This paper addresses the hole-forming process of a duckbilled hole-forming device. Based on a coupled simulation using the multi-body dynamics software RecurDyn and the discrete element software EDEM, the hole-forming mechanism of a duckbilled hole-forming device and the influence of control parameters on the hole-forming performance of the hole-forming device were studied. In this paper, we analyze the direction and speed of soil particles transported under soil disturbance by a hole-forming device through the simulation and study of the hole-forming mechanism of the hole-forming device. By controlling parameters such as the traction angle, forward speed, and mass of the hole-forming device, the influence of the control parameters on the hole-forming trajectory of the duckbilled hole-forming device was investigated. Orthogonal tests determined the optimal combination of control parameters. The results show that the hole-forming process of the hole-forming device mainly comprises squeezing and shearing the soil to form holes, and the hole-forming performance of the hole-forming device was optimal when the traction angle was 17.3°, the forward speed was 1.11 m/s, and the mass of the hole-forming device was 17.9 kg.

This study is based on the influence of power shift control on the smoothness of cotton picker shifts and proposes an optimization method for the smoothness of power shifts with different control strategies for the gearbox. Through the structural design of the power shift mechanism control module, the hydraulic power distribution of the hydraulic system of the hydraulic travel module and its control mode are analyzed, and a regional cooperative shift control strategy is proposed in conjunction with control theory. A model of cotton picker dynamics was built using AMESim simulation software. In addition, the traditional control strategy was simulated and compared with the Statement component automatic control strategy to analyze and discuss the control deficiencies in power shift smoothness. Then, a particle swarm genetic algorithm (PSGA) was constructed by integrating the PSO algorithm and the genetic algorithm to verify the effectiveness of the algorithm in improving the dynamic performance and shift smoothness of the gearbox. The algorithm was verified using bench tests, and the algorithm improved the harvesting quality and efficiency of the cotton picker.

To meet the working performance demand of cotton pickers, a hydrostatic power shift composite drive system design is proposed. This study aims to enhance the driving function of the cotton picker in various working conditions and improve its adaptability by combining a hydrostatic speed control system with a mechanical power shift structure. To achieve this, a single variable pump + double variable motor closed circuit is adopted. By adjusting the pump and motor displacement in stages, the driving speed of the cotton picker can be optimized for different working conditions. Additionally, the power shift mechanism is employed to increase the speed range and improve the transmission efficiency, enabling higher speeds to be achieved. Firstly, the main components of the composite drive system were calculated and selected, and then AMESim software was used for modeling and simulation analysis, and the results are as follows: When the cotton picker starts and picking operation stage variable displacement pump + fixed displacement dual motor speed control, the highest driving speed is 8.5 km/h. During the field and road transport operation stage fixed displacement pump + variable displacement dual motor speed regulation, the highest speed of 14.5 km/h was achieved in the field. When transferring to the road, the instant mechanical power shift speed and, the highest speed on the road was up to 27.5 km/h. Finally, the field experiment and speed ratio analysis of the drive system was conducted, and the average error of the experimental speed measurement was 0.588%. The speed ratio matching was in line with the design expectation. The results show that the hydrostatic power shift composite drive system designed in this study has good driving adaptability and can effectively meet the functions of cotton picker field picking, transport operation and road transportation in transit, which provides theoretical support for the design of cotton picker chassis drive system.

To overcome the issue of unstable speed output encountered by cotton pickers operating in harsh environments and subject to frequent external load fluctuations, a hydraulic–mechanical transmission (HMT) for cotton pickers is proposed in this study. By analyzing the driving system of the cotton picker, a Lavira-based HMT scheme is developed. The matching characteristics of the HMT speed ratio are analyzed, a continuity and smoothness test of the speed ratio of the changing segment is carried out, and the influence law of smoothness of the HMT changing segment is discussed. The results show that the HMT system effectively satisfies the driving speed requirements for both field harvesting and road transportation of cotton pickers. The HMT speed ratio is continuously controllable and the design is reasonable. The HMT load torque and the oil pressure in the main oil circuit have a significant impact on the smoothness indicators of speed reduction and dynamic load. Additionally, the flow rate of the governor valve has a notable effect on the smoothness indicator of sliding friction power. However, the engine’s output speed has no significant influence on the HMT’s smoothness. This research can provide theoretical support for the development and design of cotton picker gearboxes and the transmission characteristics and experimental research of off-road vehicle gearboxes.