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This paper investigates the connection between non-prehensile manipulation, specifically juggling, and legged locomotion, focusing on biped robots. In this direction, the hybrid nature of juggler robot dynamics and biped robots, the zero moment point stability, and the non-prehensile dynamic grasping conditions are provided and analysed. The similarities between juggling actions and bipedal robot locomotion are discussed. The descriptive and mathematical analysis demonstrates many similitudes between juggler systems with cubic objects and flat-feet biped robots in throwing, catching, and stabilization phases, and between juggler actions with impact and point-feet legged robots in their switching (hybrid) dynamic behaviours. Finally, a common control framework based on the zero dynamic concept and integral sliding mode approach is proposed, and it applies to both classes of non-prehensile juggler systems and biped robots. To test the performance of the devised control system, a three-degrees-of-freedom juggler robot and a two-link walker are selected as case studies, whose simulation results demonstrate the effectiveness and feasibility of the proposed unified control framework for both systems. [ABSTRACT FROM AUTHOR]

In continuous steel-concrete composite beams, hogging moments may occur near the internal supports. This type of bending causes compression in the bottom flange, which may buckle laterally in an ultimate limit state known as lateral distortional buckling. Despite the consideration that continuity may result in an economic design, no research had yet been conducted on the possibility of lateral distortional buckling in continuous composite beams in fire situation. This paper presents an experimental and numerical study on the lateral distortional buckling of steel concrete composite beams. Four real scale fire tests were conducted and proved that it may indeed occur. A parametric study was also developed. It has been shown that this buckling mode may lead to a reduction in the strength of composite beams of up to 50% when compared to the plastic moment. It was also noted that this buckling mode is usually accompanied by local buckling, which may occur even in compact sections, leading to a decrease in bearing capacity. These results indicate a need of reviewing the design codes to consider the possibility of lateral distortional buckling at high temperatures, as it may be more than at ambient temperature. • Four real scale composite beam fire tests under hogging moment are presented. • Lateral distortional buckling may severely reduce resistance in fire. • Lateral distortional buckling is more significant in fire than at ambient temperature. • Local buckling occurred even in compact sections. [ABSTRACT FROM AUTHOR]

[Display omitted] • Samples were collected by means of specially prepared stainless-steel canisters. • C 2 -C 12 hydrocarbons were determined using a single GC system with a capillary flow technology Deans Switch. • The resolution of C 2 and C 3 HC was increased even without a cryogenic system. • C 2 -C 12 accounted for approximately 15–35% of total HC mass in the analyzed samples. Gas chromatography (GC) determination of C 2 -C 12 hydrocarbons (HCs) in atmospheric samples is a complex task. In general, it involves employing two chromatographic systems or a double gas chromatograph, where the gaseous sample is divided into two fractions. In this study an alternative system is put forward for the analysis of ambient air samples, including urban, industrial and forest environments, indoor samples and direct exhaust vehicular samples. A single GC system was used with a capillary flow technology Deans Switch, configured with two detectors (MS and FID) and two columns (primary column - DB-624 and secondary column - PoraPlot Q-HT). Samples were collected by means of specially prepared stainless-steel canisters, and then trapped and thermally desorbed. The effectiveness of this method was assessed with two kinds of samples: ambient air collected in an urban forest where HCs concentrations are very low and indoor air collected in an enclosed underground parking lot characterized by poor ventilation and a relatively high concentration of pollutants emitted in the combustion of flex-fuel vehicles. The limits of detection (LOD) and quantification (LOQ), were 0.2 µg m−3 and 0.6 µg m−3 , respectively, for a typical injection volume of 500 mL. The results showed that the method was applicable for the analysis of all the samples and underlined the importance of C 2 HCs which cannot be determined from a conventional TO-15 US EPA Method. [ABSTRACT FROM AUTHOR]

Speciation and quantification of hydrocarbons (HC) in exhaust emissions are essential when making an evaluation of MIR (maximum incremental reactivity) and OFP (ozone forming potential) factors with different fuels. In Brazil, flex-fuel vehicles were launched in 2003 and can operate with H100 (100% hydrous ethanol, 4.0–4.9% vol/vol of water), commercial gasohol (gasoline blended with 18–27% vol/vol anhydrous ethanol) or any blend of these fuels. The main difficulties when conducting an analysis of HC with these fuels, are the presence of several contaminants, the interference of ethanol and relatively high concentrations of C 2 species. In this study, a new analytical method was employed that was based on a heart-cutting gas chromatography approach. Two flex fuel vehicles, using H100 and E22 (22% v/v of anhydrous ethanol), were tested with the EPA-75 drive cycle (in accordance with the requirements of ABNT/NBR 6601) and HC (C 2 –C 12) in the three gas exhaust phases (cold start, stabilized and hot start) were analyzed. In the case of the latest vehicle (PROCONVE L6, Tier 2 equivalent), with H100, the MIR and OFP values were 5.7 ± 0.3 and 0.032 ± 0.005 gO 3 km−1, respectively. When fueled with E22, the MIR and OFP values were determined as 3.6 ± 0.2 and 0.015 ± 0.001 gO 3 km−1, respectively. To the best of our knowledge, this was the first complete HC (C 2 –C 12) speciated analysis conducted in Brazil using H100 and E22 (without any significant contamination with ethanol as fuel) and aided by heart-cutting gas chromatography. • Heart-cutting gas chromatography approach, without a cryogenic system, was used to determine C 2 –C 12 hydrocarbons. • Contamination in hydrous ethanol samples was minimized. • Vehicles with ethanol H100 and gasoline E22 were tested. • MIR and ozone forming potentials (OFP) were calculated for H100 and E22. [ABSTRACT FROM AUTHOR]

