Enhanced Optimal Symbolic Controller Synthesis: Application to a Boiler System

Abstract

Reliable and provably correct performance of control systems in the presence of various types of uncertainties and disturbances are essential objectives that require high integrity of the whole control system. Symbolic control is a candidate method for achieving these objectives which is capable of addressing both robustness and optimality of controller. However, several challenges may arise when the symbolic control method is applied in practice. These include the load of design computations, high memory requirements for design and implementation, and oscillations caused by discretization of inputs. The focus of this work is on treatment of the mentioned challenges during symbolic control synthesis for a boiler system as the central safety critical element in a broad range of industries. To reduce the load of design computations and the required memory while preserving the control precision, a two-stage control scheme is used in which symbolic models with different resolutions are employed. The input oscillations are also reduced by minimizing the changes in the input at the steady state. The performance of the synthesized controllers for several different designs are evaluated and compared during a simulation study. The results demonstrate the suitable performance of the symbolic control method when applied to a boiler system.