| There are abundant of herbage resources in my country.But resources cannot be fully utilized,and the efficiency of converting resources into biomass energy is low.The problem lies in the loss of transportation weight and poor economic benefits under low-density baling conditions.As my country's demand for high-density bales and silage has risen in recent years,high-density baling is an effective way to use herbage reasonably and reduce costs.It is conducive to promoting the industrialization process of herbage in animal husbandry,feed reserves,biomass utilization,etc.For high-density baling,ensuring the baling rate and density is the key.This paper is based on the problems that the current compression theory about herbage is not perfect,and the density control of baler is less in China.A method for controlling bale density in real time and accurately is proposed.The method achieves accurate control of bale density by monitoring and changing the radial compression force in real time.Based on the AMESim hydraulic simulation platform,this paper obtained and analyzed the simulation results of the hydraulic system.The results show that the design scheme of hydraulic system is feasible.Firstly,the compression chamber and compression piston were designed and processed.The compression experiment was carried out after that herbage in Minshan,Gansu was selected as the experimental material.By analyzing the experimental results,the law of stress variation about herbage during pressing process and stress relaxation is obtained.When the herbage is compressed,the process of stress change is divided into two stages:loose stage and compaction stage.The process of stress relaxation is also divided into two stages:rapid relaxation stage and slow relaxation stage.Secondly,the single factor rotation was used to study the effects of water content and feeding amount on the rheological properties of herbage.The results show that under same compression displacement,the lower the water content of herbage,the greater the single feeding,the greater the stress of herbage during the compression and the residual stress after relaxation.According to the selection levels of influencing factors,when the water content of herbage is 15%and the single feeding amount is 600g,the stress during compression process is larger.By analyzing the experimental results,the compressive stress model of herbage is obtained when the water content is 15%and the single feeding amount is 600g.The model equation is?=1.41×10-33.58.Thirdly,a compression platform for testing the radial compression force is established.The testing experiment for the radial compression force was carried out with water content of 15%and single feeding amount of 600g.The linear relationship between radial and axial compression force is verified,and the relationship equation between compression density and radial compression force isFinally,according to the relationship between radial compression force and compression density,a hydraulic system model in order to achieve high-density control of bales was established based on AMESim hydraulic simulation platform.The process of drawing sketches,sub-model settings,parameter settings,and simulation operations was completed to solve operation problems and improve system functions.The simulation results of piston pressure,piston displacement and oil velocity are in line with expectations.The system operates stably and the high-density control of bales is achieved. |
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