Fluid flow measuring and proportional fluid flow control device
View Patent ↗Embodiments disclosed herein provide restrictive-flow flow measurement devices, valve improvements and signal control devices and processes that control the flow of liquids, including control processes for single-liquid calibration. In some embodiments, a valve can be adjusted by application of fuzzy logic which involves quantizing input variables into the degree to which a small set of logical values is true. In one embodiment, variables related to flow rate and change in flow rate over time can be compared to membership functions to generate fuzzy inputs, based upon which fuzzy outputs can be generated.
1. A device comprising a set of computer readable instructions stored on one or more computer readable memories and executable by one or more processors, said set of computer readable instructions comprising instructions executable to:
calculate a fluid flow rate; and
calculate an overall change in valve output based on fuzzy logic by:
comparing an error to a first set of membership functions to generate a first set of fuzzy inputs;
comparing a change in flow rate to a second set of membership functions to generate a second set of fuzzy inputs, wherein each fuzzy input from said first set of fuzzy inputs and said second set of fuzzy inputs is associated with an input degree of truth;
applying a set of rules to said first set of fuzzy inputs and said second set of fuzzy inputs to generate a set of fuzzy outputs, wherein each fuzzy output is associated with an output degree of truth;
associating each fuzzy output with a discrete change in valve output value; and
calculating said overall change in valve output based on output degree of truth of one or more of said fuzzy outputs and said discrete change in valve output value associated with each of said one or more fuzzy outputs.
2. The device of claim 1 , wherein said set of computer instructions further comprise instructions executable to drop one or more fuzzy outputs associated with particular one or more output degrees of truth.
3. The device of claim 1 , wherein said set of computer instructions further comprise instructions executable to base output degrees of truth on input degrees of truth.
4. The device of claim 1 , wherein an output degree of truth for a particular fuzzy output is equal to lowest input degree of truth for a particular set of fuzzy inputs upon which said particular fuzzy output is based.
5. The device of claim 1 , wherein said set of computer readable instructions further comprise instructions executable to generate a valve control signal based on said calculated overall change in valve output.
6. A device comprising a set of computer readable instructions stored on one or more computer readable memories and executable by one or more processors, said set of computer instructions comprising instructions executable to:
calculate a fluid flow rate;
compare a variable associated with a change in flow rate to a first set of membership functions to generate a first set of fuzzy inputs; and
compare a variable associated with a flow rate error to a second set of membership functions to generate a second set of fuzzy inputs;
wherein in each fuzzy input from said first set of fuzzy inputs and said second set of fuzzy inputs is a associated with an input degree of truth.
7. The device of claim 6 , wherein said set of instructions further comprise instructions executable to:
apply a set of rules to said fist set of fuzzy inputs and said second set of inputs to generate a set of fuzzy outputs, wherein each fuzzy output is associated with an output degree of truth.
8. The device of claim 7 , wherein said set of instructions further comprise instructions executable to:
associate each fuzzy output with a discrete change in valve output value; and
calculate an overall change in valve output based on output degree of truth of one or more of said fuzzy outputs and said discrete change in valve output value associated with each of said one or more fuzzy outputs.
9. A device comprising a set of computer readable instructions stored on one or more computer readable memories and executable by one or more processors, said set of computer readable instructions comprising instructions executable to:
compare a flow rate error to a first set of membership functions to generate a first set of fuzzy inputs;
compare a flow rate change over time to a second set of membership functions to generate a second set of fuzzy inputs, wherein each fuzzy input from said first set of fuzzy inputs and said second set of fuzzy inputs is associated with an input degree of truth;
apply a set of rules to said first set of fuzzy inputs and said second set of fuzzy inputs to generate a set of fuzzy outputs, wherein each fuzzy output is associated with an output degree of truth;
associate each fuzzy output with a discrete change in valve output value;
calculate an overall change in valve output based on said output degree of truth of one or more of said fuzzy outputs and said discrete change in valve output value associated with each of said one or more fuzzy outputs; and
generate a valve control signal based on said calculated overall change in valve output.
10. The device of claim 9 , wherein said set of computer instructions further comprise instructions executable to drop one or more fuzzy outputs associated with particular one or more output degrees of truth.
11. The device of claim 9 , wherein said set of computer instructions further comprise instructions executable to determine output degrees of truth based on input degrees of truth.
12. The device of claim 9 , wherein an output degree of truth for a particular fuzzy output is equal to lowest input degree of truth for a particular set of fuzzy inputs upon which said particular fuzzy output is based.