Order tracking method and system

Abstract

The present invention describes an order tracking system (200) and method (100) for tracking at least one order from mechanical and / or acoustic vibrations generated by a periodic excitation process of a physical system. The order tracking system (200) comprises a means for obtaining (212) a mechanical and / or acoustic vibration data of a physical system and a means for obtaining (214) system reference data. It further comprises a means for combining (224) the mechanical and / or acoustic vibration data with the system reference data and a means for applying (226) a digital FIR filter to at least the mechanical and / or acoustic vibration data for deriving based thereon at least one order.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention relates to methods and systems for studying vibrational and / or acoustic phenomena. More particularly, the present invention relates to methods and systems for tracking orders in the study or analysis of mechanical vibrations and / or noise of physical systems as well as to the application thereof.BACKGROUND OF THE INVENTION[0002]Sound and vibration phenomena often are analysed in order to optimise them, e.g. to reduce the amount of disturbance that is generated for a user or the environment, to make a product compliant with specifications or with regulations set or to identify sources of disturbance, to control a system, etc. A known way for sound and vibration analysis is making use of order tracking. Order tracking typically is applied to variable-speed systems generating sound or another mechanical vibration.[0003]Order tracking concerns the extraction of the complex envelope of order components from measured mechanical an...

AI Technical Summary

Benefits of technology

[0009]It is an object of embodiments of the present invention to provide good apparatus or methods for order tracking in the study of a noise and / or mechanical vibration of a physical system and methods and systems using them. It is an advantage of embodiments according to the present invention that an accurate order tracking technique is obtained. It is furthermore an advantage according to embodiments according to the present invention that a computational efficient order tracking technique is obtained. It is an advantage of embodiments according to the present invention that the technique is user friendly and can be tailored depending on the user's needs. The above objective is accomplished by a method and device according to the present invention.

[0010]The present invention relates to an order tracking system for tracking at least one order from mechanical and / or acoustic vibrations generated by a periodic excitation process of a physical system, the order tracking system comprising a means for obtaining mechanical and / or acoustic vibration data of a physical system, a means for obtaining system reference data characterizing the angular speed of the excitation process, a means for combining the mechanical and / or acoustic vibration data with the system reference data, and a means for applying a digital FIR filter to at least the mechanical and / or acoustic vibration data for deriving based thereon at least one order. The excitation process may be a stationary or variable speed excitation process. It is an advantage of embodiments according to the present invention that a high accuracy can be obtained. It is an advantage of embodiments according to the present invention that an efficient computational technique is obtained.

[0011]It is an advantage of embodiments according to the present invention that the FIR low-pass filter can be a sharp filter. It is an advantage of embodiments according to the present invention that the user only needs to specify the order resolution and attenuation of the filter. In other words, it is an advantage of embodiments according to the present invention that it provides a user-friendly technique for performing order tracking. It is an advantage of embodiments according to the present invention that, in contrast to the hard-to-understand parameters used in the Vold-Kalman approach, such as e.g. the HCF weighing factor, the resolution and attenuation parameters of the FIR filter are understandable and have a clear influence on the result.

Problems solved by technology

The limitations of these techniques are many and can be significant.

The two largest limitations are limited order resolution at lower rotational speeds and slow sweep rates.

The weakness of the DC-estimation approach is the assumption that the order Xk(ρ(α)) must be constant over the observation interval.

However, this assumption is only true at constant rotational speed.

However, this makes the Vold-Kalman approach computationally very heavy and explains its off-line character and use.

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