5.9 SIMULINK Block Diagrams

SIMULINK is a natural environment for simulating closed-loop systems. It is recommended that you read Module 2, Introduction to SIMULINK, and reproduce the simulation results shown in Example 5.3. Generate the block diagram shown in Figure 5-18 and run the simulations for various controller proportional gains.

Recall that the closed-loop characteristic equation for Example 5.3 is

For k_c + 10, the MATLAB roots command can be used to find that the process is on the verge of instability, with the following values for the poles:

» roots([6 11 6 11])
ans =
  -1.8333
  -0.0000 + 1.0000i
  -0.0000 - 1.0000i

Notice that this analysis can be performed for several values of k_c, to construct Table 5-1.