Study On The Leveling System Of The Body In A Self-propelled Corn Combine Harvester

Corn,as the China's largest food crop,is one of the major food crops in mountainous and hilly region in China.The slop of the agricultural land over 15 degree accounts for 12.5% of the total acreage.Due to the undulation of the land and the large slope of the agricultural land in some areas,rollover accident of the harvester is likely to occur.Therefore,the mechanized reaping ratio of corn in mountainous and hilly region is always too low.In order to improve the mechanization of corn harvest in mountainous and hilly region in China,the 4YZ-2 self-propelled corn harvester,produced by Changchun Great Agricultural Equipment Technology Co.,Ltd.,is considered as the research object to study its leveling system.This paper provides the technology support for the mechanization of corn harvest in mountainous and hilly region in China.The main aspects of this work are as follows:(1)The overall design of the body-leveling system in corn harvester.Started form the mechanical structure of the body leveling,the connected structure of the chassis of the corn harvester is modified.A floating adjustable connected structure of the chassis is proposed.Subsequently,the hydraulic system required in body-leveling system of the corn harvester is designed,and its working process is introduced.(2)The automatic body-leveling model is built.Through the abstract of the geometric relationship between the components in chassis,the mathematic model between the leveling velocity and the incline angle of the body during the process of leveling is built.The relationship between the leveling velocity and the incline angle of the body is analysed.An automatic leveling system is proposed.A device for the automatic body-leveling is designed.Subsequently,according to the planting and harvesting methods of the corn,the range of the incline angle is set.The transversal leveling capacity is 17.50 deg.The longitudinal uphill and downhill leveling capacities are 17.50 deg and 11.00 deg,respectively.On the basis of the above work,a control system for the automatic body-leveling is proposed.(3)The hardware design of the leveling system.According to the requirements of the above control system for the automatic leveling,the signal acquisition circuit of the dual-axis incline angle,circuit of wireless transmission,sending and receiving circuit of the remote signal,liquid crystal display circuit of the incline angle,and the circuit of limit switch interface are designed.On the basis of the circuit schematic design,the printed circuit board of the control system is made.After welding and plugging the functional modules into the circuit board,the whole hardware circuit is completed.The above hardware circuit provides the functional carrier for the body leveling of the corn harvester.(4)The algorithm and software design of the leveling system.According to the requirements of the above control system for the automatic leveling,the signal acquisition algorithm of the dual-axis incline angle,algorithm of wireless transmission,filtering algorithm,liquid crystal display algorithm of the incline angle,and the main algorithm for the automatic body-leveling are designed.The accuracies of the lateral incline angle ? and the longitudinal incline angle ? are set to be-1.5 deg< ? <1.5 deg and-1.5 deg< ? <1.5 deg,respectively.Finally,the above algorithms are implemented in IAR software using C language.(5)The debugging and trail of the control system.Firstly,the body-leveling algorithm is validated by the experiments conducted in laboratory.Subsequently,the relevant apparatuses are installed onto the model prototype of the corn harvester.The appropriate filtering parameters are determined by the experiments.Finally,through the indoor static trail,indoor dynamic trail,and field dynamic trail,the reliability and practicability of the control system for the automatic leveling are tested.The relation between the leveling velocity and the incline angle is analysed.According to the experiments,the overall leveling success rate of the indoor static trail is 79.09%,while the overall leveling success rate of the indoor dynamic trail is 64%.The overall leveling success rate of the field dynamic trail is 62.5%,which is slightly lower than that of the indoor dynamic trail.The main reason of the leveling failure is analysed.Leveling failure mainly occurs in the large and small incline angle.The major influences on the leveling are the mechanical vibration,hydraulic vibration,and accuracy of the sensor.The relations between the leveling velocity and the incline angle during the processes of the lateral leveling and the longitudinal leveling are analysed.The results show that with the increase of the incline angle,the leveling velocity increases during the process of the lateral leveling,while the leveling velocity decreases during the process of the longitudinal leveling.The experimental results are in good agreements with the theoretical analyses.This work provides a basis for the automatic leveling of corn harvester in China.