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Robotics, IEEE Transactions on

Issue 4 • Date Aug. 2014

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Displaying Results 1 - 25 of 28
  • Table of contents

    Publication Year: 2014 , Page(s): C1
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  • IEEE Transactions on Robotics publication information

    Publication Year: 2014 , Page(s): C2
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  • High-Gain, High Transmissibility PZT Displacement Amplification Using a Rolling-Contact Buckling Mechanism and Preload Compensation Springs

    Publication Year: 2014 , Page(s): 781 - 791
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1333 KB) |  | HTML iconHTML  

    A novel design concept of piezoelectric actuators producing large displacement while transmitting a significant amount of energy is presented. A rolling-contact buckling mechanism with a novel preload mechanism can amplify the PZT stack's displacement on the order of 100 times while transmitting several times larger work output than conventional flexure-type displacement amplification mechanisms. Existing displacement amplification mechanisms are analyzed in terms of transmissibility and are characterized with two lumped-parameter elements: serial and parallel compliances. The maximum transmissibility is attained when the parallel stiffness and the serial compliance are zero. An existing flexure mechanism using structural buckling, that produces a large displacement but a low transmissibility, is replaced by a rolling-contact mechanism that approaches the maximum criterion. Furthermore, a mechanism is presented to apply a constant preload to each PZT stack despite their movement. A prototype has been built to implement the design concept and verify the theoretical results. Experiments using the prototype demonstrate that it produces a 4.2 mm free displacement with over 60% transmissibility. View full abstract»

    Open Access
  • Design of Efficient Propulsion for Nanorobots

    Publication Year: 2014 , Page(s): 792 - 801
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    Due to the constraints imposed at low Reynolds number, the design of efficient propulsive systems for nanorobots has proven challenging. In this paper, an approach for the design of an efficient nanorobotic propulsive system was proposed. First, resistive force theory was used to develop a dynamic model for the propulsion of nanorobots, accounting for the fluid dynamics generated by the propeller (flagellum). Second, an optimal control problem was formulated and solved to balance the tradeoff between energy utilization and tracking efficiency. Finally, simulations were conducted to analyze the effect of different body to flagellum ratios (BFR) on propulsive efficiency. It was found that the optimal flexural rigidity of the nanorobot propeller was 5.8 × 10 -19N·m 2, within the range of sperm flagellum, 0.7 × 10 -19 -74.0 × 10 -19N·m 2. Simulations of multiple BFRs demonstrated that multipoint actuation of the nanopropeller was more efficient at BFRs of less than 1.0, while single actuation was only effective for nanorobots with a BFR >0.2. The results from this study could provide useful insights for the design of efficient nanorobotic propulsive systems, in terms of energy efficiency and trajectory tracking accuracy. View full abstract»

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  • Compact Robotically Steerable Image-Guided Instrument for Multi-Adjacent-Point (MAP) Targeting

    Publication Year: 2014 , Page(s): 802 - 815
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    Accurately targeting multi-adjacent points (MAPs) during image-guided percutaneous procedures is challenging due to needle deflection and misalignment. The associated errors can result in inadequate treatment of cancer in the case of prostate brachytherapy, or inaccurate diagnosis during biopsy, while repeated insertions increase procedure time, radiation dose, and complications. To address these challenges, we present an image-guided robotic system capable of MAP targeting of irregularly shaped volumes after a single insertion of a percutaneous instrument. The design of the compact CT-compatible drive mechanism is based on a nested screw and screw-spline combination that actuates a straight outer cannula and a curved inner stylet that can be repeatedly straightened when retracted inside the cannula. The stylet translation and cannula rotation/translation enable a 3-D workspace to be reached with the stylet's tip. A closed-form inverse kinematics and image-to-robot registration are implemented in an image-guided system including a point-and-click user interface. The complete system is successfully evaluated with a phantom under a Siemens Definition Flash CT scanner. We demonstrate that the system is capable of MAP targeting for a 2-D shape of the letter “H” and a 3-D helical pattern with an average targeting error of 2.41 mm. These results highlight the benefit and efficacy of the proposed robotic system in seed placement during image-guided brachytherapy. View full abstract»

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  • Coupling Movement Primitives: Interaction With the Environment and Bimanual Tasks

    Publication Year: 2014 , Page(s): 816 - 830
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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (997 KB) |  | HTML iconHTML  

