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Intelligent Robots and Systems '94. 'Advanced Robotic Systems and the Real World', IROS '94. Proceedings of the IEEE/RSJ/GI International Conference on

Date 12-16 Sep 1994

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  • Control of robotic manipulators using a CMAC-based reinforcement learning system

    Page(s): 2117 - 2122 vol.3
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    A practical learning control system is described in this paper, which is applicable to the control of complex robotic systems. In the controller, a stochastic reinforcement learning algorithm is used to learn functions with continuous outputs as control signals. The authors present a CMAC-based network incorporating stochastic real-valued units that learns to perform an underconstrained positioning task using a simulated 2-degree-of-freedom robot arm. The authors also investigate the effects of varying learning algorithm parameters View full abstract»

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  • An experimental multisensorial robotic system for disassembly automation

    Page(s): 2103 - 2110 vol.3
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    Disassembly and recycling are becoming increasingly important in our society, especially for their ecological implications. In this paper the authors present an approach to disassembly problems, which is essentially based on the concepts of multisensory integration and fusion and on the use of purposive actions to simplify perceptual tasks. The authors present a robotic system for the recognition and sorting of individual objects from a group, operations that are extremely important in most disassembly tasks. An example application of the system is described and experimental results are discussed. The effectiveness of the system in operating in a partially structured environment, shows how problems which are difficult to manage by using a single sensory modality can be solved by integrating multisensory data View full abstract»

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  • Intelligent robotic reusable manufacturing for environment conscious

    Page(s): 1986 - 1991 vol.3
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    Some existing production technologies cause environmental deterioration. It becomes a key issue to save and use resources effectively from the view point of environment protection. Therefore, trends of technologies are now changing from improving the productivity to improving the recycling. This paper presents robotic technology for automatic reusable manufacturing that more effective usage of resources than conventional manufacturing. Some examples for aircraft industry will be presented View full abstract»

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  • An agent model combining reactive and cognitive capabilities

    Page(s): 2095 - 2102 vol.3
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    Presents an abstract model of an autonomous agent that integrates reactive and cognitive behaviour. The authors state three requirements (reactivity, timely behaviour, and symbolic representation) that should be accomplished by such an integration. Due to the fact that there exists no model up to now that covers all three aspects, the authors present an abstract model of an autonomous agent that does meet these requirements. To the modules of knowledge representation, planning, scheduling, and execution, the authors add the process of evaluation that constantly supervises the environment and the agent's actions in order to ensure the agent's reactivity. To validate the proposed model, the authors discuss an implementation in a complex robot scenario View full abstract»

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  • Ecologically conscious automated disassembly system

    Page(s): 1980 - 1985 vol.3
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    Human beings are using and consuming resources to make various products. However, the resources on the earth are limited. Therefore, recycling of the resources is very important for human beings now and in the future. After use of the products, they are thrown away or burnt while discharging COx. The environment of the earth is being damaged and the resources are being exhausted. In order to reuse the resources and to protect the environment of the earth, this paper introduces a conceptual design of disassembly automation system for automated manufacturing with ecological recycling. The system employs many robots to disassemble the used products. The disassembly process has to deal with a lot of uncertainty of the used products, while assembly process does not have to deal with so much uncertainty of the products. This paper explains a configuration of the system, functions of the robots and some problems View full abstract»

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  • Analysis of space manipulators with non-specific reference links

    Page(s): 1539 - 1545 vol.3
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    In previous works on modeling of space manipulators, the satellite base or spacecraft is assumed to be at one end of the chain and the robot end-effector at the other. In this paper, a general model allowing any link on a floating kinematic chain to be either the spacecraft or the end-effector is developed and characterized. Properties discovered in the past about space manipulators are generalized to these systems with “non-specific” reference links View full abstract»

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  • Collision free minimum time trajectory planning for manipulators using global search and gradient method

    Page(s): 2184 - 2191 vol.3
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    A method for a time optimal collision free trajectory planning problem is proposed. In this paper, the dynamics of manipulator and obstacles are considered. This type of optimal trajectory planning problem is very difficult and complicated one because of the nonlinearity of manipulator dynamics and existence of obstacles. Generally, it results in a multimodal optimization problem. The proposed method is basically an iteratively improving one based on a gradient method. Firstly, two global methods (a genetic algorithm or an exact cell decomposition method) are used to search multiple initial feasible spatial paths for the gradient method. Next, the gradient method searches the time optimal solution locally with the multiple initial feasible solutions. Simulation results show that this is an effective approach to the time optimal collision free trajectory planning problem View full abstract»

