bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis and design of a robotic distance sensor
Authors: Partaatmadja O. , Benhabib B. , Goldenberg A. A. 
Published: July 2007

AbstractAnalysis and design of a robotic electrooptical distance sensor, based on the phase‐shift measurement of a modulated light intensity, is addressed in this article. The transducer of this sensor employs two light sources (light‐emitting diodes), whose intensities are modulated by different‐phase sine‐wave signals, and one photodiode receiver. The distance of an object's surface with respect to the sensor is measured by investigating the received phase shift. The experimental set‐up of the sensor, used in this research, was designed and manufactured such that various mechanical and electronic design parameters could be investigated independently. Experiments undertaken show that these parameters indeed affect the performance of the sensor. The exemplary optimization analysis carried out considered only two performance aspects of the sensor, namely, sensitivity and operational range, and yielded corresponding optimal design parameters. The optimal distance sensor analyzed illustrated that it has sufficient resolution to be useful for most existing industrial robots.
Synthesis and analysis of a new class of six‐degree‐of‐freedom parallel minimanipulators
Authors: Tsai Lung‐Wen , Tahmasebi Farhad 
Published: July 2007

AbstractA new class of 6‐degree‐of‐freedom (dof) parallel minimanipulators is introduced. The minimanipulators are designed to provide high resolution and high stiffness for fine position and force control in a hybrid serial‐parallel manipulator system. Two‐dof planar linkages and inextensible limbs are used to improve positional resolution and stiffness of the minimanipulators. The 2‐dof linkages serve as drivers for the minimanipulators. The minimanipulators require only three inextensible limbs and, unlike most of the six‐limbed parallel manipulators, their direct kinematics can be reduced to solving a polynomial in a single variable. In addition, by using three limbs instead of six other benefits such as lower possibility of mechanical interference between limbs can be realized. All of the minimanipulator actuators are base‐mounted. As a result, higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. In addition to the design discussion, kinematic analysis of the minimanipulators is also presented. © 1993 John Wiley & Sons, Inc.
Adaptive control of a stewart platform‐based manipulator
Authors: Nguyen Charles C. , Antrazi Sami S. , Zhou Zhen‐Lei , Campbell Charles E. 
Published: July 2007

AbstractThis article presents the implementation of a joint‐space adaptive control scheme used to control noncompliant motion of a Stewart platform‐based manipulator (SPBM) that is used in a facility called the Hardware Real‐Time Emulator (HRTE) developed at Goddard Space Flight Center to emulate space operations. The SPBM is comprised of two platforms and six linear actuators driven by dc motors, and possesses six degrees of freedom. The article briefly reviews the development of the adaptive control scheme, which is composed of proportional‐derivative (PD) controllers whose gains are adjusted by an adaptation law driven by the errors between the desired and actual trajectories of the SPBM actuator lengths. The derivation of the adaptation law is based on the concept of model reference adaptive control (MRAC) and Lyapunov direct method under the assumption that SPBM motion is slow as compared to the controller adaptation rate. An experimental study is conducted to evaluate the performance of the adaptive control scheme implemented to control the SPBM to track a vertical and circular paths under step changes in payload. Experimental results show that the adaptive control scheme provides superior tracking capability as compared to fixed‐gain controllers.
Kinematics and control of a fully parallel force‐reflecting hand controller for manipulator teleoperation
Authors: Bryfogle Mark D. , Nguyen Charles C. , Antrazi Sami S. , Chiou Peter C. 
Published: July 2007

