scholarly journals A Concept Design of an Adaptive Tendon Driven Mechanism for Active Soft Hand Orthosis

Proceedings ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 21
Author(s):  
Bruno Lourenço ◽  
Vitorino Neto ◽  
Rafhael de Andrade
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Vital Role ◽  
Dorsal Side ◽  
Concept Design ◽  
Cord Injury ◽  
3D Printed ◽  
Biomechanical Constraints ◽  
Active Orthosis

The Hands exert a vital role in the simplest to most complex daily tasks. Losing the ability to make hand movements, which is usually caused by spinal cord injury or stroke, dramatically impacts the quality of life. In order to counteract this problem, several assisting devices have been proposed, but they still present several usage limitations. The marketable orthoses are generally either the static type or over-expensive active orthosis that cannot perform the same degrees of freedom (DoF) that a hand can do. This paper presents a conceptual design of a tendon-driven mechanism for hand’s active orthosis. This study is a part of an effort to develop an effective and low-cost hand’s orthosis for people with hand paralysis. The tendon design proposed was thought to comply with some requisitions such as lightness and low volume, as well as fit with the biomechanical constraints of the hand joints to enable a comfortable use. The mechanism employs small cursors on the phalanges to allow the tendons to run on the dorsal side and by both sides of the fingers, allowing 2 DoF for each finger, and one extra tendon enlarges the hands’ adduction nuances. With this configuration, it is simple enough to execute the flexion and extension movements, which are the most used movements in daily actives, using one single DC actuator for one DoF to reduce manufacturing costs, or with more DC actuators to enable more natural hand coordination. This system of actuation is suitable to create soft exoskeletons for hands easily embedded into 3D printed parts, which could be merged over statics thermoplastic orthosis. The final orthosis design allows dexterous finger movements and force to grasp objects and perform tasks comfortably.

scholarly journals Kraken: A wirelessly controlled octopus-like hybrid robot utilizing stepper motors and fishing line artificial muscle for grasping underwater

2021 ◽  
Author(s):  
Yara Almubarak ◽  
Michelle Schmutz ◽  
Miguel Perez ◽  
Shrey Shah ◽  
Yonas Tadesse
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Arm Movement ◽  
Artificial Muscle ◽  
Aquatic Life ◽  
Stepper Motors ◽  
3D Printed ◽  
Arm Motion ◽  
Hybrid Actuation ◽  
Underwater Exploration

Abstract Underwater exploration or inspection requires suitable robotic systems capable of maneuvering, manipulating objects, and operating untethered in complex environmental conditions. Traditional robots have been used to perform many tasks underwater. However, they have limited degrees of freedom, manipulation capabilities, portability, and have disruptive interactions with aquatic life. Research in soft robotics seeks to incorporate ideas of the natural flexibility and agility of aquatic species into man-made technologies to improve the current capabilities of robots using biomimetics. In this paper, we present a novel design, fabrication, and testing results of an underwater robot known as Kraken that has tentacles to mimic the arm movement of an octopus. To control the arm motion, Kraken utilizes a hybrid actuation technology consisting of stepper motors and twisted and a coiled fishing line polymer muscle (TCP FL ). TCPs are becoming one of the promising actuation technologies due to their high actuation stroke, high force, light weight, and low cost. We have studied different arm stiffness configurations of the tentacles tailored to operate in different modalities (curling, twisting, and bending), to control the shape of the tentacles and grasp irregular objects delicately. Kraken uses an onboard battery, a wireless programmable joystick, a buoyancy system for depth control, all housed in a three-layer 3D printed dome-like structure. Here, we present Kraken fully functioning underwater in an Olympic-size swimming pool using its servo actuated tentacles and other test results on the TCP FL actuated tentacles in a laboratory setting. This is the first time that an embedded TCP FL actuator within elastomer has been proposed for the tentacles of an octopus-like robot along with the performance of the structures. Further, as a case study, we showed the functionality of the robot in grasping objects underwater for field robotics applications.

scholarly journals Eyes-Free Tongue Gesture and Tongue Joystick Control of a Five DOF Upper-Limb Exoskeleton for Severely Disabled Individuals

