Because according to the definition of transfer function: Laplace inverse transformation of unit impulse signal response, the unit step response is given, and the unit impulse response is obtained by derivation, and then the transfer function is obtained by Laplace inverse transformation: g (s) = 600/(s (2)+70s+600). ?

According to the transient component, the closed-loop poles are -60,-10, the denominator of the closed-loop transfer function is the characteristic formula of the second-order system: D(S)=(S+60)(S+ 10), and the steady-state component is 1. The magnification is known as 1, so the molecule is 6000.

In the negative feedback closed-loop system, it is assumed that the system has a single input r (s); Single output C(s), forward channel transfer function G(s) and negative feedback H(s). The closed-loop transfer function of this closed-loop system is G(s)/[ 1+ open-loop transfer function]. Open loop transfer function =G(s)*H(s).

Extended data:

The transfer function is determined by the essential characteristics of the system and has nothing to do with the input. Once you know the transfer function, you can calculate the output from the input or determine the input according to the required output.

If the transfer function of the system is known, we can study the output or response of the system according to various forms of input, so as to grasp the nature of the system.

If the transfer function of the system is unknown, the transfer function of the system can be determined by introducing the known input and studying the output of the system. Once the transfer function of the system is determined, the dynamic characteristics of the system can be completely described, which is different from the physical description of the system.

There are two common mathematical models for the commonly used continuous system represented by transfer function.

Baidu Encyclopedia-Closed-loop Transfer Function