Design Equations for Binary Shape Memory Actuators Under Arbitrary External Forces

2011 ◽  
Author(s):  
Andrea Spaggiari ◽  
Igor Spinella ◽  
Eugenio Dragoni
Keyword(s):  
Shape Memory ◽  
Dissipative Force ◽  
Arbitrary System ◽  
Constant Force ◽  
Shape Memory Alloy Actuator ◽  
Shape Memory Actuators ◽  
Step Procedure ◽  
Sma Actuator ◽  
Sma Spring ◽  
External Forces

The paper presents the design equations for an on-off shape memory alloy actuator under an arbitrary system of external constant forces. A binary SMA actuator is considered where a cursor is moved against both conservative and dissipative force which may be different during the push or pull phase. Three cases are analyzed and differentiated in the way the bias force is applied to the primary SMA spring, using a constant force, a traditional spring, or a second SMA spring. Closed-form dimensionless design equations are developed, which form the basis of a step-by-step procedure for an optimal design of the whole actuator.

Design equations for binary shape memory actuators under arbitrary external forces

2012 ◽  
Vol 24 (6) ◽  
pp. 682-694 ◽  
Author(s):  
Andrea Spaggiari ◽  
Igor Spinella ◽  
Eugenio Dragoni
Keyword(s):  
Optimal Design ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Arbitrary Constant ◽  
Constant Force ◽  
Dissipative Forces ◽  
Shape Memory Alloy Actuator ◽  
Shape Memory Actuators ◽  
Step Procedure ◽  
External Forces

This article presents the design equations for an on–off shape memory alloy actuator working against an external system of arbitrary constant forces. A binary shape memory alloy actuator is considered where a cursor is moved against both conservative and dissipative forces, which may be different during the push or pull phase. Three cases are analysed and differentiated in the way the bias force is applied to the primary shape memory alloy spring: using a constant force, a conventional spring or a second shape memory alloy spring. Closed-form dimensionless design equations are developed, which form the basis of a step-by-step procedure for an optimal design of the whole actuator.

Design equations for binary shape memory actuators under dissipative forces

2008 ◽  
Vol 223 (3) ◽  
pp. 531-543 ◽  
Author(s):  
I Spinella ◽  
E Dragoni
Keyword(s):  
Optimal Design ◽  
Shape Memory ◽  
Analytical Procedure ◽  
Elastic System ◽  
Constant Force ◽  
Detailed Design ◽  
Dissipative Forces ◽  
Helical Springs ◽  
Shape Memory Actuators ◽  
Step Procedure

An analytical procedure to design binary shape memory actuators is described. A generic actuator is considered where a cursor is moved against dissipative forces using an elastic system containing a primary shape memory spring and a bias (backup) element. Three typical cases are analysed and differentiated in the way the bias force is applied to the primary shape memory spring, using a constant force, a conventional spring, or a second shape memory spring. Dimensionless, closed-form relationships are developed, which form the basis of a step-by-step procedure for an optimal design of the whole actuator (primary active spring and bias element). Specific formulas regarding the detailed design of the shape memory elements of the actuator in the form of straight wires and wire helical springs are also presented.

A Multi-Purpose Method for SMA Actuator Development

2013 ◽  
Author(s):  
Sven Langbein ◽  
Alexander Czechowicz
Keyword(s):  
Standardized Testing ◽  
Shape Memory ◽  
Smart Materials ◽  
Research Work ◽  
Simulation Tools ◽  
Sma Actuators ◽  
Shape Memory Actuators ◽  
Computer Aided ◽  
Sma Actuator ◽  
Actual Shape

Shape memory alloys (SMA) are thermally activated smart materials. Due to their ability to change into a previously imprinted actual shape through the means of thermal activation, they are suitable as actuators for mechatronical systems. Despite of the advantages shape memory alloy actuators provide, these elements are only seldom integrated by engineers into mechatronical systems. Reasons are the complex characteristics, especially at different boundary conditions and the missing simulation- and design tools. Also the lack of knowledge and empirical data are a reason why development projects with shape memory actuators often lead to failures. Therefore, a need of developing methods, standardized testing of empirical properties and computer aided simulation tools is motivated. While computer-aided approaches have been discussed in further papers, as well as standardization potentials of SMA actuators, this paper focuses on a developing method for SMA actuators. The main part of the publication presents the logical steps which have to be passed, in order to develop an SMA actuator, considering several options like mechanical, thermal, and electrical options. As a result of the research work, the paper proves this method by one example in the field of SMA-valve technology.