The computation of the grasping forces for a multiarm robotic manipulation system (e.g., an anthropomorphic bimanual system) is considered in this paper. This problem is formulated as a convex optimization problem, also considering joint torque constraints. An algorithmic solution suitable for online implementation is presented, which allows a substantial reduction in the computational load by adopting a compact formulation and dynamically decreasing the number of active torque constrains. Moreover, for the case of a bimanual manipulation system, a suboptimal single-hand optimization algorithm is proposed and compared with that providing the optimal solution. Finally, a new algorithm for a valid initial-point evaluation is proposed. The effectiveness of the described methods has been tested in a simulation case study where the grasping forces of a humanoid torso equipped with two five-finger robotic hands are modified online to handle a load with a time-varying mass. [ABSTRACT FROM AUTHOR]

An approach to force and visual control of robot manipulators in contact with a partially known environment is proposed in this article. The environment is modeled as a rigid object of known geometry but of unknown and time-varying position and orientation. An algorithm for online estimation of the object pose is adopted, based on visual data provided by a camera as well as on forces measured during the interaction. This information is used by a force/position control scheme, in charge of managing the interaction. Simulation and experimental results are presented for the case of an industrial robot manipulator. [ABSTRACT FROM AUTHOR]

Abstract: A broad spectrum of issues have to be addressed in order to tackle the problem of a safe and dependable physical Human–Robot Interaction (pHRI). In the immediate future, metrics related to safety and dependability have to be found in order to successfully introduce robots in everyday enviornments. While there are certainly also “cognitive” issues involved, due to the human perception of the robot (and vice versa), and other objective metrics related to fault detection and isolation, our discussion focuses on the peculiar aspects of “physical” interaction with robots. In particular, safety and dependability are the underlying evaluation criteria for mechanical design, actuation, and control architectures. Mechanical and control issues are discussed with emphasis on techniques that provide safety in an intrinsic way or by means of control components. Attention is devoted to dependability, mainly related to sensors, control architectures, and fault handling and tolerance. Suggestions are provided to draft metrics for evaluating safety and dependability in pHRI, and references to the works of the scientific groups involved in the pHRI research complete the study. The present atlas is a result of the EURON perspective research project “Physical Human–Robot Interaction in anthropic DOMains (PHRIDOM)”, aimed at charting the new territory of pHRI, and constitutes the scientific basis for the ongoing STReP project “Physical Human–Robot Interaction: depENDability and Safety (PHRIENDS)”, aimed at developing key components for the next generation of robots, designed to share their environment with people. [Copyright &y& Elsevier]

This paper deals with the problem of position-based visual servoing in a multiarm robotic cell equipped with a hybrid eye-in-hand/eye-to-hand multicamera system. The proposed approach is based on the real-time estimation of the pose of a target object by using the extended Kalman filter. The data provided by all the cameras are selected by a suitable algorithm on the basis of the prediction of the object self-occlusions, as well as of the mutual occlusions caused by the robot links and tools. Only an optimal subset of image features is considered for feature extraction, thus ensuring high estimation accuracy with a computational cost independent of the number of cameras. A salient feature of the paper is the implementation of the proposed approach to the case of a robotic cell composed of two industrial robot manipulators. Two different case studies are presented to test the effectiveness of the hybrid camera configuration and the robustness of the visual servoing algorithm with respect to the occurrence of occlusions. [ABSTRACT FROM AUTHOR]

Abstract: An algorithm for the real-time estimation of the position and orientation of a moving object of known geometry is presented in this paper. An estimation algorithm is adopted where a discrete-time extended Kalman filter computes the object pose on the basis of visual measurements of the object features. The scheme takes advantage of the prediction capability of the extended Kalman filter for the pre-selection of the features to be extracted from the image at each sample time. To enhance the robustness of the algorithm with respect to measurement noise and modelling error, an adaptive version of the extended Kalman filter, customized for visual applications, is proposed. Experimental results on a fixed single-camera visual system are presented to test the performance and the feasibility of the proposed approach. [Copyright &y& Elsevier]

