Measurement of the Moment of Inertia for a Zero Turning Radius Mower

Abstract

<abstract> The moment of inertia (MI) is one of the important factors that affect the continuous roll behavior of a zero turning radius (ZTR) mower, and therefore, an accurate measurement or calculation of the MI is required. Previous research focused on the estimation techniques for vehicle MIs, and the measurements included a car, pickup truck, sport utility vehicle, and van, all of which have a small front/rear axle load distribution difference (i.e., the front/rear axle load distribution ratio ranges from 0.67 to 1). However, little research has investigated the MI of a ZTR mower, which has a large front/rear axle load distribution difference (i.e., the front/rear axle load distribution ratio is approximately 0.33); thus, the load distribution of a ZTR mower is more nonhomogeneous than that of the other vehicles. The primary objectives of this research were to investigate a mathematical model and a suitable MI measurement method for the ZTR mower, which is a difference in front/rear axle load distribution. A mathematical model was developed based on the principle of the pendulum method for measuring the MI in the x-, y-, and z-axes. Three ZTR mowers were used as test vehicles: a mower without a deck, a 1.2 m swath mower, and a 1.8 m swath mower. The test results were compared with the results obtained using the empirical formulas. Based on the comparison of the MIs, the results of the tests were within the range of 6.7% to 16.5% of the relative error from the values calculated using the empirical formulas. The test results indicated that the relative errors increased for mowers with a large difference in the front/rear axle load distribution.