AbstractForce feedback can enhance the efficiency of a teleoperation system by providing the operator with a sense offeelof the forces and torques arising from the interaction of the slave manipulator with the remote environment. This article addresses the kinematic analysis and control of a Parallel FOrce‐Reflecting Hand Controller (PFORHC) whose design and implementation are based on a fully parallel mechanism. Kinematic analysis on the PFORHC is performed and results in a closed‐form solution for the inverse kinematics. The forward kinematics is solved by Newton‐Raphson's method. A fixed‐gain PD control scheme is developed for force feedback control. Experiments are conducted to study the performance of the force‐reflecting capability of the PFORHC. Experimental results show that the force control scheme utilizing a handgrip force sensor provides smaller steady‐state errors as compared to the case utilizing no handgrip force sensor.
Kinematic decoupling in mechanisms and application to a passive hand controller design
Authors: Hayward Vincent , Nemri Chafye , Chen Xianze , Duplat Bertrand 
Published: July 2007

AbstractObservations regarding the kinematics of mechanisms are applied to the synthesis of a passive hand controller. It is argued that stiffness (and damping) properties are central to the effectiveness of such devices and in particular that the simplicity of these properties is crucial. What simple means is analyzed and it is shown that only certain types of manipulators can appropriately be used. In effect, decoupling is shown to be architecture and configuration dependent. The properties of parallel mechanisms are reviewed and found appropriate for restricted‐workspace hand controllers. A particular kinematic design is then derived and a practical implementation described.
Null torque‐based dynamic control for kinematically redundant manipulators
Authors: Chung W. J. , Chung W. K. , Youm Y. 
Published: July 2007

AbstractFor the dynamic control of kinematically redundant manipulators, conventional approaches to local torque minimization have induced physically unachievable joint torques that may exceed the torque limits in the tracing motion of a long end‐effector trajectory. This article presents a new control method for redundant manipulators, named the “Null Torque‐Based Dynamic Control” (NTDC), which can guarantee stability for joint torques. The proposed method resolves the redundancyat the torque level.The command torque induced by the proposed method is composed of two terms: (1) theminimum‐norm torque, which locally minimizes torque loadings at the joints; and (2) thenull torque, which is intermittently added to the minimum‐norm torque according to a kinematic criterion to globally reduce excessively large torque requirements. In particular, the concept of null torque is based on the property offull row‐rank minorsfor a Jacobian matrix—theaspectthat is a function of a manipulator's configuration. The simulation results illustrate that the proposed method is effective for torque optimization when compared with conventional methods.
Tracking control for end‐effector position and orientation of structurally flexible manipulators
Authors: Carusone Joseph , D'Eleuterio Gabriele M. T. 
Published: July 2007

AbstractA simple and effective feedback control strategy is presented for end‐effector position and orientation tracking of structurally flexible manipulators free of external forces as in space applications. The fully feedback‐driven approach employs an augmented dynamical description in which derivatives of the control inputs are included in the state. This ensures smooth control inputs to the manipulator joints. The feedback law uses gain scheduling of a series of steady‐state regulators derived by considering the manipulator at intermediate (nominally rigid and stationary) configurations along the desired trajectory. The performance of the control method is demonstrated in simulations of a planar three‐link manipulator system. Examples show that the controller can be applied successfully in discrete‐time, and that spillover does not appear to be a problem.
The applications of harmonic functions to robotics
Authors: Connolly Christopher I. , Grupen Roderic A. 
Published: July 2007

AbstractHarmonic functions are solutions to Laplace's equation. Such functions can be used to advantage for potential‐field path planning because they do not exhibit spurious local minima. Harmonic functions are shown here to have a number of properties that are essential to robotics applications. Paths derived from harmonic functions are generally smooth. Harmonic functions also offer a complete path‐planning algorithm. We show how a harmonic function can be used as the basis for a reactive admittance control. Such schemes allow incremental updating of the environment model. Methods for computing harmonic functions respond well to sensed changes in the environment, and can be used for control while the environment model is being updated.
Estimate of the two smallest singular values of the Jacobian Matrix: Application to damped least‐squares inverse kinematics
Authors: Chiaverini Stefano 
Published: July 2007

