摘要:
A preferred rotary actuator includes an actuator assembly having a torque tube formed of a shape memory alloy (SMA), a superelastic NiTinol return spring associated with the torque tube and adapted to bias the torque tube toward an initial position, and a torque tube heating element, especially a thermoelectric device, for switching the SMA to cause rotation to an object connected to the actuator or to generate a torque upon that object. The torque tube (24) includes a proximal end (32) and a distal end (34). The return spring and torque tube are connected at their ends, with the torque tube being pretwisted while in a martensitic state relative to the spring. Activation of the heating element causes the torque tube to enter an austenitic state in which it returns to its previous untwisted configuration. Removal of heat allows the torque tube to return to a martensitic state, when the return spring retwists the torque tube. A unique locking assembly 22 is used with the preferred actuator assembly. A helicopter blade twist rotation system for a rotorcraft blade 200 having a blade root 202 and a tip 204 includes a SMA rotary actuator 18 located within the blade near the blade root, and a passive torque tube (206) located within the blade and having a proximal end connected to the rotary actuator and a distal end connected to the blade near to the blade tip.
摘要:
An apparatus for use in low frequency vibration energy harvesting (VEH) and with actuators requiring a low deflection force. The apparatus includes a piezo flexure that is loaded with a compressive pre-load force to place the piezo flexure under compression. The piezo flexure may be supported at an intermediate point or at one end thereof. The compressive pre-load force produces flexes the piezo flexure into one or the other of two stable positions, these positions being offset on opposite sides of a longitudinal centerline representing the position of the piezo flexure that would be produced without the compressive pre-load force applied thereto. The compressive pre-load effectively provides a negative spring constant which “softens” the piezo flexure and enhances a responsiveness of the piezo flexure to low frequency vibration energy. The piezo flexure also operates over a much wider frequency bandwidth than conventional systems incorporating a tip mass.
摘要:
A mechanical energy generating apparatus is provided. The apparatus includes a shape changing flexure beam connected at opposing distal ends to first lever arms of a pair of opposing tilt connectors. The apparatus additionally includes a bias beam connected at opposing ends to second lever of the tilt connectors. The tilt connectors are pivotally connected to an adjustable length base such that a distance between the tilt connectors can be adjusted to flex the bias beam and exert a force on the second lever arms of the tilt connectors. The force exerted by the bias beam is transferred to the first lever arms and flexes the flexure beam to approximately a critical buckling stress point of the flexure beam. The flexure beam has a center portion configured to oscillate between a first displacement position beyond the critical buckling stress point, in a first direction, and a second displacement position beyond the buckling stress point, in the an opposing second direction, in response to an oscillating energy field applied across the flexure beam.
摘要:
A method for providing torque to assist in moving a component of a mobile platform. Biasing forces may be applied to opposing portions of a torque transferring member that enable the torque transferring member to be maintained in a position of equilibrium. A torque may be applied to one of the component and the torque transferring member such that the biasing forces cooperatively exert a torque on the torque transferring member to assist in moving the torque transferring member out from the position of equilibrium. Motion of the torque transferring member out from the position of equilibrium may be used to assist in moving the component.
摘要:
A preferred rotary actuator includes an actuator assembly having a torque tube formed of a shape memory alloy (SMA), a superelastic NiTinol return spring associated with the torque tube and adapted to bias the torque tube toward an initial position, and a torque tube heating element, especially a thermoelectric device, for switching the SMA to cause rotation to an object connected to the actuator or to generate a torque upon that object. The torque tube (24) includes a proximal end (32) and a distal end (34). The return spring and torque tube are connected at their ends, with the torque tube being pretwisted while in a martensitic state relative to the spring. Activation of the heating element causes the torque tube to enter an austenitic state in which it returns to its previous untwisted configuration. Removal of heat allows the torque tube to return to a martensitic state, when the return spring retwists the torque tube. A unique locking assembly 22 is used with the preferred actuator assembly. A helicopter blade twist rotation system for a rotorcraft blade 200 having a blade root 202 and a tip 204 includes a SMA rotary actuator 18 located within the blade near the blade root, and a passive torque tube (206) located within the blade and having a proximal end connected to the rotary actuator and a distal end connected to the blade near to the blade tip.
摘要:
A method for providing torque to assist in moving a component of a mobile platform. Biasing forces may be applied to opposing portions of a torque transferring member that enable the torque transferring member to be maintained in a position of equilibrium. A torque may be applied to one of the component and the torque transferring member such that the biasing forces cooperatively exert a torque on the torque transferring member to assist in moving the torque transferring member out from the position of equilibrium. Motion of the torque transferring member out from the position of equilibrium may be used to assist in moving the component.
摘要:
Methods for storing electrical energy discharged from a capacitive source, embodiments including developing a capacitive load in the source and closing a switch between the capacitive source and a voltage conversion block after an output voltage of the source both exceeds a threshold value and is detected to peak. The conversion block includes an inductor and the storage device connected in series and further may include a diode connected in parallel across the inductor and the storage device. Apparatus for storing electrical energy discharged from a capacitive source include embodiments having a capacitive source configured to produce an output voltage, a switch connected to the source, an inductor connected to the switch, a storage device connected to the inductor and a controller configured to close the switch after an output voltage of the source both exceeds a threshold value and is detected to peak.
摘要:
A method is disclosed for controlling a flight trajectory of a spinning projectile. In one aspect the method may involve supporting a nose of the projectile in a manner permitting the nose to be wobbled. At least one electrically responsive component may be coupled at a first end to the nose and at a second end to a base portion of the projectile. An angular position of the nose of the projectile may be sensed as the projectile flies through an atmosphere after being fired from a weapon. An electrical signal is controllably applied to the electrically responsive component, in relation to the sensed angular position of the nose, to control an attitude of the nose during flight of the projectile.