    The framework of dynamic movement primitives (DMPs) contains many favorable properties for the execution of robotic trajectories, such as indirect dependence on time, response to perturbations, and the ability to easily modulate the given trajectories, but the framework in its original form remains constrained to the kinematic aspect of the movement. In this paper, we bridge the gap to dynamic behavior by extending the framework with force/torque feedback. We propose and evaluate a modulation approach that allows interaction with objects and the environment. Through the proposed coupling of originally independent robotic trajectories, the approach also enables the execution of bimanual and tightly coupled cooperative tasks. We apply an iterative learning control algorithm to learn a coupling term, which is applied to the original trajectory in a feed-forward fashion and, thus, modifies the trajectory in accordance to the desired positions or external forces. A stability analysis and results of simulated and real-world experiments using two KUKA LWR arms for bimanual tasks and interaction with the environment are presented. By expanding on the framework of DMPs, we keep all the favorable properties, which is demonstrated with temporal modulation and in a two-agent obstacle avoidance task. View full abstract»

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  • Cooperative Visibility Maintenance for Leader–Follower Formations in Obstacle Environments

    Publication Year: 2014 , Page(s): 831 - 844
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2109 KB) |  | HTML iconHTML  

    Vision-based formation control of multiple agents, such as mobile robots or fully autonomous cars, has recently received great interest due to its application in robotic networks and automated highways. This paper addresses the cooperative motion coordination of leader-follower formations of nonholonomic mobile robots, under visibility and communication constraints in known polygonal obstacle environments. We initially consider the case of N = 2 agents moving in L-F fashion and propose a feedback control strategy under which L ensures obstacle avoidance for both robots, while F ensures visibility maintenance with L and intervehicle collision avoidance. The derived algorithms are based on set-theoretic methods to guarantee visibility maintenance, dipolar vector fields to maintain the formation shape, and the consideration of the formation as a tractor-trailer system to ensure obstacle avoidance. We furthermore show how the coordination and control design extends to the case of N > 2 agents, and provide simulation results, which demonstrate the efficacy of the control solutions. The proposed algorithms do not require information exchange among robots, but are instead based on information locally available to each agent. In this way, the desired tasks are executed and achieved in a decentralized manner, with each robot taking care of converging to a desired configuration, while maintaining visibility with its target. View full abstract»

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  • Nonlinear RISE-Based Control of an Autonomous Underwater Vehicle

    Publication Year: 2014 , Page(s): 845 - 852
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1921 KB) |  | HTML iconHTML  

    This study focuses on the development of a nonlinear control design for a fully-actuated autonomous underwater vehicle (AUV) using a continuous robust integral of the sign of the error control structure to compensate for system uncertainties and sufficiently smooth bounded exogenous disturbances. A Lyapunov stability analysis is included to prove semiglobal asymptotic tracking. The resulting controller is experimentally validated on an AUV developed at the University of Florida in both controlled and open-water environments. View full abstract»

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  • Needle Steering in 3-D Via Rapid Replanning

    Publication Year: 2014 , Page(s): 853 - 864
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (938 KB) |  | HTML iconHTML  

    Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm. View full abstract»

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  • Nonlinear Oscillations for Cyclic Movements in Human and Robotic Arms

    Publication Year: 2014 , Page(s): 865 - 879
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2281 KB) |  | HTML iconHTML  

    The elastic energy storage in biologically inspired variable impedance actuators (VIA) offer the capability of executing cyclic and/or explosive multi-degree of freedom (DoF) motions efficiently. This paper studies the generation of cyclic motions for strongly nonlinear underactuated multi-DoF serial robotic arms. By experimental observations of human motor control, a simple and robust control law is deduced. This controller achieves intrinsic oscillatory motions by switching the motor position triggered by a joint torque threshold. Using the derived controller, the oscillatory behavior of human and robotic arms is analyzed in simulations and experiments. It is found that the existence of easily excitable oscillation modes strongly depends on the damping properties of the plant. If the intrinsic damping properties are such that oscillations excited in the undesired modes decay faster than in the desired mode, then multi-DoF oscillations are easily excitable. Simulations and experiments reveal that serially-structured elastic multibody systems such as VIA or human arms with approximately equal joint damping, fulfill these requirements. View full abstract»

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  • Model-Less Feedback Control of Continuum Manipulators in Constrained Environments

    Publication Year: 2014 , Page(s): 880 - 889
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (806 KB) |  | HTML iconHTML  

    Continuum manipulators offer a means for robot manipulation in a constrained environment, where the manipulator body can safely interact with, comply with, and navigate around obstacles. However, obstacle interactions impose constraints that conform the robot body into arbitrary shapes regardless of actuator positions. Generally, these effects cannot be wholly sensed on a continuum manipulator and, therefore, render model-based controllers incorrect, leading to artificial singularities and unstable behavior. We present a task-space closed-loop controller for continuum manipulators that does not rely on a model and can be used in constrained environments. Using an optimal control strategy on a tendon-driven robot, we demonstrate this method, which we term model-less control, which allows the manipulator to interact with several constrained environments in a stable manner. To the best of our knowledge, this is the first work in controlling continuum manipulators without using a model. View full abstract»