Abstract: A proportional-derivative (PD) control with on-line gravity compensation is proposed for regulation tasks of robot manipulators with elastic joints. The work extends a previous PD control with constant gravity compensation at the desired configuration. The control law requires measuring only position and velocity on the motor side of the elastic joints, while the on-line gravity compensation torque uses a biased measure of the motor position. It is proved via a Lyapunov argument that the control law globally asymptotically stabilizes the desired robot configuration. A simulation study on a two-joint arm reveals the better performance that can be obtained with the new scheme as compared to the case of constant gravity compensation. Moreover, the proposed controller is experimentally tested on an eight-joint cable-driven robot manipulator, in combination with a point-to-point interpolating trajectory, showing the practical advantages of the on-line compensation. [Copyright &y& Elsevier]

Investigates the compliance control for elastic robot manipulators in the Cartesian space. Evaluation of the closed-loop equilibrium conditions and the asymptotic stability; Compliance control with constant gravity compensation; Reduction of the effects of joint elasticity; Analysis of control law formulations.

Human–robot interaction represents a critical factor in the design of personal robots as well as in the implementation of robot behavior and control. This work investigates and proposes solutions to the problem of controlling an anthropomorphic robot arm for personal assistance, by dealing with the peculiarities of its design, i.e. the mechanics of its cable-actuated, intrinsically compliant structure, and by emphasizing its potential in applications of physical and functional interaction with the environment and with human users.To satisfy the requirements of increasing the safety in the interaction and the robot functionality in tasks performed in cooperation with humans, three solutions are developed and tested for the considered personal robot. The initial idea is aimed at developing an efficient as well as computational convenient interaction control strategy, i.e. a compliance control scheme in the Cartesian space. The analysis of its limited performance suggests two further control strategies, i.e. a compliance control scheme in the joint space and an impedance–compliance control scheme. Their compared analysis points out that all the three solutions can safely operate in the human environment, but from a functional point of view only the last two schemes can effectively control the personal robot arm in its whole workspace.The paper describes the mechanics of the considered robot arm, with special regard to its anthropomorphism and cable-actuation and presents in details the three control schemes. They are critically evaluated through the experimental results achieved in tasks of physical and functional interaction with the environment and with human users. The impedance–compliance controller emerges as the more appropriate to the addressed application as well as to the peculiar cable-actuated structure. [Copyright &y& Elsevier]

This paper is aimed at presenting solution algorithms to the inverse kinematics of a space manipulator mounted on a free-floating spacecraft. The reaction effects of the manipulator's motion on the spacecraft are taken into account by means of the so-called generalized Jacobian. Redundancy of the system with respect to the number of task variables for spacecraft attitude and manipulator end-effector pose is considered. Also, the problem of both spacecraft attitude and end-effector orientation representation is tackled by means of a non-minimal singularity-free representation: the unit quaternion. Depending on the nature of the task for the spacecraft/manipulator system, a number of closed-loop inverse kinematics algorithms are proposed. Case studies are developed for a system of a spacecraft with a six-joint manipulator attached. [ABSTRACT FROM AUTHOR]

Vehicle emissions are the main source of hydrocarbons (HC) in many urban areas. However, the determination of HC in exhaust emissions of vehicles fueled with ethanol is a great challenge, from the analytical point of view, due to the interference of several contaminants. In this study, sampling and analytical methods were implemented and optimized. Contamination during sampling and interference of non-burned ethanol and carbonyl compounds were minimized through a rigorous sampling and analytical procedure. Two flex fuel vehicles, using 100% v/v hydrous ethanol (E100), were tested. Vehicle exhaust samples were collected during emission testing with EPA-75 drive cycle (according to ABNT/NBR 6601) for each of the three phases: cold start, stabilized and hot start. The exhaust was collected in Tedlar® bags and transferred to electropolished stainless steel canisters. HC (C 2 -C 12) in samples were analyzed using thermal desorption and gas chromatography with a mass spectrometry detector. Ethene, ethyne and ethane represented approximately 95% of measured non-methane hydrocarbons (C 2 -C 12). Aromatic compounds were considered negligible (<2%). Since speciated HC emission results are required to calculate MIR (maximum incremental reactivity) and OFP (ozone forming potential) factors, these results can be useful for technical discussions about the ozone formation in a Brazilian fuel scenario. To our knowledge, this was the first HC speciated analysis developed in Brazil using ethanol and Brazilian flex fuel vehicles. [ABSTRACT FROM AUTHOR]

Describes the design of a passivity-based controller and observer for a robot manipulator interactive with a compliant environment. Regulation of the contact force along the constrained direction; Implementation of the of the control scheme in the joint space; Tracking of the end-effector position along the unconstrained directions.

