The development of an efficient and low-damage harvesting device for mulberry leaves using a bottom-up approach

To address the low degree of mechanisation and high labour intensity of the mulberry leaf harvesting devices in the current mulberry leaf cultivation model, an efficient and low-damage harvesting linkage clamping mulberry leaf harvesting device was designed. First, the fundamental characteristics of the mulberry orchard under the leaf harvesting mode were investigated, providing a theoretical foundation for optimising the design of the harvesting device. Subsequently, for efficient and low-damage mulberry leaf harvesting requirements, the linkage clamping mechanism was optimised by targeting increased clamping force and opening width, determining the specific parameters of the linkage clamping mechanism. Experimental results indicate that the device can complete the entire mulberry branch harvesting process, including six stages: branch insertion, branch gathering, leaf harvesting, branch retraction, leaf release, and position return. Multiple mechanical protection measures were implemented to protect tender leaves and branches effectively. Finally, experimental studies were conducted on the main factors affecting the leaf harvesting rate, mulberry branch tender leaf (MBTL) damage rate, and the device's performance. The optimal parameter combination was obtained through experimental validation and parameter optimisation: a longitudinal cutting speed of 500 mm/s, a frame lifting speed of 284.2 mm/s, and a transverse cutter height of 20 mm. Under these parameters, the leaf harvesting rate reached 71.24%, and the MBTL damage rate was 2.26%. The proposed mulberry leaf harvesting machine has significant practical implications and reference value for improving the mechanisation level of mulberry gardens, promoting cost reduction, and enhancing efficiency in the sericulture industry.