2021 ◽  
Vol 15 ◽  
Author(s):  
Mostafa Mohammadi ◽  
Hendrik Knoche ◽  
Mikkel Thøgersen ◽  
Stefan Hein Bengtson ◽  
Muhammad Ahsan Gull ◽  
...  
Keyword(s):  
Visual Feedback ◽  
Upper Limb ◽  
Degrees Of Freedom ◽  
Continuous Control ◽  
Clinical Case Study ◽  
Upper Limb Exoskeleton ◽  
Control Interface ◽  
Cord Injury ◽  
First Time

Spinal cord injury can leave the affected individual severely disabled with a low level of independence and quality of life. Assistive upper-limb exoskeletons are one of the solutions that can enable an individual with tetraplegia (paralysis in both arms and legs) to perform simple activities of daily living by mobilizing the arm. Providing an efficient user interface that can provide full continuous control of such a device—safely and intuitively—with multiple degrees of freedom (DOFs) still remains a challenge. In this study, a control interface for an assistive upper-limb exoskeleton with five DOFs based on an intraoral tongue-computer interface (ITCI) for individuals with tetraplegia was proposed. Furthermore, we evaluated eyes-free use of the ITCI for the first time and compared two tongue-operated control methods, one based on tongue gestures and the other based on dynamic virtual buttons and a joystick-like control. Ten able-bodied participants tongue controlled the exoskeleton for a drinking task with and without visual feedback on a screen in three experimental sessions. As a baseline, the participants performed the drinking task with a standard gamepad. The results showed that it was possible to control the exoskeleton with the tongue even without visual feedback and to perform the drinking task at 65.1% of the speed of the gamepad. In a clinical case study, an individual with tetraplegia further succeeded to fully control the exoskeleton and perform the drinking task only 5.6% slower than the able-bodied group. This study demonstrated the first single-modal control interface that can enable individuals with complete tetraplegia to fully and continuously control a five-DOF upper limb exoskeleton and perform a drinking task after only 2 h of training. The interface was used both with and without visual feedback.

scholarly journals Computationally Efficient Magnetic Position System Calibration

2020 ◽  
Vol 2 (1) ◽  
pp. 72
Author(s):  
Stefano Lumetti ◽  
Perla Malagò ◽  
Dietmar Spitzer ◽  
Sigmund Zaruba ◽  
Michael Ortner
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Industrial Applications ◽  
Position System ◽  
Computationally Efficient ◽  
System Calibration ◽  
Practical Challenge ◽  
3D Printed ◽  
Cost Efficient ◽  
Orientation Systems

Properties such as high resolution, contactless (and thus wear-free) measurement, low power consumption, robustness against temperature and contamination as well as low cost make magnetic position and orientation systems appealing for a large number of industrial applications. Nevertheless, one major practical challenge is their sensitivity to fabrication tolerances. In this work, we propose a novel method for magnetic position system calibration based on the analytical computation of the magnetic field and on the application of an evolutionary optimization algorithm. This scheme enables the calibration of more than 10 degrees of freedom within a few seconds on standard quad-core ×86 processors, and is demonstrated by calibrating a highly cost-efficient 3D-printed 3-axis magnetic joystick.

2 DOF Compliant 3D-PLE System Demonstrating Fundamentals of Vibrations and Passive Vibration Isolation

2020 ◽  
Author(s):  
Niko Giannakakos ◽  
Ayse Tekes ◽  
Tris Utschig
Keyword(s):  
Degrees Of Freedom ◽  
Engineering Students ◽  
Vibration Isolation ◽  
Low Cost ◽  
Educational Systems ◽  
Primary System ◽  
Laboratory Equipment ◽  
Dynamics And Control ◽  
3D Printed ◽  
And Control

Abstract Mechanical engineering students often learn the fundamentals of vibrations along with the time response of underdamped, critically damped, and overdamped systems in machine dynamics and vibrations courses without any validation or visualization through hands-on experimental learning activities. As these courses are highly theoretical, students find it difficult to connect theory to practical fundamentals such as modeling of a mechanical system, finding components of the system using experimental data, designing a system to achieve a desired response, or designing a passive vibration isolator to reduce transmitted vibrations on a primary system. Further, available educational laboratory equipment demonstrating vibrations, dynamics and control is expensive, bulky, and not portable. To address these issues, we developed a low-cost, 3D printed, portable laboratory equipment (3D-PLE) system consisting of primary and secondary carts, rail, linear actuator, Arduino, and compliant flexures connecting the carts. Most of the educational systems consist of a mass limited to 1DOF motion and multi-degrees of freedom systems can be created using mechanical springs. However, in real-world applications oscillations in a system are not necessarily due to mechanical springs. Anything flexible, or thin and long, can be represented by a spring as seen in torsional systems. We incorporated 3D printed and two monolithically designed rigid arms connected with a flexure hinge of various stiffness. The carts are designed in a way such that two flexible links can be attached from both sides and allow more loads to be added on each cart. The system can be utilized to demonstrate fundamentals of vibrations and test designs of passive isolators to dampen the oscillations of the primary cart.

Design and Field Evaluation of a Robotic Apple Harvesting System with a 3D-Printed Soft-Robotic End-Effector

2019 ◽  
Vol 62 (2) ◽  
pp. 405-414 ◽  
Author(s):  
Cameron J. Hohimer ◽  
Heng Wang ◽  
Santosh Bhusal ◽  
John Miller ◽  
Changki Mo ◽  
...  
Keyword(s):  
Success Rate ◽  
Degrees Of Freedom ◽  
Low Cost ◽  
Field Evaluation ◽  
Robotic System ◽  
Fresh Market ◽  
End Effector ◽  
3D Printed ◽  
Harvesting Techniques ◽  
Field Experimentation

Abstract. Fresh market apple harvesting is a difficult task that relies entirely on manual labor. Much research has been done on the development of mechanical harvesting techniques. Several selective harvesting robots have been developed for research studies, but there are no commercially available robotic systems. This article discusses the design and development of a novel pneumatic 3D-printed soft-robotic end-effector to facilitate apple separation. The end-effector was integrated into a robotic system with five degrees of freedom that was designed to simplify the picking sequence and reduce costs compared to previous versions. Apples were successfully harvested using the low-cost robotic system in a commercial orchard during the fall 2017 harvest. A detachment success rate on attempted apples of 67% was achieved, with an average time of 7.3 s per fruit from separation to storage bin. By conducting this study in an orchard where problematic apples were not removed to increase the detachment success rate, current pruning and thinning practices were assessed to help lay the foundation for future studies and develop strategies for successfully harvesting apples that are difficult to detach. Keywords: Apple catching, Apples, Automated harvesting, Field experimentation, Harvesting robot, Soft-robotic gripper.

scholarly journals Low-cost 3D-printed inverted microscope to detect Mycobacterium tuberculosis in a MODS culture

2020 ◽  
Author(s):  
Mario Salguedo ◽  
Guillermo Zarate ◽  
Robert H. Gilman ◽  
Germán Comina ◽  
Jorge Coronel ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Low Cost ◽  
Drug Susceptibility ◽  
Optical Microscope ◽  
Manual Inspection ◽  
Inverted Microscope ◽  
3D Printed ◽  
The Cost ◽  
Proper Interpretation

AbstractBackgroundThe MODS is an important assay for early diagnosis of tuberculosis and drug susceptibility. MODS is based in the microscopic observation, underneath, of the characteristic cords of Mycobacterium tuberculosis colonies grown in liquid media. An inverted optical microscope is required to observe and interpret MODS cultures. Unfortunately, the cost of commercial inverted microscopes is not affordable in low resource settings in developing countries.MethodologyTo perform a diagnosis of tuberculosis using the MODS assay, images with modest quality are enough for proper interpretation. Therefore, the use of a high cost commercial inverted optical microscope is not indispensable. In this study, we designed a prototype of an optical inverted microscope created with a 3D printer and based on a smartphone. The system was evaluated by comparison of manual interpretations of 226 TB positive MODS culture images and 207 negative MODS culture images.SignificanceThe prototype resulted in a low-cost inverted optical microscope, with simple functioning, and whose parts have been manufactured using 3D printing techniques. The quality of the images was good enough and achieved a 100% concordance between the manual inspection with the developed microscope, and the standard diagnostics of MODS.

scholarly journals Scan-Driven Fully-Automated Pipeline for a Personalized, 3D Printed Low-Cost Prosthetic Hand

2021 ◽  
Author(s):  
Yair Herbst ◽  
shunit polinsky ◽  
Anath Fischer ◽  
Yoav Medan ◽  
Ronit Schneor ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Low Cost ◽  
User Preferences ◽  
High Price ◽  
Prosthetic Hand ◽  
Interface Control ◽  
Pcb Design ◽  
3D Printed ◽  
Automated Pipeline

