Rotor Model Updating and Validation for an Active Magnetic Bearing Based High-Speed Machining Spindle

Abstract

This paper presents an experimentally driven model updating approach to address the dynamic inaccuracy of the nominal finite element (FE) rotor model of a machining spin dle supported on active magnetic bearings. Modeling error is minimized through the application of a numerical optimization algorithm to adjust appropriately selected FE model parameters. Minimizing the error of both resonance and antiresonance frequencies simultaneously accounts for rotor natural frequencies as well as for their mode shapes. Antiresonance frequencies, which are shown to heavily influence the model's dynamic properties, are commonly disregarded in structural modeling. Evaluation of the updated rotor model is performed through comparison of transfer functions measured at the cut ting tool plane, which are independent of the experimental transfer function data used in model updating procedures. Final model validation is carried out with successful imple mentation of robust controller, which substantiates the effectiveness of the model updat ing methodology for model correction.

Adaptive Control of Active Magnetic Bearing against Milling Dynamics

“…A proportional-integral-derivative (PID) controller and adaptive feed-forward cancellation are both adopted to stabilize the system and to compensate for the shaft run-out, respectively. Similar research of spindle control or chatter suppression with the aid of AMBs have also been published in the past five years [15][16][17].…”

Rotor Model Validation for an Active Magnetic Bearing Machining Spindle Using Mu-Synthesis Approach

“…Frequency responses were obtained by injecting sine sweeps into the levitating rotor with frequencies from 50 to 4000 Hz. The frequency responses for the nominal engineering model were compared to the experimentally extracted spindle responses, as documented by Wroblewski et al [8,9] and shown in Fig. 4.…”

High-Precision Cutting Tool Tracking With a Magnetic Bearing Spindle

“…[12]. The rotor is modeled by the finite element method, and the model is corrected numerically to the experimental data [13]. Figure 3 shows the Bode plots of the model and the experimental sine sweeps of the open-loop AMB rotor system.…”

“…These components are experimentally identified and validated [12,13]. The digital hardware and the inductive load of the AMB coils are included in the model of the power amplifiers, which is generated by performing a current signal sine sweep and fitting the data using the MATLAB system identification toolbox.…”