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Robotics and Automation, IEEE Transactions on

Issue 4 • Date Aug 1991

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Displaying Results 1 - 15 of 15
  • Adaptive force control of single-link mechanism with joint flexibility

    Publication Year: 1991 , Page(s): 540 - 545
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (484 KB)  

    An adaptive force control, scheme is presented that enables a single-link mechanism with joint flexibility to track a desired force trajectory. A dynamic model of the link system is derived, based on which a two-stage controller is constructed. It is shown that although all the system parameters including environment stiffness are unknown except for some of their bounds, all signals inside the closed-loop system remain uniformly bounded. Moreover, the force tracking error is driven to zero asymptotically. Simulation examples are provided to demonstrate the effectiveness of the proposed controller View full abstract»

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  • Ultrasonic holography techniques for localizing and imaging solid objects

    Publication Year: 1991 , Page(s): 449 - 467
    Cited by:  Papers (14)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1688 KB)  

    The theory of both the monofrequency and multifrequency modes of ultrasonic holographic imaging as suitable for the requirements of object recognition in robot assembly tasks is described. The theory was implemented experimentally. Results show that the monofrequency approach provides fairly good lateral but insufficient depth resolution. By contrast, with multifrequency holography, depth resolutions of better than 3 mm and lateral resolutions of about 10 mm are attainable. New ultrasonic transducers, combined with a special signal preprocessing procedure, are a prerequisite for resolutions of this order. Typical images as obtained from several test scenes are presented. Suitable applications and possible future research are briefly outlined View full abstract»

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  • Histogramic in-motion mapping for mobile robot obstacle avoidance

    Publication Year: 1991 , Page(s): 535 - 539
    Cited by:  Papers (120)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    Histogramic in-motion mapping (HIMM) is introduced as a new method for real-time map building with a mobile robot motion. HIMM represents data in a two-dimensional array, called a histogram grid, that is updated through rapid in-motion sampling of on-board range sensors. Rapid in-motion sampling results in a map representation that is well-suited to modeling inaccurate and noisy range-sensor data, such as those produced by ultrasonic sensors, and requires minimal computational overhead. Fast map building allows the robot to use immediately the mapped information in real-time obstacle-avoidance algorithms. The benefits of this integrated approach are quick, accurate mapping and safe navigation of the robot toward a given target. HIMM has been implemented and tested on a mobile robot. Its dual functionality was demonstrated through numerous tests in which maps of unknown obstacle courses were created, while the robot simultaneously performed real-time obstacle avoidance maneuvers at speeds of up to 0.78 m/s View full abstract»

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  • A distortion-correction scheme for industrial machine-vision applications

    Publication Year: 1991 , Page(s): 546 - 551
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    Practical ways to measure and correct distortion in industrial vision systems are discussed with an emphasis on ease of use. Tests were conducted that showed that significant amounts of spatial distortion can exist in commercially available camera/lens/frame-grabber combinations. Even solid-state cameras are not immune to this phenomenon. Substantial reductions in distortion can result from a locally affine correction scheme such as the one tested. Large numbers of control points do not seem to be necessary, although increasing the number of control points does result in increased accuracy up to a point. The correction scheme developed can be extended to calibration targets for which the control points are regularly spaced View full abstract»

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  • Modeling impact on a one-link flexible robotic arm

    Publication Year: 1991 , Page(s): 479 - 488
    Cited by:  Papers (27)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (824 KB)  

    A finite-element model for a single-link flexible robotic arm including the effects of beam damping, hub inertia and both Coulomb and viscous hub friction is derived. The initial conditions required to represent impact loading are determined, and the motion of the arm under impact loading is simulated. Simulation results are compared to experimental data. From the experimental results it is concluded that this model provides an accurate representation of the physical process. It also provides a vehicle for investigating the effects of parameters of the process model, in particular, frictional effects and load profiles. Impact loading has been effectively represented in terms of initial conditions and can be applied to a range of finite-element models View full abstract»

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  • A combined optimization method for solving the inverse kinematics problems of mechanical manipulators

