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Advanced Motion Control, 1998. AMC '98-Coimbra., 1998 5th International Workshop on

Date June 29 1998-July 1 1998

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Displaying Results 1 - 25 of 122
  • AMC'98 - Coimbra. 1998 5th International Workshop on Advanced Motion Control. Proceedings (Cat. No.98TH8354)

    Publication Year: 1998
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    Freely Available from IEEE
  • Author index

    Publication Year: 1998 , Page(s): XXI - XXIII
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    Freely Available from IEEE
  • Fuzzy logic controller design for a laser scanner system

    Publication Year: 1998 , Page(s): 659 - 665
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (508 KB)  

    The paper describes the design of a fuzzy logic controller (FLC) to meet required performance specifications in a trajectory following problem involving a laser scanner system. The error and the change of error are used as inputs to the FLC, employing a proportional-derivative structure. A detailed analysis of the design factors is included. The fuzzy logic controller was found to be well suited to the system, yielding results that compared favourably to those obtained by various alternative controllers previously developed for the system View full abstract»

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  • Map interpretation in dynamic environments

    Publication Year: 1998 , Page(s): 340 - 345
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    In this paper we present a navigation system for a mobile robot that is capable of operating in dynamic environments. Mapbuilding is based on landmark detection, with landmarks being established through a process of self-organisation of the robot's sensory data. The resultant map can then be used to determine, and subsequently follow, arbitrary paths through the environment. The results of several experiments carried out with a Nomad 200 mobile robot in a dynamic environment are presented View full abstract»

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  • Navigation of mobile robots using fuzzy logic controllers

    Publication Year: 1998 , Page(s): 346 - 349
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB)  

    A fuzzy approach to the navigation control of mobile robots is presented in this paper. The problem of driving a mobile robot to a goal in an unknown environment is formulated as a fuzzy logic control problem in which local information is used to make steering and velocity decisions while the robot is moving. The fuzzy logic maps the input fuzzy sets representing the mobile robot state space determined by sensor readings to the output fuzzy sets representing mobile robot action space. We propose a direct and effective method using sensory data in order to design the fuzzy logic controller. Simulation results show the performance of the approach proposed View full abstract»

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  • Evaluation of the robustness of H control design versus pole allocation control design using of a wheeled inverted pendulum

    Publication Year: 1998 , Page(s): 59 - 63
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    The authors apply H-designed controllers to a wheeled inverted pendulum using transfer function shaping techniques. This design study motivates the use of H-techniques and shows the control procedure applied to multi-output and unstable plants. Two disturbances are considered to shape transfer functions: one corresponds to the influence of the gravity force, and the other is disturbance on the control input. Two H designs are made and compared with a design of the conventional pole allocation method to examine the relations between robust stability and closed loop transfer functions. Experimental data prove the superiority of H designs with the shaping of transfer functions View full abstract»

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  • Intelligent control of robots: status and future perspectives

    Publication Year: 1998 , Page(s): 356 - 363
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    The paper presents the status of the application of intelligent control to robots, and discusses future perspectives. We shall start with a brief introduction to the basic concepts underlying intelligent control. A human operator can control a robot without requiring a knowledge of its mathematical model, and learns how to do this. Intelligent control mimics the behaviour of a human operator, and does not require the large amount of computation associated with conventional adaptive control View full abstract»

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  • A torque control method of two-mass resonant system with PID-P controller

    Publication Year: 1998 , Page(s): 240 - 245
    Cited by:  Papers (5)
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    Proposes a torque control method of a two-mass resonant system with PID-P controller. The proposed controller consists of a PID controller with smaller gains and a P feedback compensation of the shaft torque using a torque meter. The gains of the controller can be designed by the coefficient diagram method. Analysis and experiment results show that a good transfer performance of torque can be obtained by using the proposed controller View full abstract»

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  • Safety in robotics: the Bremen Autonomous Wheelchair