Design of a 2 DOF Shape Memory Alloy Actuator Using SMA Springs

2021 ◽  
Author(s):  
Hussein F. M. Ali ◽  
Youngshik Kim
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Open Loop ◽  
Degree Of Freedom ◽  
Biologically Inspired ◽  
Loop Control ◽  
Actuator System ◽  
Sma Actuator ◽  
Sma Spring ◽  
Two Degree Of Freedom

Abstract In this paper, we developed two degree of freedom shape memory alloy (SMA) actuator using SMA springs. This module can be applied easily to various applications: device holder, artificial finger, grippes, fish robot, and many other biologically inspired applications, where small size and small wight of the actuator are very critical. This actuator is composed of two sets of SMA springs: one set is for the rotation around the X axis (roll angle) and the other set is for the rotation around the Y axis (pitch angle). Each set contains two elements: one SMA spring and one antagonistic SMA spring. We used an inertia sensor (IMU) and two potentiometers for angles feedback. The SMA actuator system is modeled mathematically and then tested experimentally in open-loop and closed-loop control. We designed and experimentally tuned a proportional integrator derivative (PID) controller to follow the set points and to track the desired trajectories. The main goal of the presented controller is to control roll and pitch angles simultaneously in order to satisfy set points and trajectories within the work space. The experimental results show that the two degree of freedom SMA actuator system follows the desired setpoints with acceptable rise time and overshoot.

Discrete Preisach Model of a Shape Memory Alloy Actuator

2016 ◽  
Vol 248 ◽  
pp. 227-234
Author(s):  
Waldemar Rączka ◽  
Jarosław Konieczny ◽  
Marek Sibielak ◽  
Janusz Kowal
Keyword(s):  
Mathematical Model ◽  
Shape Memory Alloy ◽  
Parameter Identification ◽  
Shape Memory ◽  
Preisach Model ◽  
Discrete Form ◽  
Nonlinear Characteristics ◽  
Shape Memory Alloy Actuator ◽  
Sma Actuator ◽  
Identification Model

Shape Memory Alloy is a material used to designing actuators. These actuators have many advantages. They are light, strong and silent. They are building in laboratory and tested because beside advantages they have disadvantages too. SMA actuators have nonlinear characteristics with hysteresis loop.In the first part of the paper Shape Memory Alloys are shortly described. Next mathematical model was formulated. In the paper the Preisach model was developed. Discrete form of the model was considered and implemented. After parameter identification model was implemented in LabView. Tests of the model were conducted and results were worked. Obtained characteristics of the SMA actuator are shown in the paper. At the end of the paper the conclusions were formulated.

Design Analysis in Frictional Fan Clutch Driven by SMA Spring

2011 ◽  
Vol 101-102 ◽  
pp. 7-10 ◽  
Author(s):  
Jian Zuo Ma ◽  
Peng Wei Liu
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Normal Pressure ◽  
Output Displacement ◽  
Sma Actuators ◽  
Torque Transmission ◽  
Sma Actuator ◽  
Sma Spring ◽  
Transmission Ability

This paper presents a fan clutch driven by SMA spring actuator. Based on shape memory effect of SMA, the operational principle of the fan clutch driven by SMA is introduced. The equation of the output displacement of SMA actuator in free stroke is derived. The normal pressure between driving and driven discs of the clutch generated by SMA actuators is analyzed to compute the torque transmission ability in the disc-type fan clutch. The characteristic of transmission torque is studied in detail. The results indicate that the change of temperatures has a tremendous influence on the normal pressure between driving and driven discs of the fan clutch, and the transmission torque of the fan clutch changes rapidly according to the temperatures of airflow from radiator.

Cu-AI based single crystal shape memory actuators and drives

2003 ◽  
Vol 112 ◽  
pp. 1181-1184 ◽  
Author(s):  
I. Vahhi ◽  
S. Pulnev ◽  
A. Priadko
Keyword(s):  
Single Crystal ◽  
Shape Memory ◽  
Crystal Shape ◽  
Shape Memory Actuators

The study for constant force characteristic of C-shaped superelastic SMA

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1253-1259
Author(s):  
Minghui Wang ◽  
Hongliu Yu
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Medical Device ◽  
Soft Tissues ◽  
Computational Simulation ◽  
Force Characteristic ◽  
Constant Force ◽  
Curve Shape ◽  
Artificial Sphincter ◽  
Round Bar

Clamping devices with constant force or pressure are desired in medical device, such as hemostatic forceps and the artificial sphincter, to prevent soft tissues from injures due to overloading. It is easily obtained by stretching an SMA wire. However, studies with SMA bending round bar have seldom been reported before. This paper studied constant force characteristic of C-shaped round bar with shape memory alloys. Optimization designs of the components were carried out with computational simulation. Numerical results show that the phenomenon of constant force strongly depends on contour curve shape and geometric dimensions of the C-shaped round bar of SMA component.

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