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;;;======================================================
;;; Automotive Expert System
;;;
;;; This expert system diagnoses some simple
;;; problems with a car.
;;;
;;; CLIPS Version 6.0 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 TRUE
else FALSE))
;;;**********************
;;;* ENGINE STATE RULES *
;;;**********************
(defrule normal-engine-state-conclusions ""
(declare (salience 10))
(working-state engine normal)
=>
(assert (repair "No repair needed."))
(assert (spark-state engine normal))
(assert (charge-state battery charged))
(assert (rotation-state engine rotates)))
(defrule unsatisfactory-engine-state-conclusions ""
(declare (salience 10))
(working-state engine unsatisfactory)
=>
(assert (charge-state battery charged))
(assert (rotation-state engine rotates)))
;;;***************
;;;* QUERY RULES *
;;;***************
(defrule determine-engine-state ""
(not (working-state engine ?))
(not (repair ?))
=>
(if (yes-or-no-p "Does the engine start (yes/no)? ")
then
(if (yes-or-no-p "Does the engine run normally (yes/no)? ")
then (assert (working-state engine normal))
else (assert (working-state engine unsatisfactory)))
else
(assert (working-state engine does-not-start))))
(defrule determine-rotation-state ""
(working-state engine does-not-start)
(not (rotation-state engine ?))
(not (repair ?))
=>
(if (yes-or-no-p "Does the engine rotate (yes/no)? ")
then
(assert (rotation-state engine rotates))
(assert (spark-state engine irregular-spark))
else
(assert (rotation-state engine does-not-rotate))
(assert (spark-state engine does-not-spark))))
(defrule determine-sluggishness ""
(working-state engine unsatisfactory)
(not (repair ?))
=>
(if (yes-or-no-p "Is the engine sluggish (yes/no)? ")
then (assert (repair "Clean the fuel line."))))
(defrule determine-misfiring ""
(working-state engine unsatisfactory)
(not (repair ?))
=>
(if (yes-or-no-p "Does the engine misfire (yes/no)? ")
then
(assert (repair "Point gap adjustment."))
(assert (spark-state engine irregular-spark))))
(defrule determine-knocking ""
(working-state engine unsatisfactory)
(not (repair ?))
=>
(if (yes-or-no-p "Does the engine knock (yes/no)? ")
then
(assert (repair "Timing adjustment."))))
(defrule determine-low-output ""
(working-state engine unsatisfactory)
(not (symptom engine low-output | not-low-output))
(not (repair ?))
=>
(if (yes-or-no-p "Is the output of the engine low (yes/no)? ")
then
(assert (symptom engine low-output))
else
(assert (symptom engine not-low-output))))
(defrule determine-gas-level ""
(working-state engine does-not-start)
(rotation-state engine rotates)
(not (repair ?))
=>
(if (not (yes-or-no-p "Does the tank have any gas in it (yes/no)? "))
then
(assert (repair "Add gas."))))
(defrule determine-battery-state ""
(rotation-state engine does-not-rotate)
(not (charge-state battery ?))
(not (repair ?))
=>
(if (yes-or-no-p "Is the battery charged (yes/no)? ")
then
(assert (charge-state battery charged))
else
(assert (repair "Charge the battery."))
(assert (charge-state battery dead))))
(defrule determine-point-surface-state ""
(or (and (working-state engine does-not-start)
(spark-state engine irregular-spark))
(symptom engine low-output))
(not (repair ?))
=>
(bind ?response
(ask-question "What is the surface state of the points (normal/burned/contaminated)? "
normal burned contaminated))
(if (eq ?response burned)
then
(assert (repair "Replace the points."))
else (if (eq ?response contaminated)
then (assert (repair "Clean the points.")))))
(defrule determine-conductivity-test ""
(working-state engine does-not-start)
(spark-state engine does-not-spark)
(charge-state battery charged)
(not (repair ?))
=>
(if (yes-or-no-p "Is the conductivity test for the ignition coil positive (yes/no)? ")
then
(assert (repair "Repair the distributor lead wire."))
else
(assert (repair "Replace the ignition coil."))))
(defrule no-repairs ""
(declare (salience -10))
(not (repair ?))
=>
(assert (repair "Take your car to a mechanic.")))
;;;****************************
;;;* STARTUP AND REPAIR 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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