Optimal actuator placement for controlling concentration profiles via process tomography

In this article, the optimal control of a chemical plant driven by an inverse problem is considered. More specifically, the problem of optimal actuator placement when controlling the concentration of a target substance in rapidly moving fluid is investigated. In this example, the actuators are injectors through which strong concentrate is injected into the fluid in order to obtain a desired concentration profile. The target substance is assumed to obey the stochastic convection-diffusion model and the process is monitored with electrical impedance tomography, the inverse problem of which is notoriously ill-posed even under stationary conditions. The associated reconstruction problem is formulated as a state estimation problem and is intertwined with the determination of the optimal time-varying controls. The model-based linear quadratic Gaussian control strategy is used in the determination of the control inputs. The controller settings affect both the overall controller capabilities per se and the perfor...