waashk/dblp huggingface dataset:
cad-based recognition of 3d objects in monocular images. this paper provides a method for recognizing 3d objects in a single camera image and for determining their 3d poses. a model is trained solely based on the geometry information of a 3d cad model of the object. we do not rely on texture or reflectance information of the object's surface, making this approach useful for a wide range of industrial and robot applications and complementary to descriptor-based approaches. a view-based approach that does not show the drawbacks of previous methods is applied: it is robust to noise, occlusions, clutter, and contrast changes. furthermore, the 3d pose is determined with high accuracy. the high robustness of an exhaustive search is combined with an efficient hierarchical search, a high percentage of which can be computed offline, making our method suitable even for time-critical applications. the method is especially suited for, but not limited to, the recognition of untextured objects like metal parts, which are often used in industrial environments. it allows, for example, 3d pin picking in robot applications. tracking approaches can use it for initialization.
the adelopod tumbling robot. the desire for a high mobility-to-size ratio in mobile robots has led to the exploration of many new methods of locomotion, one of which is tumbling. we believe that tumbling has a great potential to produce high mobility-to-size ratios in miniature mobile robots. in this paper we discuss tumbling locomotion and introduce the adelopod, a small two-armed tumbling robot recently developed at the university of minnesota center for distributed robotics. the adelopod achieves high mobility with low hardware complexity, making it a desirable addition to any heterogeneous team of robots.
kinematic design of an ejection-free underactuated anthropomorphic finger. this paper presents preliminary results on the design of a novel architecture of a three-phalanx underactuated finger. an ejection-free underactuated anthropomorphic hand is of the greatest interest for the field of humanoid robots. so far, all underactuated fingers lead to ejection for certain configurations. by using a second system of actuation in a three-phalanx finger, the zone of instability of this finger is reduced and the ejection problem is prevented. hence, the mathematical model of this finger is first introduced, followed by the choice of transmission ratios to be taken for the two pulley systems. finally, the zone of instability of this new architecture is presented where it is proved that ejection is avoided.
a search and rescue robot. in order to increase the effectiveness of robotic systems, the robots must be able to negotiate a variety of terrains. in urban environments this task becomes challenging as environments built for humans often have impediments such as stairs and thresholds which may be difficult or impossible for wheeled or tracked vehicles to go over. this is further complicated in search and rescue scenarios where debris and rubble from collapsed structures may further complicate the environment. in order to address these limitations a novel robotic platform, the loper, has been developed. the loper utilizes a trilobe wheel and a compliant chassis in order to traverse difficult terrain. in addition, multiple gait configurations of the trilobe wheel enable the loper to overcome a variety of obstacles, both indoors and out.
control for throwing manipulation by one joint robot. this paper proposes a throwing manipulation strategy for a robot with one revolute joint. the throwing manipulation enables the robot not only to manipulate the object to outside of the movable range of the robot, but also to control the position of the object arbitrarily in the vertical plane even though the robot has only one degree of freedom. in the throwing manipulation, the robot motion is dynamic and quick, and the contact state between the robot and the object changes. these make it difficult to obtain the exact model and solve its inverse problem. in addition, since the throwing manipulation requires more powerful actuators than the static manipulation, we should set the control input by taking consideration of the performance limits of the actuators. the present paper proposes the control strategy based on the iteration optimization learning to overcome the above problems and verifies its effectiveness experimentally.
manipulation planning with workspace goal regions. we present an approach to path planning for manipulators that uses workspace goal regions (wgrs) to specify goal end-effector poses. instead of specifying a discrete set of goals in the manipulator's configuration space, we specify goals more intuitively as volumes in the manipulator's workspace. we show that wgrs provide a common framework for describing goal regions that are useful for grasping and manipulation. we also describe two randomized planning algorithms capable of planning with wgrs. the first is an extension of rrt-jt that interleaves exploration using a rapidly-exploring random tree (rrt) with exploitation using jacobian-based gradient descent toward wgr samples. the second is the ikbirrt algorithm, which uses a forward-searching tree rooted at the start and a backward-searching tree that is seeded by wgr samples. we demonstrate both simulation and experimental results for a 7dof wam arm with a mobile base performing reaching and pick-and-place tasks. our results show that planning with wgrs provides an intuitive and powerful method of specifying goals for a variety of tasks without sacrificing efficiency or desirable completeness properties.
