Parametric Analysis of a Compliant Hinge Mechanism for a Shape Memory Alloy Actuated Arm

2017 ◽  
Author(s):  
Cody Wright ◽  
Onur Bilgen
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Elbow Joint ◽  
Parametric Analysis ◽  
Complex Geometries ◽  
Biceps Muscle ◽  
Dead Load ◽  
Revolute Joints ◽  
Material Solution ◽  
Application Requirements

A compliant hinge is proposed to replace conventional revolute joints for a shape memory alloy actuated arm-like mechanism. The arm-like mechanism is designed to replicate the articulation of the elbow joint, linking the humerus and radius, while being able to lift a dead load using a shape memory alloy wire as the biceps muscle. A parametric analysis on hinge geometry and Young’s modulus is performed to determine if a feasible geometric and material solution exists based on the application requirements. The results indicate optimum solutions are logarithmically correlated between modulus of elasticity and width-to-thickness ratio. Overlaying the results of the parametric study onto an Ashby chart indicates that large hinge widths are necessary. These results indicate more complex geometries are needed for arm-like manipulator applications.

Development and assessment of a knitted shape memory alloy-based multifunctional elbow brace

2022 ◽  
pp. 152808372110569
Author(s):  
Woo-Kyun Jung ◽  
Soo-Min Lee ◽  
Sung-Hoon Ahn ◽  
Juyeon Park
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Elbow Joint ◽  
Severe Pain ◽  
Subjective Evaluation ◽  
Wearable Devices ◽  
Joint Cartilage ◽  
Clothing Pressure ◽  
Positive Effect ◽  
Pressure Sensation

Osteoarthritis is a chronic disease that affects joint cartilage and can cause severe pain and disability. Minor neglected injuries may also result in other diseases that affect daily life. Various attempts have been made to develop wearable auxiliary devices using functional fabrics, but few have simultaneously provided both heat and pressure. Using knitted shape memory alloy (SMA) fabric, a module was manufactured that achieved bending and contraction during operation. An elbow brace that simultaneously provided heat and pressure was developed using this module. Subjective evaluation and measurements of the range of motion (ROM), changes in skin temperature ( T sk ), clothing pressure ( P c), and blood flow ( F b) were conducted on the elbow brace while being worn by 10 participants. The multifunctional elbow brace (MFEB) developed in this study generated pressure and heat that increased T sk and P c, ultimately increasing F b. In addition, the ROM of the elbow joint was increased after actuating the elbow brace. Subjective evaluation of the heat and pressure sensation demonstrated its applicability to the human body. We confirmed that the elbow brace had a positive effect on F b and increased the ROM of the joint. These results show the applicability of smart textiles to the development of various wearable devices.

scholarly journals New Design of a Soft Robotics Wearable Elbow Exoskeleton Based on Shape Memory Alloy Wire Actuators

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Dorin Copaci ◽  
Enrique Cano ◽  
Luis Moreno ◽  
Dolores Blanco
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Elbow Joint ◽  
Low Noise ◽  
Medical Rehabilitation ◽  
Shape Memory Alloy Wire ◽  
Alloy Wire ◽  
Rotation Center ◽  
Actuation System ◽  
Flexion Extension

The elbow joint is a complex articulation composed of the humeroulnar and humeroradial joints (for flexion-extension movement) and the proximal radioulnar articulation (for pronation-supination movement). During the flexion-extension movement of the elbow joint, the rotation center changes and this articulation cannot be truly represented as a simple hinge joint. The main goal of this project is to design and assemble a medical rehabilitation exoskeleton for the elbow with one degree of freedom for flexion-extension, using the rotation center for proper patient elbow joint articulation. Compared with the current solutions, which align the exoskeleton axis with the elbow axis, this offers an ergonomic physical human-robot interface with a comfortable interaction. The exoskeleton is actuated with shape memory alloy wire-based actuators having minimum rigid parts, for guiding the actuators. Thanks to this unusual actuation system, the proposed exoskeleton is lightweight and has low noise in operation with a simple design 3D-printed structure. Using this exoskeleton, these advantages will improve the medical rehabilitation process of patients that suffered stroke and will influence how their lifestyle will change to recover from these diseases and improve their ability with activities of daily living, thanks to brain plasticity. The exoskeleton can also be used to evaluate the real status of a patient, with stroke and even spinal cord injury, thanks to an elbow movement analysis.

