Method for fault detection and diagnosis of a rotary machine

• US 7,756,649 B2
• Filed: 08/28/2008
• Issued: 07/13/2010
• Est. Priority Date: 09/06/2007
• Status: Active Grant

• Current Assignee: Schenck Rotec GmbH (Durr AG)
• Original Assignee: Schenck Rotec GmbH (Durr AG)
• Inventors: Baehr, Joachim, Isermann, Rolf, Thelen, Dieter, Scheithe, Wolfgang
• Primary Examiner(s): Bui; Bryan
• Application Number:
  US12/229,950
• Publication Number:
  US 20090070050A1
• Time in Patent Office: 684 Days
• Field of Search: 702/56, 702/145
• US Class Current: 702/56
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence

Abstract

Modem rotary machine production requires built-in fault detection and diagnoses. The occurrence of faults, e.g. increased friction or loose bonds has to be detected as early as possible. Theses faults generate a nonlinear behavior. Therefore, a method for fault detection and diagnosis of a rotary machine is presented. Based on a rotor system model for the faulty and un-faulty case, subspace-based identification methods are used to compute singular values that are used as features for fault detection. The method is tested on an industrial rotor balancing machine.

Claims

1. A method for fault detection and diagnosis of a rotary machine comprising the following steps:

(a) rotating a rotor having an imbalance is rotated at a rotational speed to excite vibrations in the rotary machine due to an imbalance-caused force;

(b) measuring the rotational speed of the rotor and the vibrations in order to obtain input data quantitative for the rotational speed and the vibrations;

(c) forming an over-determined set of linear equations containing input and output data of a process of dynamic behavior of the rotary machine and unknown states of an assumed linear system for the process in an unfaulty state;

(d) extracting a number of states needed to accurately model the process in the unfaulty state by using mathematical operations to form a matrix having a rank equal to the assumed linear system; and

(e) using Singular Value Decomposition to compute singular values for obtaining an approximate indication of an order of the assumed linear system.

2. The method of claim 1, wherein the assumed linear system is formed as a linear state space system.

3. The method of claim 1, wherein a common MOESP method which uses a direct decomposition of aligned Block Hankel Matrices is used for order extraction of the number of states.

4. The method of claim 1, wherein the rotor is rotated with a sub-critical rotational speed.

5. A non-transitory computer readable medium having computer program instructions stored therein for causing a computer processor to perform the method of claim 1.