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LINEAR CONTROL SYSTEMS. Ali Karimpour Assistant Professor Ferdowsi University of Mashhad. Topics to be covered include : Nyquist stability criteria. Lecture 24. Nyquist stability criteria. Mapping. نگاشت. c'. d. c. 4. 2. a. a'. d'. b. b'. Mapping. نگاشت.
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LINEAR CONTROL SYSTEMS Ali Karimpour Assistant Professor Ferdowsi University of Mashhad
Topics to be covered include: Nyquist stability criteria. Lecture 24 Nyquist stability criteria.
Mapping نگاشت c' d c 4 2 a a' d' b b'
Mapping نگاشت s=0.5 0.2 -2 1 4 4
Mapping نگاشت r=0.5 1 -2 5 5
r=0.5 Mapping نگاشت -2 -5 1 7 6 6
Mapping نگاشت r=2.5 1 -2 7
Nyquist fundamental 1+kf(s)=0 : تعداد صفرهای RHP، 1+kf(s) Nyquist path :تعداد قطبهای RHP، 1+kf(s)
Nyquist fundamental Nyquist path 9
Nyquist fundamental Nyquist path Nyquist plot 10
Example 1: Check the stability of the following system by Nyquist method. + - -1 مثال 1: پایداری سیستم را توسط روش نایکوئیست بررسی کنید. 11
+ - -1 Example 1: Check the stability of the following system by Nyquist method. مثال 1: پایداری سیستم را توسط روش نایکوئیست بررسی کنید. 12
Nyquist fundamental Nyquist path Nyquist plot 13
مطالعه بیشتر More study + - -1 14
+ - -1 Example 2: Check the stability of following system by Nyquist method. مثال 2: پایداری سیستم را توسط روش نایکوئیست بررسی کنید. Very important Very important 15
Example 2: Check the stability of following system by Nyquist method. + - -1 Very important پایداری سیستم را توسط روش نایکوئیست بررسی کنید. How to calculate? 16
+ - -1 Example 2: Check the stability of following system by Nyquist method. پایداری سیستم را توسط روش نایکوئیست بررسی کنید. 17
+ - -1 Example 2: Check the stability of following system by Nyquist method. پایداری سیستم را توسط روش نایکوئیست بررسی کنید. 18
+ - -1 مطالعه بیشتر More study 19
+ - ٍExample 3: Check the stability of following system from the given Nyquist plot. مثال 3: پایداری سیستم را با توجه به منحنی نایکوئیست داده شده بررسی کنید. d(s) is a polynomial. System is unstable( 1 RHP zero) System is stable System is unstable( 2 RHP zero) System is unstable( 1 RHP zero)
+ - ٍExample 3: Check the stability of following system from the given Nyquist plot. مثال 3: پایداری سیستم را با توجه به منحنی نایکوئیست داده شده بررسی کنید. d(s) is a polynomial. System is unstable( 1 RHP zero) System is stable System is unstable( 2 RHP zero) System is unstable( 1 RHP zero)
+ K G(s) - R(s) C(s) + + - - Exercises تمرینها 1- Assume the following control system Find the value of k which make the system stable. Answer: k>1 2- Consider the following control system Find the value of k which make the system stable.
W=0 -1+j0 Exercises تمرینها 3- Polar plot of an open loop transfer function is shown in the following: Discuss about the stability of system. Answer: It is unstable and it has 4 unstable poles.
+ + - Exercises تمرینها 4- Discuss the stability of following system by Nyquist criteria..