In China, the hilly and mountainous areas account for 34.62% of the total cultivated land and 34.20% of the total crop sown area, covering 54.2% of the population, while contributing only 30% to the national GDP. With the overall agricultural mechanization level below 50%, it is urgently needed to accelerate the development of agricultural mechanization in hilly and mountainous areas to build an agricultural powerhouse. Based on the agricultural tillage system zoning in China, this paper conducts a zoning of agricultural mechanization in hilly and mountainous areas, taking into account factors such as the distribution of hilly and mountainous areas. Based on the resource endowment conditions, economic and social conditions and industrial economic benefits, this paper summarizes the development status of agricultural mechanization, analyzes the special scenarios of agricultural machinery application from the aspects of cultivated land conditions, soil and agronomy, and analyzes the constraints and bottlenecks of agricultural mechanization development in combination with the factors of agricultural machinery research and development, manufacturing, promotion and application in hilly and mountainous areas of China. In the context of the application scenario in hilly and mountainous areas, ten key agricultural machinery general technology needs are proposed, such as compact and lightweight specialized engines, lightweight and anti-adhesion and anti-friction materials, and simplified machine structures. Ten applicable agricultural machinery equipment needs, such as efficient and low-cost tillage equipment in sticky soil, seeding equipment for grain, oil, sugar crops, and vegetables in mountainous areas for heavy and sticky soil in gentle slopes, and transplanting equipment for rape and vegetables in mountainous areas for heavy and sticky soil in gentle slopes, are also discussed. Drawing on the experience of agricultural mechanization in hilly and mountainous areas of Japan, Republic of Korea, etc., this paper puts forward a systematic approach to promoting agricultural mechanization in hilly and mountainous areas, focusing on the integration of good machines, good seeds, good methods, good farmland, and good systems, and the four-in-one approach of research, production, promotion, and use. This approach aims to promote the high-quality development of agricultural mechanization in hilly and mountainous areas.

In order to address the issues of large inclination angles and poor pass ability encountered by small-scale combine harvesters operating in hilly regions, a design and experimental study were conducted on an automatic lifting hydraulic system for the combine's chassis. This research developed the overall structure of the automatic lifting hydraulic system for the chassis, designed and selected key components such as hydraulic cylinders with built-in displacement sensors and directional proportional valves, and proposed methods for leveling and lifting the chassis by extending or retracting the hydraulic cylinders based on the transverse inclination angle. The study employed two leveling modes: automatic and manual, to level the chassis. The hydraulic system was simulated using AMEsim software, revealing stable pressure and flow within the hydraulic cylinders during direction reversing, along with smooth displacement velocity. A leveling control strategy centered on a PLC controller and PID control method was designed, which adjusted the length of the hydraulic cylinders to regulate the chassis's attitude and to conduct a static leveling experiment. Results indicated the proportional directional valve, when adjusted to a position between 20% and 45%, it can effectively regulate the velocity of both the extension and retraction movements of the hydraulic cylinders. The adjustment time increased with larger inclination angles, but the overall adjustment error remained below 0.5° within an inclination range of 7.7°, which can meet the requirements for transverse leveling of the combine harvester's chassis. This research introduced a hydraulic system and control method to realize leveling based on the transverse angle, providing a reference for the design of the chassis leveling hydraulic system for small-scale combine harvesters.

