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 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:
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:
Ion exchange resins can be prepared by co-polymerizing a major amount (>88 mol %) of non-ionic acrylic monomer, such as methyl methacrylate, with a minor amount (3 to 12 mol %) of an ionogenous monomer such as methacrylamidopropyltrimethylammonium chloride or 2-acrylamido-2-methyl propane sulfonic acid. The resultant anion-conductive or cation conductive membranes exhibit low swelling in water and high ion-transference numbers. The membranes may be applied as coatings on neural prosthesis electrodes.
摘要:
A prosthesis electrode for electrically stimulating body tissue. The electrode has a metal tip covered by a non-metallic coating composed of a compound of the metal in the tip. Covering the non-metallic coating is an ion-conducting membrane which prevents the metal tip and the non-metallic coating from contacting the body tissue. The membrane comprises a specific ion-conducting inner membrane layer which prevents transference to the body tissue of ions in the coating which enter into undesirable reactions with the body tissue. On the outside of the inner membrane is a non-specific ion-conducting outer membrane layer which is non-toxic to body tissue and which prevents changes in salt concentration in the body tissue adjacent the electrode during a biphasic pulse of the electrode.