Force balance sensor and method therefor

Patent metadata

Field	Value
Publication number	US-10948365-B2
Application number	US-201815881237-A
Country	US
Kind code	B2
Filing date	Jan 26, 2018
Priority date	Jan 26, 2018
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

A force balance sensor including a mechanical strain amplification system including a sensor torsion member having a first end and a second end spaced from one another along a longitudinal axis of the sensor torsion member, at least one strain sensor coupled to the sensor torsion member between the first and second ends, a first torsional stiffening member coupled to the first end of the sensor torsion member, and a second torsional stiffening member coupled to the second end of the sensor torsion member, wherein the first torsional stiffening member and the second torsional stiffening member are coupled to a torque member.

First claim

What is claimed is:

1. A force balance sensor comprising:
a mechanical strain amplification system including
a sensor torsion member having a first end and a second end spaced from one another along a longitudinal axis of the sensor torsion member;
at least one strain sensor coupled to the sensor torsion member between the first and second ends;
a first torsional stiffening member coupled to the first end of the sensor torsion member; and
a second torsional stiffening member coupled to the second end of the sensor torsion member,

wherein:
the first torsional stiffening member and the second torsional stiffening member are coupled to a torque member so that both of the sensor torsion member and the torque member extend between and are couple to each the first torsional stiffening member and the second torsional stiffening member to effect torque transfer between the first torsional stiffening member and the second torsional stiffening member; and
each of the first torsional stiffening member and the second torsional stiffening member are configured to transfer torque from the torque member to a respective end of the sensor torsion member.

2. The force balance sensor of claim 1 , wherein torque is transferred from the torque member to the sensor torsion member by the first and second torsional stiffening members so as to mechanically increase strain sensed by the at least one strain sensor.

3. The force balance sensor of claim 1 , wherein the first and second torsional stiffening members increase a torsional stiffness of the torque member over a length of the mechanical strain amplification system, where twisting of the sensor torsion member disposed between the first and second torsional stiffening members, due to differential torsional forces applied at opposite ends of the torque member, is increased relative to twisting of the torque member over the length of the mechanical amplification system so as to mechanically increase strain sensed by the at least one strain sensor.

4. The force balance sensor of claim 1 , wherein each of the first torsional stiffening member and the second torsional stiffening member comprises:
a torsion bar having a first torsion bar end and a second torsion bar end separated from each other along a mechanical strain amplification system longitudinal axis; and
a first torsion bar end coupling member is disposed at the first torsion bar end and is configured to fixedly couple the first torsion bar end to the torque member;
wherein the second torsion bar end is configured to fixedly couple to the sensor torsion member.

5. The force balance sensor of claim 1 , wherein a material stiffness of each of the first torsional stiffening member and the second torsional stiffening member is higher than a material stiffness of both the sensor torsion member and the torque member.

6. The force balance sensor of claim 1 , further comprising at least one signal amplifier coupled to the at least one strain sensor.

7. The force balance sensor of claim 1 , further comprising a controller coupled to the at least one strain sensor, the controller is configured to determine a torsional displacement between the first end and the second end of the sensor torsion member based on sensor signals received from the at least one strain sensor.

8. The force balance sensor of claim 1 , wherein strain sensed by the at least one strain sensor is mechanically increased so that the strain sensed by the at least one strain sensor effects a signal from the at least one strain sensor that is above a noise threshold of the at least one strain sensor.

9. The force balance sensor of claim 1 , wherein the at least one strain sensor is coupled to the sensor torsion member so that the torque member forms an electromagnetic shield for the at least one strain sensor.

10. An aircraft comprising:
an airframe;
a control surface having a control surface frame pivotally coupled to the airframe with a torque member;
a first actuator is coupled to a first end of the torque member and is configured to pivot the control surface about a longitudinal axis of the torque member;
a second actuator is coupled to a second end of the torque member and is configured to pivot the control surface about the longitudinal axis;
a force balance sensor including
a mechanical strain amplification system including
a sensor torsion member having a first end and a second end spaced from one another along a longitudinal axis of the sensor torsion member,
at least one strain sensor coupled to the sensor torsion member between the first and second ends,
a first torsional stiffening member coupled to the first end of the sensor torsion member, and
a second torsional stiffening member coupled to the second end of the sensor torsion member,

wherein the first torsional stiffening member and the second torsional stiffening member are coupled to the torque member of the control surface.

11. The aircraft of claim 10 , wherein torque is transferred from the torque member to the sensor torsion member by the first and second torsional stiffening members so as to mechanically increase strain sensed by the at least one strain sensor.

12. The aircraft of claim 10 , wherein the first and second torsional stiffening members increase a torsional stiffness of the torque member over a length of the mechanical strain amplification system, where twisting of the sensor torsion member disposed between the first and second torsional stiffening members, due to differential torsional forces applied at opposite ends of the torque member, is increased relative to twisting of the torque member over the length of the mechanical amplification system so as to mechanically increase strain sensed by the at least one strain sensor.

13. The aircraft of claim 10 , wherein one or more of the sensor torsion member, the at least one strain sensor, the first torsional stiffening member, and the second torsional stiffening member are disposed within an interior or on an exterior of the torque member.

14. The aircraft of claim 10 , wherein each of the first torsional stiffening member and the second torsional stiffening member comprises:
a torsion bar having a first torsion bar end and a second torsion bar end separated from each other along the longitudinal axis of the sensor torsion member; and
a first torsion bar end coupling member is disposed at the first torsion bar end and is configured to fixedly couple the first torsion bar end to the torque member;
wherein the second torsion bar end is configured to fixedly couple to the sensor torsion member.

15. The aircraft of claim 10 , further comprising a controller coupled to the at least one strain sensor, the first actuator, and the second actuator, the controller is configured to:
determine a torsional displacement between the first end and the second end of the sensor torsion member based on sensor signals received from the at least one strain sensor; and
actuate one or more of the first actuator and the second actuator so that the twisting of the torque member is reduced and the sensor signals received from the at least one strain sensor are below a predetermined strain threshold.

16. The aircraft of claim 10 , wherein a torque member torsional stiffness is increased by the mechanical strain amplification system such that kt =k1 TM +k2 MSA , where kt is a total stiffness, k1 TM is a torque member stiffness, and k2 MSA is a stiffness of the mechanical strain amplification system.

17. The aircraft of claim 10 , further comprising:
a controller coupled to the at least one strain s

Assignees

• Boeing Co

Inventors

• Fox Michael Thomas
• Howell Eric Anton
• Roach Jeffrey Michael

Classifications

• G01L3/10

  involving electric or magnetic means for indicating · CPC title

• F15B2211/76

  Control of force or torque of the output member · CPC title

• F15B2211/7107

  the output members being mechanically linked · CPC title

• F15B2211/6336

  representing a state of the output member, e.g. position, speed or acceleration · CPC title

• G01L1/22

  using resistance strain gauges · CPC title