DESIGN AND TEST OF A WIRELESS MONITORING SYSTEM FOR FEED RATE IN COMBINE HARVESTER BASED ON BOTTOM PLATE PRESSURE OF CHAIN-RAKE CONVEYOR

Feed rate is a critical operating parameter in combine harvesters, as it directly influences working efficiency and harvesting quality. To enable real-time and accurate feed rate monitoring, this study proposes a wireless monitoring approach based on pressure measurements at the bottom plate of the chain-rake conveyor inlet. A coupling model relating feed rate, chain-rake speed, and bottom plate pressure was established through theoretical analysis. To enhance robustness against signal fluctuations, the trimean was selected as the feature metric. A monitoring system incorporating LoRa wireless transmission was developed to achieve data acquisition, transmission, and visualization. Bench test results showed that the established model achieved a goodness-of-fit R² of 0.9963, and the predictive relative error was below 5% under most working conditions, demonstrating that the system provides high accuracy and stability in complex operating environments. The proposed method offers an effective technical solution for feed rate monitoring in combine harvesters.