# The Current Development Status of Agricultural Machinery
## 3. Chassis Travel Mechanism System of Agricultural Machinery
### Tracked Classis Systems  
Tracked classis exhibit superior terrain adaptability compared to conventional wheeled classis, primarily due to their larger contact area and reduced ground pressure. These characteristics effectively prevent vehicle slippage and subsidence in soft soil conditions while enabling the successful traversal of ditches and rocky obstacles, thereby minimizing operational downtime. Furthermore, the compact structure and lower center of gravity inherent in tracked chassis significantly reduce the risk of rollover, making them particularly suitable for lateral slope operations and uneven terrains commonly found in hilly regions. As a result, tracked chassis have been widely adopted in agricultural machinery and orchard management equipment. International enterprises and research institutions maintain a technological lead in the development of tracked chassis. Through continuous advancements in suspension system design, modular power configurations, and intelligent control technologies, their tracked tractors and combine harvesters demonstrate excellent ground traction and terrain adaptability. As illustrated in Figure 9a, John Deere's 9470 RX quad-track tractor incorporates an enhanced drivetrain and optimized chassis design that improves traction performance on moist or loose soils while reducing soil compaction. Similarly, as shown in Figure 9b, Case IH's Steiger series quad-track tractor features articulated steering and a continuously variable transmission (CVT), supported by a robust powertrain and high-strength steel frame, ensuring reliable performance during continuous heavy-load operations across diverse terrains. However, these large-scale and high-cost systems are not well suited for China's fragmented farmlands in hilly areas with steep topography. The development of tracked agricultural machinery in China is currently driven by a combination of technological advancements, market expansion, and supportive government policies. The domestic industry is primarily led by major enterprises such as Weichai Lovol, Dongfanghong, and Wode Agricultural Equipment, with additional contributions from innovative small and medium-sized enterprises (SMEs), including Liying Machinery and O'Power Dynamics. The product range covers a variety of machinery types, including tractors, rotary tillers, and transport vehicles, with ongoing technological improvements focusing on intelligent systems and eco-friendly innovations. Representative models of Chinese-developed tracked agricultural machinery are illustrated in Figure 10.  
Although tracked chassis technology has been widely implemented in modern agricultural machinery for plowing, planting, crop management, and harvesting operations, research on tracked agricultural systems remains active, particularly in the areas of chassis stability enhancement, soil compaction mitigation, and turning radius optimization. To address issues such as slippage, subsidence, and instability under wet conditions, [PERSON] et al. [104] introduced bionic principles into ground contact mechanisms by mimicking ostrich foot cavity structures to enhance mechanical interlocking with soil. Their track  
Figure 9: Quad-track tractors produced by U.S. Companies. (**a**) John Deere 9470 RX Tractor; (**b**) Case Steiger Series Tractors. soil thrust model and adhesion regression equation established a cross-scale analytical framework for wheel-soil friction modeling, revealing the interaction effects between soil moisture content and structural parameters. This work laid a theoretical foundation for improving traction performance on wet terrain. [PERSON] et al. [105] investigated the nonlinear dynamic interactions between rollers and rubber tracks. They found that high-frequency excitation increases dynamic spring constants while decreasing viscous damping coefficients, thereby confirming the necessity of incorporating nonlinear characteristics for accurate system dynamics analysis. [PERSON] et al.