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32                                     Introduction to Control Theory











                                                                       (2.3.2)


            The output equation then reduces to:
                                         y(t)=x 1(t)                   (2.3.3)


            A more compact formulation of (2.3.2) and (2.3.3) is given by


                                                                       (2.3.4)


            where


                                           (1)
                                 U(t)=[u(t) u (t)…u (n-1)  (t)] T

            and

                                      c=[1 0 0…0].                     (2.3.5)



            EXAMPLE 2.3–1: Nonlinear Systems
            We present 2 examples illustrating such concepts:
            1.  Consider the damped pendulum equation





            A state-space description is obtained by choosing x 1=y, x 2=y, leading to





            The time history of y(t) is shown in Figure 2.3.1.



            Copyright © 2004 by Marcel Dekker, Inc.
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