study robot kinematics configurations whose inverse kinematics solutions are not known to exist a priori. Two examples are included to illustrate its capabilities. The first example provides explicit analytical solutions, previously believed nonexistent, for a 3 dof manipulator. A second example is included for a robot whose inverse kinematics solution requires intensive algebraic manipulations.
Task‐based configuration control of redundant manipulators
Authors: Seraji Homayoun 
Published: July 2007

AbstractThis article establishes new goals for redundancy resolution based on manipulator dynamics and end‐effector characteristics. These goals can be accomplished by employing the recently developed configuration control approach. Redundancy resolution is achieved by controlling the joint inertia matrix or the end‐effector mass matrix that affect the inertial torques or by reducing the joint torques due to gravity loading and payload. The manipulator mechanical advantage and velocity ratio are also used as performance measures to be improved by proper utilization of redundancy. Furthermore, end‐effector compliance, sensitivity, and impulsive force at impact are introduced as redundancy‐resolution criteria. The new goals for redundancy resolution presented in this article allow a more efficient utilization of the redundant joints based on the desired task requirements. Simple case studies using computer simulations are described for illustration.
An identification method for estimating the inertia parameters of a manipulator
Authors: Lin Shir‐Kuan 
Published: July 2007

AbstractThis article presents an off‐line identification method to estimate the minimal knowledge of the inertia parameters for determining the dynamic model of a manipulator. A new approach is proposed to find a set of the minimal knowledge of the inertia parameters. This set is recursively estimated by moving one joint at a time. The off‐line identification procedure also provides a sufficient condition for a persistently exciting trajectory. A simulation example of Stanford arm illustrates the validity and simplicity of the identification procedure.
Feedback control of robot Arm with discrete nonlinear model
Authors: Tarn T. J. , Bejczy A. K. , Ganguly S. 
Published: July 2007

AbstractThis article looks at the problem of controlling a robot arm from a discrete time perspective. We develop the theories and obtain results that feedback linearizes the discrete nonlinear system representing a PUMA 560 robot arm. The effect of sampling on the performance of the arm has been studied and shown through experiments. The results presented here, where the nonlinear robot model has been linearized and controlled completely in discrete time, are new to the robotics literature. We shown certain restrictions necessary on the sampling time of the system. The results obtained have been experimentally verified at the Center for Robotics and Automation at Washington University. Because a number of researchers have addressed the problem of loss of feedback linearizability under sampling, it was important to develop theories and obtain results in discrete time that take into consideration the effects due to sampling. This problem has been addressed here. Analysis of the control law under the assumptions of bounded input is performed and a recursive sensitivity function is derived. The results we obtain in discrete time show the dependency of the performance of the arm on the sampling time. It has been seen that with a higher sampling frequency the performance of the arm substantially improves and it is expected that close to 1000 Hz sampling rate, the peak performance of the PUMA 560 robot arm, will be reached.
Iterative learning control: A survey and new results
Authors: Moore Kevin L. , Dahleh Mohammed , Bhattacharyya S. P. 
Published: July 2007

AbstractLearning control is an iterative approach to the problem of improving transient behavior for processes that are repetitive in nature. In this article, we present some results on iterative learning control. A complete review of the literature is given first. Then, a general formulation of the problem is given. Next, we present a complete analysis of the learning control problem for the case of linear, time‐invariant plants and controllers. This analysis offers: (1) insight into the nature of the solution of the learning control problem by deriving sufficient convergence conditions; (2) an approach to learning control for linear systems based on parameter estimation; and (3) an analysis that shows that for finite‐horizon problems it is possible to design a learning control algorithm that converges, with memory, in one step. Finally, a time‐varying learning controller is given for controlling the trajectory of a nonlinear robot manipulator. A brief simulation example is presented to illustrate the effectiveness of this scheme.
Deformation identification and estimation of one‐dimensional objects by vision sensors
Authors: Chen Chichyang , Zheng Yuan F. 
Published: July 2007