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  • AGV in Japan-recent trends of advanced research, development, and industrial applications

    Page(s): 1477 - 1484 vol.3
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    Recent trends on advanced AGV are reviewed and discussed with examples. Special concern is made for automated position finding, guidance and multivehicle strategies, as well as communication systems. Focused are on engineering, electromechanical and optical problems. In addition to conventional manufacturing and advanced industrial applications, service vehicles such as floor cleaning, blind aids and off-road uses are described. New electric power supply systems are also presented View full abstract»

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  • Fast template matching based on the normalized correlation by using multiresolution eigenimages

    Page(s): 2086 - 2093 vol.3
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    Presents a fast computation method of the normalized correlation for multiple rotated templates by using multiresolution eigenimages. This method allows the authors to accurately detect both location and orientation of the object in a scene at faster rate than applying conventional template matching to the rotated object. Since the correlation among slightly rotated templates is high, the authors first apply the Karhunen-Loeve expansion to a set of rotated templates and extract “eigenimages” from them. Each template in this set can be approximated by a linear combination of these eigenimages and it substitute for the template in computing the normalized correlation. The number of eigenimages is smaller than that of original templates and computation cost becomes small. Second, the authors employ a multiresolution image structure to reduce the number of rotated templates and location search area. For the lower resolution image, the position and angle are coarsely obtained in a wide region. Then not only searching area for the position but also the range of rotation angle of templates at the next layer can be limited to the neighbor of the prior results. The authors implemented the proposed algorithm on a vision system and realized computation time around 600 msec and achieved sub pixel resolution for translation and 0.3 degree maximum error for 360 degree rotation on the 512 by 480 gray scale image. Experimental results are shown to demonstrate the accuracy, efficiency and feasibility of the proposed method View full abstract»

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  • Mobile robots in complex environments: a three-layered hierarchical path control system

    Page(s): 1891 - 1898 vol.3
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    Autonomous navigation in unknown cluttered environments is one of the corner-stones of future applications of mobile robots. The complexity even of seemingly simple problems like point-to-point travel, to be solved in real-time, calls for a hierarchical system architecture. The authors present a three-layered path control system with three modules “global planning”, “local navigation”, and “collision avoidance”. Each module is restricted to a subtask of limited competence and responsibility, allowing for on-line implementation within the associated time frame. Suitable module interaction provides the desired behavior of the overall system. This paper summarizes the main idea of each of the three modules. Experimental results with the Siemens mobile platform ROAMER illustrate the methodology and performance of the path control system in unprepared cluttered environments View full abstract»

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  • Impact estimation of a space robot at capturing a target

    Page(s): 1570 - 1577 vol.3
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    Capturing a target by a robot hand in space inevitably causes impulsive forces on the contact points. Such forces possibly give undesirable effects to both spacecraft. The authors' purpose is to study the relationships between the initial relative velocities of the hand to the target and the resulting contact impulse. The authors consider the effects of the servo stiffness and the desired joint rates for the manipulator control. Using the Laplace transformation, the authors estimate the contact impulse with these effects taken into consideration. From the estimations, it is shown that the joint stiffness increases the effective moment of inertia around its joint and as a result increases the impulsive contact forces. It is also shown that the joint rates are desired to be set as the initial joint rates to relax the contact impulse. Numerical simulations and hardware experiments are also given to validate the authors' approach View full abstract»

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  • A proposal for cooperative robot “Gunryu” composed of autonomous segments

    Page(s): 1532 - 1538 vol.3
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    This paper proposes the concept, and explains the characteristics, of a new group robot “Gunryu”, each segment of which has autonomy but at the same time moves and operates cooperatively with the other segments. Next, the mechanisms of a primary model, GR-1, which is comprised of two prototype robot units, are introduced and the conditions for operational experiments are given View full abstract»

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  • Sensor-based motion planning for multiple mobile robots in an uncertain environment

    Page(s): 1485 - 1492 vol.3
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    This paper presents an approach for decentralized motion planning for multiple mobile robots operating in a common 2D environment with unknown stationary obstacles. Each robot is capable of translatory motion and is equipped with range sensors which allow it to sense surrounding objects. Each robot knows its current position, is able to distinguish a robot from an obstacle, and can assess the instantaneous motion of any robot it can sense. Other than this, the robot has no knowledge about the scene, or of the paths or objectives of other robots; there is no mutual communication among the robots. No constraints are imposed on the paths or shapes of robots and obstacles. Each robot plans its path toward its target dynamically, based on its current position and sensory feedback. Given the assumptions of incomplete information and decentralized planning, the suggested heuristic algorithm demonstrates a remarkable robustness and ability for successful decentralized real-time motion planning in an unknown complex environment View full abstract»

