Control of a shape memory alloy actuation arrangement
US8448435B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 2009 |
| Grant date | May 28, 2013 |
| Priority date | — |
| Expiry date | Apr 5, 2030 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF03G7/066
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An SMA actuation apparatus comprises: an SMA actuator arranged to drive movement of a movable element; a current supply supplying a drive current; a detection circuit detecting a measure of the resistance of the SMA actuator; and a control unit operative to generate a closed-loop control signal supplied to current supply for controlling the power of the drive current to drive the resistance of the SMA actuator to a target value. The control unit derives: an estimate of a characteristic temperature of the SMA actuation apparatus on the basis of the supplied power, using a thermal model; and a resistance offset on the basis thereof. The closed-loop control signal is generated on the basis of the error between the measure of the resistance of the SMA actuator and the target value of the resistance of the SMA actuator, adjusted by the resistance offset to compensate for variations in resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.