Research On Load Feedback Control And Algorithm Optimization For Forage Harvester

Forage production plays an important role in animal husbandry.Currently,the mechanized harvesting of forage crops in China has gradually become popular.However,the reliability of automated operation of domestic forage harvesters lags behind that of foreign countries.Most high-end forage harvesters rely on foreign imports,resulting in a low market share.The low level of automation and operational efficiency(unit energy consumption)are important factors that lead to poor reliability of harvester operations,and the feedback control system and its algorithm for operational load are the key core technologies to solve this problem.Therefore,this article aims to improve the operational efficiency and reliability of forage harvesters.Based on the online detection of chopping load and the comparison results with the cutting blade load threshold,the study focuses on the load detection,control,and algorithm optimization of key operational components,and conducts verification experiments.The research results provide theoretical and data support for China to break through the development of high-end forage harvesters and promote the resolution of the bottleneck problem that restricts the rapid development of animal husbandry.The main research contents of this paper are as follows:Firstly,the dynamic models of key components of forage harvester,such as engine,feeding and shredding,were established,and the mathematical model of forage harvester was established.The simulation model of harvester was designed under Simuilink software,and the steady-state characteristics and disturbance transient response of key components were studied.The results show that the internal parameters and external disturbances of the key components of the harvester have significant effects on its working state.The operating system is a typical large-inertia and pure delay system of higher order,with strong nonlinearity and time variability.Secondly,based on the basic principle of liquid shock absorption,the initial value of pressure detection and the slip-efficiency relationship of the chopped transmission belt,the detection model of the optimal working efficiency of the harvester’s transmission belt pressure load is established,and the working load detection system is designed.Taking corn straw shredding as an example,the pressure load of the transmission belt was measured in real time on the forage shredding machine.The results show that the developed detection system has high accuracy,good real-time performance,economy and reliability.Thirdly,in order to reduce the influence of external disturbance on the shredding operation,it is proposed to adjust the shredding and feeding load by controlling the main circuit and adjusting the engine speed by controlling the secondary circuit.DGPC and MPC prediction techniques are used to solve the problems of non-linearity,large inertia,pure delay and external disturbance suppression.In the load-speed cascade fuzzy nonlinear predictive control model,the speed sub-loop is introduced,the operating frequency of the system is increased and the internal parameters of the system are strengthened to improve the control effect of the system to the external disturbance.The simulation and test under various working conditions show that the constructed load feedback control system has certain adaptive ability and good control effect,and realizes the online detection and feedback control of feed and cut operation load of forage harvester.Fourthly,in order to improve operation efficiency and control reliability,an optimized control algorithm for forage harvest load segmentation was proposed based on minimum energy principle,fuzzy prediction theory,power output characteristics and operation efficiency measurement threshold.Taking corn stalk as forage crop,computer simulation and harvester verification results show that under the condition of constant power output,the optimization algorithm can improve the efficiency load threshold(1207.8N)of key components of the harvester.Fifthly,the load control system of key components of forage harvester and its optimization algorithm are proved to be highly reliable by the test results,and the key operation control processes such as feeding and shredding run stably.Compared with the traditional algorithm,under the same test conditions,the steady state precision of key component operation control is improved by 29.81%,the response time is increased by 24.69%,the shredding power load threshold is increased by 57.30%,the shredding efficiency is increased by 1.52 times under guaranteed quality,and the unit energy consumption is saved by 7.25%.The optimized control algorithm has stronger adaptability to the operation parameter changes of the forage harvester and more reasonable power supply and distribution,which can significantly solve the problems of gridlock and improper power distribution of key components during the operation of the forage harvester,and significantly reduce the unit operation energy consumption.The results can be used for reference in the research and application of other mechanical load feedback control systems and their algorithm optimization.