Shape memory alloy actuator
AssigneeThe Australian National University
InventorsRoy Featherstone, Yee Teh
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Abstract
A controller (44) for a SMA actuator (2) includes an electgric power source (46) for applying an electric current through an SMA element (8), a sensor (48) to detect change in an electric resistance of the element (8); and a regulator (50) for controlling the magnitude of the applied electric current. The regulator (50) applies a first current above a safe limit current for the element (8) until a selected change in the electric resistance is detected and applies a second current less than the first current after the change is detected.
Claims51
A controller for an SMA actuator, the SMA actuator including at least one SMA element, the controller including:
- an electrical power source for applying an electrical current through the SMA element;
- a sensor to detect change in an electrical resistance of the SMA element;
- and
- a regulator for controlling a magnitude of the applied electrical current, said regulator applying a first current above a safe limit current for the SMA element until a selected change in said electrical resistance is detected and applying a second current less than said first current after said change is detected.
A method of heating at least one SMA element of an SMA actuator, the method including:
- applying an electrical current through the SMA element;
- and
- detecting change in the electrical resistance of the SMA element;
- wherein
- a first current above a safe limit current for the SMA element is applied until a selected change in said electrical resistance is detected and a second current less than said first current is applied after said change is detected.
Dependencies are inferred from the claim text.