Linear Control System
Lecture 02
Outline
   1 Laplace Transform
          Laplace Transform
          Laplace Transform using MATLAB
          Theorems of the LaplaceTransform
          Partial-Fraction Expansion
          Differential Equation Solution using LaplaceTransform
Laplace Transform
       A mathematical tool used to solve ordinary differential
       equations.
       Laplace transform
                                           ∫∞         − st dt
                      L [f(t)] = F(s) =      0− f(t)e
       wher
       e                           s = σ +jω
       Inverse Laplace transform
                                         ∫ σ+j ∞
                     L −1 [F(s)]= 2πj  1                 st
                                         σ − j ∞ F (s)e ds
       The Laplace transform has following two features:
    1.Homogeneous and particular solution of ODE in one
       operation.
    2.Convert differential equation into an algebraic equation.
Laplace Transform
   Example: Find the Laplace transform of
                           f (t)= Ae −a t u(t)
   Example: Find the inverse Laplace transform of
                                          1
                             F(s)=     (s+3)   2
Outline
   1 Laplace Transform
          Laplace Transform
          Laplace Transform using MATLAB
          Theorems of the LaplaceTransform
          Partial-Fraction Expansion
          Differential Equation Solution using LaplaceTransform
Laplace Transform using MATLAB
Outline
   1 Laplace Transform
          Laplace Transform
          Laplace Transform using MATLAB
          Theorems of the LaplaceTransform
          Partial-Fraction Expansion
          Differential Equation Solution using LaplaceTransform
Theorems of the Laplace Transform
Outline
   1 Laplace Transform
          Laplace Transform
          Laplace Transform using MATLAB
          Theorems of the LaplaceTransform
          Partial-Fraction Expansion
          Differential Equation Solution using LaplaceTransform
Partial-Fraction Expansion
        Convert the function to a sum of simpler terms.
                                 F(s) = N(s)/D(s)
    Case 1. Roots of the denominator of F (s) are real and distinct. Case 2.
    Roots of the denominator of F (s) are real and repeated. Case 3. Roots
    of the denominator of F (s) are complex or imaginary
Outline
   1 Laplace Transform
          Laplace Transform
          Laplace Transform using MATLAB
          Theorems of the LaplaceTransform
          Partial-Fraction Expansion
          Differential Equation Solution using LaplaceTransform
Differential Equation Solution using Laplace Transform
   Example
                   d 2y
                          + 12dy + 32y = 32u(t)
                   dt2          dt