Shape memory alloy actuators in smart structures: Modeling and simulation

2004 ◽  
Vol 57 (1) ◽  
pp. 23-46 ◽  
Author(s):  
Stefan Seelecke ◽  
Ingo Mu¨ller
Keyword(s):  
Optimal Control ◽  
Shape Memory Alloy ◽  
Modeling And Simulation ◽  
Shape Memory ◽  
Smart Structures ◽  
Review Article ◽  
Material Behavior ◽  
Control Methods ◽  
Time Optimal ◽  
And Control

This review article gives an overview of the new and quickly developing field of shape memory alloy (SMA) actuators in smart structures. The focus is on the aspects of modeling and simulation of such structures, a task that goes beyond classical modeling approaches as it has to combine constitutive modeling with structural and control aspects in a highly interdisciplinary way. We review developments in each of these fields, trying to combine them into a smooth picture of how to treat the problem efficiently. After a discussion of modeling aspects with particular regard to actuator applications, the simulation of standard feedback control methods is demonstrated. Subsequently, model based methods from optimal control theory are presented, accounting for the strongly nonlinear and hysteretic material behavior of SMAs. Real-time optimal control methods are introduced and, finally, aspects of finite element implementation of an SMA actuator model are discussed and illustrated by the simulation of an adaptive aircraft wing. This review article cites 155 references.

Experiment Verification and Stability Analysis of Iterative Learning Control for Shape Memory Alloy Wire

2019 ◽  
Vol 31 (4) ◽  
pp. 583-593
Author(s):  
Hitoshi Kino ◽  
Naofumi Mori ◽  
Shota Moribe ◽  
Kazuyuki Tsuda ◽  
Kenji Tahara ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Iterative Learning Control ◽  
Robot Manipulator ◽  
Learning Control ◽  
Iterative Learning ◽  
Control Methods ◽  
Experiment Verification ◽  
And Control

To achieve the control of a small-sized robot manipulator, we focus on an actuator using a shape memory alloy (SMA). By providing an adjusted voltage, an SMA wire can itself generate heat, contract, and control its length. However, a strong hysteresis is generally known to be present in a given heat and deformation volume. Most of the control methods developed thus far have applied detailed modeling and model-based control. However, there are many cases in which it is difficult to determine the parameter settings required for modeling. By contrast, iterative learning control is a method that does not require detailed information on the dynamics and realizes the desired motion through iterative trials. Despite pioneering studies on the iterative learning control of SMA, convergence has yet to be proven in detail. This paper therefore describes a stability analysis of an iterative learning control to mathematically prove convergence at the desired length. This paper also details an experimental verification of the effect of convergence depending on the variation in gain.

scholarly journals Mechanical Consequences of Dynamically Loaded NiTi Wires under Typical Actuator Conditions in Rehabilitation and Neuroscience

2021 ◽  
Vol 12 (1) ◽  
pp. 4
Author(s):  
Umut D. Çakmak ◽  
Zoltán Major ◽  
Michael Fischlschweiger
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Storage Modulus ◽  
Loss Factor ◽  
Empirical Relation ◽  
Material Behavior ◽  
Chemical Compositions ◽  
Loading Frequency ◽  
Frequency Dependency ◽  
Controlled Conditions

In the field of rehabilitation and neuroscience, shape memory alloys play a crucial role as lightweight actuators. Devices are exploiting the shape memory effect by transforming heat into mechanical work. In rehabilitation applications, dynamic loading of the respective device occurs, which in turn influences the mechanical consequences of the phase transforming alloy. Hence in this work, dynamic thermomechanical material behavior of temperature-triggered phase transforming NiTi shape memory alloy (SMA) wires with different chemical compositions and geometries was experimentally investigated. Storage modulus and mechanical loss factor of NiTi alloys at different temperatures and loading frequencies were analyzed under force-controlled conditions. Counterintuitive storage modulus- and loss factor-dependent trends regarding the loading frequency dependency of the mechanical properties on the materials’ composition and geometry were, hence, obtained. It was revealed that loss factors showed a pronounced loading frequency dependency, whereas the storage modulus was not affected. It was shown that force-controlled conditions led to a lower storage modulus than expected. Furthermore, it turned out that a simple empirical relation could capture the characteristic temperature dependency of the storage modulus, which is an important input relation for modeling the rehabilitation device behavior under different dynamic and temperature loading conditions, taking directly into account the material behavior of the shape memory alloy.

scholarly journals Iron-based shape memory alloy strips for strengthening RC members: Material behavior and characterization

2018 ◽  
Vol 173 ◽  
pp. 586-599 ◽  
Author(s):  
Moslem Shahverdi ◽  
Julien Michels ◽  
Christoph Czaderski ◽  
Masoud Motavalli
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Material Behavior ◽  
Iron Based

Strategies to enhance the biodegradation of toxic compounds using discontinuous processes

2001 ◽  
Vol 43 (3) ◽  
pp. 283-290 ◽  
Author(s):  
G. Buitrón ◽  
G. Soto ◽  
G. Vite ◽  
J. Moreno
Keyword(s):  
Optimal Control ◽  
Activated Carbon ◽  
Dissolved Oxygen ◽  
Batch Reactor ◽  
Biological Degradation ◽  
Optimal Control Strategy ◽  
Measured Variable ◽  
Time Optimal ◽  
High Concentrations ◽  
And Control

This study presents two strategies used to enhance the biological degradation of phenolic wastewaters. In the first one the operation of a sequencing batch biofilter added with granular activated carbon (SBB-AC) was studied. The second strategy presents the results of the automation of a sequencing batch reactor in order to optimize the reaction phase. In this case, the dissolved oxygen was employed to monitor and control the reactor. The results of the SBB-AC system, based on the configuration of the reactor, type and size of activated carbon and size of the packing material, are discussed. The system biodegraded efficiently (total phenol removals as high as 97%) high concentrations (600 mg/l) of a mixture of phenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol. Maximal eliminated loads of 4.33 kg COD/m3-d were achieved. For the second strategy, the applicability of an optimal control for a SBR using the dissolved oxygen as the measured variable was demonstrated. When the reactor was operated under the time-optimal control strategy, the degradation time of 4-chlorophenol was reduced. A very satisfactory operation of the reactor was observed, since the removal efficiencies were around 99%.

Design and control of a novel compliant differential shape memory alloy actuator

2015 ◽  
Vol 225 ◽  
pp. 71-80 ◽  
Author(s):  
Zhao Guo ◽  
Yongping Pan ◽  
Liang Boon Wee ◽  
Haoyong Yu
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Alloy Actuator ◽  
And Control
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