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Chapter 4 Modelling and Analysis for Process Control. Laplace Transform Definition. Input signals. (c) A unit impulse function (Dirac delta function). * Properties of the Laplace transform. Linearity Differentiation theorem. Zero initial values. Proof:. Integration theorem.
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Chapter 4Modelling and Analysis for Process Control • Laplace Transform • Definition
* Properties of the Laplace transform • Linearity • Differentiation theorem
Zero initial values Proof:
Translation theorem Proof:
Final value theorem • Initial value theorem
Complex translation theorem • Complex differentiation theorem
Example 4.1 Solution:
Example 4.2 (S1)
* Laplace transform procedure for differential equations Steps:
Exercises: a second-order differential equation (1) Laplace transform
Algebraic rearrangement Zero initials (2) Transfer function
(3) Laplace Inversion Where
Inversion method: Partial fractions expansion (pp.931) (i) Fraction of denominator and
(ii) Partial fractions where
(iii) Inversion *Repeated roots If r1=r2, the expansion is carried out as
where Inversion
*Repeated roots for m times If the expansion is carried out as
The step response: Example 4.3
(S3) Find coefficients s=0 Inversion
Example 4.4 (S1) Laplace transformation
(S2) Find coefficients s=0 s=1-j s=-1+j
(S3) Inversion and using the identity
Time delays: Consider Y(s)=Y1(s)e-st0 and
*Input-Output model and Transfer Function Ex.4.5 Adiabatic thermal process example