Nonlinear Feedback Control Based on Positive Invariance for a Nutrient Removal Biological Plant
نویسندگان
چکیده
Activated sludge wastewater treatment processes are difficult to be controlled because of their complex and nonlinear behavior; however, the control of the dissolved oxygen and nitrogen levels in the reactors plays an important role in the operation of the facility. For this reason a new approach is proposed in this work. The paper describes the theory and applications of a nonlinear control technique, i.e., the so-called nonlinear feedback control. The control law consists of a linear feedback part which is designed using the positive invariance concept technique and a nonlinear feedback part without any switching elements. The control approach structure is combined with a state space estimation algorithm, for the on-line reconstruction of unmeasured biological states of the bioprocess. The efficiency of both the control and estimation is demonstrated via computer simulations.
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