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Robotics and Automation, 2006. ICRA 2006. Proceedings 2006 IEEE International Conference on

Date 15-19 May 2006

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Displaying Results 1 - 25 of 686
  • Proceedings 2006 IEEE International Conference on Robotics and Automation - Cover

    Publication Year: 2006 , Page(s): 0_1
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  • Proceedings 2006 IEEE International Conference on Robotics and Automation [Title page]

    Publication Year: 2006 , Page(s): 0_2
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  • [Copyright notice]

    Publication Year: 2006 , Page(s): 0_3
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  • Table of contents

    Publication Year: 2006 , Page(s): I - VII
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  • A vision-based nonlinear decentralized controller for unmanned vehicles

    Publication Year: 2006 , Page(s): 1 - 6
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (510 KB) |  | HTML iconHTML  

    This paper presents a vision-based control strategy for decentralized stabilization of unmanned vehicle (UV) formations. The key point of the algorithm is that it only requires knowledge of the leader-follower relative distance and bearing. The approach is based on an output feedback controller that uses a high-gain observer to estimate derivatives of UVs relative positions. Both data are measured using a pan-controlled camera on-board the following robot which eliminates sensitivity to information flow among vehicles. A Lyapunov stability analysis guarantees that the closed-loop system is stable and the formation error can be made arbitrarily small. A virtual environment and a vision system are used to validate the proposed methodology View full abstract»

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  • Bounded torque control for robot manipulators subject to joint velocity constraints

    Publication Year: 2006 , Page(s): 7 - 12
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (311 KB)  

    This paper presents a bounded torque control design to solve the set-point regulation problem for robot manipulators subject to joint velocity constraints. The control objectives are achieved by exploiting the passivity properties of the system and utilizing barrier function ideas to reshape the control Lyapunov function. The structure of the modified control Lyapunov function is reminiscent of those used in the artificial potential field method. The resulting controllers are modified proportional-derivative controllers which are simple, intuitive, and can easily be implemented in practice. In addition, asymptotic stability of the closed-loop system is guaranteed, all joint velocity constraints are strictly satisfied for all time, and the demanded torque input is bounded in norm, irrespective of the initial condition. The effectiveness of the proposed control design is demonstrated through simulations on a 2-link planar manipulator View full abstract»

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  • A new velocity field controller for robot arms

    Publication Year: 2006 , Page(s): 13 - 18
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (309 KB) |  | HTML iconHTML  

    By using only position measurements, in this paper is discussed a new control algorithm for velocity field control of robot arms. A velocity field defines the robot desired velocity in the operational space as a function of its current position. The introduced algorithm is based on a hierarchical structure that result of using the kinematic control concept and a joint velocity controller View full abstract»

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  • Tracking control of on-line time-scaled trajectories for robot manipulators under constrained torques

    Publication Year: 2006 , Page(s): 19 - 24
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (357 KB) |  | HTML iconHTML  

    We introduce a control scheme based on using a trajectory tracking controller and an algorithm for on-line time-scaling of the reference trajectories. The reference trajectories are time-scaled according to the measured tracking errors and the detected torque/acceleration saturation. Simulations are presented to illustrate the advantages of the proposed approach View full abstract»

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  • Proxy-based sliding mode control for accurate and safe position control

    Publication Year: 2006 , Page(s): 25 - 30
    Cited by:  Papers (16)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    High-gain PID position control, which is widely used with industrial robots, involves some risks in cases of abnormal events, such as unexpected environment contacts and temporal power failures. This paper proposes a new position control method to achieve both accurate, responsive tracking during normal operation and smooth, overdamped recovery from a large positional error after abnormal events. The proposed method, which we call proxy-based sliding mode control, is a modified version of sliding mode control adapted to discrete-time systems, and also is an extension of PID control. The validity of the proposed method is demonstrated through experiments View full abstract»

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  • The design of a friction compensation control architecture for a heavy lift precision manipulator in contact with the environment

    Publication Year: 2006 , Page(s): 31 - 36
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (439 KB) |  | HTML iconHTML  

    Joint friction is a major obstacle in heavy-lift precision manipulator performance. Friction compensation is vital to the performance of these manipulators. This paper presents a friction compensation architecture for a six degree-of-freedom heavy lift manipulator which utilizes sensor-based compensation in some joints, and a combination of adaptive, and model-based compensation in the remaining joints. The adaptive approach is used when the manipulator is not in contact with the environment, and the model-based compensation is used when the manipulator or its payload nears the environment. The parameters of the model-based approach are updated by the adaptive compensation during the non-contact phase of the task. This approach is validated in simulation View full abstract»

