Modern Control System EKT 308 Root Locus and PID controllers
Modern Control SystemEKT 308
Root Locus and PID controllers
PID Controllers
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PID Controllers (contd…)
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PID Controllers (contd…)Effect of a PID controller on the system
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PID Controllers (contd…)
Whereas the original system had two poles and no zeros, now the controller + system has three poles and two zeros. The root locus of the system is shown in figure 1 below.
Fig 1: root locus of system + controller
point,Breakaway e)
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PID Controllers (contd…)
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f) Angle of arrival at –z1 and –z2
The resulting PID+System has i) Percentage overshoot to step input , less than 2% ii) Steady state error for step input will be zero. iii) Settling time will be approax 1 sec. Lower settling time can be obtained by further adjusting Kd, Kp and KI
Frequency Response
By the term frequency response, we mean the steady-state response of a system to sinusoidal input. In frequency response methods, we vary the frequency of the input signal over a certain range and study the resulting response.
Outline for Bode plot