摘要:
An actuator includes a thermally activated active material member, and an external element configured to selectively engage the member and presenting a predetermined rate of thermal conductivity configured to transfer heat energy to and/or from the member, so as to reduce the actuation period or rate of cooling after actuation, when engaged.
摘要:
An actuator includes a thermally activated active material member, and an external element configured to selectively engage the member and presenting a predetermined rate of thermal conductivity configured to transfer heat energy to and/or from the member, so as to reduce the actuation period or rate of cooling after actuation, when engaged.
摘要:
An overheating protection system adapted for use with a shape memory alloy actuator element, includes at least one switching shape memory alloy element presenting a slower activation period than that of the actuator element, and configured to selectively prevent activation of the actuator element, when the actuator element is actually or predicted to be experiencing overheating; and a circuit comprising the system, wherein the switching element and/or a circuit implement functions to modify activation of the actuator element.
摘要:
An overheating protection system adapted for use with a shape memory alloy actuator element, includes at least one switching shape memory alloy element presenting a slower activation period than that of the actuator element, and configured to selectively prevent activation of the actuator element, when the actuator element is actually or predicted to be experiencing overheating; and a circuit comprising the system, wherein the switching element and/or a circuit implement functions to modify activation of the actuator element.
摘要:
A method of controlling a shape memory alloy actuator utilizing the change in resistance exhibited by the actuator over an actuation cycle, and more preferably, a derivative thereof, to identify at least one event, and generating a response based upon the event.
摘要:
A method of controlling a shape memory alloy actuator utilizing the change in resistance exhibited by the actuator over an actuation cycle, or a derivative thereof, to identify at least one event, such as, for example, a peak, valley, change in slope without reaching a valley, or a jump in resistance within the signal plot that corresponds to the start of actuation, end of actuation, an overload case, and the introduction of a resistive element respectively, and generating a response based upon the event.
摘要:
An energy harvesting system includes a heat engine and a component. The heat engine includes a belt, a first member, and a second member. The belt includes a strip of material and at least one wire at least partially embedded longitudinally in the strip of material. The wire includes a shape memory alloy material. A localized region of the at least one wire is configured to change crystallographic phase between martensite and austenite and either contract or expand longitudinally in response to exposure to a first temperature or a second temperature such that the strip of material corresponding to the localized region also contracts or expands. The first member is operatively connected to the belt and moves with the belt in response to the expansion or contraction of the belt. The component is operatively connected to the first member such that movement of the first member drives the component.
摘要:
A method of controlling an energy harvesting system that converts excess thermal energy into mechanical energy and includes a Shape Memory Alloy (SMA) member, includes obtaining current operational parameters of the energy harvesting system, such as a maximum temperature, a minimum temperature and a cycle frequency of the SMA member. The current operational parameters are compared to a target operating condition of the energy harvesting system to determine if the current operational parameters are within a pre-defined range of the target operating condition. If the current operational parameters are not within the pre-defined range of the target operating condition, then a heat transfer rate to, a heat transfer rate from or a cycle frequency of the SMA member is adjusted to maintain operation of the energy harvesting system within the pre-defined range of the target operating condition to maximize efficiency of the energy harvesting system.
摘要:
A cooling system configured for converting thermal energy to mechanical energy includes a source of thermal energy provided by a temperature difference between a heat source having a first temperature and a coolant having a second temperature that is lower than the first temperature. The cooling system includes a cooling circuit configured for conveying the coolant to and from the heat source. The cooling circuit includes a conduit and a pump in fluid communication with the conduit and configured for delivering the coolant to the heat source. The cooling system also includes a heat engine disposed in thermal relationship with the conduit and configured for converting thermal to mechanical energy. The heat engine includes a first element formed from a first shape memory alloy having a crystallographic phase changeable between austenite and martensite at a first transformation temperature in response to the temperature difference between the heat source and coolant.