| Ratoon rice is a kind of rice that were harvested its head and stem at its first mature period,leaving 1/3 stubble and underground roots to grow up.The dormant buds on it would re-germinate and could be harvested at its second mature period.Ratoon rice can increase the yield per unit area of paddy field and the income of farmers,so in recent years the ratoon rice has been widely promoted in Chinese rice cultivation area.However,due to the harvesting of the first season of the ratoon rice with agronomic requirements of low stubble pushing rate,high stubble and working in wet mud feet field,the existing rice harvester technology is difficult to meet,resulting in the limitation of its promotion.Aiming at the above research background and the requirement of ratoon rice harvesting,this paper designed a completely tracked chassis for harvester of ratoon rice based on the theory of tracked vehicle design for the purpose of reducing the stubble pushing rate by chassis and improving ground clearance of the ratoon rice harvester.And carried on the performance test and power test,the main research content and results are as follows:(1)Simulation and analysis of the rate of stubble pushing by chassis of the completely tracked harvester for ratoon rice.Based on the tracked vehicles design theory,six influential factors were chosen to analyze: width of the cutting range Z,track gauge B,length of track on ground L,width of the track b,turning radius R0,the longitudinal distance between central axis of chassis and cuter of cutting platform X.Both a structure model of the chassis of the completely tracked ratoon rice harvester and a stubble pushing model(going straight and turning)in the field were established.Furthermore,a rice planting model was set as follows: its planting row spacing was i,hill spacing was c,and diameter of hill was br in the field.Then the influence of various parameters on the rate of stubble pushing was analyzed.Under the same planting conditions and the parameters of the completely tracked harvester,the results showed that the rate of stubble pushing δ 1 decreased with the ratio between Z and b increased when the harvester was on straight way;while on turning way,the δ2 decreased with the turning angle θ and R0 increased.The rate of stubble pushing was not affected by X.Both B and the difference between Z and B were the least common multiple between the row spacing and hill spacing was conducive to reduce rate of stubble pushing.Under the condition of the same ground pressure,the increase of the Z was beneficial to reduce the rate of stubble pushing.When a completely tracked ratoon rice harvester was designed for working in paddy field,some rules could be used for reducing the rate of stubble pushing,such as B and L should be reduced under the premise of satisfying the ground pressure;Z should be increased;B and the space between Z and B should be the least common multiple between the row spacing and hill spacing;also a rotary walking path and the preferable large turning radius R0 should be used combining shape and area of the field.The integer times of relationship between rice planting row spacing and hill spacing was suggested on agronomy.This study provided reference for the design of the chassis and the field walking scheme of the completely tracked ratoon rice harvester.(2)Analysis of the maneuvering performance of completely tracked harvester for ratoon rice.Analyze the complete tracked vehicle’s traveling principle and also analyze the relationship among traveling speed,parameters of the traveling device and motion parameters.Then analyze the turning principle,turning mechanics and turning conditions.Finally,analyze the complete tracked vehicle’s ability to go through raised path and gap.The conclusion of this analysis could provide design bases for complete tracked harvester’s chassis for ratoon rice.(3)The overall design of the complete tracked harvester for ratoon rice.Based on the analysis of the rate of stubble pushing,the analysis of the maneuvering performance of the chassis,theory of Tracked Vehicle Design and Theory of Mechanical Design,combining the environment and characteristics of harvesting ratoon rice operation in field,using Pro/E、CAD and other software as tools,designed the running system,control system,transmission system of the completely tracked harvester for ratoon rice and manufactured a prototype(4)Build of a testing platform for the chassis of the completely tracked harvester for ratoon rice.We built a power test platform which mainly contains a torque sensor.In terms of power supply,this testing platform using a 12 V DC battery for power and using a12-220 V inverter to transform the 12 V DC into 220 V AC,which is used to supply the power of the torque power meter and the torque power meter will supply the power for torque sensor.In terms of the testing methods,in this testing platform,the torque sensor can transmit the rotating speed signal and the torque signal to the torque power meter,which will display rotating speed,torque and power on it.It also can transmit these signals through a kind of software called M400,after which the laptop can save the data.The testing method which is adopted can collect the power of chassis of the complete tracked harvester for ratoon rice when it travels steadily accurately.This testing method can also acquire the power which is needed to drive the chassis directly.(5)The performance test of the completely tracked chassis of harvester for ratoon rice was carried out both on cement ground and in the field.Mainly tested speed and travel offset rate on the cement ground,chassis power consumption with different speed and different quality as the impact factor in the field,and tested its turning power consumption and turning angular velocity.The test results are as follows: 1)The actual highest speed on cement ground under different gear are as follows:Ⅰ gear 1.120 m/s,Ⅱ gear 1.403 m/s,Ⅲ gear 1.957 m/s.The actual maximum speed is less than the theoretical maximum speed;The travel offset rate on the cement ground is 4.93%,less than the provisions of 6% in GB / T 15370.4-2012 "Agricultural tractor general technical conditions Part 4: Crawler tractor".2)We did experiment in the field with an average soil robustness of 383 kPa(depth 150 mm)and an average soil moisture content of 25.98%(depth 100-150 mm).We tested the straight power consumption under the condition of the fixed chassis quality(2200kg)with different speed levels(0.6,0.8 and 1.0m/s);We also tested the angular velocity and power consumption when turning under the condition of a certain chassis quality(2200kg)and a certain initial velocity(1m/s).Conclusions are as follows: the straight power consumption by chassis of the completely tracked harvester for ratoon rice increased with the speed and quality of the whole machine increased;The turning power consumption was 13.63 kW,turning angular velocity was 0.486 rad/s and turning load ratio was 1.63 under the condition of a certain chassis quality(2200kg)and a certain initial velocity(1m/s). |
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