a miniature ceiling walking robot with flat tacky elastomeric footpads. in this paper, the design, analysis, and development of a sixteen-legged palm-sized climbing robot using flat bulk tacky elastomer adhesives as an attachment method is presented. a legged robot with four-bar based kinematics is designed and fabricated with elastomeric footpads. the proposed robot has a passive peeling mechanism for energy efficient and vibration free detachment. a rocker-type mechanism in the leg and compliant foam under the footpads are utilized for passive alignment on concave and convex surfaces. adhesion experimental data is used to estimate the adhesion and preload saturation on the footpads on different angled acrylic surface. it is showed that although the initial preload does not affect the adhesion and preload saturation point, the orientation and the weight of the robot, roughness of the surface, and waiting time between consecutive steps greatly effect the climbing performance. experimental results revealed that the robot can climb in any direction in 3d space on smooth surfaces, such as acrylic and glass. it can carry a payload of up to 2 n, which is almost twice as its own weight, on a smooth inverted surface. the robot can robustly climb vertically on relatively rough surfaces such as a painted wall or a wooden door. potential applications of this robot include inspection, exploration, maintenance, cleaning, repair, and search and rescue.
the twente humanoid head. this video shows the results of the project on the mechatronic development of the twente humanoid head. the mechanical structure consists of a neck with four degrees of freedom (dofs) and two eyes (a stereo pair system) which tilt on a common axis and rotate sideways freely providing a three more dofs. the motion control algorithm is designed to receive, as an input, the output of a biological-inspired vision processing algorithm and to exploit the redundancy of the joints for the realization of the movements. the expressions of the humanoid head are implemented by projecting light from the internal part of the translucent plastic cover.
surface identification using simple contact dynamics for mobile robots. this paper describes an approach to surface identification in the context of mobile robotics, applicable to supervised and unsupervised learning. the identification is based on analyzing the tip acceleration patterns induced in a metallic rod, dragged along a surface that is to be identified. eight features in time and frequency domains are used for classification. results show that for ten type of indoor and outdoor surfaces, reliable identification can be achieved (90.0 and 94.6 percent for a 1 and 4 seconds time-window, respectively), using a non-sophisticated classifier (artificial neural network). demonstration is done on how such a sensor and a simple control strategy can be used to guide a blind robot, using a simulation and a real differential drive robot.
laser-based geometric modeling using cooperative multiple mobile robots. in order to construct three-dimensional shape models of large-scale architectural structures using a laser range finder, a number of range images are taken from various viewpoints. these images are aligned using post-processing procedures such as the icp algorithm. however, in general, before applying the icp algorithm, these range images must be aligned roughly by a human operator in order to converge to precise positions. the present paper proposes a new modeling system using a group of multiple robots and an on-board laser range finder. each measurement position is identified by a highly precise positioning technique called cooperative positioning system (cps), which utilizes the characteristics of the multiple-robot system. thus, the proposed system can construct 3d shapes of large-scale architectural structures without any post-processing procedure or manual registration. icp is applied optionally for a subsequent refinement of the model. measurement experiments in unknown and large indoor/outdoor environments are carried out successfully using the newly developed measurement system consisting of three mobile robots named cps-v. generating a model of dazaifu tenmangu, a famous cultural heritage, for its digital archive completes the paper.
single-trocar assemblable retractor-hand for laparoscopic surgery. in laparoscopic surgery large instruments cannot be used because they cannot pass through trocars which are typically smaller than 12mm in diameter. for example, retracting an internal organ with a slender instrument is often a difficult task. to remove this limitation, we have proposed "assemblable instruments", that is, parts are inserted through trocars and assembled inside the abdominal cavity to become a large instrument and we have developed assemblable hands. however they use two trocars for assembling, which require positioning and alignment of two assembled parts. this paper presents a simple three fingered hand whose function is limited to retracting. we propose a much simpler assembling method "single trocar assembling" for the hand. experimental results verify that the hand can be assembled easily and that it can withstand a force of 25n enough to rectract a pancreas.
state transition, balancing, station keeping, and yaw control for a dynamically stable single spherical wheel mobile robot. unlike statically stable wheeled mobile robots, dynamically stable mobile robots can have higher centers of gravity, smaller bases of support and can be tall and thin resembling the shape of an adult human. this paper concerns the ballbot mobile robot, which balances dynamically on a single spherical wheel. the ballbot is omni-directional and can also rotate about its vertical axis (yaw motion). it uses a triad of legs to remain statically stable when powered off. this paper presents the evolved design with a four-motor inverse mouse-ball drive, yaw drive, leg drive, control system, and results including dynamic balancing, station keeping, yaw motion while balancing, and automatic transition between statically stable and dynamically stable states.