AbstractUsing vision sensors to study object deformation is introduced in this article. The vision sensor is used to identify the deformation characteristic and estimate the deformation behavior of flexible beams. First, a nonlinear equation describing the deformation of the beam is given. Then, cubic spline functions are used to approximate the contour of the deformed beam after the beam is detected by the vision sensor. Using the cubic spline approximation and Maclaurin's series expansion, a procedure to determine the deformation characteristic is formulated. To estimate the deformation behavior, numerical differential method to solve the nonlinear equation is used. The error of this numerical method can be controlled with the aid of the vision sensor. Finally, experimental results are given to verify that the proposed methods are effective.
Frequency domain synthesis of trajectory learning controllers for robot manipulators
Authors: Kavli Tom 
Published: July 2007

AbstractTrajectory learning control is a method for generating near to optimal feedforward control for systems that are controlled along a reference trajectory in repeated cycles. Iterative refinements of a stored feedforward control sequence corresponding to one cycle of the control trajectory is computed based upon the recorded trajectory error from the previous cycle. Several learning operators have been proposed in earlier work, and convergence proofs are developed for certain classes of systems, but no satisfactory method for design and analysis of learning operators under the presence of uncertainties in the system model have been presented. This article presents frequency domain methods for analyzing the convergence properties and performance of the learning controller when the amplitude and phase of the system transfer function is assumed to be within specified windows. Experimental results with an industrial robot manipulator confirm the theoretical results.
Passive ranging using a moving camera
Authors: Shekhar Chandra , Chellappa Rama 
Published: July 2007

AbstractThis article addresses the problem of determining the 3‐dimensional locations of salient points in the environment of a moving camera based on a monocular image sequence obtained by the camera. The camera's translational and rotational velocities are assumed to be known approximately via inertial sensors. The motion of the camera is represented by a constant velocity model. Salient points in the image sequence are extracted using Gabor wavelets and tracked using labeled graph matching. The 3‐D positions of the selected environmental points relative to the camera are then estimated recursively using an extended Kalman filter (EKF), after initialization by two‐frame motion stereo. The motion parameters of the camera are also refined simultaneously. Experimental results on real data are given. © 1992 John Wiley & Sons, Inc.
A systematic method of dynamics for flexible robot manipulators
Authors: Li Chang‐Jin , Sankar T. S. 
Published: July 2007

AbstractIn this article, a systematic method to derive dynamic equations of motion for flexible robot manipulators is developed by using the Lagrangian assumed modes method. The proposed method can be applied to dynamic simulation and control system design for flexible robot manipulators. In the proposed method, the link deflection is described by a truncated modal expansion. The operations of only 3x3 matrices and/or 3 × 1 vectors exist in the method. All the dynamics computations are performed in the link coordinate systems, where the kinematics informations are computed with the forward recursion from the base to the hand tip and the dynamics informations are computed with the return recursion. As generally compared with other existing methods, the method proposed in this article is, computationally, more simple, systematic, and efficient. A computational simulation for a single‐link flexible robot manipulator is presented to verify the proposed method. © 1992 John Wiley & Sons, Inc.
Practical fusion algorithms for rotation matrices: A comparative study
Authors: Zhuang Hanqi , Roth Zvi S. , Sudhakar R. 
Published: July 2007

AbstractMany computer vision, sensor fusion, and robotic applications require the estimation of a 3 × 3 rotation matrix from a set of measured or computed 3 × 3 noisy rotation matrices. This article classifies solution methods into three categories: nonlinear least squares, linear optimal, and linear suboptimal algorithms. Their performance is compared through simulation studies. It is shown that the linear suboptimal algorithms proposed in this article have an accuracy comparable to that of the optimal algorithms and are about five times faster. Furthermore, a particular nonlinear optimization algorithm is presented that has computational complexity similar to that of the linear optimal procedures. © 1992 John Wiley & Sons, Inc.
Analytic minimum‐norm solution for rate coordination in redundant manipulators
Authors: Varma Hareendra , Huang Ming Z. 
Published: July 2007

