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Manipulators
Kinds of Manipulators Terms modified by Manipulators Selected AbstractsOPTIMAL MECHANISM DESIGN AND DYNAMIC ANALYSIS OF A 3-LEG 6-DOF LINEAR MOTOR BASED PARALLEL MANIPULATORASIAN JOURNAL OF CONTROL, Issue 1 2004Thong-Shing Hwang ABSTRACT This paper presents the optimal mechanism design and dynamic analysis of a prototype 3-leg 6-DOF (degree-of-freedom) parallel manipulator. Inverse kinematics, forward kinematics, inverse dynamics and working space characterizing the platform motion are derived. In the presented architecture, the base platform has three linear slideways individually actuated by a synchronous linear servo motor, and each extensible vertical link connecting the upper and base platforms is actuated by an inductive AC servo motor. The linear motors contribute high-speed movements to the upper platform. This kind of architecture using hybrid (linear and AC) motors yields high level performance of motions, especially in the working space. The novel result of maximal working angles is the significant contribution of this architecture. The Taguchi Experimental Method is applied to design the optimal mechanism of the platform system, and the result is used as the actual data to build this system. [source] Position/Force Control of an Underwater Mobile ManipulatorJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 12 2003Lionel Lapierre This paper proposes a new control method applied to an underwater vehicle equipped with a robot manipulator. This control method is based on force control to stabilize the platform when the manipulator works in free or constrained space. The torque produced by the arm on the platform is estimated with a force sensor installed between the base of the manipulator and the vehicle. This allows correcting the position errors of the platform using an external force control loop. This paper presents this control law and shows some simulation results. © 2003 Wiley Periodicals, Inc. [source] A Dynamic Analysis of a Spatial Manipulator to Determine Payload WeightJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 7 2003Carl D. Crane III This paper presents a methodology whereby the payload weight of a serial manipulator can be determined from a minimum set of sensor data, i.e., joint angle and joint torque measurements. The particular manipulator geometry that is analyzed is a four degree-of-freedom serial chain that is commonly used in excavator systems. It was quite remarkable that a relatively simple solution was obtained for the payload weight considering that there are a total of nine unknown moments and cross moments of inertia of the payload together with the unknown location of the center of mass. Example calculations are presented. © 2003 Wiley Periodicals, Inc. [source] Kinematic Calibration and Pose Measurement of a Medical Parallel Manipulator by Optical Position SensorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 4 2003Shaoping Bai In the applications of parallel manipulators, kinematic calibration is required to eliminate the errors resulting from the manufacturing and assembly of both base and tools. In this paper, a calibration method of base and tool transformation is developed by virtue of optical position sensors. An error model for calibration is constructed using differential geometry method. The pose error is obtained based on pose measurement results of OPTOTRAK 3020, a commercial 3D position measurement system. An iterative least squares procedure is used to identify the error parameters in the base and tool transformations. Simulation and experiment results are presented to demonstrate the effectiveness of the method for transformation matrices calibration. © 2003 Wiley Periodicals, Inc. [source] Gain Scheduled LPV H, Control Based on LMI Approach for a Robotic ManipulatorJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 12 2002Zhongwei Yu A new approach to the design of a gain scheduled linear parameter-varying (LPV) H, controller, which places the closed-loop poles in the region that satisfies the specified dynamic response, for an n -joint rigid robotic manipulator, is presented. The nonlinear time-varying robotic manipulator is modeled to be a LPV system with a convex polytopic structure with the use of the LPV convex decomposition technique in a filter introduced. State feedback controllers, which satisfy the H, performance and the closed-loop pole-placement requirements, for each vertex of the convex polyhedron parameter space, are designed with the use of the linear matrix inequality (LMI) approach. Based on these designed feedback controllers for each vertex, a LPV controller with a smaller on-line computation load and a convex polytopic structure is synthesized. Simulation and experiment results verify that the robotic manipulator with the LPV controller always has a good dynamic performance along with the variations of the joint positions. © 2002 Wiley Periodicals, Inc. [source] CAT4 (Cable Actuated Truss,4 Degrees of Freedom): A Novel 4 DOF Cable Actuated Parallel ManipulatorJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 12 2002Craig Kossowski The CAT4 (Cable Actuated Truss,4 degrees of freedom) robot is a novel, passively jointed, parallel robot utilizing six control cables for actuation. The architecture has been under development at the Queen's University Robotics Laboratory. The robot utilizes a passive jointed linkage with 18 revolute joints to constrain the end effector motion and provide the desired structural stability, restricting the end effector to 3 translational degrees of freedom (DOF) and 1 DOF for end