## 1 Introduction  
As aging and urbanization of the labor force accelerate in South Korea, mechanization is occurring rapidly in agriculture to address the agricultural workforce shortage [1, 2]. Various agricultural machines are being supplied, and the utilization of these machines has become widespread. Accordingly, the number of accidents caused by large agricultural machines is also increasing [3]. In 2012, a total of 211 accidents involving large agricultural machines occurred in South Korea; among them, 74.4% of the accidents are attributed to the lateral overturning of tractors [4]. As a result of analyzing 817 tractor accidents in Italy from 2002 to 2012, 25.1% of all accidents were caused by overturning and rollover of tractors [5]. In Japan, 71% of tractor-related accidents were caused by overturning and rollover [6]. Globally, over 50% of agricultural machine-related deaths are caused by lateral overturning and backward rollovers [7]. Consequently, the safety of agricultural machines has emerged as an issue, and various related studies are being conducted. [PERSON] and [PERSON] [8] presented a mathematical model to analyze the lateral overturning safety of large tractors. [PERSON] [9] presented a theoretical model to analyze the safety of rear-wheel-drive tractors with regards to Phase I rollover, and [PERSON] and [PERSON] [10]presented an extended model that can apply the previously mentioned model to four-wheel-drive tractors. [PERSON] et al. [11] presented slip as a factor that affects the lateral overturning safety of agricultural machines. They evaluated the safety of agricultural machines by developing a mathematical model that can determine the slip according to the slope angle and the coefficient of friction. [PERSON] et al. [12] derived the center of gravity of a tractor, which affects lateral overturning, using trigonometric functions and polar coordinate transformation. [PERSON] et al. [13] derived a static falling down sidelong angle of a three-wheeled power tiller by experimentation. [PERSON] and [PERSON] [14] developed a test device for evaluating the lateral overturning safety of large agricultural machines. [PERSON] [3] developed a simulation model for the lateral overturning occurred when an agricultural machine goes over an obstacle on a slope. The author also demonstrated the effectiveness of the developed model by performing a test using a 1/6 reduced-scale model. [PERSON] et al. [15] analyzed the lateral overturning safety of forestry forwarders according to the load, driving speed, and size of the obstacle, and estimated the critical speed at which lateral overturning occurs using dynamic simulation. [PERSON] et al. [16] developed a mathematical model to analyze the lateral overturning safety of agricultural machines located on slopes. The safety was analyzed according to the tractor's center of gravity, track width, and wheelbase. Furthermore, it was confirmed that the distance from the ground to the center of gravity had the greatest effect on lateral overturning safety. [PERSON] et al. [17] analyzed how the position of the center of gravity affects the lateral overturning safety for an asymmetrical tractor on which a harvester is mounted using a mathematical model. [PERSON] [18] constructed a virtual field in a simulation model and evaluated the effect of the tractor's mass redistribution between front and rear part owing to the change in the slope angle on the lateral overturning safety. In spite of the various theoretical and analytical studies, currently, the tractor's safety against lateral overturning is primarily evaluated by accredited testing, but such testing is time consuming and is expensive [19]. In case of simulation study, the results can be derived relatively easily, but it is difficult to accurately determine several physical properties required for the analysis. Introduction of some uncertain physical properties can lead to obtaining incorrect results [20]. Tests utilizing a miniature model can easily reproduce various situations.