Miss-Seeding Detection and Self-Compensation System for Air-Suction Soybean Seed-Metering Device Based on Suction-Hole Seed-Carrying State Recognition

In this study, a miss-seeding detection and self-compensation system based on suction-hole seed-carrying state recognition was developed to address miss-seeding and reduced seed-spacing uniformity caused by missed pickup at suction holes in air-suction soybean seed-metering devices. A through-beam photoelectric sensor was installed between the seed-cleaning and seed-discharge zones to detect the seed-carrying state of each suction hole in real time. With a programmable logic controller (PLC) as the control unit and an encoder for seed-metering disc speed acquisition, the system performed missed-pickup identification, compensation pulse output, and operating-state monitoring. When a suction hole without a seed was detected, the control system triggered a short-term acceleration of the seed-metering disc, enabling the subsequent normally loaded suction hole to enter the seed-discharge zone in advance. In this manner, miss-seeding compensation was achieved without adding an independent supplementary seeding channel. Bench tests were conducted at different operating speeds, and the integrated system performance was evaluated under the optimized parameter combination of the auxiliary seed-delivery mechanism. The results show that the missed-pickup detection accuracy and compensation success rate ranged from 96.49% to 100.00% and from 94.55% to 100.00% over the operating speed range of 6~12 km/h, respectively. With the proposed system, the qualified seed-spacing rate increased from 92.4% to 96.0%, the miss-seeding rate decreased from 6.4% to 3.0%, and the multiple-seeding rate decreased from 1.2% to 1.0%. These results indicate that the proposed system can identify missed seed pickup before seed discharge and achieve self-compensation through short-term acceleration of the seed-metering disc, thereby improving seeding continuity and seed-spacing uniformity.