1,721,003 research outputs found
Visuo-Otolithic and Electrodermal Interactions in Experimental 3D Environments
No full textAmong the components of the ANS (Autonomic Nervous System), electrodermal activity variations (EDA) are less involved in self-motion. However, from neuroanatomical point of view, EDA variations are essentially modulated by sympathetic endings that are interconnected with the vestibular system. The aim of the present study was to analyse the latencies for reporting vertical self-motion (upward and downward) and the variations of electrodermal activity in healthy adults (17 men and 18 women aged 22 years old on average; sd 1 year and 2 month) when they were visually exposed to an experimental 3D environment via a head mounted display (HMD). The results revealed that the otolithic saccular maculae contribute differently to latencies and electrodermal activations. When self-motion was towards earth gravity, latencies and electrodermal activity were shorter in downward self-motion than in upward self-motion. We suggest that a top-down organisation connected with the visuo-otolithic information along the vertical axis, which essentially contributes to self-position, equilibrium and body-consciousness, could provide a neuromorphic model to improve space location and representation of humanoid robots
Contact Detection Approach Between Wheel and Rail Surfaces
No full textThis work presents a general formulation to identify the contact points for the interaction between wheels and rails in the context of railway dynamics simulations. This formulation treats the wheel and rail as parametric surfaces and searches the contact between each wheel strip and the rail independently to avoid the numerical difficulties due to the wheel concave zone. This methodology assumes the rail as locally straight and takes advantage that its potential contacting surface is always convex. For the evaluation of contact forces, two Hertzian-based models are employed for normal and creep forces. A trailer vehicle running on a curved track is used to demonstrate the effectiveness of this methodology
The Robot that Learns from the Therapist How to Assist Stroke Patients
No full textResults from clinical studies suggest that assisted training is beneficial for the recovery of functioning in patients with stroke and other central nervous system injuries. The training consists of the repetition of movements, which change the excitability of the brain, and due to cortical plasticity have carry-over effects. We are developing a 3D arm assistant that interfaces the patient at the hand/wrist. The development addresses three major issues: (1) the selection of the tasks that are appropriate for the training based on the level of motor abilities (2) the design of the visual feedback that enhances the motivation to train, and (3) the assessment of the performance. Therefore, our design integrates the new 3D robot assistant, various gaming based visual feedback, and software that acquires data on-line from sensors (position of the hand and force between the robot and the hand). The major novelties that the 3D arm assistant brings are the following: an automatic method of capturing movements presented by the therapist (expert), the use of the probabilistic movement representation for control of the robot, the incorporation of simple gaming with adjustable levels of difficulty, and finally, the assessment of differences between the achieved and target movements (kinematics) and interface force measured by a special handle with multiple sensors. The components of the new arm assistant in 2D have been tested and proved to work effectively in the clinical trials with stroke patients
Design and Characterization of a 3D Printed Soft Pneumatic Actuator
No full textIn soft robotics, the successful development of soft robots involves careful designing that can benefit from current technologies. The use of Finite Element Method (FEM) software and additive manufacturing is essential to optimize the design before fabrication and to facilitate the process. Therefore, we present the design of a 3D printed low-pressure soft pneumatic actuator (SPA) with 3 DoF and a material characterization method to simulate the behaviour of the system. In attempt to define a suitable material modelling method and its reliability to simulate actuator behaviours, we introduce a characterization method and corroborate its efficiency through the evaluation of the performance using the FEM and preliminary tests of the actuator performance. The purpose of this article is to help future projects to effectively simulate the behaviour of 3D printed soft pneumatic actuators to improve the design before fabrication. Throughout the description of the process to effectively fabricate a functional SPA
Dynamic Balancing of a Single Crank-Double Slider Mechanism with Symmetrically Moving Couplers
No full textThis article presents a systematic investigation of the dynamic balancing of a singlecrank-double slider mechanism of which the coupler links have symmetric motion. From the equationsof the linear momentum and angular momentum the force balance conditions and momentbalance conditions are derived. Both general and specific force balanced and moment balancedconfigurations are obtained step by step, are put in perspective, and are illustrated to gain a systematicoverview of the balancing possibilities of this type of mechanism. Also the addition of acounter-rotating element is considere
Development of Modular Compliant Anthropomorphic Robot Hand
No full textThe chapter presents the development of a modular compliant robotic hand characterized by the anthropomorphic structure and functionality. The prototype is made based on experience in development of contemporary advanced artificial hands and taking into account the complementary aspects of human bio-mechanics. The robot hand developed in the Institute Mihailo Pupin is called “Pupin hand”. The Pupin hand is developed for research purposes as well as for implementation with service and medical robot devices as an advance robot end-effector. Mechanical design, system identification, modeling and simulation and acquisition of the biological skill of grasping adopted from humans are considered in the chapter. Mechanical structure of the tendon-driven, multi-finger, 23 degrees of freedom compliant robot hand is presented in the chapter. Model of the hand is represented by corresponding multi-body rigid system with the complementary structural elasticity inserted between the particular finger modules. Some characteristic simulation results are given in the chapter in order to validate the chosen design concept. For the purpose of motion capture of human grasping skill, an appropriate experimental setup is prepared. It includes an infrared Kinect camera that combines visual and depth information about objects from the environment. The aim of using the Kinect sensor is to acquire human grasping skill and to map this natural motion to the robotic device. The novelties of the robot hand prototyping beyond to the state-of-the-art are stressed out in the conclusion
Design and Gait Control of an Active Lower Limb Exoskeleton for Walking Assistance
No full textThis paper presents an assistive lower-limb exoskeleton (ALEXO) for active walking assistance. The mechatronics design covering mechanical design, sensors selection and motor controllers are introduced. A 2-link model is built for dynamic analysis control purposes, upon which a trajectory tracking control method based on an improved computed torque control is proposed. This control method was tested with sensor data acquired from walking trials of a healthy subject, which validated the design and gait control of this exoskeleton.</p
The Framework for Mobile Robot Task Planning Based on the Optimal Manufacturing Schedule
No full textIntegrated process planning and scheduling of manufacturing entities
represents one of the most impactful processes for optimizing production systems. The result of integrated process planning and scheduling is visually presented in the form of the Gantt chart that summarizes the timing and order of all
manufacturing operations. Moreover, a sequence of actions that needs to be performed by a transportation system to ensure the smooth execution of all manufacturing processes is also incorporated within the Gantt chart. Therefore, in this
paper, we develop a framework for mobile robot action planning based on highlevel action, e.g., transporting the part from one machine to another. The idea is
to automatically plan a sequence of robot-performable actions that, if performed
accurately, results in achieving a high-level goal. The framework is developed in
the standard Robot Operative System 2 (ROS2) middleware. The system, domain, and essential entities are modeled by using Planning Domain Definition
Language (PDDL). The mobile robot actions are modeled by Behavior trees
within the PlanSys2 framework.Supported by International Federation for the Promotion of Mechanism and Machine Science (IFToMM)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
