Figure: Comparison of Shape memory actuator with others
The advantages of SMA actuators over existing solutions are reported to be:
(i) shape memory alloy actuators have highest power-to-weight ratio among light-weight technologies. which means that they have a high potential for miniaturization.
(ii) Simplicity of mechanism: Avoidance of end-of-deployment shock loadings, which are always associated with spring-deployed structures. Therefore no more need for dampers, and hence overall system complexity can be reduced.
(iii) Silent actuation: Noiseless operation, which removes the vibration disturbances to other payloads that are normally associated with motor-driven deployment.
(iv) Sensing ability: Both actuating and sensing functions can be combined by measuring changes in electrical resistance associated with the phase transformation.
(v) Low driving voltage: the shape transformation can be activated by passing an electrical current through a shape memory alloy element by applying a small voltage to it due to high electrical resistivity.
The disadvantages of SMA actuators are:
A low energy efficiency
A strong relationship between the strain operation range and fatigue life Quite a low response speed