| Crawler tractors were widely used in agricultural production because of their advantages of good traction attachment,good stability,and strong climbing ability,especially in hilly terrain with complex terrain.The lateral stability of crawler tractors is a key factor that affects their horizontal contour operations in hilly terrain.In order to improve the lateral stability of the hillside crawler tractor,this article designed an attitude adjustment experiment device of the hillside tracked tractor based on a parallel four-bar suspension,abbreviated as an attitude adjustment device.When the hillside crawler tractor is working on the lateral contour line of the slope,the attitude of the vehicle body is adjusted to ensure the body level,thereby improving the lateral stability,operation safety and comfort of the hillside crawler tractor.The main research contents and conclusions were as follows:(1)Determined a vehicle body adjustment device scheme based on a parallel four-bar suspension mechanism.Requirements for the body posture could be maintained horizontally when the hillside crawler tractor was working on a horizontal contour line on a slope with a gradient not less than 15°,three posture adjustment plans were formulated based on the existing mountain crawler tractor had the hydraulic differential height and finally the posture adjustment plan was determined as a body adjustment device based on a parallel four-bar suspension mechanism..(2)Designed an attitude adjustment device based on a parallel four-bar suspension mechanism,and analyzed theoretically the working process of the posture adjusting device.A mathematical model of parameters such as adjustment cylinder rod stroke,cantilever support length of main and the subordinate rocker,frame attitude adjustment angle,and track of crawler tractor was established,then determined the main parameters of the posture adjustment device.Carried force analysis on the components of the posture adjustment device,established a three-dimensional model of the device,and performed the finite element analysis of the master and the slave rocker using ANSYS software.It was concluded that the region of maximum strain and deformation of rockers obtained could provide a theoretical basis for the testing and analysis of attitude adjusting device.(3)Designed the hydraulic system of the attitude adjustment device to provide the driving force for the attitude adjustment device to work according to the design principle of the hydraulic system.At the same time,the selection of hydraulic components in the hydraulic system was completed.(4)Set up an attitude adjustment test system,including: dynamic signal acquisition system,strain test and analysis system and attitude information acquisition system,Using displacement sensor,strain sensors,and attitude angle sensor to measure the changes in physical quantities such as the displacement of the piston rod,the strain of master and the slave rocker and the attitude angle of the frame during the working process of the attitude adjustment device.The result showed that the maximum adjustment angle of the frame of the attitude adjustment device was 13.8° when the piston rod displacement of the adjustment cylinder was 192 mm.When the device started to adjust the posture on the slope or return to the initial position,the force of the main and the slave rocker susceptive were the largest,and the strain of the same measurement points became larger as the load increased. |
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