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  • Compliant Motion Control for Multisegment Continuum Robots With Actuation Force Sensing

    Publication Year: 2014 , Page(s): 890 - 902
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1185 KB) |  | HTML iconHTML  

    During exploration through tortuous unstructured passages by continuum robots, methods are required to minimize the force interaction between the environment and the robot along its length. This paper presents and evaluates an algorithm for compliant motion control of continuum robots subjected to multiple unknown contacts with the environment. A mapping of external wrenches to a generalized force in the configuration space of a multisegment continuum robot is presented and related to measured joint-level actuation forces. These measurements are applied as inputs to a low-level compliant motion controller. Friction and modeling uncertainties, presenting an unknown nonlinear deviation from the nominal system model, are corrected via a feed-forward estimate provided by a support vector machine. The controller is evaluated on Ø9 and Ø5 mm multisegment continuum robots. We quantify the minimal interaction forces needed to generate compliant motion and demonstrate the ability of the controller to minimize interaction forces during insertion through tortuous passages. View full abstract»

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  • Online Verification of Automated Road Vehicles Using Reachability Analysis

    Publication Year: 2014 , Page(s): 903 - 918
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4729 KB) |  | HTML iconHTML  

    An approach for formally verifying the safety of automated vehicles is proposed. Due to the uniqueness of each traffic situation, we verify safety online, i.e., during the operation of the vehicle. The verification is performed by predicting the set of all possible occupancies of the automated vehicle and other traffic participants on the road. In order to capture all possible future scenarios, we apply reachability analysis to consider all possible behaviors of mathematical models considering uncertain inputs (e.g., sensor noise, disturbances) and partially unknown initial states. Safety is guaranteed with respect to the modeled uncertainties and behaviors if the occupancy of the automated vehicle does not intersect that of other traffic participants for all times. The applicability of the approach is demonstrated by test drives with an automated vehicle at the Robotics Institute at Carnegie Mellon University. View full abstract»

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  • An Information Potential Approach to Integrated Sensor Path Planning and Control

    Publication Year: 2014 , Page(s): 919 - 934
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (8669 KB) |  | HTML iconHTML  

    This paper presents an information potential method for integrated path planning and control. The method is applicable to unicycle robotic sensors deployed to classify multiple targets in an obstacle-populated environment. A new navigation function, referred to as information potential, is generated from the target conditional mutual information, and used to design a closed-loop stable switched control law. The information potential is shown to obey the properties of potential navigation functions and to enable measurements that maximize the information value over time. The information potential is also used to construct a local roadmap for escaping local minima. The properties and computational complexity of the local roadmap algorithm are analyzed. Numerical simulation results show that the method outperforms other strategies, such as rapidly exploring random trees and classical potential field methods. View full abstract»

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  • A Variable Curvature Continuum Kinematics for Kinematic Control of the Bionic Handling Assistant

    Publication Year: 2014 , Page(s): 935 - 949
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2431 KB) |  | HTML iconHTML  

    We present a new variable curvature continuum kinematics for multisection continuum robots with arbitrarily shaped backbone curves assembled from sections with three degrees of freedom (DoFs) (spatial bending and extension, no torsion). For these robots, the forward kinematics and the differential forward kinematics are derived. The proposed model approach is capable of reproducing both the constant and variable backbone curvature in a closed form. It describes the deformation of a single section with a finite number of serially connected circular arcs. This yields a section model with piecewise constant and, thus, a variable section curvature. Model accuracy and its suitability for kinematic real-time control applications are demonstrated with simulations and experimental data. To solve the redundant inverse kinematics problem, a local resolution of redundancy at the velocity level through the use of the robot's Jacobian matrix is presented. The Jacobian is derived analytically, including a concept for regularization in singular configurations. Experimental data are recorded with Festo's Bionic Handling Assistant. This continuum robot is chosen for experimental validation, as it consists of a variable backbone curvature because of its conically tapering shape. View full abstract»

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  • Evaluating Network Rigidity in Realistic Systems: Decentralization, Asynchronicity, and Parallelization

