waashk/dblp huggingface dataset:
passive force analysis with elastic contacts for fixturing and grasping. unlike active force closure, which is a property for the multi-finger robotic hand grasping, passive force closure are involved in the grasping systems with constraining devices that cannot freely control the contact forces, such as the whole-arm grasping and manufacturing fixture. in passive grasping, the contact forces rely on the physical compliance of the system which is usually described by complex contact mechanics models. the purpose of this paper is to study the properties of a type of contact model, the linear elastic contact model, so that it is possible to determine the passive force closure condition and to understand the essential characteristics of the passive grasping. the formula to solve the passive grasping forces is derived. properties of the passive grasping is studied. the kinematic compatibility equation which describes the requirement of the coordination of contact forces is discovered, which is unique to the passive grasping. the algorithm to find the range of the preload to guarantee the passive force closure is deduced. the algorithm is demonstrated with two examples.
toward model free atmospheric sensing by aerial robot networks in strong wind fields. this paper presents a system for in situ atmospheric sensing using an aerial robot system in the presence of a strong wind field. the geostatistical concept of the variogram is used to characterize regions of the environment with high variability, which is assumed to correlate with scientific interest. after regions of interest are identified, ordered upwind methods are used to generate feasible trajectories in the face of strong background wind. the feasible trajectories are combined with the variogram characterization to select feasible paths that travel through the regions of highest interest. the system is tested in simulation using data from a simulated severe storm.
bending and kissing: computing self-contact configurations of planar loops with revolute joints. in recent work, we introduced the notion of a construction tree of simplices for a linkage l under distance constraints, and showed that the deformation space dspace(l) of such an l (i.e., its configuration space cspace(l) modulo rigid motions of ambient space respecting all system specifications) carries geometrically-defined simplex-based parameters that endow it with a "practically piecewise-convex" structure. here we present parametrizations of contact deformations of planar loops with revolute joints. we show that the bending and kissing loci, which include the self-contact subspace dscontact (generally as a strict subset) can be efficiently described by triangle-based parameters. these results further demonstrate the effectiveness of the simplex-based approach.
control of a class of thrust-propelled underactuated vehicles and application to a vtol drone. a control approach for a class of underactuated vehicles with the objective of stabilizing reference trajectories either in velocity or position is proposed. the basic modeling assumption is that the vehicle is propulsed via a thrust force along a single body-fixed direction and that it has full torque actuation for attitude control (i.e. a typical actuation structure for aircrafts, vertical take-off and landing (vtol) vehicles, submarines, etc.). additional assumptions on the external forces applied to the vehicle are also introduced for the sake of control design and stability analyses. they are best satisfied for vehicles whose shape induces lift forces with limited amplitude and which are subjected to an external force field (e.g. gravity), as in the case of vtol vehicles. the interactions of the vehicle with the surrounding fluid are often difficult to model precisely and they may significantly perturb its motion. some novel nonlinear feedback control laws are proposed to compensate for modeling errors and perform robustly against such perturbations. simulation results illustrating these properties on a realistic model of a vtol vehicle are reported.
an unsupervised adaptive strategy for constructing probabilistic roadmaps. since planning environments are complex and no single planner exists that is best for all problems, much work has been done to explore methods for selecting where and when to apply particular planners. however, these two questions have been difficult to answer, even when adaptive methods meant to facilitate a solution are applied. for example, adaptive solutions such as setting learning rates, hand-classifying spaces, and defining parameters for a library of planners have all been proposed. we demonstrate a strategy based on unsupervised learning methods that makes adaptive planning more practical. the unsupervised strategies require less user intervention, model the topology of the problem in a reasonable and efficient manner, can adapt the sampler depending on characteristics of the problem, and can easily accept new samplers as they become available. through a series of experiments, we demonstrate that in a wide variety of environments, the regions automatically identified by our technique represent the planning space well both in number and placement.we also show that our technique has little overhead and that it out-performs two existing adaptive methods in all complex cases studied.
planar catadioptric stereo: single and multi-view geometry for calibration and localization. planar catadioptric stereo vision sensors (pcs) combine a pinhole camera with two or more planar mirrors. pcs have recently received an increasing attention since a stereo view can be easily obtained without the need of exact multi-camera synchronization and calibration. in this paper we present a rigorous analytical treatment of the imaging geometry of pcs, propose new mirror calibration algorithms and introduce new multi-view properties that can be used for eye-in-hand camera localization. the effectiveness of the algorithms is shown via extensive simulation and real-data experiments on a robotic manipulator.
