High-speed response of SMA actuators

Qiu, Jinhao; Tani, Junji; Osanai, Daisuke; Urushiyama, Yuta; Dávid, Lóránt Dénes

doi:10.3233/jae-2000-199

Cited by 15 publications

(14 citation statements)

References 9 publications

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“…The heating and cooling methods inducing the phase transformation also have a considerable effect on the system response. According to 159 , heating process can be done in several ways like conducive heat transfer, radiative heat transfer with microwaves or infrared light, inductive heating, and direct Ohmic heating. It also reported in few studies that a very high-speed response SMA actuator can be achieved by using large electrical currents.…”

Section: Advantages and Disadvantagesmentioning

confidence: 99%

A survey on actuators-driven surgical robots

Nho

Phee

2016

Sensors and Actuators A: Physical

158

107

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Section: Advantages and Disadvantagesmentioning

confidence: 99%

A survey on actuators-driven surgical robots

Nho

Phee

2016

Sensors and Actuators A: Physical

158

107

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“…2, which shows quasi-static stress-strain curves at the lowest and highest temperatures that the actuator obtains, i.e., below the martensitic final temperature, M f , and above the austenitic final temperature, A f . Below M f , the SMA has a martensite phase, which is easily deformed by a preferential switching of twin variants (see e.g., [2]). Therefore, under an application of a bias stress, which is exerted by a spring or by constant pressure, the equilibrium state of the martensitic phase is point P in the figure.…”

Section: General Description Of the Experimentsmentioning

confidence: 99%

“…One way of circumventing this limitation is by developing a one-directional actuation mode based on one-occasional rapid ohmic heating of SMA elements. This concept has been tested by Qui et al [2], but with relatively long heating times of about 10 msec. As a result, the mechanical response of their SMA wires was limited by the rate of heat transfer rather than the rate of phase transformation.…”

Section: Introductionmentioning

confidence: 97%

The Mechanical Response of Shape Memory Alloys Under a Rapid Heating Pulse

Vollach¹,

Shilo²

2009

Exp Mech

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Shape memory alloy (SMA) actuators are very promising due to their large strain and work-output, but are considered to be very slow due to their cooling rate. In this article, we explore the capabilities of a fast one-directional actuation mode based on one-occasional rapid Joule heating of SMA elements. For this purpose, a unique experimental system has been developed that applies a high-voltage electric pulse to a detwined NiTi wire and measures the resulting displacement due to the martensite to austenite phase transformation. The electric pulse is tuned to produce variable temperature jump of up to 160°C within a risetime of few microseconds. One end of the wire is clamped while the displacement of the other end is monitored both by a laser doppler vibrometer and by an optical encoder that measures the displacement of a grating device. Analysis of experimental results reveals a dead time delay between the electric pulse and the wire's response, which is attributed to the austenite nucleation time and which determines the limit on the fastest possible shape memory actuation. Further analysis reveals relations between the dead weight used and the average acceleration and maximal velocity obtained. In particular, the maximal velocity correlates to a constant kinetic energy delivered by the wire, which suggests a constant integrand over the stress-strain curve regardless of the dead-weight used. A comparison of actuation performances demonstrates that our actuation experiments are significantly advantageous over other fast actuation methods in almost every actuation aspect reviewed. This demonstrates the great potential of SMA for applications that require high speeds and large displacements oneoccasional actuation.

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“…In the experiments carried out in [8] several actuators -Ti-40.8wt%Ni-9.9wt%Cu SMA cylinders with diameter 5 mm and length 50 mm were pre-compressed to the residual strain 4%. During the direct Joule heating produced by an electric condenser discharge the shortest response time was 4.6 ms and this time for constrained actuators was 6.5 ms. Evidently, this time can be related to the characteristic time of the electric current impulse, since the condensers used in this experiment had a rather big capacitance from 6 to 3 F. A similar experiment has been carried out in work [9].…”

Section: Introductionmentioning

confidence: 99%

Strain Recovery by TiNi Element Under Fast Heating

Volkov

Volkova

2018

Shap. Mem. Superelasticity

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A theoretical and experimental study of strain recovery under fast heating of a shape memory alloy (SMA) rod preliminarily stretched in the martensitic state is carried out. Two theoretical models are considered: instantaneous heating and heating with temperature variation during a finite time. In the first case it is supposed that the straight SMA rod experiences an instantaneous reverse martensitic transformation, and in the second the transformation is supposed to progress at a rate corresponding to the temperature rate. Analytical expression for the time dependence of the rod free end displacement is obtained. In the experiment a wire specimen made of titaniumnickel SMA was heated by a short impulse of electric current. The variation of the specimen length in time was registered. Thus, it has been shown that the minimum operation time of an SMA actuator (time needed for the strain recovery) can be reduced to 20 µs. Comparison of the theoretical results with the experimental ones leads to the conclusion that the displacement variation in time is controlled by the rate of heating and the inertial properties of the specimen. The incubation time of the martensitic transformation on the micro-scale apparently is estimated as less than 1 µs.

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High-speed response of SMA actuators

Cited by 15 publications

References 9 publications

A survey on actuators-driven surgical robots

A survey on actuators-driven surgical robots

The Mechanical Response of Shape Memory Alloys Under a Rapid Heating Pulse

Strain Recovery by TiNi Element Under Fast Heating

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