Manufacturing companies of washing machines(WMs) and dishwashers(DWs) need an automatic on-line inspection system to accurately monitor the mechanical characteristic of all their products. Present on-line inspection methods are scarcely effective because human operator dependent and not sufficiently reliable.
The main objective of this project is twofold:
a) to have diagnostics of mechanical defects by means of vibrations analysis, thus allowing the percentage of faulty products to decrease
b) to assure and improve the products quality as regards to the emitted noise/ vibrations level. This will happen because the knowledge of defects permits a continuous improvement of the production process.
WMs/DWs manufacturers agree that at present there are no means to reach the 'zero defects' goal. This project aims to approach this goal providing a prototype test station for house-hold appliance on-line inspection, capable to give a global evaluation of the vibroacustic quality of the machine under test, classifying it into two classes, product complying or not to specifications, according to a pass or fail quality control strategy.
The system is meant to provide a non-operator dependent evaluation of the machine vibroacoustic quality. It has to be reliable and effective in identifying faulty products and classifying the defects at the end of the production line, with a confidence level more than 99%. The maximum time required for every test should be less than 2 minutes in order to be acceptable by industry. The prototype test station will embody and rely on two main technological developments.
- A non-invasive optical sensor network for multipoint vibration measurement, based on integrated optics and fiber optics; the sensor network will measure vibrations on 4 to 8 points in a range of frequencies from 0 to 10 kHz, with peak velocity up to 0.2 m/s and resolution less than 1 micron. - A diagnostic expert system suited for operation on relatively complex mechanical systems. The diagnostic system will be capable to identify the typical mechanical defects of house-hold appliances by vibration analysis performed by means of intelligent techniques like fuzzy logic and neural networks.
Both these intermediate objectives are considered likely to lead to applications even to other fields such as automotive components and subassemblies industries.
For the project to be considerd succesfull its effectiveness in a noisy industrial production line will have to be proved.
Funding SchemeCSC - Cost-sharing contracts