The first COVID-19 case in Brazil was confirmed on February 25, 2020. Partial lockdown measures came into force in the city of Rio de Janeiro, Brazil, on March 23. While CO and NO 2 levels showed significant reductions, PM 10 levels were only reduced in the first partial lockdown week. By contrast, ozone levels increased in all studied locations. In this study, the factors leading to this behavior were analyzed. Monitoring data obtained at two automatic monitoring stations showed higher ratios between non-methane hydrocarbons and nitrogen oxides (NMHC/NO x) during the partial lockdown (up to 37.3%). The increase in ozone concentrations during the social distancing measures could be attributed to the increase in NMHC/NO x ratios since atmospheric chemistry in Rio de Janeiro is under VOC-controlled conditions. However, the increase was higher when air masses arrived from the industrial areas, not only because of the higher NMHC/NO x ratios, but also because the reactivity of VOC was highly increased by these air masses, which are rich in aromatic compounds. Unlabelled Image • Primary atmospheric pollutant concentrations decreased during the lockdown. • Ozone levels increased during lockdown in many cities of the world. • Ozone levels were related to the increase in NMHC/NO x ratios in a VOC-controlled scenario. • Air masses from the industrial areas contributed to ozone increase. [ABSTRACT FROM AUTHOR]

The first COVID-19 case in Brazil was confirmed on February 25, 2020. On March 16, the state's governor declared public health emergency in the city of Rio de Janeiro and partial lockdown measures came into force a week later. The main goal of this work is to discuss the impact of the measures on the air quality of the city by comparing the particulate matter, carbon monoxide, nitrogen dioxide and ozone concentrations determined during the partial lockdown with values obtained in the same period of 2019 and also with the weeks prior to the virus outbreak. Concentrations varied with substantial differences among pollutants and also among the three studied monitoring stations. CO levels showed the most significant reductions (30.3–48.5%) since they were related to light-duty vehicular emissions. NO 2 also showed reductions while PM 10 levels were only reduced in the first lockdown week. In April, an increase in vehicular flux and movement of people was observed mainly as a consequence of the lack of consensus about the importance and need of social distancing and lockdown. Ozone concentrations increased probably due to the decrease in nitrogen oxides level. When comparing with the same period of 2019, NO 2 and CO median values were 24.1–32.9 and 37.0–43.6% lower. Meteorological interferences, mainly the transport of pollutants from the industrial areas might have also impacted the results. Unlabelled Image • CO levels showed the most significant reductions during the partial lockdown. • NO 2 decreased in a lower extent, due to industrial and diesel input. • PM 10 levels were only reduced during the first partial lockout week. • Ozone increased due to the decrease in nitrogen oxides level in a VOC-controlled scenario. [ABSTRACT FROM AUTHOR]

This article presents information on the April 204 issue of the journal "Robotics Research." At the dawn of the new millennium, robotics is undergoing a major transformation in scope and dimension. From a largely dominant industrial focus, robotics is rapidly expanding into the challenges of unstructured environments. Interacting with, assisting, serving, and exploring with humans,the emerging robots will increasingly touch people and their lives. The goal of the International Symposium on Experimental Robotics series is to provide a forum for research in robotics that focuses on theories and principles that are validated by experiment. The meetings are conceived to bring together, in a small group setting, researchers from around the world who are in the forefront of experimental robotics research.

• Screw-based nonlinear finite element formulation for advanced modeling of flexible mechanical systems. • Input shaping predictive control algorithms for command generation and vibration control of flexible mechanical systems. • Simulation tools for predicting the motion of DEMO flexible mechanical systems for analysis, planning and control purposes. • Simulation of: Telescopic Articulated Remote Mast; Hybrid Kinematic Mechanism. • Perspectives and discussion about future research on modeling and control for DEMO remote maintenance systems. The goal of this paper is to disseminate the main results achieved within the FlexARM project. The project deals with advanced modeling techniques and predictive control strategies for flexible mechanical systems intended to be used in remote tasks inside advanced nuclear fusion reactors. This article aims at underlying the main aspect of the FlexARM methodology and paves the way towards future research in the field. [ABSTRACT FROM AUTHOR]

In this paper, a novel, robust, and simple method for automatically estimating the hand pose is proposed and validated. The method uses a multi-camera optoelectronic system and a model-based stochastic algorithm. The approach is marker-based and relies on an Unscented Kalman Filter. A hand kinematic model is introduced for constraining relative marker's positions and improving the algorithm robustness with respect to outliers and possible occlusions. The algorithm outputs are 3D coordinate measures of markers and hand joint angle values. To validate the proposed algorithm, a comparison with ground truths for angular and 3D coordinate measures is carried out. The comparative analysis shows the advantages of using the model-based stochastic algorithm with respect to standard processing software of optoelectronic cameras in terms of implementation simplicity, time consumption, and user effort. The accuracy is remarkable, with a difference of maximum 0.035r a d and 4m m with respect to angular and 3D Cartesian coordinates ground truths, respectively. [ABSTRACT FROM AUTHOR]

In this paper, we propose a nonlinear controller that stabilizes unmanned aerial vehicles in GPS-denied environments with respect to visual targets by using only onboard sensing. The translational velocity of the vehicle is estimated online with a nonlinear observer, which exploits spherical visual features as the main source of information. With the proposed solution, only four visual features have shown to be enough for the observer to operate in a real scenario. In addition, the observer is computationally light with constant numerical complexity, involving small-dimension matrices. The observer output is then exploited in a nonlinear controller designed with an integral backstepping approach, thus yielding a novel robust control system. By means of Lyapunov analysis, the stability of the closed-loop system is proved. Extensive simulation and experimental tests with a quadrotor are carried out to verify the validity and robustness of the proposed approach. The control system runs fully onboard on a standard processor, and only a low-cost sensing suite is employed. Tracking of a target whose speed exceeds 2  \mathrmm/s is also considered in the real-hardware experiments. [ABSTRACT FROM PUBLISHER]