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  • Global localization using odometry

    Publication Year: 2006 , Page(s): 37 - 42
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (330 KB) |  | HTML iconHTML  

    This paper presents a global localization technique for a robot with only linear and angular odometers. The robot, whose configuration is composed of its position and orientation, moves in a fully-known environment by alternating rotations and forward translations. We pose the problem as a discrete-time planning problem in the robot's information space, which encapsulates the uncertainty in the robot's configuration. Our contribution is to show that in any simply-connected, bounded polygonal environment, localization by odometry alone is possible, but only up to the symmetries in the environment View full abstract»

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  • Automatic self-calibration of a vision system during robot motion

    Publication Year: 2006 , Page(s): 43 - 48
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (594 KB) |  | HTML iconHTML  

    This paper presents a new technique to estimate the extrinsic parameters of a robot-vision sensor system. More in general, this technique can be adopted to calibrate any robot bearing sensor. It is based on the extended Kalman filter. It is very simple and allows an automatic self-calibration during the robot motion. It only requires a source of light in the environment and an odometry system on the robot. The strategy is theoretically validated through an observability analysis which takes into account the system nonlinearities. This analysis shows that the system contains all the necessary information to perform the self-calibration. Furthermore, many accurate simulations and experiments performed on a real platform equipped with encoder sensors and an omnidirectional conic vision sensor, show the exceptional performance of the strategy View full abstract»

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  • Adapting proposal distributions for accurate, efficient mobile robot localization

    Publication Year: 2006 , Page(s): 49 - 55
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (346 KB) |  | HTML iconHTML  

    When performing probabilistic localization using a particle filter, a robot must have a good proposal distribution in which to distribute its particles. Once weighted by their normalized likelihood scores, these particles estimate a posterior distribution over the possible poses of the robot. This paper 1) introduces a new action model (the system of equations used to determine the proposal distribution at each time step) that can run on any differential drive robot, even from log file data, 2) investigates the results of different algorithms that modify the proposal distribution at each time step in order to obtain more accurate localization, 3) investigates the results of incrementally adapting the action model parameters based on recent localization results in order to obtain proposal distributions that better approximate the true posteriors. The results show that by adapting the action model over time and, when necessary, modifying the resulting proposal distributions at each time step, localization improves-the maximum likelihood score increases and, when possible, the percentage of wasted particles decreases View full abstract»

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  • Gaussian process models for sensor-centric robot localisation

    Publication Year: 2006 , Page(s): 56 - 61
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (762 KB) |  | HTML iconHTML  

    This paper presents an approach to building an observation likelihood function from a set of sparse, noisy training observations taken from known locations by a sensor with no obvious geometric model. The basic approach is to fit an interpolant to the training data, representing the expected observation, and to assume additive sensor noise. This paper takes a Bayesian view of the problem, maintaining a posterior over interpolants rather than simply the maximum-likelihood interpolant, giving a measure of uncertainty in the map at any point. This is done using a Gaussian process framework. To validate the approach experimentally, a model of an environment is built using observations from an omni-directional camera. After a model has been built from the training data, a particle filter is used to localise while traversing this environment View full abstract»

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  • Further studies on the use of negative information in mobile robot localization

    Publication Year: 2006 , Page(s): 62 - 67
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB) |  | HTML iconHTML  

    This paper deals with how the absence of an expected sensor reading can be used to improve Markov localization. Negative information has not been used for robot localization for various reasons like sensor imperfections, and occlusions that make it hard to determine if a missing sensor reading is really caused by the absence of a feature. We address these difficulties by carefully modeling the robot's main sensor, its camera. Taking into account the viewing frustum and detected obstacles, the absence of a sensor reading can be associated with the absence of that particular feature. This information can then be integrated into the localization process. We show the positive effect on robot localization in various experiments. (a) In a specific setup, the robot is able to localize using negative information where without it, it is unable to localize. (b) We demonstrate the importance of modeling occlusions and the impact of false negatives on localization. (c) We show the positive impact in a typical run View full abstract»

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  • Incremental RANSAC for online relocation in large dynamic environments

