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Robotics and Automation, IEEE Transactions on

Issue 2 • Date April 1995

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Displaying Results 1 - 15 of 15
  • Comments on "A sliding mode controller with bound estimation for robot manipulators"

    Publication Year: 1995
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (93 KB)  

    In Su and Leung (1993), a sliding mode control method is proposed for joint trajectory tracking of robot manipulators. The method is based on the decomposition of the manipulator dynamics into the product of a constant parameter vector and a regressor matrix, originally developed by Slotine and Li (1988). This note shows that the method proposed by Su and Leung does not offer any advantage over the method of Slotine and Li.<> View full abstract»

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  • On the mobility and manipulability of general multiple limb robots

    Publication Year: 1995 , Page(s): 215 - 228
    Cited by:  Papers (55)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1016 KB)  

    In this paper, the analysis of the differential kinematics and manipulability measures of robotic systems comprised of multiple cooperating limbs is considered. The goals of this study can be articulated in four points: 1) to enumerate the degrees of freedom of the manipulation system; 2) to describe analytically all possible first-order differential motions of the system at a given configuration; 3) to evaluate in the velocity domain the functionality of a manipulation system, with respect to the task it is required to perform; and 4) to calculate the bounds for the velocities achievable by the system, given bounds on the capabilities of joint actuators. The assumptions made on the robotic system are quite general, so that many complex devices (e.g., dextrous hands, legged vehicles, whole-arm manipulators, etc.) can be dealt with in a unified and convenient framework View full abstract»

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  • Prediction of the quasistatic planar motion of a contacted rigid body

    Publication Year: 1995 , Page(s): 229 - 246
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1432 KB)  

    Planning the motion of bodies in contact requires a model of contact mechanics in order to predict sliding, rolling, and jamming. Such a model typically assumes that the bodies are rigid and that tangential forces at the contacts obey Coulomb's law. Though, usually assumed to be constant, the static and dynamic coefficients of friction vary in space and time and are difficult to measure accurately. In this paper, we study a quasistatic, multi-rigid-body model for planar systems, in which the coefficients of friction are treated as independent variables. Our analysis yields inequalities defining regions in the space of friction coefficients for which a particular contact mode is feasible. The geometrical interpretation of these inequalities leads to a simple graphical technique to test contact mode feasibility. This technique is then used to generate a nontrivial example in which several contact modes are simultaneously feasible. Despite model ambiguity, there are factors which argue in favor of using a quasistatic, rigid-body model. This point is highlighted by the successful application of our results to the planning of two manipulation tasks View full abstract»

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  • A Petri net based deadlock prevention policy for flexible manufacturing systems

    Publication Year: 1995 , Page(s): 173 - 184
    Cited by:  Papers (315)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1028 KB)  

    In this paper we illustrate a compositional method for modeling the concurrent execution of working processes in flexible manufacturing systems (FMS) through a special class of Petri nets that we call S3 PR. In essence, this class is built from state machines sharing a set of places modeling the availability of system resources. The analysis of S3PR leads us to characterize deadlock situations in terms of a zero marking for some structural objects called siphons. In order to prevent the system from deadlocks, we propose a policy for resource allocation based on the addition of new places to the net imposing restrictions that prevent the presence of unmarked siphons (direct cause of deadlocks). Finally we present the application of this technique to a realistic FMS case View full abstract»

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  • Modeling an object of revolution by zooming

    Publication Year: 1995 , Page(s): 267 - 271
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    This paper presents a system for modeling solids of revolution from a set of images taken with a zoom-lens. Using a zoom in monocular vision has interesting optical properties. The displacement of the optical center along the optical axis, when the focal length is modified, permits one to implement a triangulation process. Modeling a solid of revolution requires the estimation of the 3D location of its revolution axis. First, the authors describe an original method, using zoom properties, to compute the 3D pose of the revolution axis. It requires the detection in each image of the object axis projection. Then, the modeling algorithm is presented. It is based on the resolution of the inverse perspective problem for points detected in the images. An experimental result of reconstruction, from a real images set is finally given View full abstract»