    Publication Year: 1998 , Page(s): 524 - 529
    Cited by:  Papers (8)
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    Describes the development of a safety layer for an electrically driven wheelchair that is equipped with a ring of ultrasonic sensors. Designing this safety layer, which consists of software modules as well as hardware components, involved formal methods. An important outcome of the presented formal approach is a detailed set of hypotheses that specify the requirements the environment has to satisfy in order to allow the robot to behave as intended. The safety layer builds an abstraction of the real wheelchair which ensures that collisions are avoided, and guarantees that communication between software modules in a multi-PC environment takes place in real-time. As a first application on top of the safety layer, a driving wizard has been implemented. Its task is to adapt the wheelchair's speed depending on the situation of obstacles in the surrounding of the vehicle. The driver has no longer to bother with the question whether the planned trajectory will lead to a collision or not View full abstract»

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  • Attitude control experiments of biped walking robot based on environmental force interaction

    Publication Year: 1998 , Page(s): 70 - 75
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB)  

    In this paper, the attitude control of the biped robot based on the robust reactive force control is proposed, which can locally suppresses the unknown disturbances on the terrain. The method is investigated through the experiments of the 14-axes biped robot. The position of the center of mass and the attitude of the body is well controlled within ±0.03 [m] and ±0.04 [rad] (=±2.3 [deg]) errors View full abstract»

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  • A comparative study of a PI, neural network and fuzzy genetic approach controllers for an AC-drive

    Publication Year: 1998 , Page(s): 375 - 380
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    An increasing number of applications in high performing electrical drive systems use, nowadays, squirrel-cage induction motors. In this paper we use fuzzy genetic, neural network and PI approaches to control the speed of a field oriented AC-drive. The control methods and performances are presented and compared View full abstract»

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  • Two degree-of-freedom control with adaptive robust control for hard disk servo systems

    Publication Year: 1998 , Page(s): 604 - 610
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB)  

    A two-degree-of freedom (2DOF) control structure is proposed for read/write head servo systems of hard disk drives (HDD). This structure may be applied to both track seeking and track following, and it makes mode switches found in conventional HDD servo systems unnecessary. Two possible approaches are studied, emphasizing the rejection of disturbances and the effects of modeling uncertainties. One approach uses a disturbance observer (DOB), and the other uses adaptive robust control (ARC). Simulation results show that the 2DOF structure with ARC provides better performance than either the conventional servo system with mode switches or the 2DOF structure with DOB View full abstract»

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  • Fuzzy controller for obstacle avoidance in robotic manipulators using ultrasonic sensors

    Publication Year: 1998 , Page(s): 647 - 652
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    An application of a supervision system made up of ultrasonic sensors and fuzzy logic is presented. In fact, the combination of both technologies permits us to endow the robot with capacity to detect presence of an obstacle in a dynamic environment and to decide if an alternative path is necessary. Furthermore, given that the echo signal data can be used to obtain an approximation of position, direction of movement and velocity of the object, the fuzzy controller can be used to select “a secure point”, changing the current trajectory View full abstract»

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  • Intelligent robotic systems-from a single robot to multiple robotic system

    Publication Year: 1998 , Page(s): 706 - 712
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    There have been a lot of works on the improvement of the robotic performance. Nowadays a robot can work well under given constraints and environments. But the performance of a single robot might be limited and some needs more complex performance. To cope with the complex works, there are several approaches, such as more sophistication of a single robot and multiple robotics with different levels of capacities. In this paper, the multiple robotic system approach will show more flexibility and adaptability to various tasks and environments. The robots with different capacities, such as Cellular Robotic System (CEBOT), are one of the distributed autonomous robotic systems and consist of the heterogeneous system, thus can create intelligence for wider tasks. This paper describes these characteristics of the robotic system depending on the level View full abstract»

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  • An effective camera calibration method

