US 8,299,409 B2Granted

Fuzzy logic-based control of microwave dryers

AssigneeCorning Incorporated

InventorsParasuram Padmanabhan Harihara, Brett Alan Terwilliger

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Abstract

A fuzzy logic-based system and method for controlling the drying of material by a microwave applicator. The system includes power output controller that controls applicator output power; material sensor that detects amount of material in the applicator; and fuzzy logic controller that receives a signal from the material sensor indicating the current amount of material in the applicator and adjusts the microwave output power based on the current amount of material in accordance with fuzzy logic rules by sending a control signal to the power output controller. A membership function divides the expected range for the amount of material into multiple regions, each region having precomputed regional output settings. The regional output settings of the regions that include the current amount of material are used to compute the control signal.

Claims14

Dependent claims

A system for controlling the drying of material by a microwave applicator, the system comprising:

a power output controller that controls the microwave output power of the applicator;
a material sensor that detects the amount of material in the applicator;
a fuzzy logic controller operatively connected to the material sensor and the power output controller,
wherein the fuzzy logic controller receives a sensor signal from the material sensor indicating the current amount of material in the applicator and adjusts the microwave output power based on the current amount of material in accordance with fuzzy logic rules by sending a control signal to the power output controller;
and wherein the fuzzy logic controller comprises:
a storage module for storing fuzzy logic information, including a minimum expected value and a maximum expected value for the amount of the material in the applicator which defines an expected range for the amount of material in the applicator,
a fuzzification module for storing a membership function that divides the expected range for the amount of material in the applicator into multiple regions, and for each region of the membership function storing a minimum regional value, a maximum regional value and precomputed regional output settings;
a selection module for selecting each region of the membership function including the current amount of material in the range between the minimum regional value and the maximum regional value for that region;
and
an output processor for computing the control signal based on the precomputed regional output settings of each of the regions of the membership function selected by the selection module, wherein the output processor comprises:
a preselected maximum output power value;
a defuzzification module for calculating a minimum output power value based on the precomputed regional output settings of each region of the membership function selected by the selection module;
and
a control signal processor calculator for calculating a set of polynomial coefficients based on the maximum output power value and the minimum output power value;
and for calculating the control signal based on the set of polynomial coefficients and the current amount of material in the applicator.

12 more elements

A fuzzy logic-based method of controlling the drying of material by a microwave applicator, the method comprising:

predetermining an expected minimum amount of material in the applicator and an expected maximum amount of material in the applicator which defines an expected range for the amount of material in the applicator;
dividing the expected range for the amount of the material in the applicator into multiple regions using a membership function;
precomputing regional output settings for each of the multiple regions of the membership function;
determining a current amount of material in the applicator;
determining the regions of the membership function that include the current amount of material in the applicator,
determining the current output settings based on the regional output settings for each of the regions of the membership function that include the current amount of material in the applicator;
computing a desired output power for the applicator based on the current output settings;
and
sending a control signal to the microwave controller of the applicator with the desired output power;
wherein the precomputing regional output settings for each of the multiple regions of the membership function step comprises:
precomputing a minimum power setpoint for the applicator for each region of the membership function based on the range of the amount of material covered by that region of the membership function;
precomputing a weight-to-power-difference function relating the weight of the material to a power difference needed to overcome a temperature difference due to a variation in the amount of the material in the microwave applicator;
and
determining the minimum power setpoint for the microwave applicator using the weight-to-power-difference function.

11 more elements

A fuzzy logic-based method of controlling the drying of material by a microwave applicator, the method comprising:

predetermining a maximum power setpoint for the applicator;
predetermining an expected minimum amount of material in the applicator and an expected maximum amount of material in the applicator, defining an expected range for the amount of material in the applicator;
creating a membership function dividing the expected range for the amount of the material in the applicator into a plurality of regions;
precomputing a regional minimum power setpoint for each of the plurality of regions of the membership function;
determining a current amount of material in the applicator;
determining the regions of the plurality of regions of the membership function that include the current amount of material in the applicator,
determining an output minimum power setpoint based on the regional minimum power setpoint for each of the plurality of regions of the membership function that include the current amount of material in the applicator;
computing a desired output power for the applicator based on the output minimum power setpoint and the maximum power setpoint;
and
sending a control signal to the microwave controller of the applicator with the desired output power;
wherein the computing a desired output power for the applicator step comprises:
computing a set of polynomial coefficients based on the output minimum power setpoint and the maximum power setpoint for the applicator;
and
calculating the desired output power of the applicator using the set of polynomial coefficients.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/609,646Filed 30 Oct 2009 · us provisional application
Priority: 31 Oct 2008
Published: US 2010/0108667 A16 May 2010
Granted: 30 Oct 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H05B 6/68
Circuits: for monitoring or control
H05B 6/78
Heating using microwaves: arrangements for continuous movement of material
H05B 2206/046
Heating using microwaves: microwave drying of wood, ink, food, ceramic, sintering of ceramic, clothes, hair
H05B
Electric heating