Modeling and Tracking Control System of Shape Memory Alloy Actuator

2007 ◽  
Author(s):  
B. Y. Ren ◽  
B. Q. Chen
Keyword(s):  
Control System ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Tracking Control ◽  
Fuzzy Controller ◽  
Smart Structures ◽  
Constitutive Law ◽  
Hysteresis Model ◽  
Sma Actuators ◽  
Sma Actuator

The different Shape Memory Alloy (SMA) actuators have been widely used in the fields of smart structures. However, the accurate prediction of thermomechanical behavior of SMA actuators is very difficult due to the nonlinearity of inherence hysteresis of SMA. Therefore, the tracking control accuracy of SMA actuator is very important for the practical application of the SMA actuator. A dynamic hysteresis model of bias-type SMA actuator based on constitutive law developed by Brinson et al. and hysteresis model developed by Ikuta et al. is presented. The control systems composed of the Proportional Integral Derivative (PID) controller as well as a fuzzy controller or a fuzzy-PID composite controller for compensating the hysteresis is proposed. The effort of tracking control system is analyzed according to the simulation on the displacement of SMA actuator with the three kinds of controllers. The result can provide a reference for the application of SMA actuator in the fields of smart structures.

scholarly journals Neural Network Direct Control with Online Learning for Shape Memory Alloy Manipulators

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2576
Author(s):  
Alfonso Gómez-Espinosa ◽  
Roberto Castro Sundin ◽  
Ion Loidi Eguren ◽  
Enrique Cuan-Urquizo ◽  
Cecilia D. Treviño-Quintanilla
Keyword(s):  
Neural Network ◽  
Online Learning ◽  
Control System ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Position Control ◽  
Reference Signal ◽  
Angular Position ◽  
Hysteresis Model ◽  
Direct Control

New actuators and materials are constantly incorporated into industrial processes, and additional challenges are posed by their complex behavior. Nonlinear hysteresis is commonly found in shape memory alloys, and the inclusion of a suitable hysteresis model in the control system allows the controller to achieve a better performance, although a major drawback is that each system responds in a unique way. In this work, a neural network direct control, with online learning, is developed for position control of shape memory alloy manipulators. Neural network weight coefficients are updated online by using the actuator position data while the controller is applied to the system, without previous training of the neural network weights, nor the inclusion of a hysteresis model. A real-time, low computational cost control system was implemented; experimental evaluation was performed on a 1-DOF manipulator system actuated by a shape memory alloy wire. Test results verified the effectiveness of the proposed control scheme to control the system angular position, compensating for the hysteretic behavior of the shape memory alloy actuator. Using a learning algorithm with a sine wave as reference signal, a maximum static error of 0.83° was achieved when validated against several set-points within the possible range.

A novel robot hand with embedded shape memory alloy actuators

2002 ◽  
Vol 216 (7) ◽  
pp. 737-745 ◽  
Author(s):  
K Yang ◽  
C L Gu
Keyword(s):  
Mechanical Properties ◽  
Control System ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Outer Diameter ◽  
Robot Hand ◽  
Sma Actuators ◽  
Constant Distance

This paper describes the development of an active robot hand, which allows smooth and lifelike motions for anthropomorphic grasping and fine manipulations. An active robot finger 10mm in outer diameter with a shape memory alloy (SMA) wire actuator embedded in the finger with a constant distance from the geometric centre of the finger was designed and fabricated. The practical specifications of the SMA wire and the flexible rod were determined on the basis of a series of formulae. The active finger consists of two bending parts, the SMA actuators and a connecting part. The mechanical properties of the bending part are investigated. The control system on the base of resistance feedback is also presented. Finally, a robot hand with three fingers was designed and the grasping experiment was carried out to demonstrate its performance.

scholarly journals Multistrand, Fast Reaction, Shape Memory Alloy System for Uninhabited Aerial Vehicle Flight Control

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
M. Brennison ◽  
R. M. Barrett ◽  
L. Kerth
Keyword(s):  
Control System ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Flight Control ◽  
Alloy System ◽  
Open Loop ◽  
Flight Control System ◽  
Loop Design ◽  
Aerial Vehicle ◽  
Sma Actuator