This paper presents an experimental study on human–robot comanipulation in the presence of kinematic redundancy. The objective of the work is to enhance the performance during human–robot physical interaction by combining Cartesian impedance modulation and redundancy resolution. Cartesian impedance control is employed to achieve a compliant behavior of the robot's end effector in response to forces exerted by the human operator. Different impedance modulation strategies, which take into account the human's behavior during the interaction, are selected with the support of a simulation study and then experimentally tested on a 7-degree-of-freedom KUKA LWR4. A comparative study to establish the most effective redundancy resolution strategy has been made by evaluating different solutions compatible with the considered task. The experiments have shown that the redundancy, when used to ensure a decoupled apparent inertia at the end effector, allows enlarging the stability region in the impedance parameters space and improving the performance. On the other hand, the variable impedance with a suitable modulation strategy for parameters’ tuning outperforms the constant impedance, in the sense that it enhances the comfort perceived by humans during manual guidance and allows reaching a favorable compromise between accuracy and execution time. [ABSTRACT FROM PUBLISHER]

This paper presents a trajectory generation algorithm for a three-dimensional (3D) biped robot that can adjust the center of mass (CoM) according to the environment. We adopt a new abstract model that supports vertical motion and rotation. Differing from traditional abstract models, the proposed full centroid dynamics inverted pendulum model fully considers the robot's movement and rotation. Unlike the zero moment point (ZMP), which only ensures the feet do not flip over, we also propose a new additional stability criterion, named zero frictional moment point (ZFMP), guaranteeing no yaw rotation while walking. Next, a nonlinear model predictive control is designed to generate the CoM trajectory, torso rotational angle, and adaptive footholds to induce various biped gaits. A full-dynamics 3D humanoid robot is simulated to test the proposed method while steering, walking underneath a low door, and walking with disturbances. • A new abstract model for the biped robot. • A new stability criterion for yaw motion stability. • Walking with the variable center of mass height. • Nonlinear model prediction control for biped walking. [ABSTRACT FROM AUTHOR]

Abstract: A new method to catch a thrown ball with a robot endowed with an eye-in-hand monocular visual system integrated into a gripper is proposed. As soon as the thrown ball is recognized by the visual system, the camera carried by the robot end-effector is forced to follow a baseline in the space so as to acquire an initial dataset of visual measurements from several points of view, providing a first estimate of the catching point through a linear estimation algorithm. Hereafter, additional measurements are acquired to constantly refine the previous estimate by exploiting a nonlinear estimation algorithm. During the robot trajectory, the translational components of the camera are controlled in such a way as to follow the planned path to intercept the ball, while the rotational components are forced to keep the ball into the field of view. Experimental results performed on a common industrial robotic system prove the effectiveness of the presented solution. [Copyright &y& Elsevier]

In this paper, an intelligent variable impedance control combined with a fuzzy gain dynamic surface is proposed to improve the interaction of the robot manipulator with an unknown varied environment. The parameters of the proposed variable impedance are adapted by optimization an introduced cost function using a recurrent fuzzy wavelet network. The stability conditions for the varying inertial, stiffness and damping are presented to guarantee the stability of the variable impedance. Additionally, a fuzzy dynamic surface method is developed to tune the gains of the dynamic surface as a robust controller. The proposed fuzzy gain dynamic surface is used to force the end-effector of the manipulator to track the desired impedance profile in the presence of large disturbances. Using Lyapunov's method, the stability of the mentioned closed-loop system is proved. Finally, by using a designed simulator for IRB120 (ABB) robot, several simulations are carried out to verify the performance of the proposed method for the execution of various tasks in an unknown varied environment in the presence of large disturbances. [ABSTRACT FROM AUTHOR]

This paper presents a new procedure to design a control law using the classical interconnection and damping assignment technique within the passivity-based port-Hamiltonian framework. The sought goal is to reduce the complexity of solving the so-called matching equations. The proposed approach is applied to two case studies of planar rolling nonprehensile manipulation, namely, the ball-and-beam and the eccentric disk-on-disk. The performance of the resulting controllers is illustrated through both simulations and experimental results, showing the applicability of the design in a real setup. [ABSTRACT FROM AUTHOR]

