scholarly journals PUT-Hand—Hybrid Industrial and Biomimetic Gripper for Elastic Object Manipulation

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1147
Author(s):  
Tomasz Mańkowski ◽  
Jakub Tomczyński ◽  
Krzysztof Walas ◽  
Dominik Belter
Keyword(s):  
Force Measurement ◽  
Reaction Force ◽  
Sensory System ◽  
Optical Force ◽  
Source Codes ◽  
Usb Communication ◽  
System Node ◽  
3D Printed ◽  
High Level ◽  
Elastic Object

In this article, the design of a five-fingered anthropomorphic gripper is presented specifically designed for the manipulation of elastic objects. The manipulator features a hybrid design, being equipped with three fully actuated fingers for precise manipulation, and two underactuated, tendon-driven digits for secure power grasping. For ease of reproducibility, the design uses as many off-the-shelf and 3D-printed components as possible. The on-board controller circuit and firmware are also presented. The design includes resistive position and angle sensors in each joint, resulting in full joint observability. The controller has a position-based controller integrated, along with USB communication protocol, enabling gripper state reporting and direct motor control from a PC. A high-level driver operating as a Robot Operating System node is also provided. All drives and circuitry of the PUT-Hand are integrated within the hand itself. The sensory system of the hand includes tri-axial optical force sensors placed on fully actuated fingers’ fingertips for reaction force measurement. A set of experiments is provided to present the motion and perception capabilities of the gripper. All design files and source codes are available online under CC BY-NC 4.0 and MIT licenses.

Design and Analysis of a Novel Sensory System for a Humanoid Robot Foot

2010 ◽  
Author(s):  
Mohammad Hossein Soorgee ◽  
Aghil Yousefi-Koma ◽  
Behnam Aghbali ◽  
Maryam Kordbache ◽  
Amir Masoud Ghasemi
Keyword(s):  
Humanoid Robot ◽  
Force Measurement ◽  
Reaction Force ◽  
Sensory System ◽  
Biped Robot ◽  
Force Distribution ◽  
Force Sensors ◽  
Total Force ◽  
Rubber Layer ◽  
Zero Momentum

This paper describes a novel design of force sensors arrangement for measuring ground reaction force on a humanoid foot to find the zero momentum point (ZMP) which is usually used as a stability criterion for a walking biped robot. Precise locating of ZMP highly depends on accurate measurement of reaction force distribution on the foot. Design and fabrication of a sole for a full scale humanoid robot, “Surena” is of interest. A rubber layer is placed on robot sole parallel to force sensors to reduce the effect of impact while robot is walking. Consequently, the force measured by sensors is not total force exerted by the ground. Several foot interaction condition with ground have been modeled using finite element method and force distribution in sole rubber and sensors have been obtained. The resultant is a model which predicts the total force distribution based on four point force measurement. Several experimental situations have been tested and forces have been measured. Experimental results have shown that numerical model could predict force distribution in a good way and location of ZMP has been found successfully.

scholarly journals Evaluation of the Circularity of Recycled PLA Filaments for 3D Printers

2020 ◽  
Vol 10 (24) ◽  
pp. 8967
Author(s):  
Victor Gil Muñoz ◽  
Luisa M. Muneta ◽  
Ruth Carrasco-Gallego ◽  
Juan de Juanes Marquez ◽  
David Hidalgo-Carvajal
Keyword(s):  
Circular Economy ◽  
Protective Equipment ◽  
Fused Filament Fabrication ◽  
Circular Loop ◽  
Material Supply ◽  
3D Printers ◽  
3D Printed ◽  
Circular Economics ◽  
High Level ◽  
Additional Value