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  • Minimizing user queries in interactive assembly planning

    Publication Year: 1995 , Page(s): 308 - 312
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    This paper describes an interactive computer-aided assembly planning system that greatly reduces the human input required to construct assembly plans. The system takes a dual approach. First, most assembly operations are validated automatically from the CAD models of the assembly's parts using simple, fast techniques. Second, with each query the user is allowed to identify a set of parts that constrain a subassembly; the system uses this information to answer future queries automatically. This dual approach has proven quite powerful in experiments on real assemblies, reducing the number of queries by orders of magnitude over previous systems without sacrificing accuracy View full abstract»

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  • Sliding mode control for gradient tracking and robot navigation using artificial potential fields

    Publication Year: 1995 , Page(s): 247 - 254
    Cited by:  Papers (60)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    This paper introduces a sliding mode control strategy for tracking the gradient of an artificial potential field. The control methodology is applicable to fully actuated holonomic robotic systems with n-degrees of freedom. The controller yields exact tracking of the gradient lines and is invariant with respect to parametric uncertainty and disturbances in system dynamics. A detailed case study for mobile robots introduces the equilibrium point placement method for designing harmonic planar potential fields for circular obstacle security zones. Diffeomorph mappings can be utilized for more complex obstacle security zones. The gradient of the harmonic potential field is shown to always lead away from the obstacle security zone and to continuously approach the goal point View full abstract»

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  • A reduced-order adaptive velocity observer for manipulator control

    Publication Year: 1995 , Page(s): 293 - 303
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    In this paper a new manipulator joint velocity observer is presented. The observer is reduced in its order and it is adaptive with respect to unknown dynamic parameters. The velocity estimate produced by the observer is used in an adaptive controller for trajectory tracking. The result is locally asymptotically stable velocity observation errors and locally asymptotically stable position and velocity trajectory tracking errors. Simulations of the proposed scheme on the PUMA-560 show an improvement over a well known adaptive controller which obtains its joint velocity estimates via numerical differentiation experiments demonstrate the usefulness of the proposed observer View full abstract»

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  • Evaluation of dexterity measures for a 3-link planar redundant manipulator using constraint locus

    Publication Year: 1995 , Page(s): 282 - 285
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    This paper describes how to evaluate the performance of dexterity measures by investigating the properties of the inverse kinematic algorithms. These algorithms use redundancy to optimize the dexterity measure under the constraint of following a specified end-effector trajectory. To facilitate the investigation, a concept of the constraint locus is proposed. The constraint locus is the loci of configurations satisfying the necessary conditions for optimality of a dexterity measure in the configuration space. The topological properties of the inverse kinematic algorithm both on the configuration and operation spaces define the invertible workspace without singularities. Using the global properties of two dexterity measures, the authors provide a promising algorithm which provides a singular-free and conservative joint trajectory for tasks occupying almost the entire workspace View full abstract»

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  • Plan execution monitoring and control architecture for mobile robots

    Publication Year: 1995 , Page(s): 255 - 266
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1096 KB)  

    This paper deals with the architecture and control structure of mobile robots. The authors decompose robot functions into modules organized according to their predefined interactions: sensor modules that accomplish various processings on data from physical sensors, effector modules that issue commands to effectors, servo-processes that establish links between perception and action to achieve closed-loop behaviors, and functional units that provide specific functionalities. These modules, and hence the robot system itself, are controlled by a control system that also enables the robot to execute missions (plans) expressed in a command language. The authors introduce and discuss a generic control system structure, composed of a supervisor that interprets the plan and oversees its execution, an executive for operating and managing robot modules and resources, a surveillance manager for detecting and reacting to asynchronous events, and an error recovery module for local plan mending and correction. Several experimental examples are given View full abstract»

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  • Necessary and sufficient conditions for a unique solution of plane motion and structure