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  • Neural network for human cognitive state estimation

    Page(s): 2176 - 2183 vol.3
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    A neural network (NN) has been applied to the human cognitive state estimation based on the set of physiological measures, heart rate, blood pressure, respiration rate, skin potential response (SPR), blink rate and saccadic eye motion rate have been chosen as the representative metrical indices reflecting human mental state. The qualitative tendencies of these measures have been taken as the inputs of the NN. The human cognitive states are categorized into six pre-specified states: (1) information acquisition (IA); (2) memory related (MR); (3) thought (TH); (4) motor action (MA); (5) emotion (EM); and (6) others (OT). The adopted network a is three layer feedforward network trained with a backpropagation algorithm with forgetting. Sets of training data for learning have been collected through laboratory experiments, in which the subjects were induced to undergo a specific sequence of cognitive states. The resultant NN showed superior capability of discriminating human cognitive states based on the pattern of the physiological measures View full abstract»

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  • Trajectory planning and real-time control of an autonomous mobile robot equipped with vision and ultrasonic sensors

    Page(s): 1861 - 1866 vol.3
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    The aim of this paper is to discuss and present a navigation architecture for an autonomous mobile robot, based on the integration of ultrasonic sensors and stereo vision. The distinctive features are the integration of a “classical” planning approach and subsumption architecture for obstacle avoidance, and the fusion of visual and ultrasonic sensory data. The goal of the experiment is to plan missions between two user defined points in the environment, autonomously avoiding static and dynamic obstacles along the planned path View full abstract»

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  • Statistical estimation algorithms for ultrasonic detection of surface features

    Page(s): 1845 - 1852 vol.3
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    For several applications of interest in the robotic field, range sensing is often accomplished by means of single ultrasonic sensors. Additional information about the objects' surface, such as the orientation relative to the sensing device, has to be extracted by means of ultrasonic sensor arrays. So far, a few researchers have dealt with the problem of determining also the local curvature of curved reflectors. The aim of this paper is to investigate the minimum amount of range information needed to estimate distance, orientation and radius of cylindrical targets by means of a linear array of ultrasonic transducers. The proposed imaging problem is stated within the field of statistical estimation theory: an iterative linearised least-squares estimator, i.e. an extended Kalman filter, is designed and used for optimal processing of the sensed data. The theoretical analysis of the filtering algorithm performance allows one to elucidate the critical factors ultimately affecting the achievable accuracies of the proposed technique. Experimental results are presented, in close agreement with the predictions of the theoretical analysis View full abstract»

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  • Navigation with constraints for an autonomous mobile robot

    Page(s): 1899 - 1905 vol.3
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    This paper describes a navigation planning algorithm for a mobile robot capable of autonomous navigation in a quasi-structured, partially known and dynamic environment. This algorithm uses a description of the environment containing both operational and geometric information. An interactive program permits an operator to create the description of the environment composed of structural elements such as walls and furniture. This description is completed by the addition of operational information in the form of a network of places, routes, landmarks and recharge stations. Places and routes include constraints on the actions of the robot as well as other information needed for planning and plan execution. A separate interactive program permits an operator to compose a surveillance mission as parallel sequences of navigation tasks and surveillance tasks, subject to constraints on energy, time, risk and position uncertainty. The planning algorithm described in this paper computes an optimal path for each navigation task according to the optimisation criterion and constraints. The authors introduce the notion of efficient path applied to a new best first search algorithm solving a multiple constraints problem, The paths determination relies on a state representation adapted to deal with environment constraints. The authors demonstrate that the complexity characteristics of their algorithm are similar to those of the A* algorithm. The planning system described in this paper has been implemented on a laboratory workstation and tested using radio-modem communication with a mobile platform equipped with ultrasonic range sensors and an active stereo vision system. This system has been developed for the MITHRA family of autonomous surveillance robots as part of project EUREKA EU 110 View full abstract»

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  • A robust and effective method for bidimensional recognition of 2D and 3D objects from intensity images

    Page(s): 2044 - 2051 vol.3
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    This paper presents a robust and effective method for bidimensional recognition of 2D or 3D objects, from intensity images based on: matching of the models with symbolic structures of the scene, using of the inexact matching, intensive using of techniques for search space reduction View full abstract»

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  • Stagnation recovery behaviours for collective robotics

