Download presentation

Presentation is loading. Please wait.

Published byAlexander Veil Modified over 2 years ago

1
Controller Design, Tuning

6
Must be stable. Provide good disturbance rejection---minimizing the effects of disturbance. Have good set-point tracking---Rapid, smooth responses to set-point changes Eliminate steady state error (zero offset) Avoid excessive control action. Must be robust( or insensitive) to process changes or model inaccuracies. Performance Criteria for Closed-loop systems

10
Methods for PID controller settings Classical methods: By reaction curve for a quarter decay ratio. By on-line cycling experiment for quarter decay ratio. By tuning rules using reaction curve and integral performance criteria.

12
Reaction Curve + - L R + + y Manual input Reaction curve

14
Classical methods

18
Relay Feedback

19
Modified Z-N settings for PID control controllerKcKc II DD Original Some overshoot No overshoot 0.6 K CU 0.33 K CU 0.2 K CU P U /2 P U /3 P U /8 P U /3 P U /2 controllerKcKc II DD P PI PID 0.5 K CU 0.45 K CU 0.6 K CU - P U /1.2 P U /2 - P U /8 Original Z-N settings for PID control

20
Controller type PI PID Tyler-Luyben’s Tuning Rule

21
Controller type PI PID Tyler-Luyben vs Z-N Tuning

25
Model characterization by reaction curve FOPDT (First Order Plus Dead Time) model –Fit 1

26
FOPDT (First Order Plus Dead Time) model –Fit 2 Model characterization by reaction curve

27
–FOPDT (First Order Plus Dead Time) model Fit 3

28
Model-based tuning rules for QDR

29
PID PI P Controller

30
controllerKcKc II DD P PI PID 0.5 K CU 0.45 K CU 0.6 K CU - P U /1.2 P U /2 - P U /8 controllerKcKc II DD PI PID 0.31 K CU 0.45 K CU 2.2P U - P U /6.3 Tyreus-Luyben’s Tuning (1997) Original Z-N Tuning (1942)

31
Controller type PI PID Tyreus-Luyben vs Z-N Tuning

33
G(s) Hagglund & Astrom’s PI Tuning Rules

34
Integral performance indices ISE : IAE: ITSE: ITAE:

35
Tuning rules for optimal integral performance measures Optimal tuning parameters are obtained via simulating a basic loop: The results apply specifically to set-point change or to disturbance change. G L =G P

36
Tuning rules for optimal integral performance measures The controller used is considered as of parallel and ideal form; Parameters are Dimensionless groups, such as : K c K p, R / , D /

37
Tuning rules for optimal integral performance measures The resulted tuning parameters are fitted into the following forms: The values of a and b are tabularized.

38
Model based tuning rules for optimal integral performance measures ---II Optimal tuning parameters are obtained via simulating a basic loop: The results apply specifically to set-point change or to disturbance change. G L =G P

39
Model based tuning rules for optimal integral performance measures ---III The resulted tuning parameters are fitted into the following forms: The values of a and b are tabularized.

45
Remarks on tuning rules with integral performance indices: Remember that conversions between a series PID controller and the parallel PID controller is necessary in order to use the tuning rules. The tuning parameters for disturbance change will be too aggressive when controlling a set-point change. The reverse happens in using set-point tuning parameters to disturbance regulation. No significance in difference among rules of different integral criteria.

46
Late methods Method of Synthesis Using IMC tuning (internal model control ) or other model based rules Using ATV test to characterize the process dynamics.

47
Direct synthesis method Specify desired closed-loop transfer function. Derive PID controller follows. Tuning parameters are directly synthesized. Exactly PID controller form applies to FOPDT or SOPDT processes.

49
G p (s)G c (s) - + G o (s) r y r y H(s) ry Specified to meet requirement

51
In order to be implementable, the reference H(s) should: not allow to be assigned as “1”, in other words, a system can not be perfect in control. contain all RHP zeros of G p (s) contain the dead time of G p (s)

53
Example Choose: = 3

54
G p (s) - + r y 1/G p (s)H(s) + + d + Structure evolution from direct synthesis

55
G p (s) - + r y H(s) 1/G p (s) + + G p (s) - + ry 1/G p (s) + + G p (s) - d d H(s)

56
G p (s) - + r y 1/G p (s)H(s) + + G p (s) - d - + r y 1/G p (s)H(s) + + G p (s) - d C(s)

57
G p (s) - + r y 1/G p (s)H(s) + + G p (s) -C(s) G p (s) - + r y C(s) G p (s) - Known as IMC d d

58
G p (s) - + r y C(s) G p (s) - d

62
Internal Model Control

63
Basic equations of IMC system When G p (s)=0,

64
Equivalent conventional controller from IMC system G p (s) - + r y C(s) G p (s) - d

65
Equivalent IMC controller from conventional loop G p (s) - + r y G c (s) G p (s) - -

66
Conclusion:

67
Thus, G c (s) in a conventional loop can be designed according to how G p (s) is factorized and what F(s) is assigned.

71
PID-series filter

74
ModifiModifi Modification of set-poin to reduce overshoot

75
Modification on the proportional part, i.e. :

77
Auto-tune by relay feedback

78
Use Z-N rules to compute PID settings

79
Controller type PI PID Tyler-Luyben vs Z-N Tuning

81
DS-d-PI Tuning Rules

82
DS-d-PID Tuning Rules

Similar presentations

Presentation is loading. Please wait....

OK

Nyquist Stability Criterion

Nyquist Stability Criterion

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on product marketing strategies Ppt on area and perimeter of rectangle Ppt on pin diode switch Ppt on 5g technology Download ppt on working of human eye Ppt on solar energy in hindi Ppt on earthquake resistant buildings in india Ppt on kingdom monera Ppt on different occupations pictures Ppt on power sharing in democracy sovereign