    Publication Year: 2006 , Page(s): 68 - 75
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (770 KB) |  | HTML iconHTML  

    Vehicle relocation is the problem in which a mobile robot has to estimate the self-position with respect to an a priori map of landmarks using the perception and the motion measurements without using any knowledge of the initial self-position. Recently, random sample consensus (RANSAC), a robust multi-hypothesis estimator, has been successfully applied to offline relocation in static environments. On the other hand, online relocation in dynamic environments is still a difficult problem, for available computation time is always limited, and for measurement include many outliers. To realize real time algorithm for such an online process, we have developed an incremental version of RANSAC algorithm by extending an efficient preemption RANSAC scheme. This novel scheme named incremental RANSAC is able to find inlier hypotheses of self-positions out of large number of outlier hypotheses contaminated by outlier measurements View full abstract»

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  • Development of a new humanoid robot WABIAN-2

    Publication Year: 2006 , Page(s): 76 - 81
    Cited by:  Papers (77)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1576 KB) |  | HTML iconHTML  

    A new humanoid robot-WABIAN-2- that can be used as a human motion simulator is proposed in this paper. Its trunk is designed in order to permit rotation, and forward, backward, and sideway movement. Further, its arms are designed to support its complete weight when pushing a walk-assist machine. Moreover, it can lean on a walk-assist machine by forearm control using trunk motion. Basic walking experiments with WABIAN-2 are conducted with and without a walk-assist machine, thereby confirming its effectiveness View full abstract»

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  • Development of musculoskeletal humanoid Kotaro

    Publication Year: 2006 , Page(s): 82 - 87
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1425 KB) |  | HTML iconHTML  

    This paper presents the concepts, issues on development, and future perspectives of a novel musculoskeletal humanoid `Kotaro'. The specifications and advantages of Kotaro include muscle-driven endoskeletal structure, multiple degrees of freedom, variable physical softness, the multiple-joint spine, easily configurable muscles, distributed onbody controllers, various sorts of many sensors including eyes, ears, and whole-body tactile sensors, and so on. These characteristics would achieve a flexible body, litheness of motions, safety, and adaptability and applicability to diverse tasks which would very often appear in human's daily lives View full abstract»

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  • Modular joint design for performance enhanced humanoid robot LOLA

    Publication Year: 2006 , Page(s): 88 - 93
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (670 KB) |  | HTML iconHTML  

    The paper presents the performance enhanced humanoid robot LOLA which is currently being manufactured. The goal of the project is the realization of a fast, human-like walking motion. The robot is characterized by its lightweight construction, a modular, multi-sensory joint design with brushless motors and an electronics architecture using decentralized joint controllers. The fusion of motor, gear and sensors into a highly integrated, mechatronic joint module has several advantages for the whole system, including high power density, good dynamic performance and reliability. Additional degrees of freedom are introduced in elbow, waist and toes. Linear actuators are employed for the knee joints for a better mass distribution in the legs View full abstract»

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  • Design of the robot-cub (iCub) head

    Publication Year: 2006 , Page(s): 94 - 100
    Cited by:  Papers (34)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (826 KB) |  | HTML iconHTML  

    This paper describes the design of a robot head, developed in the framework of the RobotCub project. This project goals consists on the design and construction of a humanoid robotic platform, the iCub, for studying human cognition. The final platform would be approximately 90 cm tall, with 23 kg and with a total number of 53 degrees of freedom. For its size, the iCub is the most complete humanoid robot currently being designed, in terms of kinematic complexity. The eyes can also move, as opposed to similarly sized humanoid platforms. Specifications are made based on biological anatomical and behavioral data, as well as tasks constraints. Different concepts for the neck design (flexible, parallel and serial solutions) are analyzed and compared with respect to the specifications. The eye structure and the proprioceptive sensors are presented, together with some discussion of preliminary work on the face design View full abstract»

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  • Development of a human-like sensory feedback mechanism for an anthropomorphic talking robot

    Publication Year: 2006 , Page(s): 101 - 106
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1747 KB) |  | HTML iconHTML  

    We developed a sensor feedback mechanism for an anthropomorphic talking robot WT-5 (Waseda Talker No. 5). In human speech, sensory feedback is more important when we producing obstacle consonant sounds, such as /t/ and /d/, compared to the auditory feedback mechanism. We reproduce this mechanism by placing tactile sensors and a pressure sensor on the palate of a talking robot and reducing the error between the pressure of the human voice and the robot consonant production. In addition, we developed more efficient optimization methods than those of WT-4, using speech recognition and the pre-optimized memory of vowels. Using these mechanisms, we realized continuous mimic speaking that includes consonant sounds View full abstract»

