The production of Lycium barbarum L. is a labor-intensive industry. Multiple manual harvests are required during the harvesting season, which contributes to the high harvesting costs. The cultivation conditions of L. barbarum were investigated to increase efficiency and mitigate harvesting damage. A torsion harvester was designed according to the characteristic of infinite inflorescence and the distribution of detachment force, and the kinematics model of the harvester was established. The vibration responses of ripe and unripe fruit were obtained through ADAMS simulation of the branch model, and the influencing factors and value range of the torsion harvester were also determined. The mathematical models of ripe fruit harvesting rate, unripe fruit harvesting rate, ripe fruit damage rate and torsion angle, vibration rods distance, and vibration frequency were established by the Box-Behnken test. The influences of various factors on ripe fruit harvesting rate, unripe fruit harvesting rate, and ripe fruit damage rate were analyzed, and the best parameter combination was obtained: torsion angle 73.66°, vibration rods distance 35.51 mm and vibration frequency 19.12 Hz. Field experiment showed that the harvesting rate of ripe fruit is 95.67%, the harvesting rate of unripe fruit is 4.68%, and the damage rate of ripe fruit is 3.70%. The research results can promote the mechanization process of L. barbarum harvest, and provide a reference for vibration harvest of berries.

Lycium barbarum L.(L. barbarum) has been one of the most favorite fruits in recent years. However, manual harvesting cannot fully meet large-scale production, as the labor force decreases. It is urgent to realize efficient harvesting by picking ripe fruits rather than unripe ones. This study aims to optimize the parameters during vibration harvesting of L. barbarum under various excitation modes. The L. barbarum fruits were also selected and measured in Ningxia in western China. The normal distribution of the detachment force and detachment acceleration were plotted after measurement. It was found that the detachment force of ripe fruits was similar to that of flowers. There were overlapping areas among the unripe fruits and leaves. By contrast, the detachment acceleration was ranked in the ascending order of the ripe fruits, unripe fruits, leaves, and flowers. Ripe fruits also presented the lowest detachment acceleration without overlapping with the rest, suitable for the vibration to harvest L. barbarum. As such, the vibration-picking was employed without touching the fruits. Only the excitation area above the ripe fruit area of the branch was excited by vibration equipment, according to the characteristic of infinite inflorescence. Furthermore, the vibration head was closer to the ripe fruit area during harvesting, particularly without colliding with the ripe fruits for less damage. Three excitation modes were proposed for the branch in the corresponding vibration equipment. The upper and lower points vibrated in the same direction (simultaneous vibration); the upper point was fixed, and the lower point made a reciprocating vibration (pendulum vibration); the upper and lower points vibrated in the opposite direction (reverse vibration). The kinematics model of the clamping head was established to simulate the branch and branch-stalk fruit. The transient analysis was implemented to obtain the vibration responses of the branch under different excitation modes. The results show that the excitation modes dominated the vibration response of the branch. Moreover, the vibration response of the fruit under excitation was acquired via kinematics simulation of ADAMS. The mechanism of fruit shedding was analyzed after simulation. The results indicate that the vibration response gradually increased from the vibration head to the selection point of the branch, and then to the fruit. The verification test showed that the average relative error of branch amplitude and fruit velocity were 23.78% and 14.01%, respectively. The vibration response of L. barbarum branch, stalk, and fruit was verified after the test. The parameter experiment was taken by the Box-Behnken test. The mathematical models were then established for the picking rate of ripe fruit, picking rate of unripe fruit, damage rate of ripe fruit and vibration amplitude, excitation mode, and vibration frequency. The influences of various factors were analyzed to determine the optimal combination of parameters: the vibration amplitude was 31.13 mm; the excitation mode was pendulum vibration, and the vibration frequency was 12.59 Hz. The experiments with the optimal parameters show that the picking rates of ripe and unripe fruit were 95.14% and 4.61%, respectively, and the damage rate of ripe fruit was 2.98%. A better performance was achieved in the pendulum vibration as the optimal excitation mode. Fruit damage was minimized due to the high picking efficiency, particularly for ripe fruits. The findings can also provide valuable insights into the mechanized harvesting equipment for L. barbarum fruits.