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Robotics and Automation, 2009. ICRA '09. IEEE International Conference on

Date 12-17 May 2009

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Displaying Results 1 - 25 of 712
  • A harmonic potential field approach with a probabilistic space descriptor for planning in non-divisible environments.

    Publication Year: 2009 , Page(s): 3774 - 3779
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (842 KB) |  | HTML iconHTML  

    This paper extends the capabilities of the harmonic potential field approach to planning to cover the situation where the workspace of a robot cannot be segmented into geometrical subregions each having an attribute of its own. Instead the suggested planner accepts a holistic, task-centered, probabilistic descriptor of the workspace as an input. This descriptor is processed along with a goal point to yield the navigation policy used to direct motion. The extension is based on the physical analogy with an electric current flowing in a nonhomogeneous conducting medium. Proofs of the ability of the modified approach to avoid zero-probability (definite threat) regions and converge to the goal are provided. The capabilities of the suggested planner are demonstrated using simulation. View full abstract»

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  • A harmonic potential field approach for navigating a rigid, nonholonomic robot in a cluttered environment

    Publication Year: 2009 , Page(s): 3993 - 3999
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (423 KB) |  | HTML iconHTML  

    701 This paper demonstrates the ability of the harmonic potential field (HPF) planning approach to generate a provably-correct, constrained, well-behaved trajectory for a rigid, nonholonomic robot (a tractor-trailer robot is not rigid) in a stationary, cluttered environment. This is accomplished using a closed loop control scheme that is inspired by model predictive control (MPC). The scheme is realized using a synchronizing signal derived from the HPF along with a procedure for inverting the process the robot is using for actuating motion. Performance proofs as well as simulation results of the suggested planner are supplied. View full abstract»

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  • Force estimation in a piezoelectric cantilever using the inverse-dynamics-based UIO technique

    Publication Year: 2009 , Page(s): 2205 - 2210
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (583 KB) |  | HTML iconHTML  

    This paper presents the estimation of the force applied by a piezocantilever dedicated to micro-manipulation/microassembly. Relative to previous works, the presented method avoids the reliance on the force dynamics on the characteristics of the micro-objects. Furthermore, the estimation is a closed-loop kind technique so that convergency can be ensured efficiently. To perform these, we consider the force at the tip of a piezocantilever as an unknown input and we use an unknown input observation technique. We especially use the inverse-dynamics-based UIO technique because it is well suited for a piezo-cantilever model. The experiments show that the performances of the observer are convenient for micromanipulation/microassembly tasks. View full abstract»

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  • Effect of energy feedbacks on Virtual Slope Walking: I. Complementary Energy Feedback

    Publication Year: 2009 , Page(s): 1959 - 1965
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (647 KB) |  | HTML iconHTML  

    This paper presents our study over the effect of complementary energy feedback on virtual slope walking, while virtual slope walking is our new biped gait generation method inspired by passive dynamic walking. The energy feedback strength is defined and the walking is modeled as a step-to-step function. The Jacobi matrix eigenvalues of the function are calculated together with the basin of attraction. From the analysis, we find the characteristic of Complementary Energy Feedback is being effective on a fast gait but weak on a slow one. By making use of the complementary energy feedback in walking experiment, our robot achieves speed change from 1.5 leg/s to 4.1 leg/s. View full abstract»

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  • Bending and kissing: Computing self-contact configurations of planar loops with revolute joints

    Publication Year: 2009 , Page(s): 1346 - 1351
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (180 KB) |  | HTML iconHTML  

    In recent work, we introduced the notion of a construction tree of simplices for a linkage L under distance constraints, and showed that the deformation space DSpace(L) of such an L (i.e., its configuration space CSpace(L) modulo rigid motions of ambient space respecting all system specifications) carries geometrically-defined simplex-based parameters that endow it with a ldquopractically piecewise-convexrdquo structure. Here we present parametrizations of contact deformations of planar loops with revolute joints. We show that the bending and kissing loci, which include the self-contact subspace DSContact (generally as a strict subset) can be efficiently described by triangle-based parameters. These results further demonstrate the effectiveness of the simplex-based approach. View full abstract»

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  • Natural self motion of a robotic limb with single degree-of-redundancy

    Publication Year: 2009 , Page(s): 2925 - 2930
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (277 KB) |  | HTML iconHTML  

