摘要:
A system for and method of reducing the effects of preheat period variation in shape memory alloy actuation, include sensing the removal of motion delay due to slack, backlash, and/or compliance in the actuator and drive-train of the system, and determining actuator activation, as a result thereof.
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:
Active texturing systems adapted for selectively and reversibly modifying the texture of a surface utilizing a plurality of discrete mechanisms in communication with the reconfigurable structure.
摘要:
Actively controlled texturing systems for and methods of selectively and reversibly forming wrinkles, or modifying the amplitude, wavelength, or pattern of existing wrinkles upon a surface using active material actuation.
摘要:
A heat engine includes a first rotatable pulley and a second rotatable pulley spaced from the first rotatable pulley. A shape memory alloy (SMA) element is disposed about respective portions of the pulleys at an SMA pulley ratio. The SMA element includes a first wire, a second wire, and a matrix joining the first wire and the second wire. The first wire and the second wire are in contact with the pulleys, but the matrix is not in contact with the pulleys. A timing cable is disposed about respective portions of the pulleys at a timing pulley ratio, which is different than the SMA pulley ratio. The SMA element converts a thermal energy gradient between the hot region and the cold region into mechanical energy.
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:
Accessing interior compartments for storage or other purposes is improved by the use of one or more active material components. Activating one or more active material components carries out one or more of the following functions: opening or closing the compartment (which may include cinching a closure) and/or latching or unlatching a closure from a frame. Activation may result from a remote trigger signal. A method is provided for controlling access to an interior compartment that may be carried out by a controller operatively connected to various active material components that unlatch the closure from the frame, close the closure and cinch the closure to the frame, respectively.
摘要:
Active texturing systems adapted for selectively and reversibly modifying the texture of a surface utilizing a variably foldable structure in communication with the surface, and active material actuation to enable and/or cause folding.
摘要:
A deformable bi-stable device includes an elastically deformable member having at least two stable configurations and capable of being deformed from a first stable configuration to a second stable configuration, the element passing through an unstable configuration as it is deformed from the first stable configuration to the second stable configuration, and a shape memory polymer layer on or in the elastically deformable member. A method of using this device includes heating the shape memory polymer to a temperature sufficient to reduce the modulus of the shape memory polymer, deforming the deformable member to move from one of the first and second stable configurations to another of the first and second stable configurations, and cooling the device to a temperature sufficient to increase the modulus of the shape memory polymer.