The Influence of Deck Size on the Continuous Roll Behavior of Front-Drive Mowers

Abstract

This article presents modification and evaluation of the original continuous roll prediction model for front-drive mowers addressed by ASAE Standard S547. The original model described in this standard did not take into account the influence of the mower deck on rollover behavior and did not accurately predict the roll behavior of the mower. Lateral upset tests indicated that the mower deck influenced the rollover behavior. In addition, mower yaw and slide downhill were also observed. Therefore, the objective of this project was to modify the original model to include the mower deck size, mower yaw, and slide downhill. Using the revised model, the minimum ROPS height required for stopping the roll (critical ROPS height, or CRH) was determined. For a Deere F925 mower with regular ROPS, the CRH values predicted by the revised model were 2.50 m and 2.63 m with the deck in transport and working positions, respectively. The measured CRH values were 2.55 m and 2.67 m with the deck in transport and working positions, respectively. For inverted ROPS (the top of the ROPS tilts forward), the CRH predicted by the revised model with the deck in working position was 2.00 m. The measured CRH was 2.03 m. Field tests showed that the revised model results were very close to the field test results. The research findings show that deck size affects mower roll behavior; the mower's continuous roll tendency increases with the deck down. Due to the deck size, yaw was produced. The yaw changes the direction of the tipping axis and the height of center of gravity; therefore, it changes the roll behavior of the mower.