AbstractThe smallest singular value of the Jacobian matrix is known to be the sole reliable measure of closeness to singular configurations; its computation via a full singular value decomposition, however, is demanding in view of real‐time applications. In this article, a standard singular value estimation procedure is extended to improve the handling of singular values crossing along a given trajectory. The proposed algorithm maintains the computational efficiency of the original technique and shows higher estimation accuracy with respect to the original procedure. Case studies are developed to verify the effectiveness of the estimation procedure applied to an industrial manipulator. © 1993 John Wiley & Sons, Inc.
Experimental determination of dynamic parameters of robotic arms
Authors: Lu Ziren , Shimoga Karunakar B. , Goldenberg Andrew A. 
Published: July 2007

AbstractThis article presents a practical method for determining the dynamic parameters of robotic arms. The two unique features of the method are that it determines the friction parameters along with the inertia and mass parameters and that it does not require the measurement of joint accelerations. The method is demonstrated experimentally by determining the dynamic parameters of a closed‐chain direct‐drive arm. The precision of the determined parameter was verified in the context of computed torquebased controllers. Statistical analysis also shows that the estimated values are reliable. © 1993 John Wiley & Sons, Inc.
Stable interaction control and coulomb friction compensation using natural admittance control
Authors: Newman Wyatt S. , Zhang Yuandao 
Published: July 2007

AbstractA new control system design formulation is presented for achieving high‐performance, guaranteed‐stable impedance control. While the bandwidth of the resulting controller is no higher than alternative techniques, the new formulation significantly improves performance when Coulomb friction is present in the system. The technique requires a careful choice of the target impedance. The resulting feedback compensators are causal and have stable poles, although they are often non‐minimum phase. General rules for controller synthesis are derived. Experimental performance results are presented for a two‐mass system with internal compliance and Coulomb friction. Results demonstrate that the technique is successful in rejecting internal friction force disturbances while maintaining a passive driving‐point impedance. © 1994 John Wiley & Sons, Inc.
Minimum effort factor approach for sensor‐based control of a four‐joint 6‐dof redundant manipulator
Authors: Malladi Srinivasa R. , Valavanis Kimon P. , Mulder Michael C. 
Published: July 2007

AbstractA sensor‐driven control model and a minimum effort control algorithm in terms of time and energy expended during the execution of a movement strategy are described and validated for a multijointed cooperating robotic manipulator. Considering smooth, human‐like (anthropomorphic) movements, using joint motion profiles achievable in real time as well as sensory information from all joints, and evaluating the total work expended by each manipulator joint during the execution of a movement strategy, a minimum effort motion trajectory is synthesized to precisely and efficiently position the robotic arm end‐effector. This sensor‐based approach significantly reduces the computational requirements for such cooperative motion. The minimum effort control algorithm generates several human‐like arm movement strategies and selects the best strategy on the basis of expendable effort. The algorithm has an inherent basis to deal with obstacles in an efficient way. Detailed examples are described from the simulation studies. © 1994 John Wiley & Sons, Inc.
Vision‐based path following by using a neural network Guidance System
Authors: Luebbers P. G. , Pandya A. S. 
Published: July 2007

AbstractThis article describes a neural network controller for guidance of a robot arm, used to model some aspects of autonomous vehicle technology. The controller uses video images with adaptive view‐angles for the sensory input, and the system was configured to simulate an autonomous vehicle guidance system on a flat terrain using a high‐contrast guiding path. To demonstrate the feasibility of using neural networks in this type of application, an Intelledex 405 robot fitted with a video camera and associated vision system was used. Phase I of the project consisted of a single‐speed implementation and limited network training. Phase II featured a multi‐speed implementation using adaptively varied view‐angles based on robot arm velocity. It was shown that the neural network controller was able to control the robot arm along a path composed of path segments unlike those with which it was trained. In addition it was shown that a multi‐speed implementation with adaptive view angles improved system performance. © 1994 John Wiley & Sons, Inc.
Design of a robust adaptive control law for robotic manipulators
Authors: Lee Ho‐Hoon , Culick Fred E. C. 
Published: July 2007