evidence grid-based methods for 3d map matching. registering multiple sets of 3d range data is a crucial capability for robots. the standard method for matching two sets of range data is to convert the ranges to a point cloud representation, and then use on of the many variants of iterative closest point (icp). we present a set of alternative methods for matching 3d range scans based on a different data representation: evidence grid maps. evidence grids are robust to noise and variations in point density, can incorporate an indefinite number of ranges, and explicitly encode empty as well as occupied space. while 3d evidence grids can be huge when naively implemented, we use an optimized octree data structure to efficiently store sparse volumetric maps. to register a series of range scans, we build an evidence grid map for each scan, and then register them together using a several different methods. the first two methods are based on a 3d extension of the classic 2d lucas-kanade template matching method, and differ only in whether we match a single large region, or multiple small regions that are selected heuristically. our third method involves extracting surfaces from the evidence grids, and then running icp to register the surfaces. we demonstrate our methods and compare them to icp using two datasets collected by two different subterranean robots.
dynamic programming and skyline extraction in catadioptric infrared images. unmanned aerial vehicles (uav) are the subject of an increasing interest in many applications and a key requirement for autonomous navigation is the attitude/position stabilization of the vehicle. some previous works have suggested using catadioptric vision, instead of traditional perspective cameras, in order to gather much more information from the environment and therefore improve the robustness of the uav attitude/position estimation. this paper belongs to a series of recent publications of our research group concerning catadioptric vision for uavs. currently, we focus on the extraction of skyline in catadioptric images since it provides important information about the attitude/position of the uav. for example, the dem-based methods can match the extracted skyline with a digital elevation map (dem) by process of registration, which permits to estimate the attitude and the position of the camera. like any standard cameras, catadioptric systems cannot work in low luminosity situations because they are based on visible light. to overcome this important limitation, in this paper, we propose using a catadioptric infrared camera and extending one of our methods of skyline detection towards catadioptric infrared images. the task of extracting the best skyline in images is usually converted in an energy minimization problem that can be solved by dynamic programming. the major contribution of this paper is the extension of dynamic programming for catadioptric images using an adapted neighborhood and an appropriate scanning direction. finally, we present some experimental results to demonstrate the validity of our approach.
topology design of surgical reconfigurable robots by interval analysis. an automated design generation algorithm for a serial kinematic chain is presented for the reconfigurable robot used in a novel endoluminal surgical procedure (european union project ares). the algorithm produces the possible topologies, given the design constraints, desired performance, and available modules, such that all constraints are satisfied for every point in the desired workspace. this is achieved through the use of interval analysis methods and branch-and-bound loop that searches through the end-effector pose and the design parameter spaces. the resulting algorithm is demonstrated through an example of a serial chain manipulator made of the reconfigurable modules of the surgical robot for the application. the results are presented and discussed.
design of a modular robotic system for archaeological exploration. this paper presents the design and field tests of an intelligent robotic system for archaeological exploration. the system is designed for recording the internal environment of the underground ancient tombs. the recorded data is used for the preservation of antiques inside the ancient tombs as well as for providing the valuable references to the archaeological research. the whole system is modular and minimized in size that can be adapted for two different archaeological situations during the exploration of the ancient tombs. the robotic system can enter the covered ancient tombs through the digging holes prepared by the regular archaeological exploration. one size of the vertical digging hole is less than 12 centimeter in diameter, and the other is 50 centimeter in diameter. the archaeologists can operate on the remote station to control the robotic system with wired communication. the field test results are finally presented for validation of this archaeological robotic system design.
rollover risk prediction of an instrumented heavy vehicle using high order sliding mode observer. in this paper, an original method about heavy vehicles rollover risk prediction is presented and validated experimentally. it is based on the calculation of the ltr (load transfer ratio) which depends on the estimated vertical forces using high order sliding mode observers. the validation tests were carried out on an instrumented truck rolling on the road at various speeds and lane-change manoeuvres. many scenarios have been experienced: driving on straight line, curve line and zigzag to emphasize the rollover phenomenon and its prediction to set off an alarm to the driver.
avoiding moving outliers in visual slam by tracking moving objects. to work at video rate, the maps that monocular slam builds are bound to be sparse, making them sensitive to the erroneous inclusion of moving points and to the deletion of valid points through temporary occlusion. this paper describes the parallel implementation of monoslam with a 3d object tracker, allowing reasoning about moving objects and occlusion. the slam process provides the object tracker with information to register objects to the map's frame, and the object tracker allows the marking of features, either those on objects, or those created by their occluding edges, or those occluded by objects. experiments are presented to verify the recovered geometry and to indicate the impact on camera pose in monoslam of including and avoiding moving features.