The circular economy model offers great opportunities to companies, as it not only allows them to capture additional value from their products and materials, but also reduce the fluctuations of price-related risks and material supply. These risks are present in all kind of businesses not based on the circular economy. The circular economy also enables economic growth without the need for more resources. This is because each unit has a higher value as a result of recycling and reuse of products and materials after use. Following this circular economics framework, the Polytechnic University of Madrid (Universidad Politécnica de Madrid, UPM) has adopted strategies aimed at improving the circularity of products. In particular, this article provides the result of obtaining recycled PLA filament from waste originating from university 3D FFF (fused filament fabrication) printers and waste generated by “Coronamakers” in the production of visors and parts for PPEs (Personal Protective Equipment) during the lockdown period of COVID-19 in Spain. This filament is used in the production of 3D printed parts that university students use in their classes, so the circular loop is closed. The obtained score of Material Circularity Indicator (MCI) of this material has been calculated, indicating its high level of circularity.

scholarly journals Injury prevention in Super-G alpine ski racing through course design

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthias Gilgien ◽  
Philip Crivelli ◽  
Josef Kröll ◽  
Live S. Luteberget ◽  
Erich Müller ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Course Design ◽  
Reaction Force ◽  
Global Navigation Satellite Systems ◽  
World Cup ◽  
Satellite Systems ◽  
Turn Radius ◽  
Energy Dissipated ◽  
Global Navigation Satellite ◽  
High Level

AbstractIn Super-G alpine ski racing mean speed is nearly as high as in Downhill. Hence, the energy dissipated in typical impact accidents is similar. However, unlike Downhill, on Super-G courses no training runs are performed. Accordingly, speed control through course design is a challenging but important task to ensure safety in Super-G. In four male World Cup alpine Super-G races, terrain shape, course setting and the mechanics of a high-level athlete skiing the course were measured with differential global navigation satellite systems (dGNSS). The effects of course setting on skier mechanics were analysed using a linear mixed effects model. To reduce speed by 0.5 m/s throughout a turn, the gate offset needs to be increased by + 51%. This change simultaneously leads to a decrease in minimal turn radius (− 19%), an increase in impulse (+ 27%) and an increase in maximal ground reaction force (+ 6%). In contrast, the same reduction in speed can also be achieved by a − 13% change in vertical gate distance, which also leads to a small reduction in minimal turn radius (− 4%) impulse (− 2%), and no change in maximal ground reaction force; i.e. fewer adverse side effects in terms of safety. It appears that shortening the vertical gate distance is a better and safer way to reduce speed in Super-G than increasing the gate offset.

Numerical analysis of mechanical properties of 3D printed aluminium components with variable core infill values

2020 ◽  
Vol 1 (103) ◽  
pp. 16-24
Author(s):  
P. Baras ◽  
J. Sawicki
Keyword(s):  
Numerical Analysis ◽  
Mechanical Strength ◽  
Reference Model ◽  
Reaction Force ◽  
Solid Material ◽  
Solid Core ◽  
Compression Tests ◽  
Element Analysis ◽  
Static Compression ◽  
3D Printed

Purpose: The purpose of this paper is to present numerical modelling results for 3D-printed aluminium components with different variable core infill values. Information published in this paper will guide engineers when designing the components with core infill regions. Design/methodology/approach: During this study 3 different core types (Gyroid, Schwarz P and Schwarz D) and different combinations of their parameters were examined numerically, using FEM by means of the software ANSYS Workbench 2019 R2. Influence of core type as well as its parameters on 3D printed components strength was studied. The “best” core type with the “best” combination of parameters was chosen. Findings: Results obtained from the numerical static compression tests distinctly showed that component strength is highly influenced by the type infill choice selected. Specifically, infill parameters and the coefficient (force reaction/volumetric percentage solid material) were investigated. Resulting total reaction force and percentage of solid material in the component were compared to the fully solid reference model. Research limitations/implications: Based on the Finite Element Analysis carried out in this work, it was found that results highlighted the optimal infill condition defined as the lowest amount of material theoretically used, whilst assuring sufficient mechanical strength. The best results were obtained by Schwarz D core type samples. Practical implications: In the case of the aviation or automotive industry, very high strength of manufactured elements along with a simultaneous reduction of their wight is extremely important. As the viability of additively manufactured parts continues to increase, traditionally manufactured components are continually being replaced with 3D-printed components. The parts produced by additive manufacturing do not have the solid core, they are rather filled with specific geometrical patterns. The reason of such operation is to save the material and, in this way, also weight. Originality/value: The conducted numerical analysis allowed to determine the most favourable parameters for optimal core infill configurations for aluminium 3D printed parts, taking into account the lowest amount of material theoretically used, whilst assuring sufficient mechanical strength.

