Digital control systems control almost every piece of technology we use, from the thermostat in your fridge to oil refineries and self-driving cars. My answer to this Quora user’s question suggests an iterative process involving:

• setting objectives and goals
• modeling the plant
• designing the control structure
• testing and simulation studies
• testing on the real plant
• maintenance during operations

The important thing here is not to think of it as a linear workflow; you will jump back in the process and redo stuff several times. For some unknown reason, universities tend to focus only on the modeling and simulation study part. The world would be a more reliable place if designers were taught to think about the whole process and the whole lifecycle from the start instead of waiting for experience to sink in.