effector pitch. This central mechanism together with winched cable actuation gives a number of important benefits for applications where the advantages of a parallel robot are required in conjunction with light weight. Six electric motor driven winches control the length of the cable actuators that extend from the top frame to points on the end effector raft and jointed linkage to create a stiff, but lightweight, actuated robot. Simulation work on the robot is presented giving the kinematics, including a computational estimate of the workspace for a specific configuration. Results of computational simulation of the motion of the manipulator and a discussion of the advantages and potential difficulties are also presented. © 2002 Wiley Periodicals, Inc. [source] Robust Tracking Control For A Wheeled Mobile Manipulator With Dual Arms Using Hybrid Sliding-Mode Neural NetworkASIAN JOURNAL OF CONTROL, Issue 4 2007Ching-Chih Tsai ABSTRACT In this paper, a robust tracking controller is proposed for the trajectory tracking problem of a dual-arm wheeled mobile manipulator subject to some modeling uncertainties and external disturbances. Based on backstepping techniques, the design procedure is divided into two levels. In the kinematic level, the auxiliary velocity commands for each subsystem are first presented. A sliding-mode equivalent controller, composed of neural network control, robust scheme and proportional control, is constructed in the dynamic level to deal with the dynamic effect. To deal with inadequate modeling and parameter uncertainties, the neural network controller is used to mimic the sliding-mode equivalent control law; the robust controller is designed to compensate for the approximation error and to incorporate the system dynamics into the sliding manifold. The proportional controller is added to improve the system's transient performance, which may be degraded by the neural network's random initialization. All the parameter adjustment rules for the proposed controller are derived from the Lyapunov stability theory and e-modification such that uniform ultimate boundedness (UUB) can be assured. A comparative simulation study with different controllers is included to illustrate the effectiveness of the proposed method. [source] The RUMI manipulator and Koh colpotomiser system for total laparoscopic hysterectomyBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 2 2000Remon Keriakos Senior Registrar The initial experience in 25 patients of using the Koh Colpotomiser System in conjunction with the RUMI Manipulator, a new modified technique for performing total laparoscopic hysterectomy, is presented. Of 25 operations, 23 (92%) were completed successfully. Complications were limited to minor pre-operative haemorrhage in two patients and post-operative bleeding in another. The Koh Colpotomiser System successfully maintained a pneumoperitoneum following colpotomy, giving the operator improved visibility and access to the pelvic organs. This resulted in greater efficiency, while eliminating the difficulties of vaginal access. [source] Optimal Control of Rigid-Link Manipulators by Indirect MethodsGAMM - MITTEILUNGEN, Issue 1 2008Rainer Callies Abstract The present paper is a survey and research paper on the treatment of optimal control problems of rigid-link manipulators by indirect methods. Maximum Principle based approaches provide an excellent tool to calculate optimal reference trajectories for multi-link manipulators with high accuracy. Their major drawback was the need to explicitly formulate the complicated system of adjoint differential equations and to apply the full apparatus of optimal control theory. This is necessary in order to convert the optimal control problem into a piecewise defined, nonlinear multi-point boundary value problem. An accurate and efficient access to first- and higher-order derivatives is crucial. The approach described in this paper allows it to generate all the derivative information recursively and simultaneously with the recursive formulation of the equations of motion. Nonlinear state and control constraints are treated without any simplifications by transforming them into sequences of systems of linear equations. By these means, the modeling of the complete optimal control problem and the accompanying boundary value problem is automated to a great extent. The fast numerical solution is by the advanced multiple shooting method JANUS. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] NURBS to Avoid Boundary Orientation Poses in Serial ManipulatorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 12 2003Andrzej J. Cebula A procedure to build NURBS motion interpolants to avoid boundary orientation poses for serial manipulator architectures is presented. As an example, the PUMA architecture was used. The procedure, which emerged from B-spline curves theory, enables a local change of the NURBS motion interpolant. The change may be introduced in any arbitrary neighborhood of the chosen boundary orientation pose. Therefore, when tracking a trajectory, one may change NURBS motion interpolant value at any time instant, leaving its remaining values untouched. Recommendation for further research pertains to exploiting the flexibility of NURBS applied to robot kinematics. © 2003 Wiley Periodicals, Inc. [source] Force Transmissibility Performance of Parallel ManipulatorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 11 2003Wen-Tung Chang In this paper, a new force transmission index called the mean force transmission index (MFTI) is proposed, and the force transmissibility analysis procedure is established for parallel manipulators. The MFTI is an extended definition of the force transmission index (FTI) introduced by the authors previously. It is shown that the FTI is a function of the input velocity ratio (IVR) for a multi-DOF mechanism of the same configuration. To represent the force transmissibility by a definite value, the MFTI is defined as the mean value of the normalized FTIs function over the whole range of the IVR. The force transmissibility analysis of two planar parallel manipulators is illustrated using the MFTI method. The result is compared with that of the Jacobian matrix method and the joint force index (JFI) method. It shows that, especially for symmetric parallel manipulators, an approximate inverse-proportionality relationship exists between the JFI and MFTI, and between the maximum input torque/force and MFTI. It is concluded that the MFTI can be used as a quantitative measure of the force transmissibility performance for parallel manipulators. In the end, a design optimization problem is studied by taking the global force transmission index as the objective function. © 2003 Wiley Periodicals, Inc. [source] Pose Optimization of Serial Manipulators Using Knowledge of Their Velocity-Degenerate (Singular) ConfigurationsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 5 2003Scott B. Nokleby This work investigates the exploitation of velocity-degenerate configurations to optimize the pose of either nonredundant or redundant serial manipulators to sustain desired wrenches. An algorithm is developed that determines a desirable start point for the optimization of a serial manipulator's pose. The start-point algorithm (SPA) uses analytical expressions of the velocity-degenerate (singular) configurations of a serial manipulator to determine a pose that would be best suitable to sustain a desired wrench. Results for an example redundant serial manipulator are presented. The example results show that by using the SPA with the optimization routine, the resulting poses obtained require less effort from the actuators when compared to the poses obtained without using the SPA. It is shown that when no constraint is imposed on the position of the end-effector, the SPA excels at providing a better solution with less iterations than running the optimization without the SPA. © 2003 Wiley Periodicals, Inc. [source] Inverse Velocity and Singularity Analysis of Low-DOF Serial ManipulatorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 4 2003Yuefa Fang This paper presents a method for exact inverse velocity analysis of low-DOF (degrees of freedom n<6) serial manipulators. For a low-DOF serial manipulator, the number of independently controllable variables in the Cartesian space is equal to the number of joint variables in the joint space, and the remaining 6,n variables are linearly dependent on these independent variables. This paper employs the theory of reciprocal screws to determine a mapping between the independent velocity components in the Cartesian space and the joint rates in the joint space. It is shown that singular conditions of a low-DOF manipulator depend on choice of independent variables. A 5-DOF and a 4-DOF manipulator are analyzed, and a numerical example in which the end effector of a 4-DOF manipulator is commanded to follow a straight line is used to demonstrate the methodology. © 2003 Wiley Periodicals, Inc. [source] Dynamics and Coupling Actuation of Elastic Underactuated ManipulatorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2003Tie Shi Zhao This paper investigates the constraint and coupling characteristics of underactuated manipulators by proposing an elastic model of the manipulator and examining the second order constraint equation. A dynamic model and a coupling constraint equation are developed from a Jacobian matrix and the Newton-Euler formulation. The inertia matrix and the Christoffel tensor are analyzed and decomposed into the part concerning actuated joints and the part concerning passive joints. This decomposition is further extended to the dynamic coupling equation and generates an actuation coupling matrix and a dynamic coupling tensor. Two new dynamic coupling indices are hence identified. One is related to an actuation input and the other is related to centrifugal and Coriolis forces. The former reveals the dynamic coupling between the input and the acceleration of passive joints and gives the actuation effect on the passive joints. The latter reveals the dynamic coupling between the centrifugal and Coriolis forces and the acceleration of passive joints and provides the centrifugal and Coriolis effect on the acceleration of passive joints. The study reveals the coupling characteristics of an underactuated manipulator. This is then demonstrated in a three-link manipulator and extended to a serial manipulator with passive prismatic joint. © 2003 Wiley Periodicals, Inc. [source] An Adaptive Controller for Two Cooperating Flexible ManipulatorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 1 2003Christopher J. Damaren The control problem for two serial flexible multilink robots which carry a common rigid payload is considered. An adaptive controller with feedback and feedforward elements is presented which can track a prescribed trajectory for the payload with simultaneous vibration suppression when the manipulated payload is sufficiently large. A free load-sharing parameter appears in the passivity-based control law which allows the torque requirement to be shared between the two arms in a largely arbitrary fashion. Simulation results using a complex model are given which demonstrate excellent tracking performance in the face of complete payload uncertainty. © 