This paper details an investigation of shape memory alloy (SMA) filaments which are used to drive a flight control system with precision control in a real flight environment. An antagonistic SMA actuator was developed with an integrated demodulator circuit from a JR NES 911 subscale UAV actuator. Most SMA actuator studies concentrate on modeling the open-loop characteristics of such a system with full actuator performance modeling. This paper is a bit different in that it is very practically oriented and centered on development of a flight-capable system which solves the most tricky, practical problems associated with using SMA filaments for aircraft flight control. By using well-tuned feedback loops, it is shown that intermediate SMA performance prediction is not appropriate for flight control system (FCS) design. Rather, capturing the peak behavior is far more important, along with appropriate feedback loop design. To prove the system, an SMA actuator was designed and installed in the fuselage of a 2 m uninhabited aerial vehicle (UAV) and used to control the rudder through slips and coordinated turns. The actuator was capable of 20 degrees of positive and negative deflection and was capable of 7.5 in-oz (5.29 N cm) of torque at a bandwidth of 2.8 Hz.

Advanced Controlling of the Prototype of SMA Linear Actuator

2011 ◽  
Vol 177 ◽  
pp. 93-101 ◽  
Author(s):  
Ireneusz Dominik
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Knowledge Base ◽  
Real Time ◽  
Fuzzy Controller ◽  
Learning Algorithm ◽  
Linear Actuator ◽  
Sma Actuator ◽  
Auto Tuning ◽  
Continuous Work

During research on SMA wires the prototype of linear position actuator was built. The shape memory alloy (SMA) wires used in construction of the actuator are nonlinear and time variant. Thus, it was decided to use a fuzzy controller to control the actuator. However, because of the nature of SMA wires which work by changes of their temperature, after a few minutes of continuous work the actuator did not work accurately. In other words, the existing singleton values in a knowledge base were inappropriate. That is why each time after longer continuous work of the actuator it was needed to manually find and change the mentioned values. It took a lot of time and effort so eventually it was decided to create a real time auto-tuning algorithm which could identify crucial parameters of the actuator each time when it was needed. Together with initial values learning algorithm the advanced controlling of SMA actuator was created.

Neural Network Tracking Control of a Shape Memory Alloy Wire Actuator Without a Position Sensor

2001 ◽  
Author(s):  
G. Song ◽  
V. Chaudhry ◽  
C. Batur
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Tracking Control ◽  
Open Loop ◽  
Training Data ◽  
Position Sensor ◽  
The Neural Network ◽  
Sma Actuator

Abstract Tracking control of shape memory alloy (SMA) actuators is essential in many applications such as vibration controls. Due to the hysteresis, an inherent nonlinear phenomenon associated with SMAs, open-loop control design has proven inadequate for tracking control of these actuators. Aimed at to eliminate the position sensor to reduce cost of an SMA actuator system, in this paper, a neural network open loop controller is proposed for tracking control of an SMA actuator. A test stand, including a titanium-nickel (TiNi, or Nitinol) SMA wire actuator, a position sensor, bias springs, and a programmable current amplifier, is used to generate training data and to verify the neural networks open loop controller. A digital data acquisition and real-time control system was used to record experimental data and to implement the control strategy. Based on the training data obtained from the test stand, two neural networks are used to respectively model the forward and inverse hysteresis relations between the applied voltage and the displacement of the SMA wire actuator. To control the SMA actuator without using a position sensor, the neural network inverse model is used as a feedforward controller. The experimental results demonstrate the effectiveness of the neural network open loop controller for tracking control of the SMA wire actuator.

Self-sensing feedback control of multiple interacting shape memory alloy actuators in a 3D steerable active needle

2020 ◽  
Vol 31 (12) ◽  
pp. 1524-1540
Author(s):  
Saeed Karimi ◽  
Bardia Konh
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Electrical Resistance ◽  
Tracking Control ◽  
Surgical Instruments ◽  
Position Tracking ◽  
Position Tracking Control ◽  
Targeting Accuracy

Percutaneous needle-based intervention is a technique used in minimally invasive surgical procedures such as brachytherapy, thermal ablation, and biopsy. Targeting accuracy in these procedures is a defining factor for success. Active needle steering introduces the potential to increase the targeting accuracy in such procedures to improve the clinical outcome. In this work, a novel 3D steerable active flexible needle with shape memory alloy actuators was developed. Active needle actuation response to a variety of actuation scenarios was analyzed to develop a kinematic model. Shape memory alloy actuators were characterized in terms of their actuation strain, electrical resistance, and required electrical power to design a self-sensing electrical resistance feedback control system for position tracking control of the active needle. The control system performance was initially tested in position tracking control of a single shape memory alloy actuator and then was implemented on multiple interacting shape memory alloy actuators to manipulate the 3D steerable active needle along a reference path. The electrical resistance feedback control of the multiple interacting shape memory alloy actuators enabled the active needle to reach target points in a planar workspace of about 20 mm. Results demonstrated shape memory alloys as promising alternatives for traditional actuators used in surgical instruments with enhanced design, characterization, and control capabilities.

