waashk/dblp huggingface dataset:
leaving flatland: toward real-time 3d navigation. we report our first experiences with leaving flatland, an exploratory project that studies the key challenges of closing the loop between autonomous perception and action on challenging terrain. we propose a comprehensive system for localization, mapping, and planning for the rhex mobile robot in fully 3d indoor and outdoor environments. this system integrates visual odometry-based localization with new techniques in real-time 3d mapping from stereo data. the motion planner uses a new decomposition approach to adapt existing 2d planning techniques to operate in 3d terrain. we test the map-building and motion-planning subsystems on real and synthetic data, and show that they have favorable computational performance for use in high-speed autonomous navigation.
development of pressure-driven micro active catheter using membrane micro emboss following excimer laser ablation (meme-x) process. the world's smallest micro active catheter of φ∼300µm was successfully fabricated using membrane micro emboss following excimer laser ablation (meme-x) process. the catheter has a one-sided hollow bellows at the tip made of thin polymer membrane. the bellows is composed of a series of folded micro-chambers and microchannels connecting the micro-chambers. the folded-chambers expand on one side by increasing inner water pressure using a syringe, thus the whole bellows bends toward one direction within 0 to 180 degree. this micro active catheter should be useful for safe intravascular surgery in narrow and complicated blood vessels. moreover, the nonelectrical actuation mechanism of this catheter can be widely applied to micro-actuators and micro-robots which need high safety.
roombots-mechanical design of self-reconfiguring modular robots for adaptive furniture. we aim at merging technologies from information technology, roomware, and robotics in order to design adaptive and intelligent furniture. this paper presents design principles for our modular robots, called roombots, as future building blocks for furniture that moves and self-reconfigures. the reconfiguration is done using dynamic connection and disconnection of modules and rotations of the degrees of freedom. we are furthermore interested in applying roombots towards adaptive behaviour, such as online learning of locomotion patterns. to create coordinated and efficient gait patterns, we use a central pattern generator (cpg) approach, which can easily be optimized by any gradient-free optimization algorithm. to provide a hardware framework we present the mechanical design of the roombots modules and an active connection mechanism based on physical latches. further we discuss the application of our roombots modules as pieces of a homogenic or heterogenic mix of building blocks for static structures.
development of a robot balanced on a ball - application of passive motion to transport -. this paper proposes a robot balanced on a ball. in contrast to an inverted pendulum with two wheels, such as the segway human transporter, an inverted pendulum using a ball can traverse in any direction without changing its orientation, thereby enabling stable motion. such robots can be used in place of the two-wheeled robots. the robot proposed in this paper is equipped with three omnidirectional wheels with stepping motors that drive the ball and two sets of rate gyroscopes and accelerometers as attitude sensors. the robot has a simple design; it is controlled with a 16-bit microcontroller and runs on ni-mh batteries. it can not only stand still but also traverse on floor and pivot around its vertical axis. inverted pendulum control is applied in two axes for attitude control, and commanded motions are converted into velocity commands for the three wheels. the mechanism, control method, and experimental results including application to transport are described in this paper.
remote haptic feedback from a dynamic running machine. in this paper we present our efforts to design a system for feeding back useful haptic information from a highly dynamic running robot to a remote operator using a haptic device. without adding additional sensors, the legs of the robot are used as feelers to give the operator the capability to both explore and manipulate the robot's environment and to gather meaningful information about properties not captured by visual feedback like weight, movability and structure of an encountered object. we show the capabilities of the system in a user study with both trained and untrained operators.
the kinematic modeling and optimal paramerization of an omni-directional pipeline robot. there is no prior work on exact kinematic modeling for a pipeline robot having three powered chains. this work presents the closed-form kinematic model of the pipeline inspection robot driven by three caterpillar wheel chains. next, optimal kinematic parameters are analyzed by using isotropic index and force transmission ratio. lastly, the feasibility of the kinematic model is verified through motion simulation for a virtual pipeline equipped with elbows and t-branches.
noiseless and vibration-free ionic propulsion technology for indoor surveillance blimps. we present in this paper a novel indoor blimp that is propelled by a propulsion technology that uses no moving mechanical parts and thus is noiseless and vibration free. in our prior work reported at ieee/asme aim 2007, we demonstrated several prototype propulsive units (with asymmetric capacitor configurations) that lift themselves into air. using these basic propulsive units ("ionic flyers"), we have recently developed an indoor flying blimp that has a propulsion system with no moving mechanical parts and thus generates no noise or vibration -- the ionic propulsion blimp. the key to successfully create this novel indoor flying system is the development of a power generation system that includes an 11.1v battery which is capable of generating ∼20kv dc voltage continuously over time for a load in the mω range. the architecture of this ionic power system will be presented. a detailed parametric analysis and an optimal design methodology of the ionic flyer are also discussed. initial experimental results of the ionic propulsion blimp are also summarized in this paper.