automated mouse embryo injection moves toward practical use. taking a different architecture than manual operation and existing microrobotic systems, this paper presents the first automated system that employs novel microfabricated cell holding devices and vision-position based control of multiple motion control devices to achieve easy sample immobilization, rapid cell orientation, and fast injection of mouse embryos. the system requires minimal human involvement through a maximum of three computer mouse clicking per mouse embryo, is human operator skill independent, and is immune from fatigue. while no robotic systems have provided performance close to manual operation, according to the preliminary experimental results (n = 90) from this study, this microrobotic system demonstrated: (i) an injection speed of 9 embryos/min vs. 2 embryos/min in typical manual operation, (ii) a success rate of 98.9%, a higher rate than the best success rate (90%) achieved by proficient injection technicians with over 10 years' experience, and (iii) a high survival rate of 82.1%, a rate comparable with the best survival rate (∼80%) achieved by proficient injection technicians. further improvement of the automated system will change the way of how mouse embryos are injected and promise its practical use in biology laboratories and mouse facilities.
development of a 2-dof electrostatic haptic joystick for mri/fmri applications. this paper describes the development of a 2-dof electrostatic haptic joystick designed for neuroscience studies in an mri/fmri. the joystick is fabricated using non-magnetic materials and actuated by two high-power electrostatic motor units which produce various force fields in the horizontal plane. the electrostatic motor is a synchronous drive and thus the positioning of the joystick is achieved in an open-loop control. as for force sensing, a 2-dof force sensor is developed using non-magnetic materials and optical fibers so as to measure interaction force with a user; hence, the haptic rendering is based on the admittance control scheme that respects the rule of force-in and position-out. the operation of both the actuators and force sensor respects non-magnetic principles. thus, the haptic joystick into which these components are integrated is expected to have high mr compatibility, although the evaluation of the mr compatibility is beyond the scope of this paper. in this paper, the device performance is evaluated in the normal environment, which verifies the operation of the unique electrostatic haptic device.
context assessment strategies for ubiquitous robots. this paper presents an architecture for context-aware ubiquitous robotics applications, where mobile robots cooperate with intelligent environments to fulfill their tasks. specifically, the work is focused on distributed knowledge representation issues and context assessment strategies, and introduces a technique for on-line context recognition in highly dynamic environments. experimental validation, performed in a civillian hospital building, is described and discussed.
differentiated layer design to modify the compliance of soft pads for robotic limbs. most of robotic soft pads studied so far were made with a thick layer of homogeneous material shaped around a rigid core; their behavior has been widely investigated in the literature, mainly under compressive contact load, showing typical non-linear relationship between contact deformation and applied load (the so called power law). this paper proposes differentiated layer design, that is the adoption of a single elastic material, dividing the overall thickness of the pad into layers with different structural design (e.g. a continuous skin layer coupled with an internal layer with voids). the purpose is to modify the actual pad compliance and the resulting power law; in particular, given the material and the allowable pad thickness, to increase the compliance with respect to a non structured pad. some possible internal layer structures are described, compatible with rapid prototyping manufacturing. their compressive behaviors are tested and comparatively evaluated showing that the concept can work and be exploited for useful application.
mri-compatible hands-on cooperative control of a pneumatically actuated robot. mri compatible robots are emerging as useful tools for image guided interventions. a shared control between a user and the mri compatible robot makes it more intuitive instrument especially during setup phases of interventions. we present a mri compatible, hands-on cooperative system using innomotion robotic arm. an economic mri compatible user input sensor was developed and its functionality was tested under typical application conditions. performance improvement in phantom tasks shows promise of adding hands-on interface in mri compatible robots.
nonlinear bilateral teleoperation: stability analysis. this paper aims to take a first step towards the unification of the stability analysis for teleoperators with time-delays. it proposes a general lyapunov-like function that, upon slight modification, allows to analyze the stability of different control schemes, ranging from constant to variable time delays, with or without the scattering transformation and with or without position tracking. it also presents design examples of the corresponding lyapunov-like function for some schemes based on pd controllers and on the scattering transformation for variable time-delays.