AbstractIn this article, we present a novel method that results in efficient minimum norm solution for the rate coordination problem in redundant manipulators. The theory is developed based upon a geometric interpretation that, for minimum norm criterion, vectors orthogonal to constraint space should pass through the origin of the solution space. It is shown that, for any spatial manipulator with 1, 2, or 3 degrees of redundancy, the minimum norm rate solution can be derivedin analytic closed form.An example of the analytic formulation is given for a 3R planar case, substantiated with simulation results. The behavior of this algorithm in nonredundant and near singular situations is also discussed. The method offers an equivalent but much more efficient alternative to using the pseudoinverse in redundancy resolution and, in fact, is applicable to any underdetermined linear system. An alternative formulation of pseudoinverse arrived at in the course of the development is also presented. © 1992 John Wiley & Sons, Inc.
Kinematics of automatic guided vehicles with an inclined steering column and an offset distance: criterion for existence of inverse kinematic solution
Authors: Cheng R. M. H. , Rajagopalan Ramesh 
Published: July 2007

AbstractThis article presents the kinematic model of an automatic guided vehicle (AGV) with an inclined steering column and an offset distance. The vehicle configuration considered here employs the front wheel as the driving and steering wheel. From the kinematic model, a criterion is derived to test the existence of inverse kinematic solution. The criterion is a function of the geometric parameters of the AGV and the steering angle of the wheel. From the criterion defined, conditions for the existence of inverse kinematic solution for steering column configurations with and without inclination and offset distance are obtained. The criterion also presents the range of steering angles for which the inverse kinematic solution exists. The criterion signifies the presence of a unique solution for the motion parameters of the wheel, i.e., the wheel speed, steering angle, and steering rate for desired values of the motion parameters of the AGV, i.e., the linear and angular velocities of the AGV. This information is needed for the guidance control of AGVs based upon a kinematic control scheme (dead‐reckoning control) without using the absolute position referencing system to follow a predefined path at prescribed linear and angular velocities. © 1992 John Wiley & Sons, Inc.
Explicit dynamic equations for a chain of flexible links
Authors: Deng Zhongping , Wang Liping 
Published: July 2007

AbstractA D'Alembert‐Lagrangian approach is developed for the dynamics of a chain of flexible links. The governing equations and boundary conditions for each link are derived. While the approach is developed for chains with any numbers of links, the dynamic equations are written explicitly for a chain with two flexible links and a payload. © 1992 John Wiley & Sons, Inc.
Objects interaction using superquadrics for telemanipulation system simulation
Authors: Agba Emmanuel I. , Wong Tin‐Lup , Huang Ming Z. , Clark Andrew M. 
Published: July 2007

AbstractA high‐fidelity “hybrid” telerobotic simulator suitable for telemanipulation rehearsal, supervisory control, operator training, and human factors performance evaluation has been developed. The simulator is capable of operation in the conventional rate‐control, master/slave control, and a data‐driven preprogrammed mode of operation. It has teach/playback capability, which allows an operator to generate joint commands for real‐time teleoperation. For high‐level task execution, the operator selects a specific task from a set of menu options and the simulator automatically generates the required joint commands. In this article, an object detection strategy that has been implemented in the simulator for more realistic telemanipulation is presented. The object detection technique is based on the use of superellipsoids, which have a convenient inside‐outside function for interference testing. The technique, which treats both moving and stationary objects in a consistent manner, has proved to be easy to implement and optimize for real‐time applications. The object detection feature is also used to provide visual feedback as a low‐cost force reflection strategy.
Variable structure trajectory control of an elastic robotic arm
Authors: Madhavan Sethu K. , Singh Sahjendra N. 
Published: July 2007