Abstract Remote handling of heavy in-vessel components inside nuclear fusion reactors requires the use of large robotic mechanisms, whose numerical analysis is highly complex. As a matter of fact, these robots are subject to large deformations, either induced by the geometric configuration of their mechanical structure or by the heavy payloads they usually transport. This work was motivated by the need of deriving physical-based predictive models able to simulate the mechanical behavior of such large robotic mechanisms, while performing dynamic tasks. The method formulates the dynamics of robotic manipulators on a Lie group, and uses a finite element procedure to discretize the flexible bodies. The method is applied to a complex mechanism, the serial/parallel flexible manipulator which has been recently selected for DEMO blanket remote handling. The case studies investigated in this paper involve the simulations of this manipulator while handling the inboard and outboard blanket segments according to the sequence of maneuvers planned for their removal processes from the vessel. The results show that such dynamic simulations could give useful information for design, analysis and control of remote handling equipment. The generality of the method makes this approach prone to be easily used in simulating the dynamics of other flexible manipulators for remote handling of large in-vessel components inside nuclear fusion reactors. [ABSTRACT FROM AUTHOR]

This article focuses on ethical issues raised by increasing levels of autonomy for surgical robots. These ethical issues are explored mainly by reference to state-ofart case studies and imminent advances in Minimally Invasive Surgery (MIS) and Microsurgery. In both area, surgicalworkspace is limited and the required precision is high. For this reason, increasing levels of robotic autonomy can make a significant difference there, and ethically justified control sharing between humans and robots must be introduced. In particular, from a responsibility and accountability perspective suitable policies for theMeaningfulHuman Control (MHC) of increasingly autonomous surgical robots are proposed. It is highlighted how MHC should be modulated in accordance with various levels of autonomy for MIS and Microsurgery robots. Moreover, finer MHC distinctions are introduced to deal with contextual conditions concerning e.g. soft or rigid anatomical environments. [ABSTRACT FROM AUTHOR]

The problem of robustification of interconnection and damping assignment passivity-based control for underactuated mechanical system vis-à-vis matched, constant, and unknown disturbances is addressed in the paper. This is achieved adding an outer-loop controller to the interconnection and damping assignment passivity-based control. Three designs are proposed, with the first one being a simple nonlinear PI, while the second and the third ones are nonlinear PIDs. While all controllers ensure stability of the desired equilibrium in spite of the presence of the disturbances, the inclusion of the derivative term allows us to inject further damping enlarging the class of systems for which asymptotic stability is ensured. Numerical simulations of the Acrobot system and experimental results on the disk-on-disk system illustrate the performance of the proposed controller. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper describes the development of a remote handling control of an anthropomorphic robotic hand, the SCHUNK S5FH, using the human hand as master by measuring its motion with OptiTrack Technology. The goal of this work is to enhance manipulation studies on the human hand and to instantly transfer those studies on robotic hands. A preliminary study on methods and devices used for fingers tracking led to the choice of a simplified kinematic model of the human hand on the basis of the available motion tracking system. Using the same criteria, the analysis of protocols for markers allocation led to define the number and a method for their arrangement on the fingers and palm. In order to overcome the limitation of the Motion Capture System, a method for identification and labeling has been developed according to their anatomical arrangement. Afterwards, the tracking is performed using the constraints between marker positions on the kinematic chain of the hand and a dynamic labeling algorithm robust with respect to noise, outliers and loss of markers. The validation is performed using the right hand of different subjects and considering different tasks involving flexion/extension and abduction/adduction of fingers and thumb opposition. For testing and validation, preliminary studies on synergies for manipulation tasks such as screwing a cup, has been conducted on the human hand and transferred on the robotic hand. [ABSTRACT FROM AUTHOR]

This paper presents a method for tracking a 3D textureless object which undergoes elastic deformations, using the point cloud data provided by an RGB-D sensor and in real-time. This solution is expected to be useful for enhanced manipulation of humanoid robotic systems, especially in the case of pizza dough to be ideally manipulated by a pizza chef robot. Our tracking framework relies on a prior visual segmentation of the object in the image. The segmented point cloud is registered first in a rigid manner and then by non-rigidly fitting the mesh, based on the Finite Element Method to model elasticity, and on geometrical point-to-point correspondences to compute external forces exerted on the mesh. The system has been evaluated on synthetic and real data, and by integrating it into manipulation experiments on the RoDyMan 1 1 http://www.rodyman.eu/ . The research leading to these results has been supported by the RoDyMan project, which has received funding from the European Research Council (FP7 IDEAS) under Advanced Grant agreement number 320992 . The authors are solely responsible for its content. It does not represent the opinion of the European Community and the Community is not responsible for any use that might be made of the information contained therein. humanoid robotic platform. [ABSTRACT FROM AUTHOR]