a snake robot joint mechanism with a contact force measurement system. a snake robot can traverse cluttered and irregular environments by using irregularities around its body as pushpoints to aid the propulsion. this is denoted obstacle-aided locomotion and requires the snake robot to have two features: 1) a smooth exterior surface combined with 2) a contact force sensing system. these two features are characteristic of biological snakes, but have received limited attention in snake robot designs so far. this paper presents a joint mechanism for a snake robot aimed at meeting both these requirements. the paper details the design and implementation of the joint mechanism and presents experimental results that validate the function of the contact force measurement system.
primitive static states for intelligent operated-work machines. advanced operated-work machines, which have been designed for complicated tasks and which have complicated operating systems, requires intelligent systems that can provide the quantitative work analysis needed to determine effective work procedures and that can provide operational and cognitive support for operators. construction work environments are extremely complicated, however, and this makes state identification, which is a key technology for an intelligent system, difficult. we therefore defined primitive static states (pss) that are determined using on-off information for the lever inputs and manipulator loads for each part of the grapple and front and that are completely independent of the various environmental conditions and variation in operator skill level that can cause an incorrect work state identification. to confirm the usefulness of pss, we performed experiments with a demolition task by using our virtual reality simulator. we confirmed that pss could robustly and accurately identify the work states and that untrained skills could be easily inferred from the results of pss-based work analysis. we also confirmed in skill-training experiments that advice information based on pss-based skill analysis greatly improved operator's work performance. we thus confirmed that pss can adequately identify work states and are useful for work analysis and skill improvement.
consensus for formation control of nonholonomic mobile robots. in this article we present novel formation control laws based on artificial potential fields and consensus algorithms for a group of unicycles enabling arbitrary formation patterns for these nonholonomic vehicles. given connected and balanced graphs we are able to prove stability of the rendezvous controller by applying the lasalle-krasovskii invariance principle. further, we introduce obstacle avoidance, enabling a reactive behavior of the robotic group in unknown environments. the effectiveness of the proposed controllers is shown using computer simulations and finally, a classification w.r.t. existing solutions is done.
uav target tracking using an adversarial iterative prediction. we present a control strategy that permits a fixed wing uav to visually track a ground target. a pursuit-evasion strategy aims at optimizing the visibility of the pursuer uav after having predicted the best action for the evading target. this is achieved by using two iterative methods that optimise various mission based criteria: obstacle avoidance and visibility maximisation for the uav and stealthy motions for the target.
analysis of sliding of a soft fingertip embedded with a novel micro force/moment sensor: simulation, experiment, and application. we have investigated the deformation of a soft fingertip when it slides. this process was first simulated using the non-linear finite element analysis (fea) method. based on the results of this simulation, we designed experiments to observe the sliding and object grasping of a soft fingertip, in which a 3-dof (degree of freedom) micro force/moment sensor was embedded. with this sensor, forces and moments acting in the fingertip are measured based on the piezoresistive effect. these measurements provide information on the status of contact and sliding of a soft fingertip on a surface. based on these results, incipient slip, which has an important role in object gripping by a robot manipulator, can be realized. textile's texture recognition experiments were also conducted to assess potentials of the fingertip in tactile and texture perception.
development of mörri, a high performance and modular outdoor robot. this paper describes the development of mörri, a multi purpose robot platform. the design of this robot includes mechanical, electrical and software development. key features of the robot are modularity for multi-purpose applications, affordable size for outdoor and indoor operation, low cost, high performance, and easy to use and repair in field conditions. the main focus on software architecture development has been on creating fully-functional real-time architecture, where several algorithms and methods can be easily integrated as part of the system. as a result, this robot took part on m-elrob outdoor robot competition in july 2008 and won "camp security" scenario.
multi-robot tree and graph exploration. in this paper we present an algorithm for the exploration of an unknown graph with k robots, which is guaranteed to succeed on any graph, and which on trees we prove to be near-optimal for two robots, having optimal dependence on the size of the tree but not on its radius. we believe that the algorithm performs well on any graph, and this is substantiated by simulations. for trees with n edges and radius r, the exploration time is 2n/k + o(rk-1), improving a recent method with o(n/log k + r) [1], and almost reaching the lower bound max(2n/k, 2r). the algorithm is meant to be used in indoor navigation or cave search scenarios where the environment can be modeled as a graph. in this scenario, communication is realized by the devices being dropped by the robots at explored vertices, and the states of which are read and changed by further visiting robots. simulations on player/stage platform have been performed in both tree and graph exploration which corroborate the mathematical results.