Actuator
AssigneeCambridge Mechatronics Limited
InventorsAndrew Benjamin Simpson Brown, James Howarth, Robert Langhorne, René Kist
Life of this patent
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Abstract
A shape memory alloy (SMA) actuator comprising: a support structure (10); a moveable part (20) movable relative to the support structure; plural SMA components (30) connecting the support structure and the movable part, the SMA components are operable to controllably change the position and/or orientation of the moveable part in two or more degrees of freedom; a controller (12) for controlling the operation of the SMA components in a first operating mode during normal operation and a second operating mode in response to an event; and means configured to, during the second operating mode, maintain at least partial control of the moveable part with a subset of the plural SMA components.
Claims16
A shape memory alloy (SMA) actuator comprising:
- a support structure;
- a moveable part moveable relative to the support structure;
- plural SMA components connecting the support structure and the moveable part, wherein the SMA components are operable to controllably change the position of the moveable part and/or the orientation of the moveable part in two or more degrees of freedom;
- a controller for controlling the operation of the SMA components in a first operating mode during normal operation and a second operating mode in response to an event;
- and
- means configured to, during the second operating mode, maintain at least partial control of the moveable part with a subset of the plural SMA components;
- wherein the event comprises detecting an abnormality in at least one of the SMA components and/or receiving a command at the controller, and wherein the controller selects one or more SMA components of the plural SMA components based on the event;
- and
- wherein during the second operating mode the controller is configured to disable the selected one or more SMA components whilst operating the rest of SMA components.
A shape memory alloy (SMA) actuator comprising:
- a support structure;
- a moveable part moveable relative to the support structure;
- plural SMA components connecting the support structure and the moveable part, wherein the SMA components are operable to controllably change the position of the moveable part and/or the orientation of the moveable part in two or more degrees of freedom;
- a controller for controlling the operation of the SMA components in a first operating mode during normal operation and a second operating mode in response to an event;
- and
- means configured to, during the second operating mode, maintain at least partial control of the moveable part with a subset of the plural SMA components:
- wherein during the second operating mode, the controller is configured to move the moveable part towards an end of a moveable range in at least one degree of freedom, whilst maintaining control of the moveable part in other directions:
- and
- wherein the end of the moveable range is defined by an end stop and/or a wall, and wherein during the second operating mode, the controller is configured to move the moveable part such that the moveable part slides along a surface of the end stop and/or a surface of the wall to maintain control of the moveable part.
A method for controlling a shape memory alloy (SMA) actuator, the SMA actuator having plural SMA components connecting a support structure and a moveable part, wherein each SMA component of the plural SMA components is operable to controllably change the position of the moveable part and/or the orientation of moveable part in two or more degrees of freedom in a first operating mode, the method comprising:
- detecting an event and operating in a second operating mode,
- maintaining, during the second operating mode, at least partial control of the moveable part with a subset of the plural SMA components;
- wherein the event comprises detecting an abnormality in at least one of the SMA components and/or receiving a command at a controller, and wherein the method further comprises selecting one or more SMA components of the plural SMA components based on the event;
- and
- wherein the plural SMA components are divided into at least two sub-groups each configured to balance a tension in a respective sub-group of the at least two sub-groups, the method comprising:
- disabling all of the SMA components in a sub-group of the at least two sub-groups corresponding to the selected SMA components whilst operating the rest of SMA components in the second operating mode.
Dependencies are inferred from the claim text.