diagnostic robot

“DIAGNOSTIC ROBOT” FOR VIBRO-ACOUSTIC MEASUREMENTS IN
ACCELERATED LIFE TESTS
Concettoni E.* , Cristalli C.* , Paone N.* * , Castellini P.* * , Serafini S.* * , Chiariotti P.* *
* Gruppo Loccioni - R&I Department
Via Fiume, 60030, Angeli di Rosora (AN), IT
** Università Politecnica delle Marche – Dipartimento di Meccanica
Via Brecce Bianche, 60131, Ancona, IT
E-mail of the corresponding author: [email protected]
SUMMARY: The present paper outlines the application scenario which motivates the development of an
autonomous mobile robot for mechanical diagnostics based on vibro-acoustic testing of electromechanical
systems undergoing Accelerated Life Testing (ALT). The application for ALT of Washing Machines (WM) is
demonstrated.
Usually in ALTs laboratories hundreds of samples are tested in parallel, and the instrumentation of a huge
number of stations with sophisticated noise and vibration test equipments would be too expensive. A mobile
robot platform equipped with sensors for noise and vibration diagnostics (14 microphones array, Scanning
Laser Doppler Vibrometer (SLDV), vision system and robot arm) opens the possibility to monitor in sequence all
appliances under test . Data from microphones have been processed with a beam forming algorithm in order to
increase the signal to noise ratio and to minimize the effects on the measurement of the appliances close the
one under test, while an algorithm based on images pattern matching has been developed to enhance the
repeatability of laser spot positioning on the products.
In this paper, the main issues and problems related to the implementation of a vibro - acoustic analysis system
on a mobile robot are discussed and its performances in terms of repeatability of measures, defects recognition
through signal features extraction (e.g. faulty motors, bearings, etc…), are presented and discussed with
reference to house-hold appliance testing. Tests have been carried out both in laboratory, with few WMs in
controlled operating conditions and in a real ALT area in a washing machine factory.
KEYWORDS: Household appliances, accelerated life test , mobile robot , vibro –acoustic analysis, beam
forming, scanning laser Doppler vibrometer