Experiment 5 AIM:Write A Program To Design Proportional, Proportional+Integral, Proportional+
Experiment 5 AIM:Write A Program To Design Proportional, Proportional+Integral, Proportional+
Experiment 5 AIM:Write A Program To Design Proportional, Proportional+Integral, Proportional+
SOFTWARE: MATLAB
PROCEDURE:
THEORY:
The transfer function of the PID controller looks like the following:
𝐾𝑖 𝐾𝐷 𝑠 2 + 𝐾𝑝 𝑠 + 𝐾𝑖
𝐾𝑝 + + 𝐾𝐷 𝑠 =
𝑠 𝑠
𝐾𝑝 = Proportional gain
𝐾𝑖 = Integral gain
𝐾𝐷 = Derivative gain
A proportional controller (Kp) will have the effect of reducing the rise time and will reduce
,but never eliminate, the steady-state error. An integral control (Ki) will have the effect of
eliminating the steady-state error, but it may make the transient response worse. A
derivative control (Kd) will have the effect of increasing the stability of the system,
reducing the overshoot, and improving the transient response. Effects of each of controllers
Kp, Kd, and Ki on a closed-loop system are summarized in the table shown below.
Note that these correlations may not be exactly accurate, because Kp, Ki, and Kd are
dependent of each other. In fact, changing one of these variables can change the effect of
the other two. For this reason, the table should only be used as a reference when you are
determining the values for Ki, Kp and Kd.
1
PROBLEM STATEMENT:
SOLUTION:
1. Proportional Controller:
𝐶(𝑠) 𝐾𝑝
= 2
𝑅(𝑠) 𝑠 + 10𝑠 + (20 + 𝐾𝑝 )
𝐶(𝑠) 300
= 2
𝑅(𝑠) 𝑠 + 10𝑠 + 320
The closed-loop transfer function of the given system with a PD controller is,
𝐶(𝑠) (𝑠𝐾𝑝 + 𝐾𝐼 )
= 3
𝑅(𝑠) 𝑠 + 10𝑠 2 + (20 + 𝐾𝑝 )𝑠 + 𝐾𝐼
The closed-loop transfer function of the given system with a PID controller is,
𝐶(𝑠) (𝐾𝐷 𝑠 2 + 𝐾𝑝 s + 𝐾𝐼 )
=
𝑅(𝑠) 𝑠 3 + (10+𝐾𝐷 )𝑠 2 + (20 + 𝐾𝑝 )𝑠 + 𝐾𝐼
3
With 𝐾𝑝 =350, 𝐾𝑑 =50 and 𝐾𝐼 =300,
𝐶(𝑠) (50𝑠 2 + 350s + 300)
= 3
𝑅(𝑠) 𝑠 + 60𝑠 2 + 370𝑠 + 300
CONCLUSION:
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