Transcutaneous vagus nerve stimulation (t-VNS): A novel effective treatment for temper outbursts in adults with Prader-Willi Syndrome indicated by results from a non-blind study.

Temper outbursts are a severe problem for people with Prader-Willi Syndrome (PWS). Previous reports indicate that vagus nerve stimulation (VNS) may reduce maladaptive behaviour in neurodevelopmental disorders, including PWS. We systematically investigated the effectiveness of transcutaneous VNS (t-VNS) in PWS. Using a non-blind single case repeat measures modified ABA design, with participants as their own controls, t-VNS was evaluated in five individuals with PWS [three males; age 22-41 (M = 26.8)]. After a baseline phase, participants received four-hours of t-VNS daily for 12 months, followed by one month of daily t-VNS for two-hours. The primary outcome measure was the mean number of behavioural outbursts per day. Secondary outcomes included findings from behavioural questionnaires and both qualitative and goal attainment interviews. Four of the five participants who completed the study exhibited a statistically significant reduction in number and severity of temper outbursts after approximately nine months of daily four-hour t-VNS. Subsequent two-hour daily t-VNS was associated with increased outbursts for all participants, two reaching significance. Questionnaire and interview data supported these findings, the latter indicating potential mechanisms of action. No serious safety issues were reported. t-VNS is an effective, novel and safe intervention for chronic temper outbursts in PWS. We propose these changes are mediated through vagal projections and their effects both centrally and on the functioning of the parasympathetic nervous system. These findings challenge our present biopsychosocial understanding of such behaviours suggesting that there is a single major mechanism that is modifiable using t-VNS. This intervention is potentially generalizable across other clinical groups. Future research should address the lack of a sham condition in this study along with the prevalence of high drop out rates, and the potential effects of different stimulation intensities, frequencies and pulse widths

Design and Operational Elements of the Robotic Subsystem for the e.deorbit Debris Removal Mission

This paper presents a robotic capture concept that was developed as part of the e.deorbit study by ESA. The defective and tumbling satellite ENVISAT was chosen as a potential target to be captured, stabilized, and subsequently de-orbited in a controlled manner. A robotic capture concept was developed that is based on a chaser satellite equipped with a seven degrees-of-freedom dexterous robotic manipulator, holding a dedicated linear two-bracket gripper. The satellite is also equipped with a clamping mechanism for achieving a stiff fixation with the grasped target, following their combined satellite-stack de-tumbling and prior to the execution of the de-orbit maneuver. Driving elements of the robotic design, operations and control are described and analyzed. These include pre and post-capture operations, the task-specific kinematics of the manipulator, the intrinsic mechanical arm flexibility and its effect on the arm's positioning accuracy, visual tracking, as well as the interaction between the manipulator controller and that of the chaser satellite. The kinematics analysis yielded robust reachability of the grasp point. The effects of intrinsic arm flexibility turned out to be noticeable but also effectively scalable through robot joint speed adaption throughout the maneuvers. During most of the critical robot arm operations, the internal robot joint torques are shown to be within the design limits. These limits are only reached for a limiting scenario of tumbling motion of ENVISAT, consisting of an initial pure spin of 5 deg/s about its unstable intermediate axis of inertia. The computer vision performance was found to be satisfactory with respect to positioning accuracy requirements. Further developments are necessary and are being pursued to meet the stringent mission-related robustness requirements. Overall, the analyses conducted in this study showed that the capture and de-orbiting of ENVISAT using the proposed robotic concept is feasible with respect to relevant mission requirements and for most of the operational scenarios considered. Future work aims at developing a combined chaser-robot system controller. This will include a visual servo to minimize the positioning errors during the contact phases of the mission (grasping and clamping). Further validation of the visual tracking in orbital lighting conditions will be pursued

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Analysis and Applications of Reachability and Capability Maps for Robotic Manipulators