scholarly journals Development of Miniature Stewart Platform Using TiNiCu Shape-Memory-Alloy Actuators

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Alaa AbuZaiter ◽  
Ee Leen Ng ◽  
Suhail Kazi ◽  
Mohamed Sultan Mohamed Ali
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Pulse Width Modulation ◽  
Stewart Platform ◽  
Sma Actuators ◽  
Tilting Angle ◽  
Sma Actuator ◽  
Manipulator Robot ◽  
Tinicu Shape Memory Alloy ◽  
A Current

A Stewart platform is a parallel manipulator robot that is able to perform three linear movements, lateral, longitudinal, and vertical, and three rotations, pitch, yaw, and roll. This paper reports a 30 mm × 30 mm × 34 mm miniscale Stewart platform using TiNiCu shape-memory-alloy (SMA) actuators. The proposed Stewart platform possesses various advantages, such as large actuation force and high robustness with a simple mechanical structure. This Stewart platform uses four SMA actuators and four bias springs and performs a linearz-axis movement and tilting motions. The SMA actuators are activated by passing a current through the SMA wires using a heating circuit that generates a pulse width modulation (PWM) signal. This signal is varied to control the level of the displacement and tilting angle of the platform. The tilting direction depends on the SMA actuator that is activated, while all four SMA actuators are activated to achieve the linearz-axis movement. Each SMA actuator exerts a maximum force of 0.6 N at PWM duty cycle of 100%. The fabricated miniature Stewart platform yields a full actuation of 12 mm in thez-axis at 55°C, with a maximum tilting angle of 30° in 4 s.

Robust Tracking Control of a Shape Memory Alloy Wire Actuator

2000 ◽  
Author(s):  
Gangbing Song ◽  
Dane Quinn
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Tracking Control ◽  
Vibration Isolation ◽  
Sliding Mode ◽  
Control Design ◽  
Nonlinear Phenomenon ◽  
Robust Tracking Control ◽  
Sma Actuators ◽  
Titanium Nickel

Abstract Tracking control of shape memory alloy (SMA) actuators is essential in many applications such as vibration isolation. Due to the hysteresis, an inherent nonlinear phenomenon associated with SMAs, control design based on linear methods has proven inadequate for tracking control of these actuators. In this paper, a novel tracking controller employing a nonlinear robust compensator is proposed for SMA actuators. The control design uses the sliding-mode approach and requires no detailed information of the SMA model. To test the effectiveness of the proposed controller, a single SMA wire test stand is built. A titanium-nickel SMA wire stretched by a bias spring is used as an actuator for tracking control. Experimental results show that the SMA wire actuator under the robust control can precisely follow a sinusoidal path and the effectiveness of the proposed control strategy is demonstrated.

Finger-Like Mechanism Using Bending Shape Memory Alloys

2020 ◽  
Author(s):  
Hussein F. M. Ali ◽  
Hangyeol Baek ◽  
Taesoo Jang ◽  
Youngshik Kim
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Kinematic Model ◽  
Coordinated Control ◽  
Force Sensor ◽  
Biologically Inspired ◽  
Sma Actuators ◽  
Finger Flexion ◽  
Compliant Actuation ◽  
Sma Actuator

Abstract A biologically inspired finger-like mechanism similar to human musculoskeletal system is developed based on Shape Memory Alloy (SMA). SMA actuators are inspiring the design of a modular finger part with compact and compliant actuation. This paper describes a three-segmented finger-like mechanism. This mechanism is composed of six bending Shape Memory Alloy (SMA) actuators. As a result, our finger mechanism is compact and compliant. The insider three SMA actuator are used for finger flexion while the outsider three SMA actuators are for extension. Each segment of this mechanism can be bent and/or extended independently by actuating a corresponding bending SMA actuator. Furthermore, full bending motion can be achieved by applying coordinated control of the three SMA actuators. Bending and stretching motions of the proposed mechanism are finally demonstrated. The work space of the three-segment finger is studied to verify the reachable points by the end tip. The kinematic model is developed to study the motion of the mechanism. The performance evaluation is executed using force sensor and a temperature monitoring of the corresponding SMA actuators. The simulation and experimental results indicate that the SMA-based finger module can achieve effectively the desired motions as designed.

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