1. A method of modifying an actuator for a fluid regulator, the actuator comprising an actuator housing, a diaphragm, a linkage, and a vent opening formed in the actuator housing, the diaphragm disposed in the actuator housing and separating the actuator housing into a first chamber and a second chamber, the linkage operatively connected to the diaphragm and arranged to be operatively connected to a valve stem, the first chamber hydraulically connected to a fluid outlet of a regulator body to sense a fluid pressure at the fluid outlet, and the vent defining an air exhaust path out of the second chamber to surrounding ambient atmosphere, wherein the method comprises steps of:
providing a damper comprising a ball check valve; and
operatively securing the damper to the vent so as to control flow of air exhausted though the vent, wherein the ball check valve is arranged to allow air to exhaust from the second chamber through the vent when air pressure within the chamber exceeds a set point pressure and to prevent air from entering the second chamber through the vent.
2. The method of claim 1, wherein the step of operatively securing includes securing the damper in the vent.
3. The method of claim 2, wherein the damper further comprises a sleeve, and the ball check valve is disposed in the sleeve, the step of operatively securing further comprising the step of inserting the sleeve into the vent.
4. The method of claim 3, wherein the step of operatively securing comprises releasably coupling the sleeve to the vent.
5. The method of claim 4, wherein the step of operatively securing comprises threadedely engaging the sleeve to the vent.
6. The method of claim 1, wherein the damper comprises:
a sleeve including a bore;
a valve seat disposed within the bore;
a ball shiftably disposed in the bore, the ball arranged to shift from a closed position seated against the valve seat to an open position disposed away from the valve seat; and
a spring positioned to bias the ball toward the valve seat, the spring arranged to allow the ball to shift to the open position when fluid pressure within the selected chamber exceeds a threshold pressure to thereby vent fluid pressure from the selected chamber; and
wherein operatively securing the damper to the vent comprises operatively coupling the sleeve to the vent opening.
7. The method of claim 6, wherein the sleeve defines an inlet, an outlet, and the bore extends from the inlet to the outlet, wherein a spring seat is disposed in the bore spaced apart from the valve seat toward the outlet, and the spring is disposed in the bore between the ball and the spring seat.
8. The method of claim 7, wherein the valve seat comprises a body that can be removably coupled to the sleeve, and wherein providing a damper comprises removably coupling the body of the valve seat to the sleeve.
9. The method of claim 7, wherein the spring seat comprises a body that can be removably coupled to the sleeve, and wherein providing a damper comprises removably coupling the body of the spring seat to the sleeve.
10. The method of claim 7, wherein the spring comprises a coil spring having a first end and a second end, the first end engaging the ball, and the second end engaging the spring seat.
11. The method of claim 7, further comprising a protective cover operatively covering the outlet.
12. The method of claim 1, further comprising:
disposing a stabilizer valve in the vent.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of estimating a distance between a mobile node and a base station, said method comprising:
providing a display on the mobile node;
providing a time of flight subsystem including circuitry incorporated in the mobile node and the base station and generating a time of flight distance signal by periodically transmitting a time of flight signal between the mobile node and the base station and measuring the time taken for transmission of the time of flight signal therebetween;
providing an accelerometer on the mobile node and generating an accelerometer signal therewith;
initializing the value of a distance estimate signal based on the time of flight distance signal;
detecting a human step based on variances in the accelerometer signal;
changing the value of the distance estimate signal by a predetermined quantum only upon detection of a human step, wherein the value of the distance estimate signal is increased by the predetermined quantum responsive to the time of flight distance signal being greater than the distance estimate signal and wherein the value is decreased by the predetermined quantum responsive to the time of flight distance signal being less than the distance estimate signal; and
periodically displaying the value of the distance estimate signal on the display.
2. A method according to claim 1, including passing a raw time of flight distance signal generated by the time of flight subsystem through a smoothing filter to thereby generate a smoothed time of flight distance signal utilized by said changing step.
3. A method according to claim 2, wherein the smoothing filter is a digital biased median filter that is biased low.
4. A method according to claim 2, including passing a raw accelerometer signal generated by the accelerometer through a smoothing filter to thereby generate a smoothed accelerometer signal utilized by said detecting step.
5. A method according to claim 4, wherein the smoothing filter comprises a digital median filter.
6. A method according to claim 4, wherein whether the smoothed time of flight distance signal is greater than or less than the distance estimate signal is determined based on the value of smoothed time of flight distance signal at the substantially the same instant in time when a human step is detected.
7. A method according to claim 4, wherein whether the smoothed time of flight distance signal is greater than or less than the distance estimate signal is determined based on an average of the smoothed time of flight distance signal as generated over a predetermined period of time before the detection of the human step.