Robotic arms are the most popular robots on the market. Technology behind the arm manipulators and their sensors is getting more accessible, which results in an increased interest from both commercial and research communities. Autonomous applications of robotic arms needs a combination of good sensory input and previous knowledge to speed up application development. Path planning for the robotic end effector, required to design a trajectory to move from an initial to a goal position, requires both knowledge of the kinematic structure of the robot as well as sensory information coming from the environment, that helps to identify key elements like the objects to manipulate, surfaces of support or possible obstacles. The kinematic structure that results from a design stage is fixed, and knowledge of the workspace of the robot and its dexterity in this space can be preprocessed to speed up on-line applications.This thesis proposes a novel way to address the problem of computing the workspace of a robotic arm and its dexterity within this space. Our proposed off-line analysis of reachability is designed to answer questions about workspace shape and quality. We show how to use the precomputed structure for on-line grasp selection, operational workspace selection, collision free path planning, path validation or robot pose selection.Our approach builds on top of the concept of reachability and capability maps. Traditional methods to generate such maps use forward or inverse kinematics, and we investigate the advantages and limitations of both. We later propose a hybrid method which combines their advantages while maintaining low generation time. Quality of the results is evaluated by a prediction accuracy test. The structure of the map is designed such that it is also suitable for on-line applications. Real-time visual information is incorporated into the map’s data structure to improve real-world interactions such as grasp selection or collision-free path planning. To con-clude, several examples of real applications that illustrate the usefulness of the map are presented and discussed.Validerat; 20140517 (global_studentproject_submitter

Planning Realistic Interactions for Bimanual Grasping and Manipulation

This work presents a dual arm grasp planning architecture that includes two relevant aspects often neglected: differences in hand actuation, and realistic forces applicable by the end effectors. The introduction of an actuation matrix allows considering differences in contact forces that can be generated between, for instance, a fully actuated and an underactuated hand. The consideration of realistic forces allows the computation of real magnitudes of forces and torques that can be resisted by the grasped object. The manipulability workspace can also be computed based on the capability maps, thus providing all the possible motions that can be imparted on the grasped object while respecting the dual hand grasp constraints. The joint consideration of these factors allow the selection of a good grasp for a desired bimanual manipulation

Interpreting Manipulation Actions: from Language to Execution

Processing natural language instructions for execution of robotic tasks has been regarded as a means to make more intuitive the interaction with robots. This paper is focused on the applications of natural language processing in manipulation, specifically on the problem of recovering from the instruction the information missing for the manipulation planning, which has been traditionally assumed to be available for instance via pre-computed grasps or pre-labeled objects. The proposed approach includes a clustering process that discriminates areas on the object that can be used for different types of tasks (therefore providing valuable information for the grasp planning process), the extraction and consideration of task information and grasp constraints for solving the manipulation problem, and the use of an integrated grasp and motion planning that avoids relying on a predefined grasp database

Reachability and Dexterity: Analysis and Applications for Space Robotics

The utility of a mobile manipulator largely depends on its kinematic structure and mounting point on the robot body. The reachable workspace of the robot can be obtained offline and modeled as a discretized map called Reachability map. A Capability map is obtained by including some quality measure for the local dexterity of the manipulator, which helps to identify good and bad regions for manipulation. Once the maps are obtained based on forward or inverse kinematic methods, they can be used for numerous analysis tasks such as robot kinematics and workspace quality assessment, robot mounting point analysis or redundancy and failure analysis. This paper covers basic aspects of the Reachability and Capability map generation and storage, and shows particular applications of the maps for space robotics

Planning Fail-Safe Trajectories for Space Robotic Arms

A frequent concern for robot manipulators deployed in dangerous and hazardous environments for humans is the reliability of task executions in the event of a joint failure. A redundant robotic manipulator can be used to mitigate the risk and guarantee a post-failure task completion, which is critical for instance for space applications. This paper describes methods to analyze potential risks due to a joint failure, and introduces tools for fault-tolerant task design and path planning for robotic manipulators. The presented methods are based on off-line precomputed workspace models. The methods are general enough to cope with robots with any type of joint (revolute or prismatic) and any number of degrees of freedom, and might include arbitrarily shaped obstacles in the process, without resorting to simplified models. Application examples illustrate the potential of the approac

Reachability and Capability Analysis for Manipulation Tasks

An offline analysis of the reachability of a robotic arm saves time for online queries like grasp selection or path planning. Reachability data is complemented with indices that quantify the goodness of one region in space to create a capability map, which can be computed based either on forward or inverse kinematics. This paper discusses the advantages and limitations of those methods, and proposes a hybrid method to improve the generation time while guaranteeing complete exploration of the space. The correctness of the results is studied with a prediction accuracy test. To illustrate the utility of a capability map, real-time visual information is incorporated to the map to help in the selection of grasp poses, or in path planning from an initial to a final pose