scholarly journals Development of a Bendable Outsole Biaxial Ground Reaction Force Measurement System

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2641 ◽  
Author(s):  
Junghoon Park ◽  
Sangjoon Kim ◽  
Youngjin Na ◽  
Yeongjin Kim ◽  
Jung Kim
Keyword(s):  
Measurement System ◽  
Ground Reaction Force ◽  
Force Measurement ◽  
Reaction Force ◽  
Force Plate ◽  
Force Sensors ◽  
Measurement Systems ◽  
Cantilever Structure ◽  
Force Measurement System ◽  
Anterior Posterior

Wearable ground reaction force (GRF) measurement systems make it possible to measure the GRF in any environment, unlike a commercial force plate. When performing kinetic analysis with the GRF, measurement of multiaxial GRF is important for evaluating forward and lateral motion during natural gait. In this paper, we propose a bendable GRF measurement system that can measure biaxial (vertical and anterior-posterior) GRF without interrupting the natural gait. Eight custom small biaxial force sensors based on an optical sensing mechanism were installed in the proposed system. The interference between two axes on the custom sensor was minimized by the independent application of a cantilever structure for the two axes, and the hysteresis and repeatability of the custom sensor were investigated. After developing the system by the installation of force sensors, we found that the degree of flexibility of the developed system was comparable to that of regular shoes by investigating the forefoot bending stiffness. Finally, we compared vertical GRF (vGRF) and anterior-posterior GRF (apGRF) measured from the developed system and force plate at the same time when the six subjects walked, ran, and jumped on the force plate to evaluate the performance of the GRF measurement system.

scholarly journals A Soft Five-Fingered Hand Actuated by Shape Memory Alloy Wires: Design, Manufacturing, and Evaluation

2020 ◽  
Vol 7 ◽  
Author(s):  
Filomena Simone ◽  
Gianluca Rizzello ◽  
Stefan Seelecke ◽  
Paul Motzki
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Force Measurement ◽  
Optimal Placement ◽  
Flexible Structure ◽  
Flexible Joints ◽  
3D Printed

This work presents a novel five-fingered soft hand prototype actuated by Shape Memory Alloy (SMA) wires. The use of thin (100 μm diameter) SMA wire actuators, in conjunction with an entirely 3D printed hand skeleton, guarantees an overall lightweight and flexible structure capable of silent motion. To enable high forces with sufficiently high actuation speed at each fingertip, bundles of welded actuated SMA wires are used. In order to increase the compliance of each finger, flexible joints from superelastic SMA wires are inserted between each phalanx. The resulting system is a versatile hand prototype having intrinsically elastic fingers, which is capable to grasp several types of objects with a considerable force. The paper starts with the description of the finger hand design, along with practical considerations for the optimal placement of the superelastic SMA in the soft joint. The maximum achievable displacement of each finger phalanx is measured together with the phalanxes dynamic responsiveness at different power stimuli. Several force measurement are also realized at each finger phalanx. The versatility of the prototype is finally demonstrated by presenting several possible hand configurations while handling objects with different sizes and shapes.

A Study on Accuracy Improvement of Ground Reaction Force Measurement Using Wearable Force Plates

2016 ◽  
Vol 2016 (0) ◽  
pp. J2320102
Author(s):  
Takahito SUZUKI ◽  
Kiyoshi HIROSE ◽  
Haruka CHIBA ◽  
Akiko KONDO ◽  
Hitoshi DOKI
Keyword(s):  
Ground Reaction Force ◽  
Force Measurement ◽  
Reaction Force ◽  
Accuracy Improvement
Sign in / Sign up

Export Citation Format

Share Document