    Publication Year: 1991 , Page(s): 489 - 499
    Cited by:  Papers (57)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (780 KB)  

    A new method for computing numerical solutions to the inverse kinematics problem of robotic manipulators is developed. The method is based on a combination of two nonlinear programming techniques and the forward recursion formulas, with the joint limitations of the robot being handled implicitly as simple boundary constraints. This method is numerically stable since it converges to the correct answer with virtually any initial approximation, and it is not sensitive to the singular configuration of the manipulator. In addition, this method is computationally efficient and can be applied to serial manipulators having any number of degrees of freedom View full abstract»

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  • Adaptive PD controller for robot manipulators

    Publication Year: 1991 , Page(s): 565 - 570
    Cited by:  Papers (121)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    Referring to the point-to-point control problem, a proportional and derivative (PD) control algorithm is presented that is adaptive with respect to the gravity parameters of robot manipulators. The proposed controller is shown to be globally convergent. Following the same approach, an application to the tracking problem is also presented. Simulation tests are included, with reference to a robot having three degrees of freedom. These tests show that the performances of the adaptive PD controller are scarcely influenced by the initial error View full abstract»

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  • Nonholonomic path planning of space robots via a bidirectional approach

    Publication Year: 1991 , Page(s): 500 - 514
    Cited by:  Papers (97)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (776 KB)  

    The path planning of nonholonomic motion of space robot systems is discussed. A space vehicle with a 6-DOF (degrees of freedom) manipulator is described as a nine-variable system with six inputs. It is shown that, by carefully utilizing the nonholonomic mechanical structure, the vehicle orientation in addition to the joint variables of the manipulator can be controlled by actuating only the joint variables. The nonholonomic mechanical structure of space robot systems is shown. A rigorous mathematical proof of the nonholonomic nature of the free-flying space robot systems is provided using Frobenius's theorem. A method for nonholonomic motion planning for space robot systems is established by using a Lyapunov function View full abstract»

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  • Simulation of cooperating robot manipulators on a mobile platform

    Publication Year: 1991 , Page(s): 468 - 478
    Cited by:  Papers (16)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (840 KB)  

    The dynamic equations of motion are presented for two or more cooperating manipulators on a freely moving mobile platform. The system of cooperating robot manipulators forms a closed kinematic chain where the force of interaction must be included in the formulation of robot and platform dynamics. The formulation includes the full dynamic interactions from arms to platform and arm tip to arm tip, and the possible translation and rotation of the platform. The equations of motion are shown to be identical in structure to the fixed-platform cooperative manipulator dynamics. The structure of the closed-chain dynamics, allows the use of any solution for the open topological tree of base and manipulator links. The number of degrees of freedom (DOF) of the system is sufficiently large to make recursive dynamic calculation methods potentially more efficient than closed-form solutions. A complete simulation with two 6-DOF manipulators of a free-floating platform is presented along a with a multiple-arm controller to position the common load View full abstract»

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  • Recognizing and locating a known object from multiple images

    Publication Year: 1991 , Page(s): 434 - 448
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1312 KB)  

    An approach to recognizing and locating a partially visible object from multiple images for a pile of parts is proposed. The image-to-model correspondence is established through an examination of the consistency between the surface patches extracted from the images and the patches described in an object model. To obtain the scene description, which is composed of parameterized surface patches, the scene's needle map is derived by a modified photometric stereo method. The needle map is then segmented into primitive surfaces, and the resultant patches are identified and described by using a modified Hough transformation based on the Gaussian spherical maps of the patches. To interpret the scene description, the object model is built with a frame structure to describe geometric features of the model patches. By a search process guided by some heuristic planning strategies based on the fuzzy-set concept, sets of patches considered to be possibly on the surface of the model object are extracted from the scene description. The candidate sets are tested and the locations and orientations of the corresponding object instances are computed. Results of two experiments are reported View full abstract»

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  • Time, Petri nets, and robotics

    Publication Year: 1991 , Page(s): 417 - 433
    Cited by:  Papers (42)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1576 KB)  

