An accurate self-sensing method for the control of shape memory alloy actuated flexures
Journal
Sensors and Actuators A: Physical
Journal Volume
163
Journal Issue
1
Start Page
323
End Page
332
ISSN
09244247
Date Issued
2010
Author(s)
Fan, Chen Hsien
Abstract
This paper proposes an accurate self-sensing method for the control of shape memory alloy (SMA) actuated flexures. SMA actuators exhibit large strain, high energy density, and can be successfully employed in flexures for miniature automation applications. A promising approach to obtain strain feedback for motion control is through an accurate self-sensing. The presented technique builds a self-sensing model based on the SMA strain to resistance curves. To overcome the inaccuracies resulting from hysteresis, the resistance curves can be influenced by sufficient pretension force to exhibit very small hysteresis gaps. The curve shapes are shown to be robust against external stiffness and temperature variations. The curves are then modeled by fitted polynomials so that strain values are directly obtained from measured SMA resistance. Accurate self-sensing control is demonstrated through step response and sinusoidal tracking experiments. Two flexural mechanisms are illustrated to show how the technique can be successfully implemented to various contexts.
Subjects
Flexural Mechanism
Hysteresis Model
Self-sensing Actuator
Shape Memory Alloy
Automation Applications
Control Of Shape
Curve Shape
Flexural Mechanism
High Energy Densities
Hysteresis Gaps
Hysteresis Model
Large Strains
Resistance Curves
Self-sensing
Self-sensing Actuators
Self-sensing Control
Shape Memory Alloy
Sma Actuators
Strain Feedback
Strain Values
Temperature Variation
Actuators
Alloys
Hysteresis
Shape Memory Effect
Cerium Alloys
Type
journal article