The Dynamic Stability Index Calculator for Agricultural Tractors Equipped with Front End Loader
To be published on November 21, 2019 by SAE International in United States
Event: NuGen Summit
The study aims to evaluate the lateral stability of tractor-front end loader system in consideration with difficult work conditions based on various loader bucket lifting heights from ground while driving a system on transversal slopes. In the proposed method the centre of gravity of tractor-front end loader system was calculated and analysed to evaluate the transversal overturning of the system. This overturning of the system was analysed by applying mathematical equations presented in past studies and compared with the newly developed prediction model for 3 test tractors of 25 HP. The excel spreadsheet comprised of mathematical equations used to calculate the Tractor Stability Index (TSI) on transverse slope with respect to loader bucket height and payload in dynamic condition. A criterion has been defined to categorize the Tractor Stability Index (TSI) poor to excellent on a scale of 0 to 4 where <0 being the very poor, 0-2 Poor, 2-4 Good and >4 being the excellent. It was observed that the centre of gravity of the system became lower after lowering the loader bucket closer to the ground. The system was found to be more unstable when the loader bucket is raised, and tractor is moving on the angle of transverse slopes. From the experimental study, the TSIs at a transverse slope of 15°, bucket lift height 1 m & payload 100 kg for Tractor-1, Tractor-2 & Tractor-3 were found 0.3, 1.2 & 1.3 respectively. For Tractor-1, Tractor-2 & Tractor-3 the maximum recommended bucket lifting height & transverse slope angle where system is workable were 1 m & 15°, 1.2 m & 16° and 1.3 m & 17° respectively. Also, it has been observed that lowering the loader bucket to minimum ground position will not help to avoid overturn on transverse slope in a great extent. Thus, study confirmed that the best strategy for stabilizing a tractor against overturn is to lower the tractor's centre of gravity and increase the tractor's wheel track width simultaneously.