    Based on the Petri net (PN) theory a particular class of condition/event nets called Ω, suitable for modeling repetitive workcell tasks, is defined. Nets ∈Ω are either deterministic or exhibit a restricted kind of conflict called choice among alternatives. It is shown how the repetitive behavior of such a net may be studied by decomposing this conflict into deterministic components associated with mutually exclusive alternatives. A unified description of the important temporal extensions of PN theory is presented, with emphasis on formal analysis. The PN notion of coverability is extended in the temporal sense and it is demonstrated that, for nets ∈Ω, the period of repetition (cycle time) can be directly computed from the durations associated with the individual operations, once the decomposition into components is performed. When the durations are specified in the form of minimum and maximum values, this period of repetition may be described by optimistic and pessimistic bounds. A typical assembly example adapted from work with a multirobot workcell testbed is also presented to illustrate two forms of temporal analysis View full abstract»

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  • Automated guided vehicle with absolute encoded guide-path

    Publication Year: 1991 , Page(s): 562 - 565
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    An automated guided vehicle (AGV) having the ability to recover its absolute position anywhere on the guide-path is described. It uses an original guide-path encoding technique, based on the properties of pseudorandom binary sequences, resulting in a minimum code complexity of 1 bit per quantization step. An experimental AGV system was built to test the proposed absolute position measurement method and its application for AGV navigation when unexpected obstacles are encountered on the guide-path. The results recommend this technique for implementation as a stand-alone function to cost-effectively upgrade existent optically guided industrial AGVs View full abstract»

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  • An approximation schema for the estimation of buffer sizes for manufacturing facilities

    Publication Year: 1991 , Page(s): 551 - 562
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (976 KB)  

    A unified approach to the production planning and scheduling problem of a flexible manufacturing system with failure-prone machines is considered. The proposed method is based on the concept of Gershwin's hedging point strategy. A hierarchical controller is proposed in which the upper levels use an inventory hedging point for production planning. At the lower level of the controller the concept of a buffer hedging point is introduced and used to obtain the size of the machine buffers and to derive the schedule for the manufacturing system. The estimation of the buffer size is not based on any optimization procedures; instead, it relies on an argument that allows decoupling of the operation of every machine. The net result is a hedging point concept that is applicable to all levels of the hierarchy. It is also shown how the buffer hedging point concept is related to the just-in-time manufacturing strategy. Results are presented from a small, scaled-down computer-controlled flexible manufacturing system and from several simulated cases View full abstract»

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  • Position control of manipulator with passive joints using dynamic coupling

    Publication Year: 1991 , Page(s): 528 - 534
    Cited by:  Papers (87)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    A method of controlling the position of a manipulator composed of active and passive joints is described. The active joints have actuators and position sensors. The passive joints have holding brakes instead of actuators. While the brakes are released, the passive joints are indirectly controlled by the motion of the active joints using the coupling characteristics of manipulator dynamics. While the brakes are engaged, the passive joints are fixed and the active joints are controlled. The position of the manipulator is controlled by combining these two control modes. The basic principle of the control method and the conditions that ensure the controllability of the passive joints are described. An algorithm for point-to-point control of the manipulator is presented. The feasibility of the method is demonstrated by simulations for a manipulator with two degrees of freedom View full abstract»

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  • Parallel and sequential mutual exclusions for petri net modeling of manufacturing systems with shared resources

    Publication Year: 1991 , Page(s): 515 - 527
    Cited by:  Papers (139)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1220 KB)  

    A theoretical basis for Petri net synthesis methods is provided that can be used to model systems with shared resources, and to make the resulting nets bounded, live, and reversible. Two resource-sharing concepts, parallel mutual exclusion (PME) and sequential mutual exclusion (SME), are formulated in the context of the Petri net theory. A PME models a resource shared by distinct independent processes, and an SME is a sequential composition of PMEs, modeling a resource shared by sequentially related processes. The conditions under which a net containing such structures remains bounded, live, and reversible are derived View full abstract»

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Aims & Scope

This Transactions ceased production in 2004. The current retitled publications areIEEE Transactions on Automation Science and Engineering and IEEE Transactions on Robotics.

Full Aims & Scope