Design And Experiment Of Real-time Bale Density Monitoring System Of Round Baler

Bale density is one of main performance indicators of baling mac1 hine operating quality,the real-time monitoring for bale density can obtain the straw bale weight,the change of the straw bale weight of the operation area and the total amount of grass of the operation area,which has important research significance straw bale density for stable control of straw bale density.This paper aim at the round bale density monitoring,design a set of Bale Density Monitoring System of Round Baler in real-time.The main content of the article is shown below:1)Proposed the bale dynamic weighing method Based on the pressure testing and attitude angle : Designed the bale dynamic weighing plummer based on the analysis of round bale bales process.Through the force analysis of plummer in the process of unloading bale,built the mathematics model of bale dynamic weighing bale.Analyzed the movement process of bale and plummer and the change of the stress,acceleration and attitude angle of the data acquisition platform on plummer based on ADAMS.Analyzed the pressure curve and filtered the pressure signal and provided the theoretical basis for bale density monitoring system design.2)The overall scheme design of Real-time Bale Density Monitoring System of Round Baler: Based on the mathematical model of bale dynamic weighing and the analysis of system function,technical requirements,determined the overall scheme of the monitoring system composed of bale dynamic weighing plummer,signal acquisition module,processor,serial communication module storage module,LCD display module and power module.Completed the plan optimizing test of bale dynamic weighing plummer,taken the length of the supporting structure,the width of the weighing platform and the distance between the end of weighing platform with end of the fixed frame as the test factors.The smoothness of the effective data segment of the weighing system was taken as the evaluation index for this research.The results show that when the length of the supporting structure was 1.2m and the width ofweighing platform was 0.6m,and the distance of the weighing platform from the end of the supporting structure was 0.1 m,the effective data segment is most stable.3)The design of real-time bale density monitoring System of round baler :completed the selection of sensors and processors,designed the hardware circuit of the monitoring system,and based on hardware circuit completed the software design of the monitoring system.Simulated bale rolling process,concluded the weighing signal of bale dynamic weighing system is primary concentrated in low frequency of 5Hz by the frequency spectrum analysis on the weighing signal in the process of rolling.Completed the FIR filter design and achieved the application of the digital filter by STM32 processor.Compared bale dynamic weighing signal before and after the original signal filtering,the result showed that the filter to bale dynamic weighing signal has a great filtering effect.4)The test and experiment of real-time bale density monitoring system of round baler: Completed the testing work of round baler bale density monitoring system,result show the system was normal.Completed the static calibration experiment of the weighing system and the calibration experiment of the mathematics model of bale dynamic weighing,obtained a static calibration equation of the weighing system and a calibration equation of the mathematics model of bale dynamic weighing.Respectively measured the confirmatory repeatability test on the bales which actual weight is 280.1kg and 405.3 kg.The maximum error of estimated value is 3.6319%,and the maximum error of the revised value by calibration equation is 3.4047%.The experimental results showed that the accuracy of the bale dynamic weighing system is less than 5% and the system is reliable,conform the requirements of the system.Observed and analyzed the change of the backpack hydraulic cylinder rod cavity when round baler working.