CONTRIBUTION TO COMPENSATION FOR ENCODER GEOMETRY IN TIME INTERVAL TORSIONAL VIBRATION MEASUREMENT, SIMULATION AND EXPERIMENT

The time interval torsional vibration measurement technique, when used in low cost application together with gear or zebra tape encoder, can posses problems regarding non-uniform encoder segments geometry. Such a problem is usually manifested as high-level order content in frequency spectrum. To prevent mentioned problem an in-situ segment compensation method is proposed that creates a time reference array representative of actual angular segments geometry. To test the compensation method capability a simulation of torsional vibration are presented. The measurements were performed with a non-contact eddy current sensor and toothed wheel together with National Instruments PCI card at the sampling frequency of 10 kHz. Although no comparative tests with actual torsional vibration are given, the test results show good capabilities in high level order reduction at nearly constant running speed as well as at slowly changing running speed.