Objective  To address the problems of low efficiency and poor precision in traditional manual lettuce seeding, as well as uneven furrowing depth and inconsistent seeding spacing caused by the small seed size, this paper designs an intelligent control system for lettuce seeding based on multi-sensor fusion and multi-motor coordinated control. The system aims to fill the research gap in special precision seeding control systems for small-sized vegetable seeds represented by lettuce, and to improve the automation and precision of lettuce seeding operations.

Method Adopting a modular design concept, an embedded hardware architecture with the STM32 microcontroller as the core was constructed, and the software and hardware development of the control system was completed. Environmental perception information fusion processing was realized by integrating multi-modal sensing units. A multi-motor coordinated control and encoder signal acquisition channel dynamic switching mechanism based on the PCA9685 driver chip and CD4052 analog multiplexer was designed. A single-stage-cascade PID composite control algorithm fused with attitude feedback was proposed to ensure the operation stability of the system under complex terrain conditions. An OLED display module and an android bluetooth low energy (BLE) interactive terminal were equipped to realize convenient human-computer interaction.

Result The results of field tests showed that in the test field, the furrow depth qualification rate of the lettuce seeder was 77.3%, the missing seeding rate was 5.9%, the emergence rate reached 49.1%, the total time-consuming for a single operation was 57 seconds, the operation efficiency was about 3 times that of traditional manual seeding, and the overall operation cost was significantly lower than that of the traditional manual seeding method.

Conclusion The performance of the designed control system meet the requirements for prototype development and can provide a theoretical basis and technical support for the intelligent upgrading of precision seeding equipment for small-sized vegetable seeds.