To address the problems of high damage rate, low seeding accuracy, and poor seeding generally in the seeding process, a general-purpose seeding device was designed in this study based on the principle of mechanical pneumatic combined seeding. The air-blowing-type cleaning and seed unloading of the device laid the conditions for precise seeding and flexible seeding. In addition, single-factor experiments were performed on seeds (e.g., soybeans, corn, and rape-seeds) with different particle sizes and shapes to verify the general properties of the seed metering device. A multi-factor response surface optimization experiment was performed by applying soybean seeds as the test object to achieve the optimal performance parameters of the seed metering device. At a seed-clearing air velocity of 16.7 m/s, a seed feeding drum speed of 13.7 r/min, and a hole cone angle of 35.6°, corresponding to the optimal performance index, the qualified index, the replay index, and the missed index reached 97.94%, 0.03%, and 2.03%, respectively. The verification test results are consistent with the optimized ones. As indicated from the results, the seed metering device exhibits good general properties, low damage rate, great precision, and high efficiency; it is capable of meeting general seeding operations of different crop seeds and technically supporting for the reliability and versatility of the seeder.

In view of the current situation of the low degree of mechanized harvesting of rape shoots, combined with the study of the material characteristics of rape shoots, the core components of the harvester were designed and analyzed, and a rape shoots harvester was designed and manufactured. The front-end cutter of the harvester cuts the stalks of rape shoots, while the clamping and conveying device transports and steers the stalks flexibly to achieve low damage and orderly harvesting. The forward speed of the machine, the speed of the clamping belt and the clamping gap were selected as the test factors, while the rate of missed cut, missed clamping, and plant damage were selected as the evaluation indexes for the single-factor and response surface optimization tests. Field validation test showed that the machine could effectively cut and transport rape shoots at a forward speed, clamping belt speed and clamping gap of 0.42 m/s, 0.89 m/s and 11.43 mm, respectively (missed cut rate, 2.63%; missed clamp rate, 4.84%; and plant damage rate, 5.22%). This study provides a reference for the research and optimization of the flexible harvesting device for rape shoots.