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;;;======================================================
;;; Automotive Expert System
;;;
;;; This expert system diagnoses some simple
;;; problems with a car.
;;;
;;; CLIPS Version 6.3 Example
;;;
;;; To execute, merely load, reset and run.
;;;======================================================
;;****************
;;* DEFFUNCTIONS *
;;****************
(deffunction ask-question (?question $?allowed-values)
(printout t ?question)
(bind ?answer (read))
(if (lexemep ?answer)
then (bind ?answer (lowcase ?answer)))
(while (not (member ?answer ?allowed-values)) do
(printout t ?question)
(bind ?answer (read))
(if (lexemep ?answer)
then (bind ?answer (lowcase ?answer))))
?answer)
(deffunction yes-or-no-p (?question)
(bind ?response (ask-question ?question yes no y n))
(if (or (eq ?response yes) (eq ?response y))
then yes
else no))
;;;***************
;;;* QUERY RULES *
;;;***************
(defrule determine-engine-state ""
(not (engine-starts ?))
(not (repair ?))
=>
(assert (engine-starts (yes-or-no-p "Does the engine start (yes/no)? "))))
(defrule determine-runs-normally ""
(engine-starts yes)
(not (repair ?))
=>
(assert (runs-normally (yes-or-no-p "Does the engine run normally (yes/no)? "))))
(defrule determine-rotation-state ""
(engine-starts no)
(not (repair ?))
=>
(assert (engine-rotates (yes-or-no-p "Does the engine rotate (yes/no)? "))))
(defrule determine-sluggishness ""
(runs-normally no)
(not (repair ?))
=>
(assert (engine-sluggish (yes-or-no-p "Is the engine sluggish (yes/no)? "))))
(defrule determine-misfiring ""
(runs-normally no)
(not (repair ?))
=>
(assert (engine-misfires (yes-or-no-p "Does the engine misfire (yes/no)? "))))
(defrule determine-knocking ""
(runs-normally no)
(not (repair ?))
=>
(assert (engine-knocks (yes-or-no-p "Does the engine knock (yes/no)? "))))
(defrule determine-low-output ""
(runs-normally no)
(not (repair ?))
=>
(assert (engine-output-low
(yes-or-no-p "Is the output of the engine low (yes/no)? "))))
(defrule determine-gas-level ""
(engine-starts no)
(engine-rotates yes)
(not (repair ?))
=>
(assert (tank-has-gas
(yes-or-no-p "Does the tank have any gas in it (yes/no)? "))))
(defrule determine-battery-state ""
(engine-rotates no)
(not (repair ?))
=>
(assert (battery-has-charge
(yes-or-no-p "Is the battery charged (yes/no)? "))))
(defrule determine-point-surface-state ""
(or (and (engine-starts no)
(engine-rotates yes))
(engine-output-low yes))
(not (repair ?))
=>
(assert (point-surface-state
(ask-question "What is the surface state of the points (normal/burned/contaminated)? "
normal burned contaminated))))
(defrule determine-conductivity-test ""
(engine-starts no)
(engine-rotates no)
(battery-has-charge yes)
(not (repair ?))
=>
(assert (conductivity-test-positive
(yes-or-no-p "Is the conductivity test for the ignition coil positive (yes/no)? "))))
;;;****************
;;;* REPAIR RULES *
;;;****************
(defrule normal-engine-state-conclusions ""
(runs-normally yes)
(not (repair ?))
=>
(assert (repair "No repair needed.")))
(defrule engine-sluggish ""
(engine-sluggish yes)
(not (repair ?))
=>
(assert (repair "Clean the fuel line.")))
(defrule engine-misfires ""
(engine-misfires yes)
(not (repair ?))
=>
(assert (repair "Point gap adjustment.")))
(defrule engine-knocks ""
(engine-knocks yes)
(not (repair ?))
=>
(assert (repair "Timing adjustment.")))
(defrule tank-out-of-gas ""
(tank-has-gas no)
(not (repair ?))
=>
(assert (repair "Add gas.")))
(defrule battery-dead ""
(battery-has-charge no)
(not (repair ?))
=>
(assert (repair "Charge the battery.")))
(defrule point-surface-state-burned ""
(point-surface-state burned)
(not (repair ?))
=>
(assert (repair "Replace the points.")))
(defrule point-surface-state-contaminated ""
(point-surface-state contaminated)
(not (repair ?))
=>
(assert (repair "Clean the points.")))
(defrule conductivity-test-positive-yes ""
(conductivity-test-positive yes)
(not (repair ?))
=>
(assert (repair "Repair the distributor lead wire.")))
(defrule conductivity-test-positive-no ""
(conductivity-test-positive no)
(not (repair ?))
=>
(assert (repair "Replace the ignition coil.")))
(defrule no-repairs ""
(declare (salience -10))
(not (repair ?))
=>
(assert (repair "Take your car to a mechanic.")))
;;;********************************
;;;* STARTUP AND CONCLUSION RULES *
;;;********************************
(defrule system-banner ""
(declare (salience 10))
=>
(printout t crlf crlf)
(printout t "The Engine Diagnosis Expert System")
(printout t crlf crlf))
(defrule print-repair ""
(declare (salience 10))
(repair ?item)
=>
(printout t crlf crlf)
(printout t "Suggested Repair:")
(printout t crlf crlf)
(format t " %s%n%n%n" ?item))
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