| Rice has been one of the main food crops in China.Ridge building has great significance to ensure the water for rice growth,and it has been one of the important means of water storage in paddy field.Dense and reasonable ridge can prevent the occurrence of water infiltration and ensure the demand for water during rice growth.The research on the mechanism of mechanical ridge building in paddy field and the method of high-quality ridge building is great significance to reduce the waste of water resources,improve the operation efficiency,reduce the labor intensity of ridge building and reduce the risk of rice production.The mechanical ridge building of paddy field mainly has the problems of poor soil collection performance and insufficient ridge suppression,and the continuous mechanical construction of ridge at the junction of paddy field cannot be realized.It is mainly reflected in the uneven soil amount and soil amount distribution,low ridge firmness and poor stability,and no effective ridge reconstruction method has been formed.In view of the above problems,combined with the requirements of ridge building technology in paddy field of Heilongjiang province,this paper uses the methods of theoretical analysis,numerical simulation and experimental design to study the operation performance of the key components of the rotary single side ridger in paddy field,rotary cutting soil collecting components,feather superposition suppression device and multi link rotary adjustment mechanism,in order to provide theoretical data support and technical reference for the creation and optimization of ridger in standard paddy field and key operation components.The main contents of this paper were as follows:(1)Determination of soil basic characteristics in rice growing area in Heilongjiang provinceTaking the paddy field black soil in Heilongjiang province as the research object,the basic characteristics of soil particles are measured and analyzed through physical test methods and self built test-bed,mainly including physical characteristics such as soil moisture content,soil permeability coefficient and soil bulk density,friction characteristics such as soil static friction coefficient and soil accumulation angle,soil firmness,soil shear strength and other mechanical characteristics,It provides an important reference basis for the performance test and numerical simulation parameter setting of subsequent rotary cutting soil collecting parts and feather superposition suppression device.(2)Mechanism analysis and performance numerical simulation test of rotary cutting soil collectorThe theoretical analysis of the soil taking stage and soil throwing stage of the rotary cutting soil collector was carried out,and the soil particle kinematics model was established.The working process of the rotary cutting soil collector was numerically simulated by the discrete element software EDEM,and the working mechanism of the rotary cutting soil collector was revealed.This paper mainly explored the influence of the working parameters of the rotary cutting soil collector on its soil collection performance.Taking the rotary cutting soil collector of the rotary unilateral ridger in paddy field as the research carrier,the soil collection virtual simulation optimization test was carried out.The single factor test results showed that the soil collection performance decreased gradually with the increase of working speed,decreased gradually with the increase of forward speed,and increased first and then decreased with the increase of soil depth;The multi factor test results showed that when the working speed of the rotary cutting soil collector was 515.02r/min,the forward speed was 0.6 km/h and the sampling depth was 200 mm,the soil collection quality and stability of the rotary cutting soil collector were the best,the soil collection rate wass 87.22% and the variation coefficient of soil collection uniformity was 6.73%.(3)Simulation analysis and performance test of operation process of feather superposition type pressing deviceCombined with the physical characteristics of soil particles,this paper analyzed the resistance of the feather superposition suppression device in the process of ridge building,determined the main working parameters and completed the parametric design of the feather superposition type pressing device,Based on the finite element method,the rigid flexible coupling simulation model was established by using ANSYS and ADAMS to carry out the numerical simulation and optimization test of the process of building ridge.The multi factor test results showed that when the soil moisture content was 24%,the working speed of the feather superposition type pressing device was 360 r/min and the forward speed was 0.6 km/h,the ridge building performance,operation quality and stability of the feather superposition type pressing device were the best,its horizontal working resistance was 1083.43 N,and the variation coefficient of the uniformity of ridge firmness was 6.52%.(4)Structural design and mechanism analysis of multi link rotary adjusting mechanismAccording to the principle of guide rod mechanism,taking the ridge building working part integrated by rotary cutting soil collecting part and pressing device as the carrying carrier,a multi link rotary adjustment mechanism was designed,and the overall structure and working principle were described and analyzed.The displacement,velocity and acceleration models of the multi link rotary adjustment mechanism were established to clarify the motion law between the rods in the process of offset and rotary adjustment.Based on Ackerman steering principle,the tractor steering model was established to solve the tractor fixed-point turning trajectory and critical position;It also analyzed the moving track and position of the ridge building operation components in the stage I,II and III of ridge building at the corner,clarifies the constraint conditions of each connecting rod in the process of ridge building,and obtained the structure and operation parameters of each rod and the installation parameters of servo electric cylinder,which provided theoretical support for the solution of subsequent motion curves and the design of control system.(5)Design and performance test of rotary control systemThe multi link rotation adjustment control system was designed,the motion curves of the offset and rotation of the multi link rotation adjustment mechanism in each stage of ridge building at the corner were solved,and the hardware structure and software system of the rotation adjustment control system were designed.In order to further explore the influence of the structural parameters and working parameters of the multi link rotary adjustment mechanism on the offset and rotary performance,the indoor rotary adjustment performance test was carried out,focusing on the control accuracy of the rotary adjustment process,so as to provide theoretical and data support for the optimal design of the multi link rotary adjustment mechanism and the integrated configuration of the whole machine of the rotary unilateral ridger in paddy field.(6)Integrated design and field experiment of rotary unilateral ridger in paddy fieldCombined with the agronomic requirements of ridge building of paddy field in Heilongjiang province,it was equipped with multi-level transmission speed change system,fast hitch device,tillage depth adjustment mechanism,direction tail wheel assembly and other components,and the rotary unilateral ridger in paddy field which can continuously build the ridge at the corner of paddy field was integrated and designed.In order to test the field operation performance of the rotary unilateral ridger in paddy field,the basic morphological characteristic parameters of the ridge were measured,focusing on the research on the uniformity of ridge firmness and ridge straightness,intuitively and effectively analyzed the adaptability of the rotary unilateral ridger in paddy field to different soil conditions in Heilongjiang province,and form a systematic research system on the construction mechanism of standard ridge machinery together with the previous research content.This paper will provide reliable technical reference and theoretical support for the further research of ridger in paddy field,effectively promoted the popularization and application of mechanical ridge building technology in paddy field,promoted the construction of high-standard farmland,and speed up the whole process of mechanization of rice production. |
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