| Heilongjiang Province is one of the main provinces for rice cultivation.The growth of weeds in paddy fields directly affects the quality and yield of rice.The implementation of green,scientific and effective weed control technology in paddy fields is of great significance to achieve high quality and high yield of rice and improve soil structure.Mechanical weeding operation space between the paddy fields is small,and it is easy to damage the seedlings during work.In addition,the weeding operation experiment is limited by the season,and the design and development cycle is long.Aiming at the above problems,this paper designs an inverted V-shaped counter-rotating between plant weeding component for paddy fields.The component has been theoretically analyzed,simulated and tested in the laboratory,and has been verified in the field.The inverted "W" 9-point sampling method was used to count and classify the weeds in the paddy fields after 20 days of transplanting rice seedlings in Jiamusi City.The diameter and height of rice seedlings,barnyardgrass,and dwarf grass were measured.characteristic.The geometric analysis calculation and experiment of the weeding components among the paddy fields have determined their main structural parameters.The fuzzy comprehensive evaluation method is adopted to select the component materials.MATLAB 2018 b software is used to simulate the motion equation of the spring tooth,and the trajectory of the spring tooth is obtained.Through the indoor test,the "fish scale"-shaped soil cutting trajectory was obtained,which verifies the consistency between the theoretical analysis of the component and the motion simulation.Using Creo 5.0,Hyper Mesh 2017,LS-Pre Post and LS-DYNA software to jointly simulate the interaction process of paddy field weeding components and soil.The single-point ALE multi-substance body unit algorithm is used to couple the soil and water with multi-substances,which realizes the material transportation between the soil and the water layer under the disturbance of the inter-plant weeding component;the inter-plant weeding component and the soil are established through the penalty function method.The fluid-solid coupling finite element model of water interaction.By analyzing the stress field and the flow field of the soil-water model,the dynamic behavior process of soil cutting by weeding parts in paddy field is explained.Using single factor test and orthogonal test,simulation analysis of the influence of machine forward speed,rotary velocity of component and thickness of water layer on coupling stress and soil disturbance rate.Developed a test bench for intelligent paddy field weeding components between plants,and calibrated the machine’s forward speed and component rotation speed.According to the simulation test results,the quadratic orthogonal rotation test is carried out with the three factors of machine forward speed,component rotation speed and water layer thickness combined with the response surface method,and the first-order interaction of each factor and its effect on the interaction between the paddy field weeding component and the soil is obtained.The influence law of stress and weeding rate during operation.The primary and secondary sequence of factors affecting stress is: thickness of water layer > machine forward speed > rotary velocity of component > machine forward speed×thickness of water layer > rotary velocity of component ×thickness of water laye r > machine forward speed × rotary velocity of component;the primary and secondary sequence of factors affecting weeding rate is: rotary velocity of component >thickness of water layer > machine forward speed > rotary velocity of component × thickness of water layer> machine forward speed × rotary velocity of component > machine forward speed ×thickness of water layer,which is consistent with the conclusion of simulation test.Using multiobjective optimization design combined with Design-Expert 8.0.6 software optimization module,the optimal solution can be obtained when the machine’s forward speed is 0.76 m/s,the rotary velocity of component is 112.00 r/min,and the thickness of water layer is 0.01 m.In order to verify the optimization results,indoor and field experiments were carried out.The experimental results showed that the relative error between the optimized results and the experimental results is 0.42%,the relative error of the weeding rate is 0.80%,and the seedling damage rate is 4.16%,which meets the requirements of the weeding component in the paddy field.Agronomic requirements for mechanical weeding. |
