Sizing up the situation

UK researchers are developing wireless miniature sensors which can detect wear and tear in machinery and predict when it might break down, thus reducing maintenance costs for industry and potentially improving safety.

The research — part of Dynamite, a European project involving 17 academic and industrial partners — is being carried out at

.

According to Dr Andrew Starr from the university's school of mechanical, aerospace and civil engineering, the entire project is linked by the concept of 'e-maintenance'. The sensors that his team are developing will form part of a suite of mobile monitoring technology that could be integrated into a variety of applications such as trains and agricultural vehicles, as well as in manufacturing and plant machinery.

One requirement of the sensors is that they must be self-powered. Starr said that this is because in conventional sensors the cable that carries the data also delivers power. 'It is very important that they are self-powered and so we need a clever strategy to generate sufficient power to deliver signals from the sensor — not continuously, but when they are required,' said Starr. Only very small amounts of power are required to run the system as researchers envisage they will only have to give occasional indications that the entire system is healthy rather than continuously stream unnecessary data.

These sporadic signs of health will continue until the system begins to degrade and then the sensors can begin to provide more detailed regular information.

As the sensor's power consumption is likely to be just in microwatts this could be sourced from vibrations (see also

), heat or even solar sources depending on the location of the sensor.

One of the key challenges will be developing a sensor that can measure a number of different parameters simultaneously and yet still be small enough to fit inside a machine.

'Making it the size of a cigarette packet is tricky and a matchbox is quite hard — but getting it down to the size of a thick postage stamp is really very difficult indeed,' said Starr.

Although the project is still in its infancy Starr expects that industrial partners will want the sensor to be able to monitor temperature, vibration and strain.

The software developed for the technology will need to process raw data and decide when an alert needs to be given, thus only supplying useful information regarding the machine's condition.

According to Starr there are a number of different applications in the transport sector. Although Fiat and Volvo are both partners in the project, he does not expect consumers will want to see the sensors in private vehicles as the market would not accept the extra cost.

A prototype should be developed within the next two years, but the researchers plan to wait before they commit to any one wireless standard, due to the fast-paced nature of the wireless industry.

'Condition monitoring is all about being a machine doctor,' said Starr. 'We want to know about a system's health and prevent technical problems before they happen, which will undoubtedly save time and money.'