Sample Projects Page

PID Controller in CLIPS with Sample output data:

         CLIPS (V6.24 06/15/06)
CLIPS> (defglobal ?*pe* = 0 ?*integral* = 0 ?*error* = 0 ?*derivative* = 0
                  ?*op* = 0 ?*cycle* = 1 ?*sp* = 0 ?*ap* = 0 ?*wt* = 0 ?*newPos* = 0
                  ?*kp* = 0 ?*ki* = 0.0041666 ?*kd* = 0.01 ?*dt* = 30)
CLIPS> (deffunction pid_func (?sp ?ap)
(bind ?*sp* ?sp)
(bind ?*ap* ?ap)
(bind ?*pe* (- ?*sp* ?*ap*))
(bind ?*integral* 0)
(
while (> 1 0.9)
(bind ?*error* (- ?*sp* ?*ap*))
(bind ?*integral* (+ ?*integral* (* ?*error* ?*dt*)))
(bind ?*derivative* (/ (- ?*error* ?*pe*) ?*dt*))
(bind ?*op* (+ (+ (* ?*kp* ?*error*) (* ?*ki* ?*integral*)) (* ?*kd* ?*derivative*)))
(bind ?*pe* ?*error*)
(printout t "Current error value is: " ?*error* crlf)
(printout t "The output pid value is: " ?*op* crlf)
(bind ?*newPos* (/ ?*ap* ?*op*))
(printout t "The theoretical new error will be: " (- (abs ?*newPos*) ?*sp*) crlf)
(printout t "The theoretical new position will be: " (abs ?*newPos*) crlf)
(bind ?*cycle* (+ ?*cycle* 1))
(loop-for-count 3 do (printout t "Waiting time.." crlf))
(printout t "Going to cycle " ?*cycle* " , what is the actual valve position?" crlf)
(bind ?*ap* (read))
(printout t "===========================================" crlf)
))
CLIPS> (defrule pid_control
(start pid control)
=>
(printout t "Please enter the values for set-point, and actual-position: " crlf)
(pid_func (read) (read))
)
CLIPS> (assert (start pid control))
[Fact-0>
CLIPS> (run)
Please enter the values for set-point, and actual-position:
50
60
Current error value is: -10
The output pid value is: -1.24998
The theoretical new error will be: -1.99923198771181
The theoretical new position will be: 48.0007680122882
Waiting time..
Waiting time..
Waiting time..
Going to cycle 2 , what is the actual valve position?
48.0007680122
===========================================
Current error value is: 1.9992319878
The output pid value is: -0.996080255993042
The theoretical new error will be: -1.81034086018939
The theoretical new position will be: 48.1896591398106
Waiting time..
Waiting time..
Waiting time..
Going to cycle 3 , what is the actual valve position?
48.1896591398
===========================================
Current error value is: 1.8103408602
The output pid value is: -0.773853976854896
The theoretical new error will be: 12.2722898390376
The theoretical new position will be: 62.2722898390376
Waiting time..
Waiting time..
Waiting time..
Going to cycle 4 , what is the actual valve position?