2. Underlying control systems

The underlying control systems can be generally represented as shown in figure 2 with :

• {u (t )} and {y (t )} respectively designate the input and output of the system to be controlled, in this case the digital-to-analog converter, actuator, process itself, sensor, anti-overlap filter and analog-to-digital converter;

• {v (t )} represents all disturbances affecting the operation of the system to be controlled, in particular load disturbances and measurement noise at the input and output of the system to be controlled;

• {y *(t )} designates the reference sequence that can be generated from the setpoint sequence {u*(t )} as follows: