Development of Soft Type Metering Device for Garlic Planter and Performance Analysis in Accordance with Design Parameters

The main goal of a garlic planter is to plant garlic cloves individually with even spacing, requiring minimization of missed or multiple plantings. This study adopted an air-suction metering device to increase planting speed. To handle irregularly shaped garlic cloves effectively, soft silicone suction holes were fabricated and attached to the metering device. Performance was assessed by varying suction hole diameters (8, 11, 14, and 17 mm) and material hardness levels (1.4, 16.7, and 27.2 HA Shore A) at multiple-metering rates. The optimal metering rate of 98.2% was achieved with a 14 mm suction hole diameter and 16.7 HA hardness. This success was attributed to the soft suction hole effectively conforming to the garlic clove surface. The findings revealed a critical limitation: when metering rates exceeded 90%, multiple-metering rates increased linearly, indicating inherent constraints of air-suction techniques for single-seed metering. These results provide valuable insights into design parameters needed to improve reliability, operational efficiency, and mechanization performance of garlic planters. The metering device type is expected to be applicable to autonomous or unmanned agricultural machines, advancing agricultural mechanization capabilities.