    Publication Year: 1998 , Page(s): 171 - 174
    Cited by:  Papers (4)
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    Proposes a method for camera calibration that could be used in stereo systems subject to slight change in any camera parameter, as well as in stereo head navigation. A pinhole camera model plus linear and radial distortion is considered. An extended Kalman filter (EKF) is used to recover pinhole parameters and a Newton Raphson (NR) algorithm is used to obtain distortion terms. With the pinhole model the position and orientation of the camera is immediately recovered because the extrinsic and intrinsic parameters have been explicitly calculated, this is necessary for the modeling of the camera in a 3D environment. The only strong requirement for the proper convergence of the calibration algorithm is a good initial approximation to the solution. The method allows us to recalibrate the system easily if a small change has taken place. In that case, the initial approximation required for the EKF is supplied by the old parameters of the camera, after which the convergence is very quickly achieved. The on-going work is related to the application of this algorithm to the calibration of the cameras for stereo head navigation, allowing a 3D description of the environment surrounding the camera movements. The algorithm has been tested in the 3D reconstruction of real objects through a path described by a stereo camera system. Numerical results have been compared with a classical least square error algorithm. Reported errors by EKF are similar of those by LSE View full abstract»

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  • Robust motion control in redundant motion systems

    Publication Year: 1998 , Page(s): 135 - 140
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (404 KB)  

    In this paper, a motion control for redundant manipulator based on observer is proposed. In the conventional control for redundant manipulators, the pseudo-inverse matrix and null space vector of Jacobian matrix are used for the end-effector motion control and configuration control, respectively. However, the calculation of such motion controller becomes more complicated as the number of the degree-of-freedom increases. In the proposed motion control, the null space motion controller is combined with the workspace motion controller by using the observer-based robust control technique. Accordingly, the design process and the total calculation of the motion controller is much simplified, and our approach realize the null space effects without much effort in calculating the null space term (I-J+J). The validity of the proposed method is confirmed by the several numerical results in the Slink planar redundant manipulator View full abstract»

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  • Ultrasonic sensing classification of foundry pieces applying neural networks

    Publication Year: 1998 , Page(s): 653 - 658
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    This work describes an inspection and classification system based on ultrasonic sensing that is developed for application to foundry pieces which will later be machined within the automobile industry. In the manufacturing of foundry pieces, small defects can sometimes be found after casting, which although not critical for the final use of the piece, affect the manufacturing processes detrimentally, especially in machining tasks. The inspection system tries to solve this problem in an automated way applying ultrasonic identification techniques. In this field, ultrasonic tools appear to be a powerful technique for the quality control of processes because of their capacity to recognise and classify pieces. The ultrasonic signal reflected by a piece is mathematically treated and two neural network designs are developed to perform the discrimination between machinable and nonmachinable piece. This work forms part of the investigative tasks of a collaboration project between the Engineering Control Group of the University of Cantabria and FUNDIMOTOR S.A. (Nissan Group) View full abstract»

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  • Implementing schema-theoretic models of animal behavior in robotic systems

    Publication Year: 1998 , Page(s): 246 - 253
    Cited by:  Papers (2)
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    Formal models of animal sensorimotor behavior can provide effective methods for generating robotic intelligence. We describe how schema-theoretic models of the praying mantis are implemented on a hexapod robot equipped with a real-time color vision system. The model upon which the implementation is based was developed by ethologists studying mantids. This implementation incorporates a wide range of behaviors, including obstacle avoidance, prey acquisition, predator avoidance, mating, and chantlitaxia behaviors View full abstract»

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  • Real-time control for VIDET using Simulink

    Publication Year: 1998 , Page(s): 559 - 564
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    In this paper we discuss the real-time force-feedback control structure for the VIDET system. In this application the scheme for the controller is defined as a dual cooperative task. The control force setpoint is derived from the human response interface, whereas the actuator position is controlled in real-time so that the force setpoint is maintained. After introducing the application, the control system architecture will be explained. Finally the implementation and realization in MATLAB-Simulink is discussed View full abstract»

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  • Redundancy optimization for mechanical manipulators

    Publication Year: 1998 , Page(s): 405 - 410
    Cited by:  Papers (4)
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    Redundant manipulators have some advantages when compared with classical arms because they allow the trajectory optimization, both on the free space and in the presence of obstacles, and the resolution of singularities. For this type of manipulators, the proposed kinematic control algorithms adopt generalized inverse matrices. The generalized inverse control scheme is tested through several experiments which reveal the difficulties that often arise, namely by showing that we may get non-optimal arm configurations and chaotic-like motions. Motivated by these problems we present a new method that optimizes the manipulability through a least square polynomial approximation to determine the joints positions. The experiments confirm the superior performance of the proposed algorithm for redundant and hyper-redundant manipulators View full abstract»

