Evaluation of a commercial tractor safety monitoring system using a reverse engineering procedure

There is a high rate of work-related deaths in agriculture. In Italy, despite the obligatory installation of ROPS, fatal accidents involving tractors represent more than 40% of work-related deaths in agriculture. As death is often due to an overturn that the driver is incapable of predicting, driver assistance devices that can signal critical stability conditions have been studied and marketed to prevent accidents. These devices measure the working parameters of the tractor through sensors and elaborate the values using an algorithm that, taking into account the geometric characteristics of the tractor, provides a risk index based on models elaborated on a theoretical basis. This research aimed to verify one of these stability indexes in the field, using a commercial driver assistance device to monitor five tractors on the University of Bologna experimental farm. The setup of the device involved determining the coordinates of the center of gravity of the tractor and the implement mounted on the tractor. The analysis of the stability index, limited to events with a significant risk level, revealed a clear separation into two groups: events with high values of roll or pitch and low speeds, typical of a tractor when working, and events with low values of roll and pitch and high steering angle and forward speed, typical of travel on the road. The equation for calculating the critical speed when turning provided a significant contribution only for events that were typical of travel rather than field work, suggesting a diversified calculation approach according to the work phase.