towards swarms of communication-enabled and intelligent sensotaxis-based bacterial microrobots capable of collective tasks in an aqueous medium. experimental data and proofs of concepts are used to show the feasibility of providing the basic components and functionalities required for the implementation of intelligent untethered 150 × 300µm bacterial microrobots capable of sophisticated collective tasks under computer supervision and coordination. more specifically, we show that it is possible to embed within such microrobots, photovoltaic cells supplying ∼4µw necessary to power an internal microelectronic circuit providing embedded intelligence with the capability to communicate commands and data wirelessly to an external computer. we also show that such data or commands transmitted wirelessly could be used to instruct an external computer to send a swarm of flagellated bacteria to move such microrobots towards a specific target based on various sensory information acquired with specific sensors embedded in each microrobots. similar to chemotaxis used by several species of flagellated bacteria, the algorithms used to move such microrobots could be governed by a larger range of sensory means, leading to what we refer to here as sensotaxisbased hybrid microrobots. the possibility of transmitting a request to a central computer to send a swarm of flagellated magnetotactic bacteria to provide propulsion and steering in order to move accurately to desired locations would allow such microrobots to perform collective tasks. a simple example suggesting the possibility of implementing accurate collective tasks by such hybrid microrobots is demonstrated experimentally where a microstructure emulating a v-shaped microrobot is moved and rotated autonomously using a swarm of approximately 3000 flagellated bacteria towards another similar v-shaped microstructure to form the character 'm' as in microrobot.
camera self-calibration for sequential bayesian structure from motion. computer vision researchers have proved the feasibility of camera self-calibration -the estimation of a camera's internal parameters from an image sequence without any known scene structure. various self-calibration algorithms have been published. nevertheless, all of the recent sequential approaches to 3d structure and motion estimation from image sequences which have arisen in robotics and aim at real-time operation (often classed as visual slam or visual odometry) have relied on pre-calibrated cameras and have not attempted online calibration. in this paper, we present a sequential filtering algorithm for simultaneous estimation of 3d scene estimation, camera trajectory and full camera calibration from a sequence of fixed but unknown calibration. this calibration comprises the standard projective parameters of focal length and principal point along with two radial distortion coefficients. to deal with the large non-linearities introduced by the unknown calibration parameters, we use a sum of gaussians (sog) filter rather than the simpler extended kalman filter (ekf). to our knowledge, this is the first sequential bayesian autocalibration algorithm which achieves complete fixed camera calibration using as input only a sequence of uncalibrated monocular images. the approach is validated with experimental results using natural images, including a demonstration of loop closing for a sequence with unknown camera calibration.
control of locomotion with shape-changing wheels. we present a novel approach to controlling the locomotion of a wheel by changing its shape, leading to applications to the synthesis and closed-loop control of gaits for modular robots. a dynamic model of a planar, continuous deformable ellipse in contact with a ground surface is derived. we present two alternative approaches to controlling this system and a method for mapping the gaits to a discrete rolling polygon. mathematical models and dynamic simulation of the continuous approximation and the discrete n-body system, and experimental results obtained from a physical modular robot system illustrate the accuracy of the dynamic models and the validity of the approach.
which landmark is useful? learning selection policies for navigation in unknown environments. in general, a mobile robot that operates in unknown environments has to maintain a map and has to determine its own location given the map. this introduces significant computational and memory constraints for most autonomous systems, especially for lightweight robots such as humanoids or flying vehicles. in this paper, we present a novel approach for learning a landmark selection policy that allows a robot to discard landmarks that are not valuable for its current navigation task. this enables the robot to reduce the computational burden and to carry out its task more efficiently by maintaining only the important landmarks. our approach applies an unscented kalman filter for addressing the simultaneous localization and mapping problems and uses monte-carlo reinforcement learning to obtain the selection policy. based on real world and simulation experiments, we show that the learned policies allow for efficient robot navigation and outperform handcrafted strategies. we furthermore demonstrate that the learned policies are not only usable in a specific scenario but can also be generalized towards environments with varying properties.
effects of haptic and graphical force feedback on teleoperated palpation. direct haptic feedback and graphical force feed-back have both been hypothesized to improve the performance of robot-assisted surgery. in this study we evaluate the benefits of haptic and graphical force feedback on surgeon performance and tissue exploration behavior during a teleoperated palpation task of artificial tissues. seven surgeon subjects (four experienced in robot-assisted surgery) used a 7-degree-of-freedom teleoperated surgical robot to identify a comparatively rigid rigid target object (representing a calcified artery) in phantom heart models using the following feedback conditions: (1) direct haptic and graphical feedback, (2) direct haptic only, (3) graphical feedback only, and (4) no feedback. to avoid the problems of force sensing in a minimally invasive surgical environment, we use a position-exchange controller with dynamics compensation for direct haptic feedback and a force estimator displayed via tool-tip tracking bar graph for graphical force feedback. although the transparency of the system is limited with this approach, results show that direct haptic force feedback minimizes applied forces to the tissue, while coupled haptic and graphical force feedback minimizes subject task error. for experienced surgeons, haptic force feedback substantially reduced task error independent of graphical feedback.