    The self motion of a kinematically redundant robotic limb with single degree of redundancy is analyzed, focusing thereby on the nonlinear self-motion component. The role of this component has been completely ignored in past studies on self motion. It is shown that Jacobian pseudoinverse-based resolution - the usual resolution method for nonlinear self-motion - yields poor dynamic performance. A special type of self motion is identified based on the natural metric on the self-motion manifold and the energy conservation principle. This type of self motion is shown to have superior dynamics in terms of torque requirement and to avoid abrupt fluctuations in acceleration in the vicinity of singular points. View full abstract»

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  • Interference estimated time of arrival on a 6-DOF cable-driven haptic foot platform

    Publication Year: 2009 , Page(s): 1067 - 1072
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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB) |  | HTML iconHTML  

    A Cable-Driven Locomotion Interface employs two independent cable-driven haptic foot platforms constrained in six degrees of freedom (6-DOF). Its control system and its geometry are designed for performing a wide range of trajectories that could generate cable interferences. This paper presents and analyzes computational methods for determining which cable can be released from an active actuation state while allowing control in a minimal tension state, thereby ensuring that both platforms stay in a controllable workspace. One challaging task is to develop light and fast computational algorithms for hard real time processes included in haptic display applications. Seeing that releasing a cable from an active actuation state might generate discontinuities in tension values in the other cables, this paper proposes collision prediction schemes named Interference Estimated Time of Arrival in order to reduce or completely eliminate such discontinuities. View full abstract»

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  • Effects of geometric imperfections to the control of redundantly actuated parallel manipulators

    Publication Year: 2009 , Page(s): 1782 - 1787
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB) |  | HTML iconHTML  

    The model-based control of robotic manipulators relies on an exact model of the manipulator. Redundantly actuated PKM posses the ability to exhibit internal prestress that does not affect its environment. This allows for a purposeful distribution of control forces, taking into account secondary tasks, such optimal force distribution, active stiffness, and backlash avoiding control. In the presence of kinematic uncertainties this feature can become a serious problem since then the control forces may be annihilated or even some of the intentional prestress components may interfere with the environment. The effect of such kinematic uncertainties and the application of standard model-based control schemes is analyzed in this paper. It is shown that, in the presence of model uncertainties, it leads to parasitic perturbation forces that can not be compensated by the controls. An amended version of the augmented PD and computed torque control scheme is proposed that removes the parasitic feedback forces. View full abstract»

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  • A numerical solution to the ray-shooting problem and its applications in robotic grasping

    Publication Year: 2009 , Page(s): 2080 - 2085
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (281 KB) |  | HTML iconHTML  

    Based on the distance algorithm by Gilbert et al., this paper presents a numerical algorithm for computing the intersection of the boundary of a compact convex set with a ray emanating from an interior point of the set, which is known as the ray-shooting problem. Affinely independent points on the boundary of the convex set are also determined such that the intersection point can be written as their convex combination. Because of its high efficiency and other good qualities, this algorithm provides superior solutions to three fundamental problems in robotic grasping, i.e., force-closure test, contact force optimization, and grasp quality evaluation, which can be formulated as the ray-shooting problem. View full abstract»

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  • Rollover risk prediction of an instrumented heavy vehicle using high order sliding mode observer

    Publication Year: 2009 , Page(s): 64 - 69
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1814 KB) |  | HTML iconHTML  

    In this paper, an original method about heavy vehicles rollover risk prediction is presented and validated experimentally. It is based on the calculation of the LTR (load transfer ratio) which depends on the estimated vertical forces using high order sliding mode observers. The validation tests were carried out on an instrumented truck rolling on the road at various speeds and lane-change manoeuvres. Many scenarios have been experienced: driving on straight line, curve line and zigzag to emphasize the rollover phenomenon and its prediction to set off an alarm to the driver. View full abstract»

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  • Utilizing reflection properties of surfaces to improve mobile robot localization

    Publication Year: 2009 , Page(s): 4287 - 4292
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (451 KB) |  | HTML iconHTML  

