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.

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 Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loading Rate ◽  
Effective Elastic Modulus ◽  
Maximum Energy ◽  
Numerical Results ◽  
Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

Mechanical properties of a NiTi-Pd high-temperature shape memory alloy

1994 ◽  
Author(s):  
Kuang-Hsi Wu ◽  
Y. Q. Liu ◽  
Michael J. Maich ◽  
Hsien-Kuei Tseng
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Shape Memory Alloy ◽  
Shape Memory

Structural fatigue and fracture of shape memory alloy actuators: Current status and perspectives

2021 ◽  
pp. 1045389X2110572
Author(s):  
Md Mehedi Hasan ◽  
Theocharis Baxevanis
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Current Status ◽  
Structural Fatigue ◽  
Sma Actuators ◽  
Empirical Relations ◽  
Fatigue And Fracture ◽  
And Performance ◽  
Commercial Applications ◽  
Crack Growth Rates

Shape Memory Alloy (SMA)-actuators are efficient, simple, and robust alternatives to conventional actuators when a small volume and/or large force and stroke are required. The analysis of their failure response is critical for their design in order to achieve optimum functionality and performance. Here, (i) the existing knowledge base on the fatigue and overload fracture response of SMAs under actuation loading is reviewed regarding the failure micromechanisms, empirical relations for actuation fatigue life prediction, experimental measurements of fracture toughness and fatigue crack growth rates, and numerical investigations of toughness properties and (ii) future developments required to expand the acquired knowledge, enhance the current understanding, and ultimately enable commercial applications of SMA-actuators are discussed.

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