3d model selection from an internet database for robotic vision. we propose a new method for automatically accessing an internet database of 3d models that are searchable only by their user-annotated labels, for using them for vision and robotic manipulation purposes. instead of having only a local database containing already seen objects, we want to use shared databases available over the internet. this approach while having the potential to dramatically increase the visual recognition capability of robots, also poses certain problems, like wrong annotation due to the open nature of the database, or overwhelming amounts of data (many 3d models) or the lack of relevant data (no models matching a specified label). to solve those problems we propose the following: first, we present an outlier/inlier classification method for reducing the number of results and discarding invalid 3d models that do not match our query. second, we utilize an approach from computer graphics, the so called 'morphing', to this application to specialize the models, in order to describe more objects. third, we search for 3d models using a restricted search space, as obtained from our knowledge of the environment. we show our classification and matching results and finally show how we can recover the correct scaling with the stereo setup of our robot.
vision-tactile-force integration and robot physical interaction. this paper presents an approach for integrating vision, tactile and force sensors in a robotic manipulation framework. having an initial estimation of the object pose in the environment, a position-based visual servoing loop controls the hand for task execution, based on the input received from a model-based articular pose estimator following the virtual visual servoing approach. the visual control is combined with another control signal obtained from tactile feedback, through a set of selection matrices that can be modified at runtime in order to select the best modality for a given cartesian degree of freedom. the result of the preliminary integration is modified by an impedance force controller, in charge of performing the task motion along the task direction, at the same time that forces are regulated on the rest of directions. the design of the controller allows to perform the task even if a sensor is not available or provides inaccurate data. several experiments are performed, first by considering only force feedback, and then adding vision and, finally, tactile information. errors in the estimation of the object initial position are manually introduced in the experiments, and results show how the vision-tactile-force combination is able to deal with them, performing much better than the vision-force and force-alone approaches.
a new framework for force feedback teleoperation of robotic vehicles based on optical flow. this paper proposes the use of optical flow from a moving robot to provide force feedback to an operator's joystick to facilitate collision free teleoperation. optic flow is measured by wide angle cameras on board the vehicle and used to generate a virtual environmental force that is reflected to the user through the joystick, as well as feeding back into the control of the vehicle. the coupling between optical flow (velocity) and force is modelled as an impedance - in this case an optical impedance. we show that the proposed control is dissipative and prevents the vehicle colliding with the environment as well as providing the operator with a natural feel for the remote environment. the paper focuses on applications to aerial robotics vehicles, however, the ideas apply directly to other force actuated vehicles such as submersibles or space vehicles, and the authors believe the approach has potential for control of terrestrial vehicles and even teleoperation of manipulators. experimental results are provided for a simulated aerial robot in a virtual environment controlled by a haptic joystick.
lightweight high performance integrated actuator for humanoid robotic applications: modeling, design & realization. actuation of robotic systems is still an open question and represents a big challenge. demanding performances including high power to mass ratio, capability of producing high power at low speed within a small-occupied volume are some of the key issues that required careful consideration. these criteria aimed to increase autonomy of humanoid robots. in this paper, a novel hydrostatic transmission actuator is proposed. the proposed actuator is controlled by displacement and has capacities for energy storage. this leads to an optimal solution in terms of power consumption. first, the proposed hydrostatic actuation principle is explained. a simplified hydraulic scheme to illustrate the energy storage capability is then provided. a mathematical model of the proposed solution is detailed showing our ability to access to the payload "jerk". the built prototype is presented and its properties are outlined. finally, a prototype of the actuator and the preliminary results of the actuator performance are presented, demonstrating the novelty of our solution.
skillful manipulation based on high-speed sensory-motor fusion. this video introduces the demonstration of skillful manipulation using a high-speed robot system. the system consists of visual and tactile sensors at a rate of 1 khz and a high-speed hand-arm manipulator. the high-speed sensory-motor fusion improves not just the speed of existing robot manipulations, but robotic skills by introducing the features peculiar to high-speed motion. based on such a concept, new variations of skillful manipulation were achieved.