8. A method according to claim 4, wherein detecting a human step includes examining the smoothed accelerometer signal for the occurrence of two serial local peaks, each of which exceeds a predetermined amplitude, within a predetermined range of time periods indicative of human gait.
9. A method according to claim 8, wherein detecting a human step further includes examining the smoothed accelerometer signal for a slope within a predetermined range of slopes indicative of human gait.
10. A method according to claim 1, wherein the value of the distance estimate signal is changed by a different predetermined quantum depending on whether the distance estimate signal is being increased or decreased, and wherein the predetermined quantum by which the distance estimate signal is increased is lower than the predetermined quantum by which the distance estimate signal is decreased.
11. A system that provides an estimate of the distance between a mobile node and a base station, said system comprising:
a display disposed on the mobile node;
a time of flight subsystem including circuitry incorporated in the mobile node and the base station for generating a time of flight signal between the mobile node and the base station, measuring the time taken for transmission of the time of flight signal, and generating a time of flight distance signal based on the measured time;
an accelerometer, mounted in the mobile node, for generating an accelerometer signal;
a distance filter for generating the distance estimate, the distance filter configured to (i) initialize the value of a distance estimate signal based on the time of flight distance signal, (ii) detect a human step based on variances in the accelerometer signal, and (iii) change the value of the distance estimate signal by a predetermined quantum only upon detection of said human step, wherein the value of the distance estimate signal is increased by the predetermined quantum responsive to the time of flight distance signal being greater than the distance estimate signal and wherein the value is decreased by the predetermined quantum responsive to the time of flight distance signal being less than the distance estimate signal; and
wherein said system is operable to periodically display the value of the distance estimate signal on the display.
12. A system according to claim 11, including a smoothing filter, wherein the smoothing filter receives a raw time of flight distance signal generated by the time of flight subsystem, and generates a smoothed time of flight distance signal that is utilized in determining the change in the distance estimate signal.
13. A system according to claim 12, wherein the smoothing filter comprises a digital biased median filter that is biased low.
14. A system according to claim 12, including a smoothing filter, wherein the smoothing filter receives a raw accelerometer signal generated by the accelerometer and generates a smoothed accelerometer signal utilized in the detection of the human step.
15. A system according to claim 14, wherein the smoothing filter comprises a digital median filter.
16. A system according to claim 14, wherein whether the smoothed time of flight distance signal is greater than or less than the distance estimate signal is determined based on the value of smoothed time of flight distance signal at the substantially the same instant in time when a human step is detected.
17. A system according to claim 14, wherein whether the smoothed time of flight distance signal is greater than or less than the distance estimate signal is determined based on an average of the smoothed time of flight distance signal as generated over a predetermined period of time before the detection of the human step.
18. A system according to claim 14, wherein the distance filter detects a human step by examining the smoothed accelerometer signal for the occurrence of two serial local peaks, each of which exceeds a predetermined amplitude, within a predetermined range of time periods indicative of human gait.
19. A system according to claim 18, wherein the distance filter detects a human step by examining the smoothed accelerometer signal for a slope within a predetermined range of slopes indicative of human gait.
20. A system according to claim 11, wherein the value of the distance estimate signal is changed by a different predetermined quantum depending on whether the distance estimate signal is being increased or decreased, and wherein the predetermined quantum by which the distance estimate signal is increased is lower than the predetermined quantum by which the distance estimate signal is decreased.
21. A method of estimating a distance between a mobile node and a base station, said method comprising:
providing a display on the mobile node;
providing a time of flight subsystem including circuitry incorporated in the mobile node and the base station and generating a time of flight distance signal by periodically transmitting a time of flight signal between the mobile control node and the base station and measuring the time taken for transmission of the time of flight signal therebetween;
providing a radio signal strength subsystem including circuitry incorporated in the mobile node and the base station and generating an SSI distance signal based on a strength of a radio signal received by one of the mobile node and the base station;
providing an accelerometer on the mobile node and generating an accelerometer signal therewith;
fusing the SSI distance signal and the time of flight distance signal to generate a fused distance signal;
initializing the value of a distance estimate signal based on the fused distance signal;
detecting a human step based on variances in the accelerometer signal;
changing the value of the distance estimate signal by a predetermined quantum only upon detection of a human step, wherein the value of the distance estimate signal is increased by the predetermined quantum responsive to the fused distance signal being greater than the distance estimate signal and wherein the value is decreased by the predetermined quantum responsive to the fused distance signal being less than the distance estimate signal; and
periodically displaying the value of the distance estimate signal on the display.