Simulink Control Design™ - MathWorks

• You tune a control system in discrete time, but specify the gain profile in continuous
  time.


• The software modifies the asymptotes of the specified gain profile to improve numeric
  stability.

Continuous-Time Gain Profile for Discrete-Time Tuning

When you tune a discrete-time control system, you can specify frequency-dependent

tuning goals using discrete-time or continuous-time transfer functions. If you use a

continuous-time transfer function, the tuning algorithm discretizes the transfer function

before tuning. For instance, suppose that you specify a tuning goal as follows.

W = zpk([],[0 -150 -150],1125000);

Req = TuningGoal.MaxLoopGain('Xloc',W);

Suppose further that you use the tuning goal with systune to tune a discrete-time genss

model or slTuner interface. CL is the resulting tuned control system. To examine the

result, generate a tuning-goal plot.

viewGoal(Req,CL)

10 Control System Tuning