AbstractThis article introduces a variable structure system scheme to control the end effector trajectory of a two‐link flexible robotic arm. Because control of the actual tip position leads to unstable zero dynamics, control of points in the neighborhood of the tip is considered. An output is chosen as the sum of the joint angle and tip elastic deformation times a constant factor for each link. For the chosen output, a discontinuous output control law is derived based on the variable structure theory. The control law thus derived accomplishes the desired trajectory tracking of the output. A linear stabilizer is designed using the pole assignment technique for the final capture of the terminal state and stabilization of the elastic modes. Simulation results are presented to show that in the closed‐loop system large maneuvers can be performed in the presence of payload uncertainty, thereby exhibiting the robustness of the controller.
A preliminary experiment in dual‐channel tactile information flow
Authors: Taylor R. M. , Kawarizadeh B. , Hemami H. , Boyer K. L. 
Published: July 2007

AbstractRecent developments in theoretical robotics, sensor technology and fusion, and on‐line processing allow for both anthropomorphic behavior on the part of robots, as well as tactile and environmental intelligence. This article considers the feasibility, use, and applications of dual‐channel tactile information flow. In single‐channel systems, the tactile sensors are exclusively mounted on the robot, whereas in dual‐channel systems both the robot and the environment with which it interacts are supplied with sensors. A test bed is described by which a number of single‐ and dual‐channel experiments are carried out. The focus of the dual channel experiments is on its use as this additional channel of sensory perception and on its potential for application in future robotic systems.
Joint trajectory generation for redundant robots in an environment with obstacles
Authors: Guo Z. Y. , Hsia T. C. 
Published: July 2007

AbstractCollision avoidance is an absolutely essential requirement for a robot to complete a task in an environment with obstacles. For kinematically redundant robots, collision avoidance can be achieved by making full use of the redundancy. In this article, the problem of determining collision‐free joint space trajectories for redundant robots in an environment with multiple obstacles is considered, and the “command generator” approach is employed to generate such trajectories. In this approach, a nondifferentiable distance objective function is defined and is guaranteed to increase wherever possible along the trajectory through a vector inN(J), the null space of Jacobian matrixJ.Algorithms that implement this nondifferentiable optimization problem are fully developed. It is shown that the proposed collision‐free trajectory generation scheme is efficient and practical. Extensive simulation results of a four‐link robot example are presented and analyzed.
Null space damping method for local joint torque optimization of redundant manipulators
Authors: Kang Hee‐Jun , Freeman Robert A. 
Published: July 2007

AbstractIn this article, a null space damping method is proposed that solves the stability problem commonly encountered in existing local joint torque optimization techniques applied to redundant manipulators. The damped joint motion is stable and globally outperforms undamped techniques in the sense of torque minimization capability. In addition, simulation results show that the resulting damped joint motion becomes conservative after an initial transient stage for cyclic end‐effector trajectories, while undamped pseudoinverse solutions are reported to never lead to conservative motion. Three undamped and damped joint torque optimization algorithms are considered and discussed with comparison to the previous literature. The effectiveness of the proposed null space damping method is demonstrated by the results of two computer simulations. In addition, the minimization of electrical power consumption is addressed with respect to the results of this article.
Real‐time trajectory generation in multi‐RCCL
Authors: Lloyd John , Hayward Vincent 
Published: July 2007

AbstractThis article describes the design of the trajectory generator for a robot programming system called Multi‐RCCL, which is a package of “C” routines for doing real‐time manipulator control in a UNIX environment. RCCL has been used successfully in developing robot control applications in numerous research and industry facilities over the last several years. One of its strongest features is the ability to integrate real‐time sensor control into the manipulator task specification. RCCL primitives supply the trajectory generator with target points for motions in joint or Cartesian coordinates. Other primitives allow the code developer to specify on‐line functions that can modify the target points, or possibly cancel motion requests, in response to various sensor or control inputs. The design requirements of the trajectory generator are that it be able to integrate these on‐line modifications into the overall robot motion and provide a smooth path between adjacent motions even when sensor inputs make the future trajectory uncertain. © 1993 John Wiley & Sons, Inc.