    Publication Year: 2014 , Page(s): 950 - 965
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    In this paper, we consider the problem of evaluating the rigidity of a planar network, while satisfying common objectives of real-world systems: decentralization, asynchronicity, and parallelization. The implications that rigidity has in fundamental multirobot problems, e.g., guaranteed formation stability and relative localizability, motivates this study. We propose the decentralization of the pebble game algorithm of Jacobs et al. , which is an O(n2) method that determines the generic rigidity of a planar network. Our decentralization is based on asynchronous messaging and distributed memory, coupled with auctions for electing leaders to arbitrate rigidity evaluation. Further, we provide a parallelization that takes inspiration from gossip algorithms to yield significantly reduced execution time and messaging. An analysis of the correctness, finite termination, and complexity is given, along with a simulated application in decentralized rigidity control. Finally, we provide Monte Carlo analysis in a Contiki networking environment, illustrating the real-world applicability of our methods, and yielding a bridge between rigidity theory and realistic interacting systems. View full abstract»

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  • Online Coverage by a Tethered Autonomous Mobile Robot in Planar Unknown Environments

    Publication Year: 2014 , Page(s): 966 - 974
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (857 KB) |  | HTML iconHTML  

    This paper is concerned with an online tethered coverage (TC), in which a mobile robot of size D is attached to a fixed point S by a cable of finite length L. Starting at S, the robot has to cover an unknown planar environment that contains obstacles and return to S with the cable fully retracted. The paper first establishes an optimal offline TC methodology, then introduces the TC algorithm that performs an online TC using position and local obstacle detection sensors. The performance of the TC algorithm is measured by its competitiveness, determined by measuring its total online path length l relative to the optimal offline solution lopt . The paper establishes that the TC algorithm has a competitive performance of l ≤ 2 L/D lopt. The paper additionally establishes a lower bound of l ≥ log(L/D) lopt over a generic family of TC algorithms of which the TC algorithm is a special case. Execution example and experiments with a tethered recoiling mechanism illustrate the usefulness of the TC algorithm. View full abstract»

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  • Sophia-3: A Semiadaptive Cable-Driven Rehabilitation Device With a Tilting Working Plane

    Publication Year: 2014 , Page(s): 974 - 979
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (645 KB) |  | HTML iconHTML  

    Sophia-3 (string-operated planar haptic interface for arm rehabilitation) is a planar cable-driven device with a tilting working plane. It represents the first application of the adaptive cable-driven design paradigm recently introduced by the authors, featuring a moving pulley-block that allows the robot to achieve excellent force capabilities, despite the low number of cables. This study presents the design, kinematics, and control of the device and results of experimental validation on healthy subjects. View full abstract»

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  • Optimal Path Following for Differentially Flat Robotic Systems Through a Geometric Problem Formulation

    Publication Year: 2014 , Page(s): 980 - 985
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (419 KB) |  | HTML iconHTML  

    Path following deals with the problem of following a geometric path with no predefined timing information and constitutes an important step in solving the motion-planning problem. For differentially flat systems, it has been shown that the projection of the dynamics along the geometric path onto a linear single-input system leads to a small dimensional optimal control problem. Although the projection simplifies the problem to great extent, the resulting problem remains difficult to solve, in particular in the case of nonlinear system dynamics and time-optimal problems. This paper proposes a nonlinear change of variables, using a time transformation, to arrive at a fixed end-time optimal control problem. Numerical simulations on a robotic manipulator and a quadrotor reveal that the proposed problem formulation is solved efficiently without requiring an accurate initial guess. View full abstract»

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  • Energy-Efficient Gait Planning and Control for Biped Robots Utilizing the Allowable ZMP Region

    Publication Year: 2014 , Page(s): 986 - 993
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (864 KB) |  | HTML iconHTML  

    Energy-efficient gait planning and control is established for biped robots, which utilizes the allowable zero moment point (ZMP) region. Based on 3-D linear inverted pendulum mode (LIPM), we construct a practical gait planning algorithm for a given travel distance minimizing the energy consumed by the actuators of humanoid joints with 1) an online gait synthesis (GSYN) algorithm to generate a complete walking cycle (a starting step, several cyclic steps, and a stopping step) compromising waking stability and energy efficiency at the fully utilizing allowable ZMP region and with 2) effective gait parameter optimization to maximize the energy efficiency of the gaits generated by GSYN, finding two optimal parameters-number of steps and average walking speed-satisfying geometrical constraints, friction force limit, and yawing moment limit to guarantee feasible motions. The proposed algorithm was verified through simulations, and the gait control system was implemented on a DARwIn-OP humanoid robot. View full abstract»

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  • A Motion Planning Strategy for a Spherical Rolling Robot Driven by Two Internal Rotors

