Design And Test On Loss Sowing Detection And Reseeding System Of Precision Sowing For Hybrid Rice

The precision seeding method of rice with cavity-type has the advantages of simplifying the seeding mechanism and reducing seed damage.Aiming at the problem of miss-seeding holes during the hill-drop direct seeding process of the cavity-type precision and smallamount seed-metering device of hybrid rice,combining with the method of combined pulse,a novel loss sowing detection method and a variable-speed in-situ reseeding strategy were proposed,and a mathematical model of curve speed reseeding under different continuous missing seeding conditions was constructed.At the conventional seeding rate,the detection of missed seeding,in situ reseeding,and the overall performance test were carried out.The following is a summary of the particular research content:(1)In system scheme design.A kind of detection system for missing seeding and in-situ reseeding of rice with a small amount of precision seeding was designed by combining the cavity seeding method and photoelectric detection technology.The construction method of the combined pulse of the loss sowing detection environment and the loss sowing detection decision with the light curtain covering of the cavity were described.The dynamics model of rice seed movement in the detection area of the cavity was established,the design of key structural parameters was completed,and the motor control principle of S-curve variable speed reseeding was determined.The overall scheme of the system provided the foundation for the design and selection of the software and hardware.(2)The system hardware design was based on the design concept and performance requirements of the loss sowing detection and reseeding system.Component selection and configuration were carried out for the core controller,seeding drive module,signal acquisition module,display alarm module,and system power supply module.The circuit system design of the system hardware modules was completed through Altium Designer 20.(3)The modular design of software system functions was developed on the Free RTOS embedded real-time operating system platform.The loss sowing detection algorithm and variable-speed in-situ reseeding algorithm were designed based on the channel light curtain scanning loss sowing detection method and combined pulse loss sowing determination concept.Programs such as the loss sowing detection program,the variable-speed reseeding program,and the system operation visualization program were developed to design the loss sowing detection and variable-speed in-situ reseeding algorithm.(4)Performance testing of the system was conducted.The loss sowing detection,in-situ reseeding,and overall operational performance of the system were tested under different seeding conditions.The detection error of the loss sowing detection subsystem was no more than 0.80% under different rotational speeds and variable rotational speeds and no more than1.20% under vibrational conditions.The detection error under different seeding speeds in the field was no more than 2.13%.The initial deviation angle of variable speed reseeding of the driving motor was no more than 0.12°,the error of variable speed adjustment time was no more than 0.0008 s,and the error of variable speed motion angle was no more than 0.12°.The proposed "loss-filling combination" reseeding strategy was able to accurately control variable speed reseeding and keep the range of the reseeding trajectory consistent with the normal seeding trajectory range.The average difference in hole diameter between the two trajectories was no more than 1.48 mm,and the difference in qualified rate was no more than1.35%.The average difference in hole distance was no more than 1.01 mm,and the difference in the coefficient of variation was less than 0.59%.The in-situ reseeding of the system was successfully implemented.The overall reseeding rate of the system was no less than 90%,and the simple mechanical seeding mechanism equipped with the loss sowing detection and reseeding system reduced the miss-seeding rate from no less than 10.67% to no more than 1.33%.The qualified rate was increased from no more than 78.20% to above89.33%,significantly improving the precision and efficiency of seeding 1-3 grains of rice.Under the conventional seeding speed in the field,the qualified rate of sedding increased to86.49%,the missed seeding rate dropped to 2.70%,the qualified rate of hole diameter was79.46%,and the coefficient of variation of hole distance was 10.58%.All the seeding indicators can meet the seeding requirements of rice precision and small hole direct seeding.