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:
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 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 energy harvesting system for converting thermal energy to mechanical energy includes a heat engine that operates using a shape memory alloy active material. The shape memory alloy member may be in thermal communication with a hot region at a first temperature and a cold region at a second temperature lower than the first temperature. The shape memory alloy material may be configured to selectively change crystallographic phase between martensite to austenite and thereby one of contract and expand in response to the first and second temperatures. A thermal conduction element may be in direct contact with the SMA material, where the thermal conduction element is configured to receive thermal energy from the hot region and to transfer a portion of the received thermal energy to the SMA material through conduction.
摘要:
A device for selectively controlling and varying a frictional force level at an interface between two bodies, includes a first contact body having at least one surface, a second contact body having at least one surface in physical communication with the first contact body, and an active material in operative communication with a selected one or both of the first contact body and the second contact body, wherein the active material is configured to undergo a change in a property upon receipt of an activation signal wherein the change in a property is effective to change the frictional force level at the interface between the at least one surface of the first contact body and the at least one surface of the second contact body.
摘要:
An energy harvesting system for converting thermal energy to mechanical energy includes a heat engine that operates using a shape memory alloy active material. The shape memory alloy member may be in thermal communication with a hot region at a first temperature and a cold region at a second temperature lower than the first temperature. The shape memory alloy material may be configured to selectively change crystallographic phase between martensite to austenite and thereby one of contract and expand in response to the first and second temperatures. A thermal conduction element may be in direct contact with the SMA material, where the thermal conduction element is configured to receive thermal energy from the hot region and to transfer a portion of the received thermal energy to the SMA material through conduction.