A Flexible Cleaning Loss Sensing Module for Wheat Combine Harvesters with Reduced Error Using Vertically Distributed PVDF Sensing Array

Highlights PVDF thin film array sensing module proposed for wheat cleaning loss monitoring. 4×2 PVDF sensor array reduces signal aliasing by 0.48%. Accuracy error <4% achieved through vertical array layout. Flexible design enables easy sensor replacement. Abstract. PVDF flexible piezoelectric sensors have the advantages of a simple structure and fast response speed, and have broad application prospects in the field of grain cleaning loss monitoring. However, most current cleaning loss sensors still face the problems of low sensitivity, difficulty in disassembly and assembly, and large cleaning loss monitoring errors. Based on this, this paper proposes a vertically distributed PVDF flexible thin film sensing array module for cleaning loss. The performance of the PVDF sensor unit was first characterized, and the difference in signal characteristics between grains and short straws was studied. When grains collide with a sensing array, the voltage distribution among the sensing units was recorded, and the accuracy of cleaning loss monitoring for sensing modules was tested. The influence of array layout and installation method on accuracy was studied by comparing the sensing results. In addition, a signal conditioning circuit for the sensor, which counts the signals through an MCU, was designed. The test results show that the accuracy error of the cleaning loss monitored by the sensor module proposed in this study is less than 4%, which is 0.48% lower than previous reported studies. Keywords: Combine harvesters, Cleaning losses, Precision agriculture, PVDF thin film, Sensors.