Characteristic Parameter Estimation of AMB Supported Coupled Rotor System

In this article, a rotor–bearing–coupling system supported by Active Magnetic Bearings (AMBs) is numerically simulated to estimate the characteristic parameters of AMB, residual unbalance, and misalignment parameters. The system is modeled with two rigid massless rotors each having a rigid disc and an AMB at its mid-span, mounted on flexible bearings and connected together with a flexible coupling. Proportional–Differential–Integrator (PID) is used to control the controlling current in AMB. Lagrange’s equation is used to obtain the linear equations of motion (EOMs) of the system. The developed EOM is solved by the fourth order Runga–Kutta method to generate the displacement and current responses. The time domain responses are converted into frequency domain by using Fast Fourier Transform (FFT) and full spectrum analysis is carried out to estimate the characteristic parameters of rotor AMB system. The estimation of parameters is performed based on least squares approach in frequency domain. The proposed methodology is tested against different levels of measurement error and modelling error to check the robustness of the algorithm.