Traditional plant disease diagnosis methods are mostly based on expert diagnosis, which easily leads to the backwardness of crop disease control and field management. In this paper, to improve the speed and accuracy of disease classification, a plant disease detection and classification method based on the optimized lightweight YOLOv5 model is proposed. We propose an IASM mechanism to improve the accuracy and efficiency of the model, to achieve model weight reduction through Ghostnet and WBF structure, and to combine BiFPN and fast normalization fusion for weighted feature fusion to speed up the learning efficiency of each feature layer. To verify the effect of the optimized model, we conducted a performance comparison test and ablation test between the optimized model and other mainstream models. The results show that the operation time and accuracy of the optimized model are 11.8% and 3.98% higher than the original model, respectively, while F1 score reaches 92.65%, which highlight statistical metrics better than the current mainstream models. Moreover, the classification accuracy rate on the self-made dataset reaches 92.57%, indicating the effectiveness of the plant disease classification model proposed in this paper, and the transfer learning ability of the model can be used to expand the application scope in the future.

Severe plant entanglement and high power consumption are the main problems of the up-cut rotary blade during Cyperus esculentus harvesting. Optimization of the rotary blade edge can enhance the soil-cutting and plant-crushing performance. In this study, the double-eccentric circle method was used to design the edge curve of the IT245 rotary blade. The edge curve’s dynamic sliding-cutting angle of equidistant points was analyzed to verify that the optimized rotary blade (IT245P) met the requirements of Cyperus esculentus harvesting. In order to accurately simulate the fragmentation of Cyperus esculentus plants after interaction with the rotary blade, the Hertz–Mindlin with Bonding contact model was selected to establish the flexible model of Cyperus esculentus plants. The plant–soil–rotary blade discrete element model was constructed to conduct simulation tests with power consumption and the plant-crushing ratio as evaluation indexes. The field experiment was carried out with tillage depth stability and power consumption as the experimental indexes. The results of the simulation test and field experiment showed that the power consumption of the IT245P rotary blade was reduced by 13.10%, and the plant-crushing rate was increased by 11.75% compared with the IT245 rotary blade. The optimal operating parameters were 1.08 m/s for forward speed, 107.11 mm for tillage depth, and 258.05 r/min for shaft speed. Under such a combination, the tillage depth stability and the power consumption were 94.63% and 42.35 kW. This study showed that a rotary blade with a double-eccentric circular curve could better realize plant-crushing and consumption reduction and meet the operation requirements of Cyperus esculentus and other Chinese medicinal materials’ harvesting.

Soil blocking and plant entanglement are the main challenges in Cyperus esculentus harvesting and excavating. The structure of the rotary blade is one of the critical factors affecting plant crushing and soil throwing performance. Inspired by the composite motion of longitudinal soil cutting and lateral soil throwing of the oriental mole cricket, a bionic rotary blade was designed with the contour curve of the excavation edge and excavation surface of its forefoot claw toe. The bionic rotary blade’s mechanical and kinematic analysis revealed its cutting mechanism. A flexible plant soil, bionic, rotary blade discrete element model was developed to simulate the Cyperus esculentus digging process. The optimal excavation edge and excavation surface were selected by a single factor experiment, and the optimal operating parameters of the bionic rotary blade were obtained by quadratic regression orthogonal rotational combination design. The results showed that the bionic rotary blade, based on the excavation edge and excavation surface of mole cricket first claw toe, had the longest throwing distance and the largest number of broken bonds. The best combination of operating parameters of the bionic rotary blade was 11.16 mm for blade spacing, 0.66 m/s for forward speed, and 300 rpm for shaft speed. The field experiment was carried out according to the best parameters. The results showed that the bionic rotary blade’s average soil throwing distance and plant crushing rate were 632.30 mm and 81.55%, respectively; thereby, not only meeting the requirements of Cyperus esculentus harvesting, but proving superior to the operation performance of the Chinese standard rotary blade IT245 and rotary blade with optimized cutting edge (IT245P). The results of this study can provide bionic design ideas and methods for the design of soil-cutting-based tillage machinery’s soil-engaging components, such as the rotary blade and returning blade.

Currently, the mechanized harvesting method of Cyperus esculentus is mainly based on rotary excavation, but there are problems such as high working resistance, high damage rate, and high buried fruit rate in the working process. This paper focuses on the analysis of the movement trajectory of the positive-rotating and counter-rotating Cyperus esculentus excavation device, establishes a agglomerate model of soil-Cyperus esculentus tuber-Cyperus esculentus root system-mechanism, and conducts discrete element simulation tests on Cyperus esculentus agglomerates under different soil layers. According to Expert test optimization, the optimal structural parameters of the counter-rotating blade are determined: the radius of gyration is 151 mm, the inclination angle of the cutting edge is 42.5°, and the working width is 318 mm. The comparative test of the positive-rotating rotary tillage method under the optimal structural parameters shows that the working resistance is reduced by 11.25%, and the torque of the tool shaft is reduced by 16.11%, which proves that the designed anti-rotation excavation structure has the effect of reducing resistance. To further test the harvesting performance of the Cyperus esculentus excavation device, field harvesting tests were conducted, and the results showed that the buried fruit rate of the counter-rotating excavation device was reduced by 11.6%, and the damage rate was reduced by 6.1% year-on-year. This study shows that the design of the counter-rotating excavation device can further improve the harvesting performance of Cyperus esculentus based on reduced resistance harvesting and meet the requirements of Cyperus esculentus harvesting.

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