Study On Working Condition Intelligent Monitoring System Of Combine Harvester Based On CAN-bus

CAN bus,as one of the field bus (controller area network), has a unique design thought, good functional characteristics, high reliability and strong anti-jamming ability of the scenes.CAN protocal was selected as the foundation of agricultural machinery application of standard agreement. In order to realize the intellectualized operation of the combine harvester,and improve and ensure the operation quality, high efficiency,safety, dependable and steady when it was working. some foreign advanced combined harvesters have equipped with feeding amount, grain moisture, working speed, header height, GPS positioning and etc,realized the operation parameters of the working speed,header height, feeding amount, threshing cylinder speed, grain loss rate to monitor, display and control. And have the intelligent function of fault diagnosis and alarm, calculation and statistical work area, consumption rate and production. Nowadays, combines electronic and automation level in our country is generally low, the quality and technology level differ2-4generations compared to the same products abroad. The operation on the high side, has serious loss rate of grain restricted the development of domestic combined harvesters. It is an urgent need to study the corresponding monitoring system, to combine the performance parameters of comprehensive adjustment. Therefore achieving combined harvesters intelligent monitoring state to the work the Chinese agricultural mechanization development, and achieving the agricultural production is of great significance to the modernization.Firstly, the CAN bus technology present situation at home and abroad develop trend. of and the combine information acquisition are analyzed, aimd at achieving the process of information acquisition, transmission, storage and display when the combine harvester is working, monitored in real-time the key information drivers required the walking speed of the combines, feeding rate,grain loss rate,header height, threshing cylinder speed,crop screw conveyor speed, grain flow etc.Secondly, a set of intelligent monitoring system of the combined harvesters which is working condition based on CAN-bus was designed. The acquisition nodes used STC89C52RC as core processors,The terminal used S3C2410as core processor and Linux as operating system.The walking speed of combine harvester was monitored using of radar speed sensor through the Doppler effect,using the timer by measuring period method,pulse threshing cylinder speed and crop screw conveyor speed were monitored, the header height was monitored by ultrasonic technique,the feed quantity was monitored by the use of squeeze pressure test principle to achieve,thegrain traffic was monitored by the use of flow sensor, and the use of grain loss sensor for grain total loss rate was monitored.CAN module is composed of SJA1000and PCA82C250, worked out the applicable to combine communication protocol and achieved the basic CAN bus communication function based on CAN agreement. The interface design used the QT technology with the appending Library of lib_qwt. The storage and Query of data is realized by SQLite database.Finally, the monitoring system was tested for CAN communications and simulated field experiment,interface in the terminal can detect the work states of point nodes, and real-time parameters are briefly analyzed. Through the operation commissioning, the system can meet the basic requirement of reliability and real-time, and has a good application prospect.