2003 Wiley Periodicals, Inc. [source] Obstacle Avoidance for Spatial Hyper-Redundant Manipulators Using Harmonic Potential Functions and the Mode Shape TechniqueJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 1 2003F. Fahimi This paper deals with the obstacle avoidance problem for spatial hyper-redundant manipulators in known environments. The manipulator is divided into two sections, a proximal section that has not entered the space among the obstacles and a distal section among the obstacles. Harmonic potential functions are employed to achieve obstacle avoidance for the distal section in three-dimensional space in order to avoid local minima in cluttered environments. A modified panel method is used to generate the potential of any arbitrary shaped obstacle in three-dimensional space. An alternative backbone curve concept and an efficient fitting method are introduced to control the trajectory of proximal links. The fitting method is recursive and avoids the complications involved with solving large systems of nonlinear algebraic equations. The combination of a three-dimensional safe path derived from the harmonic potential field and the backbone curve concept leads to an elegant kinematic control strategy that guarantees obstacle avoidance. © 2003 Wiley Periodicals, Inc. [source] Translational Parallel Manipulators: New ProposalsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 12 2002Raffaele Di Gregorio Translational parallel manipulators are parallel manipulators wherein the end-effector performs only spatial translations. This paper presents a new family of translational parallel manipulators. The manipulators of this family are independent constraint manipulators. They have three limbs that are topologically identical and have no rotation singularity. The limbs of these manipulators feature five one-degree-of-freedom kinematic pairs in series. Four joints are revolute pairs and the remaining one, called T-pair, is a kinematic pair that can be manufactured in different ways. In each limb, three adjacent revolute pairs have parallel axes and the remaining revolute pair has an axis that is not parallel to the axes of the other revolute pairs. The mobility analysis of the manipulators of this new family is addressed by taking into account two different choices for the actuated pairs. One of the results of this analysis is that the geometry of a translational parallel manipulator free from singularities can be defined for a particular choice of the actuated pairs. © 2002 Wiley Periodicals, Inc. [source] A Class of Transpose Jacobian-based NPID Regulators for Robot Manipulators with an Uncertain KinematicsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 11 2002C. Q. Huang Transpose Jacobian-based controllers present an attractive approach to robot set-point control in Cartesian space that derive the end-effector posture to a specified desired position and orientation with neither solving the inverse kinematics nor computing the inverse Jacobian. By a Lyapunov function with virtual artificial potential energy, a class of complete transpose Jacobian-based Nonlinear proportional-integral-derivative regulators is proposed in this paper for robot manipulators with uncertain kinematics on the basis of the set of all continuous differentiable increasing functions. It shows globally asymptotic stability for the result closed-loop system on the condition of suitable feedback gains and suitable parameter selection for the corresponding function set as well as artificial potential function, and only upper bound on Jacobian matrix error and Cartesian dynamics parameters are needed. The existing linear PID (LPID) regulators are the special cases of it. Nevertheless, in the case of LPID regulators, only locally asymptotic stability is guaranteed if the corresponding conditions are satisfied. Simulations demonstrate the result and robustness of transpose Jacobian-based NPID regulators. © 2002 Wiley Periodicals, Inc. [source] Structural Properties of Inertia Matrix and Gravity Vector of Dynamics of Rigid ManipulatorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 11 2002ba Ignacy In this paper, with the use of Euler-Lagrange formalism, it has been proven which joint variables can influence entries of the inertia matrix and the gravity vector of dynamics of a manipulator relative to the kinematic structure of the manipulator. Some formulas, alternative to well-known ones, are presented that allow us to compute the inertia matrix and the gravity vector without using a trace operator. These formulas are computationally inexpensive and provide an inspiration for interesting interpretations. Complexity indices are defined that are able to evaluate the complexity of dynamics of manipulators based on their kinematics. A key role of the accumulated pseudoinertia matrix of the manipulator has been shown. © 2002 Wiley Periodicals, Inc. [source] Indoctrination, Coercion and Freedom of WillPHILOSOPHY AND PHENOMENOLOGICAL RESEARCH, Issue 2 2003GIDEON YAFFE Manipulation by another person often undermines freedom. To explain this, a distinction is drawn between two forms of manipulation: indoctrination is defined as causing another person to respond to reasons in a pattern that serves the manipulator's ends; coercion as supplying another person with reasons that, given the pattern in which he responds to reasons, lead him to act in ways that serve the manipulator's ends. It is argued that both forms of manipulation undermine freedom because manipulators track the compliance of their victims, while neutral causal mechanisms do not. Manipulators see to it that their victims comply