System and method for a pressure signal linearization transfer function

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.