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  • Distributed motion control of an electric vehicle

    Publication Year: 1998
    Cited by:  Papers (1)
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    Summary form only given. INRIA has developed an electric vehicle for pedestrian areas which includes advanced motion control in order to enhance the safety of drivers and to introduce various forms of automated driving. The vehicle, called CyCab, has 4-wheel drive and 4-wheel steer implemented through 4 electric motors (one in each wheel) for propulsion, 4 electric motors (one for each wheel) for mechanical braking and one electric motor for steering the 4 wheels which are mechanically linked. The control of these 9 electric motors (plus all the sensory equipment and battery management) is performed through a set of 6 microcontrollers on a CAN network. The purpose of this paper is to present this architecture and its advantages in term of safety, price and performances, in particular to implement complex automated tasks. We will also present the software tools (based on synchronous techniques) needed to program the applications in a distributed environment. Two prototypes of these vehicles are now operational at INRIA and the company Robosoft is now selling this product on the market View full abstract»

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  • Behavioural control using modified Sugeno inferencing

    Publication Year: 1998 , Page(s): 635 - 640
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    Describes the design and construction of a behavioural controller for an autonomous vehicle using fuzzy logic. Discussed are the desirable properties of a behavioural controller, and how they may be implemented using fuzzy logic. Issues regarding the suitability of fuzzy logic are considered and used to indicate the motivation for modification of the fuzzy system. The nature of the fuzzy system used, and the modifications that have been made to the standard zero order Sugeno inference engine are illustrated View full abstract»

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  • Use of eigenspace techniques for position estimation

    Publication Year: 1998 , Page(s): 267 - 271
    Cited by:  Papers (1)
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    Presents a method for solving the problem of mobile robot localisation in an indoor environment. It is based on an approach in which the scene is “learned” by taking images from a large number of positions (x, y) and orientations (θ) along a 2D grid. The positioning problem is then reduced to a problem of associating an unknown input image with a “learned” image. A brute force solution requires too many image correlations, and would be computationaly too expensive to provide a system running in real-time. To overcome this problem, the image set is compressed using principal components analysis, converting the search problem into an addressing problem. The aim is to obtain a low dimensional subspace, in which the visual workspace is represented as a continuous appearance manifold. This method allows a process to determine the current robot pose by projecting an unknown input image into the eigenspace, and comparing its exact position to the appearance manifold View full abstract»

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  • Sensorless position control of induction motors. An emerging technology

    Publication Year: 1998 , Page(s): 1 - 14
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (976 KB)  

    Concepts for sensorless position control of induction motor drives rely on anisotropic properties of the machine rotor. Such anisotropies can be incorporated as periodic variations of magnetic saliencies in various ways. The built-in spatial anisotropy is detected by injecting a high-frequency flux wave into the stator. The resulting stator current harmonics contain frequency components that depend on the rotor position. Models of the rotor saliency serve to extract the rotor position signal using phase-locked loop techniques. A different approach makes use of the parasitic effects that originate from the discrete winding structure of a cage rotor. It has the merit of providing high spatial resolution for incremental positioning without sensors. The practical implementation of sensorless position identification, and of a high-accuracy position control system are reported View full abstract»

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  • An experimental testbed for position and force control of robotic manipulators

    Publication Year: 1998 , Page(s): 222 - 227
    Cited by:  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    In this paper a low cost open architecture PC-based controller for a planar two-degree of freedom robotic manipulator is described. The system is based on an available low price commercial PC interface board and all of the control software runs on a Pentium 100 MHz computer to control the arm. The driving kernel of software for supervisory, management and control was developed in a high level language (C++) and enables the analysis of several position and force/position control strategies for research and practical applications. The preliminary experimental results for the given tracking trajectories reveal an accurate position tracking performance and have shown also good force control results in the presence of a non-rigid environment, with conventional digital PID controllers View full abstract»

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