Research On The Prediction Of The Center Of Mass And The Influencing Factors Of Zero Turning Radius Mower Under Longitudinal Conditions

The Zero Turning Radius lawn mower has the problem of being prone to driving accidents caused by vertical overturning when working longitudinally.This paper studies the centroid position that determines its vertical tipping critical point and the factors that affect the centroid position.The external factors that affect the change of the position of the center of mass of the lawn mower may be the operating slope angle.The factors of the lawn mower itself include the mower cutter and the position of the liquid centroid of the fuel tank.Around these influencing factors,the following work was carried out.Based on various longitudinal working conditions of zero-turn radius mower when working on the slope,a parameterized prediction model of the center-of-mass position of the zero-turn radius mower was establelished.The calculation formula of the center of mass position of the mower was obtained when the height of the mower cutter,the driving slope angle,the amount of fuel in the fuel tank and the size of the fuel tank changed.Based on MATLAB,the source program was written with the centroid calculation formula as the control equation.The value of the center of mass position of the lawn mower under different input conditions was obtained.Four factors including the height of the mower cutter,the slope angle,the amount of oil,and the shape of the fuel tank were selected to design an orthogonal test that affects the position of the center of mass of the lawn mower.Based on the SPSS software,the orthogonal test results were analyzed.The sensitivity of the four factors to the centroid positions in the X and Z directions that mainly affect the critical angle ? was obtained.The test shows that the height of the mower cutter has a significant effect on the center of mass of the mower.The position of the center of mass moves forward and down by up to 8.96%and 7.58% in the X and Z directions respectively.The influence of the oil quantity is followed by 2.32% and 0.36%,while the slope angle and the shape of the tank are the weakest.According to the sensitivity analysis,the oil volume and slope angle have a significant effect on the center of mass of the liquid.Based on FLUENT,a tank simulation model was es Tablelished to simulate the complex situation of the tank liquid.The intersection of the tank liquid surface and the tank wall was verified.The data of the liquid centroid position under different oil volume and slope angle were also obtained.The simulation results showthat the amount of oil has a more significant effect on the center of mass of the tank than the slope angle.And that different centroid positions result in different liquid pressure on the tank wall,which affects the vertical tipping critical position of the lawn mower.Aiming at the result that the height of the mower cutter and the amount of oil in the fuel tank have the most significant influence on the centroid position of the mower,based on the mass response method,the centroid position parameters of the zero-turn radius mower under different heights of the mower cutter and the amount of oil were experimentally measured and error analysis was carried out.The effectiveness of the parameterized prediction model and sensitivity analysis of the mower centroid was verified.The experimental results show the changes of centroid positions in the X and Z directions that determine the vertical tipping critical position.As the amount of oil decreases,the centroid position of mower advances and drops by 2.50% and 1.19% respectively in the X and Z directions.Abrupt change occurs during the process from full oil to 2/3 oil and then gradually smoothes.As the height of the mower cutter increases,the center of mass of the mower moves forward and down by 8.11% and 7.36% respectively in the X and Z directions and the position basically changes linearly.