    Publication Year: 1995 , Page(s): 304 - 308
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    This paper presents necessary and sufficient conditions for uniquely determining the motion and structure of a planar surface from any number of monocular images. The authors first show an uncertain situation for the two-view plane motion problem in which an infinite number of solutions may result. Although this situation rarely occurs in real situations, it does raise visual ambiguities under certain circumstances, e.g., when some images are observed through a mirror. The understanding of this situation therefore helps analyze reflected images which are often seen in daily life. Then, the authors present necessary and sufficient conditions for a unique solution of plane motion and structure from any number of views. These algorithm-independent conditions enhance understanding about the problem of estimating plane motion and structure from image sequences and may be used to determine the uniqueness of the solution of the motion and structure of a planar surface View full abstract»

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  • Efficient search and hierarchical motion planning by dynamically maintaining single-source shortest paths trees

    Publication Year: 1995 , Page(s): 198 - 214
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1596 KB)  

    Hierarchical approximate cell decomposition is a popular approach to the geometric robot motion planning problem. In many cases, the search effort expended at a particular iteration can be greatly reduced by exploiting the work done during previous iterations. In this paper, we describe how this exploitation of past computation can be effected by the use of a dynamically maintained single-source shortest paths tree. We embed a single-source shortest paths tree in the connectivity graph of the approximate representation of the robot configuration space. This shortest paths tree records the most promising path to each vertex in the connectivity graph from the vertex corresponding to the robot's initial configuration. At each iteration, some vertex in the connectivity graph is replaced with a new set of vertices, corresponding to a more detailed representation of the configuration space. Our new, dynamic algorithm is then used to update the single-source shortest paths tree to reflect these changes to the underlying connectivity graph View full abstract»

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  • A weighted least-norm solution based scheme for avoiding joint limits for redundant joint manipulators

    Publication Year: 1995 , Page(s): 286 - 292
    Cited by:  Papers (65)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (628 KB)  

    It is proposed to use weighted least-norm solution to avoid joint limits for redundant joint manipulators. A comparison is made with the gradient projection method for avoiding joint limits. While the gradient projection method provides the optimal direction for the joint velocity vector within the null space, its magnitude is not unique and is adjusted by a scalar coefficient chosen by trial and error. It is shown in this paper that one fixed value of the scalar coefficient is not suitable even in a small workspace. The proposed manipulation scheme automatically chooses an appropriate magnitude of the self-motion throughout the workspace. This scheme, unlike the gradient projection method, guarantees joint limit avoidance, and also minimizes unnecessary self-motion. It was implemented and tested for real-time control of a seven-degree-of-freedom (7-DOF) Robotics Research Corporation (RRC) manipulator View full abstract»

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  • Symbolic construction of models for multibody dynamics

    Publication Year: 1995 , Page(s): 271 - 281
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (792 KB)  

    New algorithms are presented for deriving joint kinematic relations and these are integrated with Poincare's form of Lagrange's equations to generate the dynamical equations of motion for rigid multibody chains. Software is described which performs all of the required symbolic constructions. Examples are given View full abstract»

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  • A remote manipulator for forestry operation

    Publication Year: 1995 , Page(s): 185 - 197
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1444 KB)  

    The remote manipulator described consists of two arms: a 3-DOF main lifting arm (aerial device), and a 6-DOF robot manipulator (treejib) mounted at the upper end of the aerial device. Each arm is single-joint rate controlled, with the reference joint rate being proportional to the corresponding joint displacement of a corresponding hand controller. Both controllers are kinematically equivalent to each of the two arms. Two of the treejib joints are instrumented for position feedback, and the corresponding hand controller joints are motorized and also position controlled. This ensures that no excessive force is exerted on the tool during contact with the branches. The system is of a master-slave rate controlled force reflective type. The design presented has novel features such as a quick connect-disconnect coupler for hydraulic tools and a force reflective master in a form of a small kinematic replica of the slave. The system has been extensively field tested. The results were very promising, however several modifications to the basic concept used to automate the specific operations are necessary 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