Apparatus for cost effective wireless actuator using SMA and MRC

Patent metadata

Field	Value
Publication number	US-9777715-B2
Application number	US-201514597143-A
Country	US
Kind code	B2
Filing date	Jan 14, 2015
Priority date	Jan 14, 2015
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A system and method for wirelessly controlling a shape memory alloy (SMA) actuator using magnetic resonant coupling (MRC). The SMA actuator is part of a receiver circuit including an actuator coil, where the SMA actuator is configured into a certain shape. The system includes a transmitter circuit having a transmitter coil and a controller, where the transmitter coil receives an AC current that causes the transmitter coil to generate an oscillating magnetic field in resonance with the actuator coil in the receiver circuit and be magnetically coupled thereto. The current induced in the actuator coil creates heat that reconfigures the SMA actuator to provide the actuation.

First claim

What is claimed is:

1. A magnetic resonant coupling (MRC) actuation circuit comprising:
a transmitter circuit including a controller, a base coil, a variable current source and a tuning capacitor, said variable current source selectively providing a predetermined alternating current to the base coil in combination with a capacitance provided by the tuning capacitor so as to generate an oscillating magnetic field at a predetermined frequency; and
at least one receiver circuit including a shape memory alloy (SMA) actuator and an actuator coil, said controller selectively providing the frequency of the oscillating magnetic field to be tuned to the actuator coil through MRC so as to heat the SMA actuator and cause it to change its configuration,
where the controller adjusts the transmitter circuit to fine tune the oscillating magnetic field, based on a change of phase of reflected impedance of the receiver circuit, when the SMA actuator changes its configuration.

2. The MRC circuit according to claim 1 wherein the receiver circuit includes a variable capacitor in electrical communication with the SMA actuator and the actuator coil, said SMA actuator operating as a resistive load in the at least one receiver circuit.

3. The MRC circuit according to claim 1 wherein the SMA actuator operates both as an inductor and a parasitic capacitance in the receiver circuit.

4. The MRC circuit according to claim 1 wherein the at least one receiver circuit is a plurality of receiver circuits, wherein the controller changes the frequency of the oscillating magnetic field to be selectively tuned to all of the receiver circuits.

5. The MRC circuit according to claim 1 wherein the MRC circuit is a vehicle circuit and the actuator is a vehicle actuator.

6. The MRC circuit according to claim 5 wherein the transmitter circuit is separate from the vehicle and the receiver circuit is on the vehicle.

7. A magnetic resonant coupling (MRC) actuation circuit comprising:
a transmitter circuit including a controller, a base coil, a variable current source and a tuning capacitor, said variable current source selectively providing a predetermined alternating current to the base coil in combination with a capacitance provided by the tuning capacitor so as to generate an oscillating magnetic field at a predetermined frequency; and
a receiver circuit including a shape memory alloy (SMA) actuator being configured as an actuator coil, said controller selectively providing the frequency of the oscillating magnetic field to be tuned to the actuator through MRC so as to heat the actuator and cause it to change its configuration,
where the controller adjusts the transmitter circuit to fine tune the oscillating magnetic field, based on a change of phase of reflected impedance of the receiver circuit, when the SMA actuator changes its configuration.

8. The MRC circuit according to claim 7 wherein the receiver circuit includes a variable capacitor in electrical communication with the SMA actuator.

9. The MRC circuit according to claim 7 wherein the SMA actuator operates both as an inductor and a parasitic capacitance in the receiver circuit.

10. The MRC circuit according to claim 7 wherein the MRC circuit is a vehicle circuit and the actuator is a vehicle actuator.

11. The MRC circuit according to claim 10 wherein the transmitter circuit is separate from the vehicle and the receiver circuit is on the vehicle.

12. A magnetic resonant coupling (MRC) actuation circuit for actuating a device on a vehicle, said MRC circuit comprising:
a transmitter circuit including a controller, a base coil, a variable current source and a tuning capacitor, said variable current source selectively providing a predetermined alternating current to the base coil in combination with a capacitance provided by the tuning capacitor so as to generate an oscillating magnetic field at a predetermined frequency; and
a plurality of receiver circuits each including a shape memory alloy (SMA) actuator and an actuator coil, said controller selectively providing the frequency of the oscillating magnetic field to be separately tuned to the actuator coil in each of the receiver circuits through MRC so as to heat the SMA actuator and cause it to change its configuration,
where the controller adjusts the transmitter circuit to fine tune the oscillating magnetic field, based on a change of phase of reflected impedance of each of the receiver circuits, when the SMA actuator changes its configuration.

13. The MRC circuit according to claim 12 wherein each of the receiver circuits includes a variable capacitor in electrical communication with the SMA actuator and the actuator coil.

14. The MRC circuit according to claim 12 wherein the SMA actuator operates both as an inductor and a parasitic capacitance in the receiver circuits.

15. The MRC circuit according to claim 12 wherein the transmitter circuit is separate from the vehicle and the plurality of receiver circuits is on the vehicle.

16. The MRC circuit according to claim 12 wherein the actuator coil of each of the receiver circuits is positioned within a perimeter of the base coil and substantially on a same plane as the base coil.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Laifenfeld Moshe
• Suplin Vladimir

Classifications

• H02J50/12

  of the resonant type · CPC title

• G01R27/02

  Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00) · CPC title

• H01F38/14

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title

• B23Q15/00

  Automatic control or regulation of feed movement, cutting velocity or position of tool or work · CPC title

• Y02T90/14

  Plug-in electric vehicles · CPC title