Parametric identification of the mathematical model of the micro-arc oxidation process

Abstract

Abstract An electrical equivalent circuit for the micro-arc oxidation process, taking into account the resistance of the electrolyte, the resistance of the coating of the part in the form of a parallel connection of a nonlinear active resistance and reactive capacitive resistance is presented. A mathematical model describing the behavior of the electric equivalent circuit of the micro-arc oxidation process is proposed. A procedure for determining the parameters of this model, including the construction of an oscillogram of the cell resistance change and its approximation; evaluation of resistance values and capacitance of the equivalent circuit of a galvanic cell has been developed. A method for calculating the dynamic characteristics of a model of the micro-arc oxidation process is proposed. Based on the identification results, its nonlinear Simulink model is developed. The adequacy of the model is verified by comparing the calculated and experimental voltages and currents of the galvanic cell. The maximum voltage simulation error with respect to Umax does not exceed 7%, the maximum current simulation error with respect to Imax does not exceed 10%. On the basis of experimental measurements of voltages and currents using the developed method of parametric identification, the dependences of the change in model parameters on the oxidation time are obtained. It has been established that the change in the coating resistance of a part depends on the thickness of the coating being built up. The remaining parameters of the equivalent circuit in the process of micro-arc oxidation change insignificantly.