HVAC Control in the New Millennium.pdf - HVAC.Amickracing

HVAC Control in the New Millenniumplanted into the machine, without using complex equations.Temperature balancing can be done with the IF...THEN function infuzzy control (See Table 6-3).Table 6-3. Rules for Fuzzy Temperature Control————————————————————————————————Antecedent BlockConsequent BlockRule 1 If temperature is moderately Then reduce fuel moderatelylow and almost stillbut quicklyRule 2 If temperature is moderatelylow and falling slowlyRule 3 If temperature is moderatelylow and rising slowlyRule 4 If temperature is moderatelyhigh and almost stillRule 5 If temperature is moderatelyhigh and falling slowlyRule 6 If temperature is moderatelyhigh and rising slowlyThen increase fuel moderatelyand a little quicklyThen do not change fuel flowmuchThen decrease fuelmoderately but quicklyThen decrease fuelmoderately and alittle quicklyThen do not changefuel flow muchRule 7 If temperature is at setpoint Then do not change fueland almost stillflow much————————————————————————————————The antecedent blocks (IF... phrases describe the states that thespace can be in, and the consequent blocks (THEN... phrases) describehow the temperature should change in response to these states (SeeTable 6-4).Fuzzy expressions such as moderate, almost, and a little are used.If the condition is true, the measure of fulfillment of the statement isequal to 1.0, if the condition is false, the measure of fulfillment is 0.0. Avalue between 0.0 and 1.0 is possible for anything between true andfalse.©2001 by The Fairmont Press, Inc. All rights reserved.