DESIGN AND PARAMETER OPTIMIZATION OF A PNEUMATIC AIR-JET PRE-SEPARATION MECHANISM FOR TRANSPLANTING

To address the issues of high damage rates and low success rates in seedling picking due to adhesion between seedlings and pots in the picking mechanism of an automatic transplanter, this study proposes a pre-separation method for pot seedlings based on airflow impact. Unlike the traditional jacking or vibrating-assisted separation method, this method achieves pre-separation through non-contact airflow impact and minimizes mechanical damage to the root-soil composite. Based on this method, a seedling pre-separation mechanism was designed and integrated into the seedling picking mechanism. By establishing a mechanical model of the airflow impact force, the influence of the nozzle aperture and air pressure on the separation effect was revealed. Parameter optimization and functional verification were completed using 50-day-old tomato seedlings. Experimental results showed that the pre-separation success rate of pot seedlings was 93.3% under the optimal combination of a 5 mm nozzle aperture and 125 kPa air pressure. After integration into the seedling pick-up mechanism, the pick-up success rate was 94.4%, with a damage rate of only 1.4%. This study confirmed that air-blowing pre-separation technology can effectively eliminate adhesion between pot seedlings and their pots, significantly reducing damage to seedlings and providing a feasible technical solution for developing a low-damage, automatic transplanter seedling pick-up mechanism.