even in the face of forces that threaten to derail them from the manipulator's desired course. It is suggested that this has an impact on freedom because part of what we desire in wanting to be free is the availability of forms of life very different from those we actually enjoy. [source] Welding Automation in Space-Frame Bridge ConstructionCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 3 2001Alistair Greig The SPACES system has been proposed as an alternative for long-span bridge construction. Tubular space frames offer a structurally more efficient solution for bridges, but they have been considered too expensive because the joints at the nodal intersections of the tubular members are difficult and expensive to weld. The benefits of the SPACES system can only be realized by using a computer-integrated construction system to drive down the fabrication costs. A key component of the computer-integrated construction is the robotic welding system. This article describes the development of a lightweight automated welding system for the joining of tubular members. It addresses the geometry of intersecting cylinders and the kinematics and design of a 5-degree-of-freedom manipulator. Summary solutions are given for both. The control software is described briefly, and mention of the welding tests and overall business process is also made. A consortium of U.K. industry and universities is conducting the work. [source] Experiments on stabilizing receding horizon control of a direct drive manipulatorELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 5 2008Yasunori Kawai Abstract In this paper, the application of receding horizon control to a two-link direct drive robot arm is demonstrated. Instead of terminal constraints, a terminal cost on receding horizon control is used to guarantee stability, because of the computational demand. The key idea of this paper is to apply receding horizon control with a terminal cost derived from the energy function of the robot system. The energy function is defined as the control Lyapunov function by considering inverse optimality. In experimental results, stability and performance are compared with respect to the horizon length by applying receding horizon control and inverse optimal control to the robot arm. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(5): 33,40, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10113 [source] Fuzzy sliding-mode control with rule adaptation for nonlinear systemsEXPERT SYSTEMS, Issue 4 2006Lon-Chen Hung Abstract: A fuzzy sliding-mode control with rule adaptation design approach with decoupling method is proposed. It provides a simple way to achieve asymptotic stability by a decoupling method for a class of uncertain nonlinear systems. The adaptive fuzzy sliding-mode control system is composed of a fuzzy controller and a compensation controller. The fuzzy controller is the main rule regulation controller, which is used to approximate an ideal computational controller. The compensation controller is designed to compensate for the difference between the ideal computational controller and the adaptive fuzzy controller. Fuzzy regulation is used as an approximator to identify the uncertainty. The simulation results for two cart,pole systems and a ball,beam system are presented to demonstrate the effectiveness and robustness of the method. In addition, the experimental results for a tunnelling robot manipulator are given to demonstrate the effectiveness of the system. [source] A numerical method for the determination of dextrous workspaces of Gough,Stewart platformsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2001L. J. du Plessis Abstract An optimization approach to the computation of the boundaries of different dextrous workspaces of parallel manipulators is presented. A specific dextrous workspace is the region in space in which, at each position of the working point, a manipulator can control the orientation of its upper working platform through a specified range of orientation angles. Here the dextrous workspace is determined from the intersection of suitably chosen fixed orientation workspaces, which are found by application of a constrained optimization algorithm. The procedure is simple and has the considerable advantage that it may easily be automated. The method is illustrated by its application to both a planar and spatial Gough,Stewart platform. Copyright © 2001 John Wiley & Sons, Ltd. [source] Stochastic stability of a neural-net robot controller subject to signal-dependent noise in the learning ruleINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 6 2010Abraham K. Ishihara Abstract We consider a neural network-based controller for a rigid serial link manipulator with uncertain plant parameters. We assume that the training signal to the network is corrupted by signal-dependent noise. A radial basis function network is utilized in the feedforward control to approximate the unknown inverse dynamics. The weights are adaptively adjusted according to a gradient descent plus a regulation term (Narendra's e -modification). We prove a theorem that extends the Yoshizawa D-boundedness results to the stochastic setting. As in the deterministic setting, this result is particularly useful for neural network robot control when there exists bounded torque disturbances and neural net approximation errors over a known compact set. Using this result, we establish bounds on the feedback gains and learning rate parameters that guarantee the origin of the closed-loop system is semi-globally, uniformly bounded in expected value. Copyright © 2009 John Wiley & Sons, Ltd. [source] Robust adaptive fuzzy