Apparatus and control method for feeder system for flowable material

Abstract

An apparatus for precisely controlling the feed rate of a feeder comprises: a motor operatively connected to the feeder to cause dispensing of the feeder when the motor is driven; a control circuit for supplying, when actuated, an AC voltage supply to the motor for driving of the motor; a counter disposed in communication with the control circuit for actuation thereof when an overflow signal is generated by the counter; a latch controller disposed in communication with the counter for enablement and disablement of the counter, the latch controller disabling the counter when the overflow signal is generated by the counter; a detector connected to the AC voltage supply for detecting when the AC voltage crosses over a median voltage thereof, the detector further disposed in communication with the latch controller for enablement of the counter when the median voltage is detected; and a fuzzy logic controller disposed in communication with the counter for generating an output to the counter that loads a determined count into the counter such that the counter generates an overflow signal within a time interval equal to a determined percentage of the half period of the AC voltage. The control circuit includes a pair of silicon control rectifiers disposed in parallel but reversed to one another resulting in each silicon control rectifier being able to supply the AC voltage to the motor during opposite half periods of a time period of the AC voltage if continuously actuated.

What is claimed is:  
     
         1 . A method of determining an appropriate change to a regulator that controls an outflow of a flowable material from a supply of the flowable material, comprising the steps of: 
 for a plurality of small time intervals during the outflow,    (a) calculating values representative of a rate of weight change of the supply of the flowable material based on weight measurements taken over said small time intervals;    (b) calculating values representative of a rate error based on said calculated values for the rate of weight change and based on a setpoint value for the rate of weight change;    (c) determining a value representative of an appropriate change to the regulator for maintaining the outflow at the setpoint value for the rate of weight change by applying fuzzy logic control to said calculated values representative of the rate error.    
     
     
         2 . The method of    claim 1   , further comprising calculating values representative of the change in the rate error based on said calculated values for the rate error, and applying fuzzy logic control to said calculated values representative of the change in the rate error.  
     
     
         3 . The method of    claim 1   , wherein said calculated values representative of a rate of weight change are average values.  
     
     
         4 . The method of    claim 1   , wherein said calculated values representative of a rate error are average values.  
     
     
         5 . The method of    claim 1   , further comprising weighing the supply of the flowable material during the plurality of small time intervals.  
     
     
         6 . The method of    claim 1   , further comprising determining the setpoint value by weighing the outflow of the flowable material from the supply of the flowable material.  
     
     
         7 . An apparatus for precisely controlling the driving of a motor, comprising: 
 (a) a control circuit operatively connected to the motor which provides a voltage supply to the motor for driving the motor when the control circuit is actuated;    (b) a timing circuit disposed in communication with said control circuit for actuating said control circuit after a determined time interval;    (c) a fuzzy logic controller disposed in communication with said timing circuit for determining said time interval; and    (d) a sensor disposed in communication with said fuzzy logic controller for measuring a rate of a supply of flowable material that is dispensed by the feeder.