    Publication Year: 2014 , Page(s): 993 - 1002
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    This paper deals with a motion planning problem for a spherical rolling robot actuated by two internal rotors that are placed on orthogonal axes. The key feature of the problem is that it can be stated only in dynamic formulation. In addition, the problem features a singularity when the contact trajectory goes along the equatorial line in the plane of the two rotors. A motion planning strategy composed of two trivial and one nontrivial maneuver is devised. The trivial maneuvers implement motion along the geodesic line perpendicular to the singularity line. The construction of the nontrivial maneuver employs the nilpotent approximation of the originally nonnilpotent robot dynamics, and is based on an iterative steering algorithm. At each iteration, the control inputs are constructed with the use of geometric phases. The motion planning strategy thus constructed is verified under simulation. View full abstract»

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  • A Selective Retraction-Based RRT Planner for Various Environments

    Publication Year: 2014 , Page(s): 1002 - 1011
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    We present a novel randomized path planner for rigid robots to efficiently handle various environments that have different characteristics. We first present a bridge line test that can identify narrow passage regions and then selectively performs an optimization-based retraction only at those regions. We also propose a noncolliding line test, which is a dual operator to the bridge line test, as a culling method to avoid generating samples near wide-open free spaces. These two line tests are performed with a small computational overhead. We have tested our method with different benchmarks that have varying amounts of narrow passages. Our method achieves up to several times improvements over prior RRT-based planners and consistently shows the best performance across all the tested benchmarks. View full abstract»

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  • Curvature-Bounded Traversability Analysis in Motion Planning for Mobile Robots

    Publication Year: 2014 , Page(s): 1011 - 1019
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (595 KB) |  | HTML iconHTML  

    We consider the geometric problem of deciding whether a narrow planar passage can be traversed by a curve that satisfies prespecified upper bounds on its curvature. This problem is of importance for path- and motion-planning of autonomous mobile robots, particularly when vehicle dynamical constraints are considered during planning. For a special case of narrow passages, namely, rectangular channels, we present a fast numerical algorithm to determine if a given channel may be traversed via curvature-bounded paths. We demonstrate that the proposed algorithm can affirm traversability in cases where the most recent result in the literature fails. View full abstract»

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  • On Intensity-Based Nonmetric Visual Servoing

    Publication Year: 2014 , Page(s): 1019 - 1026
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (897 KB) |  | HTML iconHTML  

    This paper considers the problem of vision-based robot stabilization where the equilibrium state is defined via a reference image. Differently from most solutions, this study directly exploits the pixel intensities with no feature extraction or matching and uses only nonmetric information of the observed scene. Intensity-based techniques provide higher accuracy, whereas not requiring metric information increases their versatility. In this context, this paper further exploits the epipolar geometry and its intrinsic degeneracies. Such degeneracies always occur when that stabilization is sufficiently close to the equilibrium, regardless of the object shape. This remarkable fact allows the development of new vision-based control strategies with varying degrees of computational complexity and of prior knowledge. Importantly, they are arranged hierarchically from the simplest to the state-of-the-art ones, all in a unified framework. Three new local methods are then presented, and their closed-loop performances are experimentally assessed using both planar and nonplanar objects, under small and large displacements, simulating and employing a six-degree-of-freedom robotic arm. View full abstract»

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  • Visual Servoing Trajectory Tracking of Nonholonomic Mobile Robots Without Direct Position Measurement

    Publication Year: 2014 , Page(s): 1026 - 1035
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB) |  | HTML iconHTML  

    Localization is one of the most difficult and costly problems in mobile robotics. To avoid this problem, this paper presents a new controller for the trajectory tracking of nonholonomic mobile robots using visual feedback without direct position measurement. This controller works on the basis of a novel adaptive algorithm for estimating the global position of the mobile robot online using natural visual features measured by a vision system and its orientation and velocity measured by odometry and Attitude and Heading Reference System (IMU&Compass) sensors. The nonholonomic motion constraint of mobile robots is fully taken into account, compared with most of the existing visual servo controllers for mobile robots. The Lyapunov theory is used to prove that the proposed adaptive visual servo controller gives rise to asymptotic tracking of a desired trajectory and convergence of the position estimation to the actual position. A graphical processing unit is adopted to implement the proposed adaptive controller in parallel to achieve real-time detection and tracking of visual features. Experiments on a mobile robot are conducted to validate the effectiveness and robust performance of the proposed controller. View full abstract»

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Aims & Scope

IEEE Transactions on Robotics covers both theory and applications on topics including: kinematics, dynamics, control, and simulation of robots and intelligent machines and systems.

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Meet Our Editors

Editor-in-Chief
Frank Park
Seoul National University