System and method for a pressure signal linearization transfer function

• US 9,086,189 B2
• Filed: 05/16/2012
• Issued: 07/21/2015
• Est. Priority Date: 05/16/2012
• Status: Active Grant

• Current Assignee: Leggett & Platt Canada Co. (Leggett & Platt Incorporated)
• Original Assignee: Leggett & Platt Canada Co. (Leggett & Platt Incorporated)
• Inventors: Zhao, Xiao Ming, Colja, Renato, Blendea, Horia
• Primary Examiner(s): Ali, Mohammad
• Assistant Examiner(s): Laughlin, Nathan
• Application Number:
  US13/473,070
• Publication Number:
  US 20130306161A1
• Time in Patent Office: 1,161 Days
• Field of Search: 700/14, 700/46, 700/281, 700/282, 700/283, 700/301
• US Class Current: 1/1
• CPC Class Codes: A47C 7/00 Parts, details, or accessories of chairs or stools attaching to floor A47B91/08
• CPC Class Codes: B60N 2/665 using inflatable bladders
• CPC Class Codes: F17D 3/00 Arrangements for supervising or controlling working operations
• CPC Class Codes: Y10T 137/0396 Involving pressure control

Abstract

A method for operating a pneumatic lumbar support between a deflated position and an inflated position. The method includes inflating a bladder of the pneumatic lumbar support; sensing a pressure within the bladder using a pressure sensor; producing an inflation output signal from the pressure sensor, wherein the inflation output signal is a function of time; and converting the inflation output signal using an inflation-deflation transfer function.

Claims

1. A method for operating a pneumatic lumbar support between a deflated position and an inflated position, comprising:

inflating a bladder of the pneumatic lumbar support;

sensing a pressure within the bladder using a pressure sensor;

producing an inflation output signal from the pressure sensor, wherein the inflation output signal is a function of time;

converting the inflation output signal using an inflation-deflation transfer function, wherein at least a portion of the inflation-deflation transfer function converts a non-linear portion of the inflation output signal to a linear function; and

adjusting displacement of the bladder based on the converted inflation output signal.

2. The method of claim 1, further comprising:

deflating the bladder of the pneumatic lumbar support;

sensing the pressure within the bladder using the pressure sensor;

producing a deflation output signal from the pressure sensor, wherein the deflation output signal is a function of time;

converting the deflation output signal using the inflation-deflation transfer function, wherein at least a portion of the inflation-deflation transfer function converts a non-linear portion of the deflation output signal to a linear function; and

adjusting displacement of the bladder based on the converted deflation output signal.

3. The method of claim 1, wherein,

from the deflated position to a first inflation separating point, the inflation-deflation transfer function comprises a linear function;

from the first inflation separating point to a second inflation separating point, the inflation-deflation transfer function comprises the inflation output signal of the pressure sensor; and

from the second inflation separating point to the inflated position, the inflation-deflation transfer function comprises a linear function.

4. The method of claim 2, wherein,

from the inflated position to a first deflation separating point, the inflation-deflation transfer function comprises a linear function;

from the first deflation separating point to a second deflation separating point, the inflation-deflation transfer function comprises the deflation output signal of the pressure sensor; and

from the second deflation separating point to the deflated position, the inflation-deflation transfer function comprises a linear function.

5. The method of claim 3, wherein, from the first inflation separating point to a second inflation separating point, the inflation-deflation transfer function equals the inflation output signal of the pressure sensor plus a shift factor.

6. The method of claim 4, wherein, from the first deflation separating point to a second deflation separating point, the inflation-deflation transfer function equals the deflation output signal of the pressure sensor plus a shift factor.

7. The method of claim 3, wherein the first inflation separating point comprises a point corresponding to a first tangent on a curve of the inflation output signal, wherein the first tangent has a first slope value.

8. The method of claim 7, wherein the second inflation separating point comprises a point corresponding to a second tangent on a curve of the inflation output signal, wherein the second tangent has a second slope value.

9. The method of claim 8, wherein the first slope value is approximately equal to the second slope value.

10. The method of claim 4, wherein the first deflation separating point comprises a point corresponding to a third tangent on a curve of the inflation output signal, wherein the third tangent has a third slope value.