AbstractIn this article, a robust adaptive control scheme for robotic manipulators is designed based on the concept of performance index and Lyapunov's second method. Compensators are selected for a given feedback system by using a quadratic performance index. Then the stability of the system is proven based on Lyapunov's method, where a Lyapunov function and its time‐derivative are derived from the selected compensators. In the process of stabilization, stability bounds are obtained for disturbances, control gains, adaptation gains, and desired trajectories, in the presence of feedback delay due to digital computation and first‐order hold in the control loop. © 1994 John Wiley & Sons, Inc.
Torque optimization schemes for kinematically redundant manipulators
Authors: Chen Tsing‐Hua , Cheng Fan‐Tien , Sun York‐Yih , Hung Min‐Hsiung 
Published: July 2007

AbstractOne of the important applications for the resolution of redundant manipulators is torque optimization, due to the fact that the actuators used for driving a manipulator have finite power ratings. Nevertheless, not many algorithms have been proposed to accomplish this objective. A survey of the existing local torque optimization control schemes is given in this article. It will be shown that all of them either encounter instability problems for long trajectories or fail in certain cases. For remedying these problems, the authors present the Minimum Velocity Norm (MVN) method, which is the most common approach for kinematic redundancy resolution and has never been adopted for torque optimization by other researchers. Simulation results show that the simple MVN method is moderate for short movements and is stable for long movements. Also, the MVN method can be applied to cases that may not be accomplished by some other approaches. Therefore, the MVN method is better than the other existing approaches for torque optimization. © 1994 John Wiley & Sons, Inc.
Relation between global velocity and local torque optimization of redundant manipulators
Authors: Hu B. , Teo C. L. , Lee H. P. 
Published: July 2007

AbstractIn this article, the relation between the global optimization of joint velocity and local optimization of joint torque is investigated. The local minimization of the weighted joint torques can be matched to the global optimization of the corresponding weighted joint velocities when the weighted matrices satisfy certain sufficient conditions. A straightforward matching is obtained using the local optimization of the inertia inverse weighted dynamic torque and the global minimization of the kinetic energy. Another easy solution can be found, as will be shown later, if the inertia matrix is a constant and gravity is neglected. Based on that, it can be seen why a Cartesian robot, which has a constant inertia matrix, is always stable. © 1994 John Wiley & Sons, Inc.
Inverse cartesian trajectory control and stabilization of a three‐axis flexible manipulator
Authors: Yim Woosoon 
Published: July 2007

AbstractThis article treats the question of end point trajectory control of a flexible manipulator based on the nonlinear inversion technique. The manipulator has two rigid links and the third link is elastic. A parameterization of the Cartesian coordinates of a point close to the end effector position is suggested. Using these coordinates as output variables, an inverse feedback control law is derived for tracking reference Cartesian trajectories. The stability of the zero dynamics associated with the end point motion control is examined. It is shown that inverse control of the end point causes divergent oscillatory flexible modes. In addition, for regulating the end point to a fixed position, a linear stabilizer is designed to damp the elastic vibration. Simulation results are presented to show that in the closed‐loop system, reference end point trajectories can be accurately followed in spite of the parameter uncertainty in the arm dynamic model. © 1994 John Wiley & Sons, Inc.
Operating robot manipulators through kinematic singularities using a continuously sliding mode control
Authors: Chang Tai‐Heng , Hurmuzlu Yildirim 
Published: July 2007