In response to the problems of poor speed stability and degraded spraying quality of 4WID high-clearance self-propelled electric sprayers caused by changes in external road gradients and lowered payloads resulted from internal liquid spraying under complex operating conditions, a fixed-speed cruise control algorithm with a layered control approach is proposed based on an analysis of the structure and longitudinal dynamic characteristics of 4WID high-clearance self-propelled electric sprayers. The control algorithm model receives the user-specified desired speed and inputs acceleration control signals to the longitudinal dynamic system model through algorithmic calculation to realize the tracking of the sprayer to the desired speed. The structure of the longitudinal dynamic system mainly includes five parts: the inverse longitudinal kinematic model, the acceleration-braking switching model, the torque allocation model, the motor model, and the longitudinal kinematic model. The inverse longitudinal kinematic and longitudinal kinematic models of the sprayer can be obtained by analyzing the force on the body of the sprayer under the condition of driving on a slope. Meanwhile, in order to establish a reasonable four-wheel torque allocation strategy, the analysis is conducted under the condition that the sprayer has both pitching and tilting motions of the body, and the slip rate of each driving wheel is used as the basis for allocation, ensuring the optimal torque moment of each wheel under different operating conditions and ensuring the balanced power of the sprayer. The speed cruise control adopts a layered control approach, which realizes the effective tracking of the speed of the spraying machine through the establishment of the upper PID control and the lower fuzzy PID control. By defining fuzzy control rules, the PID parameters of the lower layer controller are automatically adjusted to ensure the good adaptability of the speed cruise control system to various complex operating conditions. A control model is established using Matlab/Simulink, and the control system is simulated and analyzed. The experimental results show that the designed speed cruise control system can effectively control the speed of the sprayer under typical operating conditions. Specifically, the performance of the system is excellent under conditions of external disturbance and self-weight variation, with overshoot less than 2%, response time less than 0.2 s, and steady-state error approaching 0, verifying the accuracy of the control algorithm used.

Traditional angle sensors have problems such as insufficient accuracy and complex installation and debugging when measuring the deflection angle of tractor guide wheels, which hinder the high precision and stability requirements of tractor automatic navigation operations. Therefore, this paper aims to construct and validate a novel system based on the principles of Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS), which is capable of real-time calculation of dynamic angles of the tractor's steering wheel. First, a in-depth analysis of GNSS/INS fusion principles was conducted, and corresponding GNSS/INS data measurement bench tests were designed to obtain measurement values from angle sensors. Subsequently, three filtering algorithms, namely Kalman Filter (KF), Extended Kalman Filter (EKF), and Unscented Kalman Filter (UKF), were employed to filter the angle measurement values, evaluating metrics such as overshoot, response time, and stability, and the results showed that UKF performed best in this system. Second, steering and straight-line performance tests were conducted under different conditions (asphalt road and farmland) for tractor automatic navigation. In the steering performance tests, fixed measurements at different angles of 1°, 5°, and 15° were conducted, and the results showed that the response time of the two environments was the smallest at 1°, but both produced the largest overshoot. At the same time, an increase in angle demonstrated a significant reduction in steady-state error. In the straight-line automatic navigation performance tests, the maximum lateral deviations for asphalt road and farmland were 17.51 mm and 18.52 mm, respectively, with system errors of 10.45 mm (2σ) and 21.07 mm (2σ). A comparison between the two conditions indicated superior performance metrics on asphalt road, yet both conditions met the requirements of precision, response time, and stability for automatic navigation systems, thus suitable for tractor automatic navigation operations.

To effectively identify tea buds in complex environments and improve the precision of intelligent harvesting while minimizing damage to tea trees, this study addresses the issues of low detection accuracy and poor robustness exhibited by traditional target detection algorithms in tea gardens, and proposes YOLOv7-tea model for tea bud identification and detection based on an improved YOLOv7, so as to achieve rapid recognition and detection of tea buds. First, tea bud images were collected and annotated, and data augmentation was performed to construct a tea bud dataset. Next, the CBAM attention mechanism module was introduced into three feature extraction layers of the YOLOv7 backbone network to enhance the model's feature extraction capability; the SPD-Conv module was used to replace the SConv module in the neck network's downsampling module to reduce the loss of small object features; and the EIoU loss function was employed to optimize box regression, thereby improving the accuracy of the predicted boxes. Finally, a comparative experiment was conducted between other target detection models and the YOLOv7-tea model using the tea bud image dataset as a sample, and the recognition effect of tea buds shot at different distances and angles was tested. The experimental results show that the YOLOv7-tea network model outperforms the YOLOv7 model in terms of precision (P), recall (R), and mean average precision (mAP) by 2.87, 6.91, and 8.69 percentage points, respectively. Additionally, the model has a faster detection speed and exhibits higher confidence scores in the recognition and detection of tea buds in complex backgrounds. The YOLOv7-tea model constructed in this study demonstrates better recognition performance for small-sized tea leaf buds, reducing instances of missed detection and false alarms. It exhibits good robustness and real-time performance, offering valuable insights for estimating tea yield and implementing intelligent harvesting.

