Simulink Control Design™ - MathWorks

The control system consists of two feedback loops. The inner loop (static output feedback)

provides stability augmentation and decoupling. The outer loop (PI controllers) provides

the desired setpoint tracking performance. The main control objectives are as follows:

• Track setpoint changes in theta, phi, and r with zero steady-state error, rise times of
  about 2 seconds, minimal overshoot, and minimal cross-coupling


• Limit the control bandwidth to guard against neglected high-frequency rotor dynamics
  and measurement noise


• Provide strong multivariable gain and phase margins (robustness to simultaneous
  gain/phase variations at the plant inputs and outputs, see diskmargin for details).

We use lowpass filters with cutoff at 40 rad/s to partially enforce the second objective.

Controller Tuning

You can jointly tune the inner and outer loops with the systune command. This command

only requires models of the plant and controller along with the desired bandwidth (which

is function of the desired response time). When the control system is modeled in Simulink,

you can use the slTuner interface to quickly set up the tuning task. Create an instance

of this interface with the list of blocks to be tuned.

ST0 = slTuner('rct_helico',{'PI1','PI2','PI3','SOF'});

13 Control System Tuning Examples