An identification method for multi-mass-systems in speed-sensorless operation

Identification procedures for multi-mass-systems are a key factor during the commissioning of the plant to gain the mechanical parameters such as inertias or stiffness of the shafts. Only with the knowledge of these values the controllers of the drive can be parameterized in the correct manner to achieve the desired behavior of the plant. Further, with respect to cost reduction and improvement of reliability, speed-sensorless driven plants have become subject of investigation in academia and industry. The present paper proposes an identification procedure for a two-mass-system controlled with the estimated speed value of a Luenberger observer structure. For identification purposes, the plant is excited with Pseudo-Random-Binary-Signal and the system response is measured in the calculated speed signal. A signal processing procedure based on the Welch-method yields the frequency response of the system. Though the resonant frequency of the plant is clearly identified, in speed-sensorless operation the presented identification procedure implies certain restrictions and particularities that will be presented in the following chapters.