Complete and detailed 3D scanning of cultural heritage artifacts is a still time-consuming process that requires skilled operators. Automating the digitization process is necessary to deal with the growing amount of artifacts available. It poses a challenging task because of the uniqueness and variety in size, shape and texture of these artifacts. Scanning devices have usually a limited focus or measurement volume and thus require precise positioning. We propose a robotic system for automated photogrammetric 3D reconstruction. It consists of a lightweight robotic arm with a mounted camera and a turntable for the artifact. In a virtual 3D environment, all relevant parts of the system are modeled and monitored. Here, camera views in position and orientation can be planned with respect to the depth of field of the camera, the size of the object and preferred coverage density. Given a desired view, solving inverse kinematics allows for collision-free and stable optimization of joint configurations and turntable rotation. We adopt the closed-loop inverse kinematics (CLIK) algorithm to solve the inverse kinematics on the basis of a particular definition of the orientation error. The design and parameters of the solver are described involving the option to shift the weighting between different parts of the objective function, such as precision or mechanical stability. We then use these kinematic solutions to perform the actual scanning of real objects. We conduct several tests with different kinds of objects showing reliable and sufficient results in positioning and safety. We present a visual comparison involving the real robotic system with its virtual environment demonstrating how view poses for different-sized objects are successfully planned, achieved and used for 3D reconstruction. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the postural synergy configuration subspace given by the fundamental eigengrasps of the UB Hand IV is derived from experiments, and a simplified synergy-based strategy for planning grasps is proposed. The objectives of this work are, on one side, the simplification of grasp synthesis in a configuration space of reduced dimensions and, on the other side, the attainment of a human-like behavior for anthropomorphic hands. A reference set of 36 hand postures, chosen with the goal of covering the entire grasp variety referring to a recently proposed taxonomy, has been considered for the evaluation of the hand synergies. With the aim of defining general properties of the three predominant synergies, the reference set of hand postures has been applied to other two anthropomorphic robot hands, and the obtained synergies have been compared with the ones computed considering the UB Hand IV kinematics. Moreover, the synthesis of new grasps, not contained in the reference set of hand postures, has also been achieved by means of the synergy subspace. The experiments carried out demonstrate that the adopted synergy-based planning method works efficiently for all the considered grasps even if not contained in the reference set used for the evaluation of the postural synergies. [Copyright &y& Elsevier]

In this paper, the problem of controlling a robot manipulator in task space, while guaranteeing a compliant behavior for the redundant degrees of freedom, is considered. This issue may arise in the case where the robot experiences an interaction on its body, especially in the presence of humans. The proposed approach guarantees correct task execution and compliance of the robot’s body during intentional or accidental interaction in the null space of the main task, simultaneously. The asymptotic stability of the task-space error is ensured by using suitable observers to estimate and compensate the generalized forces acting on the task variables, without using joint torque measurements. Two different controller–observer algorithms are designed, and they are based on the task-space error and on the generalized momentum of the robot, respectively. The performance of the proposed algorithms is verified in experiments on a 7R lightweight robot arm. [ABSTRACT FROM PUBLISHER]

Highlights: [•] We used 242 proposals to European calls in robotics. [•] We focused on the research profiles, collaboration patterns and research topic trends. [•] Belgium and Sweden are countries with high project proposal production, with high quality. [•] Single partner proposals have significantly lower quality than multi-partner proposals. [•] The number of countries involved shows no influence on the quality of the proposals. [ABSTRACT FROM AUTHOR]

This paper presents a dynamic-level control algorithm to meet simultaneously multiple desired tasks based on allocated priorities for redundant robotic systems. It is shown that this algorithm can be treated as a general framework to achieve control over the whole body of the robot. The control law is an extension of the well-known acceleration-based control to the redundant robots, and considers also possible interactions with the environment occurring at any point of the robot body. The stability of this algorithm is shown and some of the previously developed results are formulated using this approach. To handle the interaction on robot body, null space impedance control is developed within the multi-priority framework. The effectiveness of the proposed approaches is evaluated by means of computer simulation. [ABSTRACT FROM AUTHOR]

This article presents new closed-loop schemes for solving the inverse kinematics of constrained redundant manipulators. In order to exploit the space of redundancy, the end-effector task is suitably augmented by adding a constraint task. The success of the technique is guaranteed either by specifying the constraint task ad hoc or by resorting to a task priority strategy, instead of previous inverse kinematics schemes that use the Jacobian pseudoinverse, the schemes in this work are shown to converge using the Jacobian transpose. A number of case studies illustrate different ways of solving redundancy in the context of the proposed schemes. [ABSTRACT FROM AUTHOR]

The novel underactuated design of the PRISMA HAND I and its multimodal control based on integrated electromyographic signals and voice commands is presented. Due to limitations of EMG sensors and residual physiological signals of amputees, a smart solution utilizing a voice recognition module has been integrated into the EMG control to realize advanced intuitive commands and easy connection with the arm. Inspired by neuroscience studies on the human hand, two motor synergies have been implemented. The thumb adduction/abduction independent motion allows in-hand manipulation. The transmission system is based on whiffletree and pulleys for motion differentiation and on antagonistic elastic tendons. Using EMG and voice commands, the motors are moved together in a certain number of combination suitably and easily programmed using Arduino electronic prototyping. The use of a current sensor allows controlling the strength of the grasp to handle also fragile objects. The contributions of this work are: the bio-inspired design of kinematics and motion couplings by means of two motor synergies, the simple and efficient control interface allowing easy connection to the arm and intuitive use, finally, the cost reduction using economic hardware and mechanical components while preserving performance. • This paper presents a new hand prototype realized with 3D printing. • The design exploits recent results on postural synergies of the human hand. • The contributions are bio-inspired design, efficient control interface and cost reduction. • The hand is underactuated and uses two motors. • The control is based on integrated electromyographic signals and voice commands. • PHI is a lowcost hand that can be easy commercialized. [ABSTRACT FROM AUTHOR]