semi-decentralized control for a class of large-scale nonlinear systems using input,output linearization conceptINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2010H. Yousef Abstract Stable direct and indirect adaptive fuzzy controllers based on input,output linearization concept are presented for a class of interconnected nonlinear systems with unknown nonlinear subsystems and interconnections. The interconnected nonlinear systems are represented not only in the canonical forms as in Yousef et al. (Int. J. Robust Nonlinear Control 2006; 16: 687,708) but also in the general forms. Hybrid adaptive fuzzy robust tracking control schemes that are based on a combination of an H, tracking theory and fuzzy control design are developed. In the proposed control schemes, all the states and signals are bounded and an H, tracking control performance is guaranteed without imposing any constraints or assumptions about the interconnections. Extensive simulation on the tracking of a two-link rigid robot manipulator and a numerical example verify the effectiveness of the proposed algorithms. Copyright © 2009 John Wiley & Sons, Ltd. [source] Agricultural robot for radicchio harvestingJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 6-7 2006Mario M. Foglia In the last few years, robotics has been increasingly adopted in agriculture to improve productivity and efficiency. This paper presents recent and current work at the Politecnico of Bari, in collaboration with the University of Lecce, in the field of agriculture robotics. A cost effective robotic arm is introduced for the harvesting of radicchio, which employs visual localization of the plants in the field. The proposed harvester is composed of a double four-bar linkage manipulator and a special gripper, which fulfills the requirement for a plant cut approximately 10 mm underground. Both manipulator and end-effector are pneumatically actuated, and the gripper works with flexible pneumatic muscles. The system employs computer vision to localize the plants in the field based on intelligent color filtering and morphological operations; we call this algorithm the radicchio visual localization (RVL). Details are provided for the functional and executive design of the robotic arm and its control system. Experimental results are discussed; obtained with a prototype operating in a laboratory testbed showing the feasibility of the system in localizing and harvesting radicchio plants. The performance of the RVL is analyzed in terms of accuracy, robustness to noises, and variations in lighting, and is also validated in field experiments. © 2006 Wiley Periodicals, Inc. [source] A multidegree-of-freedom manipulator for curtain-wall installationJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 5 2006Chang Soo Han Recently, the trend in architectural forms has been towards larger and taller buildings. Building materials are, therefore, also becoming larger and heavier. Typical construction machineries are not adequate for handling such materials, and most construction works are still managed by a human operator. Construction processes are, therefore, fraught with a number of problems, including frequent accidents, high construction cost, and heterogeneous construction quality depending on the experience of the workers. Automation has been introduced at various sites to address these construction problems. In this paper, the process of a curtain-wall installation in a skyscraper is analyzed, and the prototype of a construction robot for curtain-wall installation (CRCWI) is proposed. Use of the proposed CRCWI can reduce the need for manpower and the construction period and cost, and can assure safety in the curtain-wall construction site. The performance of the proposed CRCWI was verified with a real application test in a skyscraper construction site. © 2006 Wiley Periodicals, Inc. [source] A collision-avoidance scheme for redundant manipulators: Theory and experimentsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 12 2005R. V. Patel The development of a collision- and self-collision-avoidance scheme for redundant manipulators is discussed in this paper. The method is based on modeling the arm and its environment by simple geometric primitives (cylinders and spheres). A compact method of detecting collisions between two cylinders is introduced. By resorting to the notions of dual angles and dual vectors for representing the axes of cylinders in space, a characterization of different types of collisions is introduced. The performance of the proposed scheme is demonstrated for a seven degrees-of-freedom redundant manipulator via simulations and experiments. © 2005 Wiley Periodicals, Inc. [source] Fuzzy control of robot manipulator with a flexible toolJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 7 2005Aria Alasty In some tasks, a rigid robot manipulator handles a long, slender, and flexible tool, which usually has not been equipped with vibration measuring devices. This situation makes a different tool tip position control problem. In this paper, a new method will be presented for simultaneous tip position and vibration suppression control of a flexible tool on a rigid-link 3-DOF robot. This approach uses fuzzy logic rule-based controllers without using any sensors and actuators on the tool or a priori knowledge about the tool. Numerical simulation of robot and tool set has been accomplished and results support the fact that designed fuzzy controllers perform remarkably well in reducing vibrations and precision guidance of robot tool tip for tracking various trajectories. © 2005 Wiley Periodicals, Inc. [source] | |||||||||||||