6dof haptic cooperation over large latency network with wave variables for virtual prototyping. this paper describes a 6 dofs haptic cooperative platform dedicated to cad objects simulation and virtual prototyping tasks. this system is based on several distributed physical engines linked together by a network subject to time delay. to deal with the destabilizing effect of time delay, a wave variable transformation is used. the wave variable formalism is adapted to the platform, therefore the behavior of each physical engine is similar. several prototyping tasks have been tested on this system. a case is presented where two users are manipulating two distinct objects and interacting with each other.
automatic high-precision self-calibration of camera-robot systems. in this article a new method is presented to obtain a full and precise calibration of camera-robot systems with eyein-hand cameras. it achieves a simultaneous and numerically stable calibration of intrinsic and extrinsic camera parameters by analysing the image coordinates of a single point marker placed in the environment of the robot. the method works by first determining a rough initial estimate of the camera pose in the tool coordinate frame. this estimate is then used to generate a set of uniformly distributed calibration poses from which the object is visible. the measurements obtained in these poses are then used to obtain the exact parameters with cma-es (covariance matrix adaptation evolution strategy), a derandomised variant of an evolution strategy optimiser. minimal claims on the surrounding area and flexible handling of environmental and kinematical limitations make this method applicable to a range of robot setups and camera models. the algorithm runs autonomously without supervision and does not need manual adjustments. our problem formulation is directly in the 3d space which helps in minimising the resulting calibration errors in the robot's task space. both simulations and experimental results with a real robot show a very good convergence and high repeatability of calibration results without requiring user-supplied initial estimates of the calibration parameters.
eye-in-hand stereo visual servoing of an assistive robot arm in unstructured environments. we document the progress in the design and implementation of a motion control strategy that exploits visual feedback from a narrow baseline stereo head mounted in the hand of a wheelchair mounted robot arm (wmra) to recognize and grasp textured adl objects for which one or more templates exist in a large image database. the problem is made challenging by kinematic uncertainty in the robot, imperfect camera and stereo calibration, as well as the fact that we work in unstructured environments. the approach relies on separating the overall motion into gross and fine motion components. during the gross motion phase, local structure on an object around a user selected point of interest (poi) is extracted using sparse stereo information which is then utilized to converge on and roughly align the object with the image plane in order to be able to pursue object recognition and fine motion with strong likelihood of success. fine motion is utilized to grasp the target object by relying on feature correspondences between the live object view and its template image. while features are detected using a robust real-time keypoint tracker, a hybrid visual servoing technique is exploited in which tracked pixel space features are utilized to generate translational motion commands while a euclidean homography decomposition scheme is utilized for generation of orientation setpoints for the robot gripper. experimental results are presented to demonstrate the efficacy of the proposed algorithm.
dynamically diverse legged locomotion for rough terrain. in this video, we demonstrate the effectiveness of a kinodynamic planning strategy that allows a high-impedance quadruped to operate across a variety of rough terrain. at one extreme, the robot can achieve precise foothold selection on intermittent terrain. more surprisingly, the same inherently-stiff robot can also execute highly dynamic and underactuated motions with high repeatability. this range of dynamic motion is possible through careful reasoning about the coupled dynamics during underactuated phases of motion. our results demonstrate visceral progress toward realization of one of the central theoretically claims giving legged locomotion a "leg-up" over wheeled robotics: that appropriate design of control can produce a set of capabilities which span a dynamic range from deliberate foothold selection through acrobatic-style motion on a single, particular robot.
inertial aided sift for time to collision estimation. visual time to collision estimation for small or micro air vehicles is challenging due to aggressive 6-dof motion, real time performance requirements and significant size, weight and power constraints of the platform. recent work in collision detection using insect inspired optical flow based methods have been demonstrated in low power hardware implementations [1][2][3][4], but have not achieved the obstacle detection and false alarm rate performance necessary for practical deployment. this performance is sensitive to correspondence errors in the optical flow field, so one approach to improving performance is to use a richer feature set for correspondence, along with calibrated inertial information from the platform to aid correspondence. in this video, we show proof of concept results for such an approach. estimation results are noisy, but encouraging, and given that sift feature correspondence has been demonstrated in real time on low power gpus, it has the potential for future small uav integration.
