Passivity-Based Control
By the Passivity Theorem, the negative-feedback interconnection of two strictly passive
systems and is always stable.
Since the water tank system is passive, it makes sense to require that the controller be
strictly passive to guarantee closed-loop stability even when the plant model is
inaccurate.
Compensator Tuning using Control System Tuner
You can use the Control System Tuner app to tune the Controller block.
Step 1: Launch the Control System Tuner app from the Simulink model
Passive Control of Water Tank Level