    Page(s): 1883 - 1890 vol.3
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    Accomplishing useful tasks with a collection of decentralized mobile robots will require control methods that deal effectively with a number of unique problems that impede the system's progress. Reactive control architectures can easily cause the problems of stagnation and cyclic behaviour, both characterized by a lack of progress in achieving a task. In this paper the authors present one possible solution to stagnation recovery, motivated from the study of group transport in ants and demonstrate its use in a box-pushing task. By using stagnation recovery behaviours, which are triggered by a lack of progress in the task-achieving activity of the system, the collective system can monitor its own advancement in a decentralized manner. A set of such behaviours are progressively ordered using timeouts, with each set designed for a specific recovery strategy. The stagnation recovery behaviours have been tested in simulation with the results to be mapped onto a set of ten autonomous robots presently under construction View full abstract»

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  • Towards obtaining all possible contacts-growing a polyhedron by its location uncertainty

    Page(s): 1788 - 1795 vol.3
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    This paper provides a general and exact method of growing a polyhedral object in three-dimensional Cartesian space to take into account its orientation and position uncertainties. The work is particularly motivated by the need for automatically recognizing contact situations among objects in spite of uncertainties. The technique of growing surface elements of a polyhedron by uncertainty can be used to extract the set of all possible contact situations among polyhedral objects in the presence of location uncertainties, which can then serve as a basis for further and more accurate extraction of contact information by additional sensing means, such as vision and force/moment sensing View full abstract»

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  • Cooperating multiple behavior-based robots for object manipulation

    Page(s): 1524 - 1531 vol.3
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    A multiple vehicle robot system for cooperative object manipulation is described. This system consists of a host and several distributed behavior-based vehicle robot agents. A strategy on cooperatively organizing the behavior-based robots which only have limited ability in manipulation is discussed. An extended subsumption architecture, which has some layers for manipulation and cooperation, is built for each vehicle robot. A simulator and some simulation results are also shown View full abstract»

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  • Motion planning with dynamic constraints for manipulators in the presence of moving obstacles

    Page(s): 1930 - 1937 vol.3
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    This paper deals with acceleration (or torque) constraints in motion planning of a manipulator among moving obstacles. It is known that motion planning with dynamic constraints in dynamic environments can be formulated in a state-time space. This paper shows that acceleration constraints of a manipulator can be represented as parabolas in a local small motion so that admissible velocities are efficiently computed. An algorithm is also presented for planning the optimal trajectory for a manipulator on a given path. To improve computation efficiency, this algorithm does not construct or search the total 3D state-time space but only a subspace corresponding to admissible regions in the 2D time-configuration and state spaces. Its usefulness is shown by a simulation for a 6 DOF manipulator View full abstract»

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  • Control of a mastication robot for reduction of jaw joint force focusing on musculus temporalis

    Page(s): 1824 - 1831 vol.3
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    A mastication robot is a jaw motion simulator that has similar structure and function to the human masticatory system. This paper describes an optimal reduction of the jaw joint force focusing on the fan shape of the musculus temporalis (M.temporalis) spreading around the side of skull. The shape of M.temporalis is simplified as two independent lines, and the jaw joint force is computed by using linear programming. Furthermore the actuators corresponding to the anterior and posterior parts of M.temporalis are assigned separately. The 28% reduction of jaw joint force was confirmed experimentally by using robot View full abstract»

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  • The user interface for interactive robotic workstations

    Page(s): 1682 - 1686 vol.3
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    The importance of the user interface within interactive robotic workstations is examined and design criteria are discussed. The command of an interactive robotic device is considered as a direct manipulation system and the potential benefits of graphical user interfaces for such systems are outlined. Aspects of current work in user interface design are introduced in the context of the Cambridge University Robot Language (CURL). Interface development tools and evaluation techniques are described. Finally, the future of robot user interfaces is examined with respect to recent advances in computing technology View full abstract»

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  • A supervisory system for the URMAD robotic unit

    Page(s): 1687 - 1694 vol.3
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    This paper reports part of the work related to the design and development of the URMAD system, a mobile robotic unit purposely devised to assist the severely disabled in a household environment. A supervisory system based on distributed decision making and functional distribution has been designed and implemented on a VME/OS9 architecture. This system is capable of executing typical domestic tasks expressed in a synthetic command language extracted from everyday vocabulary. The user's requests can be easily specified by using a Windows-like graphical user interface and are translated into the command language by an interpreter running on a personal computer. In the paper, a general overview of the URMAD system is provided. A detailed description of the proposed modular architecture for the supervisory system, of its various modules and of the command language, is presented. Finally, the hardware and software implementation of the first prototype of the system and some preliminary experimental tests and simulations are reported View full abstract»

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