Remote mobile fatigue monitoring system

HGL has worked with a major world-wide manufacturer of heavy plant machinery to develop a system for monitoring accumulated fatigue damage on vehicles. The system makes use of HGL's standard low-power, embedded Dragonfly acquisition system, together with a web application developed specifically to address this requirement.

The standard Dragonfly acquisition system features an on-board automotive-grade power supply, so that it can be safely powered by any DC input from 8 V to 30 V, even during operation of the vehicle ignition. The Dragonfly unit is sufficiently compact that it can be fitted to the vehicle without the operator needing to know that it is there.

To meet the customer requirement, the fatigue monitoring systems are fitted with GPRS modems so that they can dial out to the web server periodically. Custom firmware on the internal controller board provides real-time stress lifing calculations, building up a pattern of stress-strain cycles in a rainflow matrix.

The web application allows the customer to access data from the vehicle fleet, to download individual report files or to display graphs of accumulated damage over time. Damage is calculated using standard S-N curves, for user-selected classes of weld.

Plant Equipment for fatigue monitoring