    A main difficulty that arises in the context of probabilistic localization is the design of an appropriate observation model, i.e., determining the likelihood of a sensor measurement given the pose of the robot and a map of the environment. Many successful approaches to localization rely on data provided by range sensors, e.g., laser range scanners. When using such data one normally has to deal with erroneous maximum-range readings that occur due to poor-reflecting surfaces. In general, these readings cannot be distinguished from readings obtained when no obstacle is within the measurement range of the sensor. Therefore, existing localization techniques treat these readings alike in the observation model. In this paper, we present a novel approach that explicitly considers the reflection properties of surfaces and thus the expectation of valid range measurements. In addition to the expected range measurement, we compute the probability of reflectance for a beam given the relative pose of the robot to the obstacle taking into account the angle of incidence of the beam. We estimate the reflection properties of surfaces using data collected with a mobile robot equipped with a laser range scanner. As we demonstrate in experiments carried out with a real robot, our technique leads to significantly improved localization results compared to a state-of-the-art observation model. View full abstract»

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  • Motion planning for a golf swing robot based on reverse time symmetry and PGCTC control

    Publication Year: 2009 , Page(s): 4000 - 4005
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (625 KB) |  | HTML iconHTML  

    A new golf swing robot performing high-speed golf swings has been developed by the authors. This paper deals with the motion planning problem of the golf swing. At first, the reverse time symmetry and single pendulum inherences in manipulator dynamics are introduced. Then, by utilizing the first inherence, the Rest-to-Point motion planning problem for the backswing and downswing is transformed into a reverse time symmetric Point-to-Rest motion planning problem. Finally, based on the second inherence, a Proportional plus Gravity and Coupling Torque Compensation (PGCTC) control scheme is developed to solve both the reverse time symmetric Point-to-Rest motion planning problem for the backswing and downswing and the forward time Point-to-Rest problem for the follow-through. Simulation shows the effect of the proposed method. View full abstract»

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  • Semi-supervised particle filter for visual tracking

    Publication Year: 2009 , Page(s): 3928 - 3933
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (327 KB) |  | HTML iconHTML  

    In this paper, a semi-supervised particle filter approach is proposed for visual tracking. The combination of semi-supervised learning and particle filter is very natural since the unlabelled samples are generated by particle propagation. In addition, the proposed semi-supervised particle filter can online select different features for robust tracking. To the best knowledge of the authors, this is the first time for the semi-supervised learning technology to be incorporated into the framework of particle filter. Finally, the performance of the proposed approach is evaluated using real visual tracking examples. View full abstract»

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  • A genericity condition for general serial manipulators

    Publication Year: 2009 , Page(s): 2951 - 2956
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (190 KB) |  | HTML iconHTML  

    Generic manipulators possess the desireable properties that their set of singulartities is a smooth manifold, and that the drop of rank of the manipulator Jacobian is bounded. A sufficient condition for genericity is the transverse-regularity of its Jacobian mapping in any configuration. In this paper a necessary and sufficient condition for transverse-regularity is presented. The condition is based on the manipulator's joint screws and their screw products. It is also shown that a manipulator is non-generic if it can attain a pose where the rank of the manipulator's screw system together with the screw products is not the maximal rank of the Jacobian. View full abstract»

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  • A dynamic programming approach to multi-level supervision

    Publication Year: 2009 , Page(s): 908 - 913
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (317 KB) |  | HTML iconHTML  

    Using dynamic programming (DP), this paper presents a multi-level supervisory control implementation in the standard hierarchical discrete-event control framework. For a class of hierarchically consistent discrete-event systems, the DP algorithm developed implements a multi-level nonblocking controller with reduced off-line complexity of control synthesis and increased on-line transparency of control operations. An example illustrates the on-line control operations of the algorithm. View full abstract»

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  • ‘Teleportation’-Based Motion Planner for Design Error Analysis

    Publication Year: 2009 , Page(s): 914 - 920
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (675 KB) |  | HTML iconHTML  

    Probabilistic path planning techniques have proven to be vital for finding and validating solutions for difficult industrial assembly tasks. Nevertheless, the failure of a path planner to find a solution to a task does not suggest how to correct the error. We suggest a methodology to identify possible bottlenecks and present an algorithm to analyze the extent to which the design must be modified in order for the task to complete successfully. We validate our algorithm on two industrial problems involving design errors, and explain how to interpret the results in order to improve the design. View full abstract»

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  • SLAM in large indoor environments with low-cost, noisy, and sparse sonars

    Publication Year: 2009 , Page(s): 1395 - 1401
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (478 KB) |  | HTML iconHTML  