The paper proposes a novel framework for registering and segmenting 3D point clouds of large-scale natural terrain and complex environments coming from a multisensor heterogeneous robotics system, consisting of unmanned aerial and ground vehicles. This framework involves data acquisition and pre-processing, 3D heterogeneous registration and integrated multi-sensor based segmentation modules. The first module provides robust and accurate homogeneous registrations of 3D environmental models based on sensors' measurements acquired from the ground (UGV) and aerial (UAV) robots. For 3D UGV registration, we proposed a novel local minima escape ICP (LME-ICP) method, which is based on the well known iterative closest point (ICP) algorithm extending it by the introduction of our local minima estimation and local minima escape mechanisms. It did not require any prior known pose estimation information acquired from sensing systems like odometry, global positioning system (GPS), or inertial measurement units (IMU). The 3D UAV registration has been performed using the Structure from Motion (SfM) approach. In order to improve and speed up the process of outliers removal for large-scale outdoor environments, we introduced the Fast Cluster Statistical Outlier Removal (FCSOR) method. This method was used to filter out the noise and to downsample the input data, which will spare computational and memory resources for further processing steps. Then, we co-registered a point cloud acquired from a laser ranger (UGV) and a point cloud generated from images (UAV) generated by the SfM method. The 3D heterogeneous module consists of a semi-automated 3D scan registration system, developed with the aim to overcome the shortcomings of the existing fully automated 3D registration approaches. This semi-automated registration system is based on the novel Scale Invariant Registration Method (SIRM). The SIRM provides the initial scaling between two heterogenous point clouds and provides an adaptive mechanism for tuning the mean scale, based on the difference between two consecutive estimated point clouds' alignment error values. Once aligned, the resulting homogeneous ground-aerial point cloud is further processed by a segmentation module. For this purpose, we have proposed a system for integrated multi-sensor based segmentation of 3D point clouds. This system followed a two steps sequence: ground-object segmentation and color-based region-growing segmentation. The experimental validation of the proposed 3D heterogeneous registration and integrated segmentation framework was performed on large-scale datasets representing unstructured outdoor environments, demonstrating the potential and benefits of the proposed semi-automated 3D registration system in real-world environments. [ABSTRACT FROM AUTHOR]

Coordinates play an essential role in the description of real world objects and physical processes. In robotics, coordinates are used to describe the kinematic structure and the kinematic and dynamic behavior. The description mostly takes place in charts, assigned by the observer of the robotic system. However, it is crucial that the described physical process does not depend on the coordinate choice of the observer. In this work we show the relation between coordinates and manipulability analysis. Manipulability measures are dependent of joint coordinates of the robot and task coordinates in the workspace of the robot. Both relations can be analyzed with tensor geometry. We remove the dependency on joint coordinates through the use of an appropriate metric. With the help of tensor contraction, the resulting induced metric in the workspace can be transformed into a coordinate invariant matrix. After applying eigenvalue decomposition on this matrix, we can visualize the dynamic manipulability of a robot as a coordinate invariant ellipsoid. [ABSTRACT FROM AUTHOR]

Introduction: Criteria for classification, indication and choice of a surgical device to treat proximal humeral fractures are still controversial. We report an original technique based on a mechanical concept with a structural principle of a triangle as a rigid body applied to the humeral head fractures in association with other devices. This retrospective study aims to describe in detail the surgical technique and results at long time follow up.Methods and Material: We analysed two series of 101 patients with proximal humeral fractures (mean age, 52.9 y; range 19-78 y) treated between 2001 and 2012 reporting the clinical and radiological results. In the first series of 23 cases (mean age 51.4 y, range 35-74 y) we used as support a bone piece taken from allograft or autologous tricortical iliac crest and shaped as a triangular pyramid during the operation; while in the second series of 78 cases (mean age 53.6 years, range 29-78 years, SD 13.5 years) a triangular titanium cage was used in 69 patients while in 9 allograft or bone substitute was used as augmentation. An analytical retrospective study was done to understand the mechanical function of medial augmentation composed by a solid body in association with different types of synthesis to stabilize properly a proximal humeral fracture.Results: We obtained excellent and good results in 83,2% of patients, fair in 12,8% and bad in 4% in terms of active anterior elevation, external and internal rotation, pain and strength according to Constant and DASH score.Conclusion: A medial solid body, especially in titanium material and shaped as trapezoidal/pyramidal form used to fill the secondary bone loss in complex instable proximal humeral fracture, allows an anatomic reduction and stable fixation in association with simple and more complex tools and it provides a better biomechanical environment for union and maintenance of alignment. [ABSTRACT FROM AUTHOR]