fast point feature histograms (fpfh) for 3d registration. in our recent work [1], [2], we proposed point feature histograms (pfh) as robust multi-dimensional features which describe the local geometry around a point p for 3d point cloud datasets. in this paper, we modify their mathematical expressions and perform a rigorous analysis on their robustness and complexity for the problem of 3d registration for overlapping point cloud views. more concretely, we present several optimizations that reduce their computation times drastically by either caching previously computed values or by revising their theoretical formulations. the latter results in a new type of local features, called fast point feature histograms (fpfh), which retain most of the discriminative power of the pfh. moreover, we propose an algorithm for the online computation of fpfh features for realtime applications. to validate our results we demonstrate their efficiency for 3d registration and propose a new sample consensus based method for bringing two datasets into the convergence basin of a local non-linear optimizer: sac-ia (sample consensus initial alignment).
control of hopping speed and height over unknown rough terrain using a single actuator. we present a method for controlling the forward speed and the apex height of a one-legged hopping robot over rough terrain, using a single actuator located at the robot hip. the control algorithm is comprised of two elements, the forward speed control and the height control. the only input to the system is the torque applied by the hip actuator. the control is demonstrated to perform tracking of desired forward speed trajectories and desired apex height trajectories. simulation and experimental results on the sahr (single actuator hopping robot) experimental setup are presented and compared. it is shown that the robot follows both trajectories closely in simulation as well as in experiment. also the robot is tested successfully on a rough terrain course, which includes inclined ground and an abrupt drop in height of over 25% the length of the robot leg. the robot has no knowledge of its environment. further, the robot is made to run over the course a number of times, to demonstrate the control robustness.
gatmo: a generalized approach to tracking movable objects. we present gatmo (generalized approach to tracking movable objects), a system for localization and mapping that incorporates the dynamic nature of the environment while maintaining semantic labels. objects in the environment are broken down into multiple mobility levels, from static (walls) to highly mobile (people), by maintaining a history of object movement. object classification is accomplished through a multi-layer, multi-hypothesis approach that does not rely on any static features such as shape or size. maps are stored in an efficient manner that incorporates a history of previous orientations of each object. gatmo is initialized with a static map; it subsequently changes the map over time as objects in the map change position.
monocular stereo image processing using viewpoint switching iris. in the recent years, intensive studies have been carried out on the measurement of distance by using stereo camera systems. however, image systems with multiple image sensors are usually very complex and are inconvenient to use. in this paper, we present a new method that is based on the fact that the viewpoint depends on the position of aperture. we show images from different viewpoints can be obtained by using a monocular system. in the proposed method, stereo image analysis is carried out by using a viewpoint switching iris. a prototype of the viewpoint switching iris has be developed, which can be used along with a monocular camera for distance measurement. furthermore, we have verified that this system can be used to a moving object by using a compensation method.
voice coil based hopping mechanism for microrobot. hopping is a very efficient locomotion method for a robot in an unconstructed environment or a complicated terrain. small hopping robots have many interesting properties in comparison to the larger ones. however, relatively little research has been reported on hopping microrobot, while most of existing designs of hopping robots are not suitable to scale down. in this paper we propose a novel hopping mechanism that is based on the working principle of voice coil actuator. this mechanism is relatively easy to miniaturize and the hopping performance improves in a smaller scale. two prototypes are developed based on electromagnetic simulation and an analytic model of hopping process. the first prototype has a dimension of φ30 mm × 10 mm and a mass of 41.59 g, with a hopping height of about 45 mm. the second one has a dimension of φ14 mm × 6 mm and a mass of 4.94 g, and achieves a hopping height of about 65 mm.
real-world robot navigation amongst deformable obstacles. in this paper, we consider the problem of mobile robots navigating in environments with non-rigid objects. whereas robots can plan their paths more effectively when they utilize the information about the deformability of objects, they also need to consider the influence of the interaction with the deformable objects on their measurements during the execution of their navigation task. in this paper, we present a probabilistic approach to identify the measurements influenced by the deformable objects. based on a learned statistics about the influence of the deformable objects on the measurements, the robot is able to perform a sensor-based collision avoidance of unforeseen objects. we present experiments carried out with a real robot that illustrate the practicability of our approach.
