Existing pecan mechanized harvesters have been limited to the fruit removal efficiency and adaptability in recent years. In this study, a hydraulically-driven differential vibration was proposed with the dual-drive counter-rotating for pecan harvesting operations. Firstly, the overall structure was realized for the vibration-based shaker of the harvester suitable for the large pecan trees. A picking model was developed to couple rigid-flexible dynamic vibration, in order to simulate the interaction between the clamping-vibration component and the main trunk of the pecan tree. The clamping assembly was treated as a rigid body, while the tree trunk was modeled as a flexible body. A systematic analysis was also performed on their coupled vibratory dynamics. Then, the variation patterns were determined for the excitation force under counter-rotating differential vibration. The influencing factors on the harvesting performance were identified as the base rotational speed for one of the hydraulically driven motors, the differential rotation coefficient between the two hydraulically driven motors, and the vibration duration applied to the pecan tree. Secondly, finite element simulation software was adopted to design the structure and operation parameters of key parts of excitation and clamping, in order to enhance the performance of the system. Specifically, the geometry of the eccentric mass blocks was refined, including their structural configuration, eccentric offset distance, and mass moment of inertia, according to the structural parameters and material selection of the excitation main shaft. Additionally, the parameters of the dual hydraulic-driven motors were established to determine the design value of the clamping preload force. Finally, a pecan picking machine was trial-produced under picking test conditions. A full machine performance test was then conducted to verify the simulation. The results showed that the optimal operating parameters were a base rotational speed of 1 200 r/min, a rotational coefficient of 0.8 based on the base speed, and a vibration duration of 10 s, particularly for the mature pecan trees with trunk diameters of 35-45 cm, the harvester achieved a fruit picking rate of 88.8% in a single shaking pass per tree under this condition. Considering the damage caused by vibration to the tree body and the actual harvesting effect, adjust the optimal vibration time to 7 s, and The comprehensive performance verification test results of the whole machine under this condition showed that the average pecan picking rate was 85.0% in a single shaking pass per tree, without any destructive damage to the tree trunk. Meanwhile, the average harvesting efficiency was 40 trees per hour, which was approximately 16 times that of manual harvesting. The developed harvester fully met the high requirements of efficiency and adaptability during mechanical harvesting of pecan in orchards.

Harvesting equipment is closely related to the harvesting quality and efficiency, particularly for the Chinese wolfberry. In this study, a method of arrayed vibration unit was proposed in the mechanized harvesting equipment, according to the agronomy of hedgerow type Chinese wolfberry bilateral fruit hanging planting. The structural design of the arrayed vibration components and the fruit receiving platform was carried out, and then the walking, conveying, sorting and stability analysis of the whole machine were carried out. The arrayed layout parameters of different stubble numbers of Chinese wolfberry Xia Guo in Ningxia were measured. A series of significant paramerers were conducted to determine the vibration unit structure, vibration frequency, vibration angle, the crawler assembly, the transmission structure and driving of horizontal and vertical conveyor belts, the position of fruit receiving basket and lifting conveyor belt and the wind speed of debris sorting. Furthermore, the driving stability of the whole machine was verified on the slope. After that, the performance tests of the whole machine were carried out to evaluate the feasibility and efficiency of the mechanism, according to the test conditions and walking, harvesting and sorting. The selected indicators and the results showed that the maximum running speed of the whole chassis in all conditions was up to 0.252 m/s, the minimum turning radius was limited in 1.86 m, the maximum slope was 32°, the maximum crossing ditch width was no more than 0.5 m, and the maximum crossing step height was 11 cm. All the indicators were verified for the better walking performance, compared with the traditional. The harvesting object was taken as the sixth crop of Chinese wolfberry in Xiaguo, Ningxia Ningqi No.1. The amplitude was fixed at 15 mm. The optimum operating conditions were as follows: the driving speed was 1 300 r/min, vibration time was 5 s, the picking efficiency of mature Chinese wolfberry was 4 037 fruits per minute, the net picking rate of mature Chinese wolfberry was 88.95%, the damage rate of mature Chinese wolfberry was 3.64%, the damage rate of dried mature Chinese wolfberry was 4.17%, the comprehensive false picking rate of immature fruits, olives and flowers was 3.80%, and the efficiency ratio of mechanical picking to human picking was 26.91. All the performance indicators were presented that the Chinese wolfberry fruit of mechanized picking was fully met the requirements of its commercial processing. In addition, the wind speed was determined to be at least 5 m/s, which was beneficial to the separation of fruits and leaves.