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  • Humanoid synthesis using Clifford algebra

    Publication Year: 2006 , Page(s): 107 - 112
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (737 KB) |  | HTML iconHTML  

    One of the challenges in the simulation of human motion, either applied to humanoid robots or avatars in virtual environments, is to design a kinematics structure and a set of joint trajectories that move a robot or avatar in a human-like manner. In this paper, a technique is introduced to create accurate human-like motion with a simplified topology as a reference. Using an optical motion capture system, a finite number of key poses are captured from different subjects performing full body articulated movements. Motion is modeled using the Clifford algebra of dual quaternions and dimensional synthesis techniques are applied to generate the kinematic skeleton of a 3D avatar or robot. The synthesized kinematic skeleton provides location of joints and dimensions of the links forming the limbs, as well as the joint trajectories. Five serial chains constitute our approximation to the human skeleton. Revolute, universal and spherical joints are employed, although other topologies can be used in a similar fashion. Several real datasets are evaluated and results demonstrate that good accuracy can be obtained at interactive rates using the presented methodology. The results show that using simple serial chains in combination with dimensional synthesis suffices to generate the mechanical structure and trajectories of a humanoid robot or 3D avatar mimicking human motion View full abstract»

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  • Smooth interpolation of orientation by rolling and wrapping for robot motion planning

    Publication Year: 2006 , Page(s): 113 - 118
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB) |  | HTML iconHTML  

    This paper investigates a novel procedure to calculate smooth interpolation curves of the rotation group SO3, which is commonly considered as the standard representation of rigid-body's orientations. The algorithm is a combination of rolling and wrapping with the pull back/push forward technique. One remarkable advantage of this approach is that interpolation curves are given in closed form, which brings convenience for implementations on real-time control systems. A numerical example along with some visualization results is presented as well View full abstract»

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  • Ridge-valley path planning for 3D terrains

    Publication Year: 2006 , Page(s): 119 - 124
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (835 KB) |  | HTML iconHTML  

    This paper presents a tactical path planning algorithm for following ridges or valleys across a 3D terrain. The intent is to generate a path that enables an unmanned vehicle to surveil with maximum observability by traversing the ridges of a terrain or to operate with maximum covertness by navigating the valleys. The input to the algorithm is a 3D triangle mesh model for the terrain of interest. This mesh may be non-uniform and non-regular. Thus, the algorithm leverages research from computer graphics and computer vision to identify ridge-valley features on the terrain. These features serve as "obstacles" for an artificial potential field algorithm. The valleys are obstacles for a surveillance path, or the ridges are obstacles for a covert path. We incorporate geodesic-rather than Euclidean-distances into the potential field formulation to extend path planning to 3D surfaces. We present the theory of our proposed algorithm and provide experimental results View full abstract»

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  • A motion planning processor on reconfigurable hardware

    Publication Year: 2006 , Page(s): 125 - 132
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB) |  | HTML iconHTML  

    Motion planning algorithms enable us to find feasible paths for moving objects. These algorithms utilize feasibility checks to differentiate valid paths from invalid ones. Unfortunately, the computationally expensive nature of such checks reduces the effectiveness of motion planning algorithms. However, by using hardware acceleration to speed up the feasibility checks, we can greatly enhance the performance of the motion planning algorithms. Of course, such acceleration is not limited to feasibility checks; other components of motion planning algorithms can also be accelerated using specially designed hardware. A field programmable gate array (FPGA) is a great platform to support such an acceleration. An FPGA is a collection of digital gates which can be reprogrammed at run time, i.e., it can be used as a CPU that reconfigures itself for a given task. In this paper, we study the feasibility of an FPGA based motion planning processor and evaluate its performance. In order to leverage its highly parallel nature and its modular structure, our processor utilizes the probabilistic roadmap method at its core. The modularity enables us to replace the feasibility criteria with other ones. The reconfigurability lets us run our processor in different roles, such as a motion planning co-processor, an autonomous motion planning processor or dedicated collision detection chip. Our experiments show that such a processor is not only feasible but also can greatly increase the performance of current algorithms View full abstract»

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