    Simultaneous localization and mapping (SLAM) is a well-studied problem in mobile robotics. However, the majority of the proposed techniques for SLAM rely on the use of accurate and dense measurements provided by laser rangefinders to correctly localize the robot and produce accurate and detailed maps of complex environments. Little work has been done on the use of low-cost but noisy and sparse sonar sensors for SLAM in large indoor environments involving large loops. In this paper, we present our approach to SLAM with sonar sensors by applying particle filtering and a line-segment-based map representation with an orthogonality assumption to map indoor environments much larger and more challenging than those previously considered with sonar sensors. Results from robotic experiments demonstrate that it is possible to produce good maps of large indoor environments with large loops despite the inherent limitations of sonar sensors. View full abstract»

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  • Above 40g acceleration for pick-and-place with a new 2-dof PKM

    Publication Year: 2009 , Page(s): 1794 - 1800
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1104 KB) |  | HTML iconHTML  

    This paper introduces a new two-degree-of-freedom parallel manipulator producing two translations in the vertical plane. One drawback of existing robots built to realize those dof is their lack of rigidity along the transversal axis, another one being their limited ability to provide very high acceleration. Indeed, these architectures cannot be lightweight and stiff at the same time. The proposed architecture is a spatial mechanism which guarantees a good stiffness along the transversal axis. This parallel architecture is composed by two actuated kinematic chains, and two passive chains built in the transversal plane. The key feature of this robot comes from the passive chains which are coupled for creating a kinematic constraint: the platform stays in one plane. A stiffness analysis shows that the robot can be lighter and stiffer than a classical 2 dof mechanism. A prototype of this robot is presented and preliminary tests show that accelerations above 40 g can be achieved while keeping a low tracking error. View full abstract»

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  • Development of robot hand aiming at nursing care services to humans

    Publication Year: 2009 , Page(s): 3663 - 3669
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (809 KB) |  | HTML iconHTML  

    This paper describes a multi-joint robot finger with soft compliant mechanism for safe and comfortable nursing-care services. In proposed mechanism, we utilize 2 different types of elastic elements at fingertip and MP joint (Metacarpa-Phalangeal Joint), respectively, so as to realize soft and stable contact with human body. At fingertip, a hemisphere shaped silicone gum cushion is mounted, while eight cylindrical cushions are placed between the motor and the link inside MP joint. These cushions deform easily and, as a result, absorb external forces exerted from multiple directions. Furthermore the amplitudes and the directions of applied forces can be estimated with the information of changes in the pressure of each cushion.We examined the fundamental characteristics and performance of this finger module through several experiments. View full abstract»

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  • Piezoelectrically driven silicon microgrippers integrated with sidewall piezoresistive sensor

    Publication Year: 2009 , Page(s): 2989 - 2994
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1699 KB) |  | HTML iconHTML  

    This paper presents the design, fabrication, and application of an piezoelectrically driven microgripper integrated sidewall piezoresistive force sensor for measuring the gripping force. Surface and bulk micromachining technology is employed to fabricate end-effectors and sensor of the microgripper from a single crystal silicon wafer. Vertical sidewall surface piezoresistor etching technique is used to form the side direction sensors. The end-effectors of the gripper are four-bar structures. Two fixed cantilever beams integrated with piezoresistive sensor are designed to sense the gripping force, and a piezoelectrically driven microactuator is designed to provide the force to operate the other two movable bars. The piezoelectrically driver adhered with the silicon end-effectors generates a linear horizontal motion 9 mum, which is amplified to 30 mum at the bar tip of the microgripper. Then the range of the operation is 25 mum - 140 mum. Testing results verify that the vertical sidewall surface piezoresistor etching technique is effective. The sensitivity of the piezoresistive sensors is better than 72 V/N, and the resolution is better than 3 muN. View full abstract»

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  • Basic study of biarticular muscle's effect on muscular internal force control based on physiological hypotheses

    Publication Year: 2009 , Page(s): 4195 - 4200
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (558 KB) |  | HTML iconHTML  

    In a musculoskeletal structure, the internal force among muscles plays an important role. Changing the internal force enables to control not only joint angles but also impedance, so that vertebrate animals can produce a motion according to a situation. Focusing on a musculoskeletal system with two links and six muscles, this paper investigate the effect of biarticular muscles when feedforward position control is inputted. This control gives the constant internal force balancing at desired posture as feedforward input, based on the EP hypothesis in physiology. From the result, we point out that the biarticular muscles can reduce the convergent time of the motion, and they also can stabilize the system. View full abstract»