ci-graph: an efficient approach for large scale slam. when solving the simultaneous localization and mapping (slam) problem, submapping and graphical methods have shown to be valuable approaches that provide significant advantages over the standard ekf solution: they are faster and can produce more consistent estimates when using local coordinates. in this paper we present ci-graph, a submapping method for slam that uses a graph structure to efficiently solve complex trajectories reducing the computational cost. unlike other submapping slam approaches, we are able to transmit and share information through maps in the graph in a consistent manner by using conditionally independent submaps. in addition, the current submap always summarizes, without further computations, all information available making ci-graph be an intrinsically "up to date" algorithm. moreover, the technique is also efficient in memory requirements since it does not need to recover the full covariance matrix. to evaluate ci-graph performance, the method has been tested using a synthetic manhattan world and victoria park data set.
combining search and action for mobile robots. we explore the interconnection between search and action in the context of mobile robotics. the task of searching for an object and then performing some action with that object is important in many applications. of particular interest to us is the idea of a robot assistant capable of performing worthwhile tasks around the home and office (e.g., fetching coffee, washing dirty dishes, etc.). we prove that some tasks allow for search and action to be completely decoupled and solved separately, while other tasks require the problems to be analyzed together. we complement our theoretical results with the design of a combined search/action approximation algorithm that draws on prior work in search. we show the effectiveness of our algorithm by comparing it to state-of-the-art solvers, and we give empirical evidence showing that search and action can be decoupled for some useful tasks. finally, we demonstrate our algorithm on an autonomous mobile robot performing object search and delivery in an office environment.
safe, stable and intuitive control for physical human-robot interaction. for physical human-robot interaction, safety and dependability are of utmost importance due to the potential risk a relatively powerful robot poses for human beings. from the control standpoint, it is possible to increase this level of safety by guaranteeing that the robot will never exhibit any unstable behaviour. however, stability is not the only concern in the design of a controller for such a robot. during human-robot interaction, the resulting cooperative motion should be truly intuitive and should not restrict in any way the human performance. for this purpose, we have designed a new variable admittance control law that guarantees the stability of the robot during constrained motion and also provides a very intuitive human interaction. the first characteristic is provided by the design of a stability observer while the other is based on a variable admittance control scheme that uses the force derivative as a way to predict human intention. the stability observer is based on a previous stability investigation of cooperative motion which implies the knowledge of the interaction stiffness. a method to accurately estimate this stiffness online using the data coming from the encoder and from a multi-axis force sensor at the end effector is also provided. the stability and intuitivity of the control law were verified in a user study during a cooperative drawing task with a 3 degree-of-freedom (dof) parallel robot.
high dynamic range stereo vision for outdoor mobile robotics. we present a technique for high-dynamic range stereo for outdoor mobile robot applications. stereo pairs are captured at a number of different exposures (exposure bracketing), and combined by projecting the 3d points into a common coordinate frame, and building a 3d occupancy map. we present experimental results for static scenes with constant and dynamic lighting as well as outdoor operation with variable and high contrast lighting conditions.
real-time monocular visual odometry for on-road vehicles with 1-point ransac. this paper presents a system capable of recovering the trajectory of a vehicle from the video input of a single camera at a very high frame-rate. the overall frame-rate is limited only by the feature extraction process, as the outlier removal and the motion estimation steps take less than 1 millisecond with a normal laptop computer. the algorithm relies on a novel way of removing the outliers of the feature matching process. we show that by exploiting the nonholonomic constraints of wheeled vehicles it is possible to use a restrictive motion model which allows us to parameterize the motion with only 1 feature correspondence. using a single feature correspondence for motion estimation is the lowest model parameterization possible and results in the most efficient algorithms for removing outliers. here we present two methods for outlier removal. one based on ransac and the other one based on histogram voting. we demonstrate the approach using an omnidirectional camera placed on a vehicle during a peak time tour in the city of zurich. we show that the proposed algorithm is able to cope with the large amount of clutter of the city (other moving cars, buses, trams, pedestrians, sudden stops of the vehicle, etc.). using the proposed approach, we cover one of the longest trajectories ever reported in real-time from a single omnidirectional camera and in cluttered urban scenes, up to 3 kilometers.
least absolute policy iteration for robust value function approximation. least-squares policy iteration is a useful reinforcement learning method in robotics due to its computational efficiency. however, it tends to be sensitive to outliers in observed rewards. in this paper, we propose an alternative method that employs the absolute loss for enhancing robustness and reliability. the proposed method is formulated as a linear programming problem which can be solved efficiently by standard optimization software, so the computational advantage is not sacrificed for gaining robustness and reliability. we demonstrate the usefulness of the proposed approach through simulated robot-control tasks.