Panax Notoginseng is one of the most extensively cultivated and utilized bulk medicinal materials in China, and Yunnan Province is the main producing area for Panax Notoginseng in the country. Due to the influence of terrain and agronomic requirements, traditional agricultural machinery faces difficulties in entering the planting areas for operation, resulting in the current manual operation of Panax Notoginseng transplantation. Therefore, the development of a Panax Notoginseng transplanting machine is crucial for promoting the industrialization of Panax Notoginseng. As the crucial load-bearing structure of the transplanting machine, the frame significantly affects the overall performance of the vehicle. This paper focuses on the structural analysis of the transplanting machine frame, aiming to improve the performance of the frame and the entire vehicle, and provide theoretical basis for frame structural design. A three-dimensional model of the frame is established using SolidWorks software and imported into ANSYS software for static finite element analysis. After determining the relative error range between the stress values obtained from static electrical tests and experimental stress values, the dynamic loading performance of the frame under different working conditions and the modal vibration deformation analysis of the first eight modes are conducted. The analysis results indicate that the frame exhibits good strength performance, but significant deformation occurs at the seat position, indicating insufficient stiffness of the structure. Topology optimization is employed to optimize the frame design, aiming to reduce frame deformation while ensuring reasonable stress distribution. By altering the arrangement of diagonal brace brackets, the goal of reducing deformation is achieved. According to the optimization design results, the total mass of the frame increases by 8.739%, while the deformation is reduced by 88.268%, and the maximum stress is decreased by 11.693%. The improved frame exhibits reduced maximum stress and significantly improved deformation, demonstrating the applicability of finite element method and topology optimization technology in guiding the structural design of transplanting machine frames.

With the development of agricultural science and technology, the utilization of crop straw has become more diversified, and its demand has also increased. This paper aims to solve the disadvantages of small round baler in hills and mountainous areas, such as easy scattering of bales, unadjustable number of net layers and low degree of automation. The net-wrapping device was modularized, including the design of the net feeding mechanism, the net cutting mechanism, the detection mechanism and the control circuit, and the mechanical analysis of the net feeding mechanism was carried out. The operation parameters of the device are detected by the detection device, and send to corresponding execution instructions to the feeding mechanism and cutting mechanism after processing by the controller, thus realizing the automatic operation of feeding, winding and cutting, and realizing the adjustable number of winding layers. When the net is wrapped, the friction torque limit component exerts tension on the net, so that the net is more tightly wound, the mechanical analysis found that the net tension depends on the compression spring elasticity, and the corresponding adjustment method is provided. The performance test results show that the device has stable performance and reliable operation. It can automatically wrap the hay bale of Φ 500 mm×700 mm. The wire net covers the side of the bale without leakage and entangling. When the number of layers is 3, the success rate is 95% and the anti-fall rate is 83.3%. When the number of layers is 4, the success rate of wrapping is 100%, and the anti-fall rate is 90%. When the number of net layers is 5, the success rate of net-wrapping and the anti-fall rate of bale are 100%. This paper designed a small automatic net-wrapping mechanism for small round baler in hills and mountains areas, the test verified that the performance of the machine is stable and reliable, meet the design requirements. When the number of layers is 3, the cost performance of flat operation is the highest, and when the operation is hilly and mountainonous areas, it needs to be adjusted to 4-5 layers to the slope of the operation.