Control systems theory
Quantized control systems
Many industrial plants with high parametric uncertainties, both for constructive simplicity and/or in order to minimize the operation cost, usually become commanded with signals that may only assume a finite number of values.
A new technique for control design has been developed, with controllers characterized by control signals that may assume only a finite number of values, in order to force a SISO linear plant, subject to disturbances and parametric uncertainties, to track a given sufficiently regular reference trajectory.
The used approach is based on Lyapunov method and allows designing a control law, with prescribed levels of the control signal, which guarantees to follow the reference trajectory with prefixed values of the tracking error and of its derivatives until , where is the order of the plant, and in particular with preassigned values of the error and of its first derivative. The proposed control law is a generalization of the traditional relay control laws and of the sliding mode ones. It is quite robust, guarantees the convergence of the error in a prefixed time, generally has a relatively low switching frequency and it can be easily realized with a low cost microcontroller.
An embedded microprocessor system, which implements this new multi-values
control law, has been also realized. The realized prototypal controller has been
used for controlling a ceramic firing process.