The process of fitting a prosthetic hand that is a comfortable, functional, easy to use, has an acceptable appearance and overall improves the amputees' quality of life is a complex, tedious and costly process. The very high price tag due to the time spent on manually fitting the device by a trained specialist makes these devices inaccessible to large portions of the population. We present a concept and preliminary results for a fully automated fitting and manufacturing pipeline for a personalized low-cost prosthetic hand. The hand is personalized in almost every aspect, from appearance to user interface, control and feedback. The pipeline only requires a 3D printer, a RealSense camera, a few basic mechanical components and basic tools for the model assembly. The user scan-driven data and the user preferences initiate a fully-automated pipeline which culminates in a customized, easy-to-assemble PCB design and ready to print STL files, including the optimized orientation, support and layout, such that the final parts are only one click away. We believe that the proposed pipeline and design can substantially improve quality of life for amputees and could potentially be expanded to other medical applications.

scholarly journals A 10-17 DOF Sensory Gloves with Harvesting Capability for Smart Healthcare

2019 ◽  
Vol 15 (2) ◽  
Author(s):  
Alfiero Leoni ◽  
Vincenzo Stornelli ◽  
Giuseppe Ferri ◽  
Giancarlo Orengo ◽  
Vito Errico ◽  
...  
Keyword(s):  
Power Consumption ◽  
Degrees Of Freedom ◽  
Low Cost ◽  
Operation Time ◽  
Meaningful Improvement ◽  
Electronic Circuitry ◽  
Smart Healthcare ◽  
Measurement Results ◽  
Detailed Assessment ◽  
3D Printed

We here present a 10-17 Degrees of Freedom (DoF) sensory gloves for Smart Healthcare implementing an energy harvesting architecture, aimed at enhancing the battery lasting when powering the electronics of the two different types of gloves, used to sense fingers movements. In particular, we realized a comparison in terms of measurement repeatability and reliability, as well as power consumption and battery lasting, between two sensory gloves implemented by means of different technologies. The first is a 3D printed glove with 10 DoF, featuring low-cost, low-effort fabrication and low-power consumption. The second is a classical Lycra® glove with 14 DoF suitable for a more detailed assessment of the hand postures, featuring a relatively higher cost and power consumption. An electronic circuitry was designed to gather and elaborate data from both types of sensory gloves, differing for number of inputs only.  Both gloves are equipped with flex sensors and in addiction with the electronics (including a microcontroller and a transmitter) allow the control of hand virtual limbs or mechanical arts in surgical, military, space and civil applications.Six healthy subjects were involved in tests suitable to evaluate the performances of the proposed gloves in terms of repeatability, reproducibility and reliability. Particular effort was devoted to increase battery lasting for both glove-based systems, with the electronics relaying on Radio Frequency, Piezoelectric and Thermoelectric harvesters. The harvesting part was built and tested as a prototype discrete element board, that is interfaced with an external microcontroller and a radiofrequency transmitter board. Measurement results demonstrated a meaningful improvement in battery operation time up to 25%, considering different operating scenarios.

Qualität von additiv hergestellten PLA-Bauteilen*/Quality of additively manufactured PLA components – How the print direction influences the mechanical properties and the distortion of 3D-printed PLA components

2018 ◽  
Vol 108 (06) ◽  
pp. 419-425
Author(s):  
H. Möhring ◽  
T. Stehle ◽  
D. Becker ◽  
R. Eisseler
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Low Cost ◽  
Three Dimensional ◽  
Filling Ratio ◽  
Additive Fertigung ◽  
3D Printed

Die additive Fertigung eröffnet neue Gestaltungs- und Optimierungsfreiheitsgrade für oberflächen- und strukturoptimierte Bauteile. Mit diesen Verfahren lassen sich selbst komplexe räumliche Strukturen kostengünstig herstellen. Der vorliegende Artikel untersucht den Einfluss der Druckrichtung und des Füllgrads auf die mechanischen Eigenschaften, den Verzug sowie die erreichbaren Formgenauigkeiten am Beispiel von mit 3D-Druck über den FDM-Prozess erzeugten PLA-Bauteilen.   Additive manufacturing opens up new possibilities for optimizing components with regard to surfaces and structures. These processes allow producing even the most complex three-dimensional structures at comparatively low cost. This paper analyzes how the print direction and the filling ratio affect the mechanical properties, the distortion, as well as the achievable geometrical accuracies, by using 3D-printed PLA components produced by FDM processes.

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