Design and Analysis of Artificial Muscle Robotic Elbow Joint Using Shape Memory Alloy Actuator

2019 ◽  
Vol 21 (2) ◽  
pp. 249-256 ◽  
Author(s):  
Hyung-Bin Park ◽  
Dong-Ryul Kim ◽  
Hyung-Jung Kim ◽  
Wei Wang ◽  
Min-Woo Han ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Elbow Joint ◽  
Artificial Muscle ◽  
Shape Memory Alloy Actuator

Shape Memory Alloy Actuated Vertical Deploy Air Dam: Part 1 — Performance Requirements and Design

2012 ◽  
Author(s):  
Alan L. Browne ◽  
Nancy L. Johnson ◽  
Hanif Muhammad ◽  
Jeffrey Brown
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Active Materials ◽  
Vehicle Performance ◽  
Working Models ◽  
Performance Requirements ◽  
Technical Issues ◽  
System Robustness ◽  
Height Change ◽  
Application Requirements

Airflow over/under/around a vehicle can affect many important aspects of vehicle performance including vehicle drag (and through this vehicle fuel economy) and cooling/heat exchange for the vehicle powertrain and A/C systems. The vast majority of known devices in current use to control airflow over/under/around the vehicle are of fixed geometry, location, orientation, and stiffness. The project whose performance requirements, design, and build phases are described in this paper was successful in developing an SMA actuator based approach to the on-demand reversible deployment of an air dam through vertical translation. Beyond feasibility, the initial bench top working models demonstrated an active materials based approach which would add little weight to the existing stationary system, and could potentially perform well in the harsh under vehicle environment due to a lack of exposed bearings and pivots. This demonstration showed that actuation speed, force, and cyclic stability all could meet the application requirements. The solution, a dual point balanced actuation approach based on shape memory alloy wires, uses straight linear actuation to produce a reversible height change of 50 mm. Key technical issues with regard to design remaining to be resolved given the harsh under vehicle environment are in most part related to improved system robustness, a prime example being mechanism sealing.

scholarly journals Workspace analysis of 3-DOF U-shape base planar parallel robotic motion stage using shape memory alloy restoration technique (SMART) linear actuators

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Deep Singh ◽  
Rutupurna Choudhury ◽  
Yogesh Singh ◽  
Manidipto Mukherjee
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Heat Dissipation ◽  
Parallel Manipulators ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Revolute Joints ◽  
Restoration Technique ◽  
Low Weight ◽  
Linear Actuators

AbstractThe applications of lightweight planar parallel robotic manipulators are increasing enormously because of its various desirable characteristics such as low weight, lower inertia and higher stiffness. Higher accelerations and accuracies can be achieved in planar parallel manipulators. Also, shape memory alloy restoration technique (SMART)-based linear actuators are replacing huge and bulky linear actuators. This study presents the kinematic design of smart linearly actuated family of U-shape base planar parallel robotic manipulator. With the aid of solid modelling software, different available configurations were modelled and their workspace was analysed. The developed 3-DOF motion stages (18 unique configurations) were fabricated using fused deposition modelling process, and the top three configurations having higher workspace were further experimented. It is interesting to observe that the actual or experimental workspace of a particular manipulator configuration is further minimised from the predicted or feasible workspace. It is due to the presence of passive links, singularities, friction between the parts, heat dissipation, force distribution, stiffness, etc. The present study depicts the experimental workspace of the top three configurations, namely PPR-PRP-PRR, PRP-PPR-PRP and PRP-PPR-PRR. Since none of the experimental workspace observed is equal or higher than the model workspace, an efficiency loss in terms of workspace reduction was calculated to understand the acceptability of the configurations in different domains. Apart from the loss, the result disclosed that the actual workspace of all the manipulators was within the feasible workspace domain of mobile platform. The PPR-PRP-PRR manipulator was found to possess highest experimental workspace than other configurations. Note: P, P, and R refer to active prismatic, passive prismatic and passive revolute joints respectively.

Structure and mobility of martensite variant interfaces in a Cu-Zn-AI shape memory alloy

2003 ◽  
Vol 112 ◽  
pp. 519-522 ◽  
Author(s):  
W. Cai ◽  
J. X. Zhang ◽  
Y. F. Zheng ◽  
L. C. Zhao
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Martensite Variant
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