Detection of active-material overheat conditions without temperature sensor

摘要

A system, for use in protecting an active-material actuator from overheating without using a temperature sensor. The system includes an active material being transformable between a first state and a second state in response to a pre-determined stimulus, and being pre-tensioned to at least a pre-determined threshold, yielding the pre-tensioned active material. The system also includes a processing unit configured to perform operations comprising obtaining a value for electrical resistance of the pre-tensioned active material, estimating, based on the electrical resistance obtained, an strain value for the active material, yielding an estimated strain value, and obtaining an actual strain value for the active material. The operations also include determining a difference between the estimated strain value estimated and the actual strain value and determining, based on the difference determined, whether an overheating condition exists for the active material.

主权项

1. A system, for use in protecting an active-material actuator from overheating without using a temperature sensor, comprising:
an active material being:
transformable between a first state and a second state in response to a pre-determined stimulus; andpre-tensioned to at least a pre-determined threshold, yielding the pre-tensioned active material; and a processing unit configured to perform operations comprising:
obtaining a value for electrical resistance of the pre-tensioned active material;estimating, based on the electrical resistance obtained, an strain value for the active material, yielding an estimated strain value;obtaining an actual strain value for the active material;determining a difference between the estimated strain value estimated and the actual strain value; anddetermining, based on the difference determined, whether an overheating condition exists for the active material.