Research On An Intelligent Monitor For Yield Mapping System Of Grain Combine Harvester

Data acquisition in fields, especially yield data acquisition, is an important step in precision agriculture. The goal of this project lay in the study and development of a practical and low cost yield monitor system for grain combine harvesters. This paper introduced the study and development of a console for the grain yield monitor system.Yield monitor console is the center of a yield monitor system. It collects data from sensors; display and store them after processing. The development of the console was based on a low cost microcontroller P80C592. The hardware platform met the needs for collecting 4 analog signals (grain flow, grain moisture, temperature and header height) and 2 digital signals (ground speed and elevator speed). It supported a CompactFlash^TM (CF) card access to store yield data. Touch screen and liquid crystal display were applied in the hardware as a friendly man-machine interface. Its CAN2.0A interface enabled it to access Controller Area Network (CAN) easily. The software used interrupts to coordinate real time multitasks in the system. Performance tests showed that the software worked stably on the hardware. The software module of writing CF card had a good compatibility in running on different microcontrollers with 8051 core.The yield monitor console was used to calibrate sensors of the system. There were 3 kinds of tests, including laboratory test, combine harvester test and field test. Laboratory test showed that the grain flow sensor had a relatively good linearity. After the combine harvest test, calibration equations were found for header height sensor and elevator speed sensor; and real time calibration methods were proposed for grain flow sensor and ground speed sensor. Field test proved that the real time calibration method significantly improved the measurement accuracy of grain flow.