11. The method of claim 10, wherein the second deflation separating point comprises a point corresponding to a fourth tangent on a curve of the inflation output signal, wherein the fourth tangent has a fourth slope value.

12. The method of claim 1, wherein the bladder is housed within a vehicle seat.

13. The method of claim 2, wherein the inflation-deflation transfer function is determined by

determining a flow rate transfer function using the pressure within the bladder to estimate a flow rate;

determining at least one of a linearized output pressure and a linearized displacement from the bladder pressure using the flow rate transfer function; and

adjusting the flow rate transfer function to produce the inflation-deflation transfer function.

14. The method of claim 13, wherein adjusting the flow rate transfer function comprises adjusting the flow rate transfer function to produce the inflation-deflation transfer function such that the inflation-deflation transfer function output is approximately the same during inflation and deflation when the pressure within the bladder is the same.

15. A system for operating a pneumatic lumbar support between a deflated position and an inflated position comprising:

a seat;

an inflatable bladder associated with the seat;

an inflation device for inflating and deflating the inflatable bladder;

a pressure sensor for measuring pressure within the inflatable bladder; and

a controller in communication with the inflation device and the pressure sensor, the controller configured to perform the method of claim 1.

16. A method for operating a pneumatic lumbar support between a deflated position and an inflated position, comprising:

inflating a bladder of the pneumatic lumbar support;

sensing a pressure within the bladder using a pressure sensor;

producing an inflation output signal from the pressure sensor, wherein the inflation output signal is a function of time;

converting the inflation output signal using an inflation-deflation transfer function; and

adjusting a rate of inflation based on the converted inflation output signal, wherein

from the deflated position to a first inflation separating point, the inflation-deflation transfer function comprises a linear function;

from the first inflation separating point to a second inflation separating point, the inflation-deflation transfer function comprises the inflation output signal of the pressure sensor; and

from the second inflation separating point to the inflated position, the inflation-deflation transfer function comprises a linear function.

17. The method of claim 16, further comprising:

deflating the bladder of the pneumatic lumbar support;

sensing the pressure within the bladder using the pressure sensor;

producing a deflation output signal from the pressure sensor, wherein the deflation output signal is a function of time;

converting the deflation output signal using the inflation-deflation transfer function; and

adjusting a rate of deflation based on the converted deflation output signal, wherein

from the inflated position to a first deflation separating point, the inflation-deflation transfer function comprises a linear function;

from the first deflation separating point to a second deflation separating point, the inflation-deflation transfer function comprises the deflation output signal of the pressure sensor; and

from the second deflation separating point to the deflated position, the inflation-deflation transfer function comprises a linear function.

18. A method for operating a pneumatic lumbar support between a deflated position and an inflated position, comprising:

inflating a bladder of the pneumatic lumbar support;

sensing a pressure within the bladder using a pressure sensor;

producing an inflation output signal from the pressure sensor, wherein the inflation output signal is a function of time;

converting the inflation output signal using an inflation-deflation transfer function;

adjusting a rate of inflation based on the converted inflation output signal, deflating the bladder of the pneumatic lumbar support;

sensing the pressure within the bladder using the pressure sensor;

producing a deflation output signal from the pressure sensor, wherein the deflation output signal is a function of time;

converting the deflation output signal using the inflation-deflation transfer function;

adjusting a rate of deflation based on the converted deflation output signal;

wherein the inflation-deflation transfer function is determined by determining a flow rate transfer function using the pressure within the bladder to estimate a flow rate;

determining at least one of a linearized output pressure and a linearized displacement from the bladder pressure using the flow rate transfer function; and

adjusting the flow rate transfer function to produce the inflation-deflation transfer function.

19. The method of claim 18, wherein adjusting the flow rate transfer function comprises adjusting the flow rate transfer function to produce the inflation-deflation transfer function such that the inflation-deflation transfer function output is approximately the same during inflation and deflation when the pressure within the bladder is the same.

20. The method of claim 18, wherein the bladder is housed within a vehicle seat.