AbstractPlanning the motion of end‐effectors of robot manipulators can be carried out more directly in the Cartesian space compared to the joint space. Yet, Cartesian paths may include singular configurations where conventional control schemes suffer from excessive joint velocities and loss of tracking accuracy. The difficulties arise because the Jacobian matrix that is used to establish a linear relation between the velocities in the task and joint spaces loses rank at singularities. The problem can be resolved by using a local second‐order approximation of robot kinematics for the joint velocities, which is called Resolved Motion Quadratic Rate Control. In this article, we present a control strategy based on this approach and a recently developed variable structure control scheme. The controller receives Cartesian inputs whenever the manipulator is outside the singular domain. Otherwise, it uses resolved motion quadratic rate control to compute the required joint inputs. Numerical simulation is performed to show that the proposed control scheme provides accurate tracking of the desired motion without inducing excessive control activity when operating robot manipulators through singular configurations. © 1994 John Wiley & Sons, Inc.
A correlation between the state‐space and the task‐oriented path in the presence of obstacles for mechanical manipulators
Authors: Marchis V. , Petrone F. , Sinatra R. 
Published: July 2007

AbstractThis article proposes workspace analysis for redundant robot manipulators in the presence of obstacles. The analysis, based on a 3R planar robot and disk‐shaped obstacles, is considered in detail and a computer program is developed for the calculation of the collision‐free region of redundant robots. The research focuses on the state space of the robot with its end‐effector forced to follow a linear path, with particular consideration of the effects of the link geometries and the location of the obstacles. © 1994 John Wiley & Sons, Inc.
Joint stick‐slip friction compensation of robot manipulators by using smooth robust controllers
Authors: Cai L. , Songag G. 
Published: July 2007

AbstractIn this article, two new smooth robust nonlinear compensators have been developed, respectively, for positional regulation and trajectory tracking of rigid robot manipulators with internal joint stick‐slip friction. The proposed controllers can improve not only the positioning accuracy but also the smoothness of motion. No exact knowledge of the friction models is required for the design of the controllers. Furthermore, the tracking controller is also robust with respect to the uncertain link parameters. Using Lyapunov's direct method, we can show that the time‐invariant positional regulation controller guarantees the global boundedness stability of the closed‐loop system, while the time‐varying positional tracking controller guarantees the global asymptotic stability of the closed‐loop system. The numerical simulations of the controllers on a two‐link robot are presented as illustrations. © 1994 John Wiley & Sons, Inc.
Vsc motion and force control of robot manipulators in the presence of environmental constraint uncertainties
Authors: Yao Bin , Chan S. P. , Wang Danwei 
Published: July 2007

AbstractDue to task kinematic modelling inaccuracy, constraint functions imposed on robot manipulators may not be known exactly. In this article, a variable structure control (VSC) method is developed for robust motion and constrained force control of robot manipulators in the presence of parametric uncertainties, external disturbances, and constraint function uncertainties. The method is based on a particular structure of the constrained robot, in which motion control and force control are treated together. The proposed VSC controller provides the sliding mode and reaching transient response with prescribed qualities. A sufficient condition to guarantee the robot does not lose contact with the constraint surface is given. Detailed simulation results illustrate the proposed method. © 1994 John Wiley & Sons, Inc.
Robustness analysis of a pd controller with approximate gravity compensation for robot manipulator control
Authors: Hsia T. C. 
Published: July 2007

AbstractAsymptotically stable robot manipulator control in both joint space and Cartesian space can be achieved by using a PD controller with gravity torque compensation. However, the stability of this class of control law has not been analyzed with the use of estimated gravity torques. The objective of this article is to present such a stability proof assuming uncertainty in the gravity estimate. The proof is carried out for the Cartesian space controller. The result is supported by computer simulation. © 1994 John Wiley & Sons, Inc.
Mobile robot path planning based on hierarchical hexagonal decomposition and artificial potential fields
Authors: Hou Edwin S. H. , Zheng Dan 
Published: July 2007

AbstractIn this article, a new algorithm based on an artificial potential field and hierarchical cell decomposition technique is developed to solve the find‐path problem for a mobile robot. The complete map of the workspace including obstacle locations is assumed to be known a priori. The basic cell structure used for decomposition is a hexagon. The artificial potential field is based on an attractive force from the goal position and repelling forces from the obstacles. Computer simulations of the algorithm for various obstacle scenarios are also presented. © 1994 John Wiley & Sons, Inc.