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  • Robust servo-control for underwater robots using banks of visual filters

    Publication Year: 2009 , Page(s): 3583 - 3588
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1836 KB) |  | HTML iconHTML  

    We present an application of machine learning to the semi-automatic synthesis of robust servo-trackers for underwater robotics. In particular, we investigate an approach based on the use of Boosting for robust visual tracking of color objects in an underwater environment. To this end, we use AdaBoost, the most common variant of the Boosting algorithm, to select a number of low-complexity but moderately accurate color feature trackers and we combine their outputs. The novelty of our approach lies in the design of this family of weak trackers, which enhances a straightforward color segmentation tracker in multiple ways. From a large and diverse family of possible filters, we select a small subset that optimizes the performance of our trackers. The tracking process applies these trackers on the input video frames, and the final tracker output is chosen based on the weights of the final array of trackers. By using computationally inexpensive, but somewhat accurate trackers as members of the ensemble, the system is able to run at quasi real-time, and thus, is deployable on-board our underwater robot. We present quantitative cross-validation results of our spatio-chromatic visual tracker, and conclude by pointing out some difficulties faced and subsequent shortcomings in the experiments we performed, along with directions of future research in the area of ensemble tracking in real-time. View full abstract»

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  • Control of a four-steering, planar five-bar linkage-walker

    Publication Year: 2009 , Page(s): 2957 - 2964
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (210 KB) |  | HTML iconHTML  

    This paper introduces and describes a new type of wheeled locomotor referred to as a "four-steering, planar five-bar linkage-walker." This wheeled locomotor is a nonholonomic mechanical system that consists of five links, five rotational joints, and four steering systems. The five links coupled by the five joints form a closed-loop. The four steering systems are attached to four of the five links. Each of the four links has its own steering system at its middle point. The wheeled locomotor transforms the rotations of the five joints into movement by using the four steering systems. This means that the wheeled locomotor performs undulatory locomotion in which it transforms a change in its internal shape into the generation of its net displacement. In addition, a virtual joint is added to one of the ends of the first link. The virtual joint couples the first link and a virtual link which has a virtual axle at its middle point and a virtual steering system at its end. It is proven that, by assuming the presence of such virtual mechanical elements, it is possible to convert the kinematic equation of the wheeled locomotor into a five-chain, single-generator chained form in differential geometry. Based on chained form, a path-following feedback control method that enables the wheeled locomotor to follow a straight line is derived. The validity of the mechanical design of the wheeled locomotor, the transformation of its kinematic equation into chained form, and the path-following feedback control method is verified by computer simulation. View full abstract»

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  • Qualitative robot localisation using information from cast shadows

    Publication Year: 2009 , Page(s): 220 - 225
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (407 KB) |  | HTML iconHTML  

    Recently, cognitive psychologists and others have turned their attention to the formerly neglected study of shadows, and the information they purvey. These studies show that the human perceptual system values information from shadows very highly, particularly in the perception of depth, even to the detriment of other cues. However with a few notable exceptions, computer vision systems have treated shadows not as signal but as noise. This paper makes a step towards redressing this imbalance by considering the formal representation of shadows. We take one particular aspect of reasoning about shadows, developing the idea that shadows carry information about a fragment of the viewpoint of the light source. We start from the observation that the region on which the shadow is cast is occluded by the caster with respect to the light source and build a qualitative theory about shadows using a region-based spatial formalism about occlusion. Using this spatial formalism and a machine vision system we are able to draw simple conclusions about domain objects and egolocation for a mobile robot. View full abstract»

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  • Torque modeling and analysis of spherical cctuators with iron stator

    Publication Year: 2009 , Page(s): 164 - 169
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (529 KB) |  | HTML iconHTML  

    This paper presents a ball-joint-like three-degree-of-freedom (3-DOF) permanent magnet (PM) spherical actuator which features a ball-shaped rotor with multiple PM poles and a spherical iron stator with air-core coils. Torque output of this PM spherical actuator is formulated analytically. Based on the torque model, simulation result of the actuator torque variation is presented. In addition, the effect of the stator iron on the torque output is evaluated. View full abstract»

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