【作者】 李因武；

【导师】 李建桥；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2005， 博士

【摘要】 综合分析土壤/固体界面粘附系统的影响因素和性能指标,明确提出将软测量技术应用于界面粘附系统动态过程的数值模拟,选择法向压力和含水量为辅助变量,估算难以直接测量的法向粘附力、切向粘附力、摩擦力。在试验研究土壤/金属界面法向粘附特性的同时,分析不同试验条件下平面板表面法向压力的分布规律,比较平面板与曲面板表面受力状况的不同,利用软测量技术和平面板表面法向压力回归方程,对模型铲刀推土过程的阻力进行数值计算,并以此为样本构建BP 神经网络,对模型铲刀土壤动态粘附系统进行数值模拟并对模拟试验结果进行试验验证。结果表明,将软测量技术应用于土壤/推土板界面粘附系统动态过程的研究,以模拟试验部分代替真实试验的方法可行。研究结果为土壤/推土板界面粘附系统动态过程的研究提供了有力手段。更多还原

【Abstract】 Adhesive interface system exists between soil and the surfaces of soil-engaging components on a variety of terrain machines including tillage and sowing machines. This phenomenon of soil adhesion not only increases the working resistance and energy consumption of these machines, but also decreases the quality of work. Adhesive interface system is an important object in the study of Soil Adhesion Mechanics, and the simulation of dynamic process on the adhesion interface system between soil and solid is a new method in the study of Machine Soil Dynamics. Base on the result of Soil Adhesion Mechanics and Machine Soil Dynamics, a structural model is confirmed by analyzing the inflection factor and performance target of the adhesion interface system. Method to obtain the performance equation of the adhesion interface system between soil and solid, functional relation between the inflection factor and performance target is discussed. Soft-sensing technique is a hotspot in the process control and measurement, parameter and variable, which are difficulty to measure directly, can be estimated by those parameters and variables, which can be measured directly. Application of soft-sensing technique in the study dynamic process on the adhesion interface system between soil and solid is bring forward in the paper. Normal pressure and moisture content being selected as secondary variable to estimate or calculate those performance targets of the adhesion interface system, such as normal adhesion force, tangential adhesion force and friction. Soft-sensing technique offer a new method in the quantitative study of adhesive interface system. A test schedule for the soil dynamic adhesion property has been established for the loading speed, unloading speed, and wave range of normal loads. Test results show that normal adhesion force increases with the enlarging of loading speed, unloading speed and the amplitude of load under the test condition. The faster the contact speed between the soil surface and the steel sample, the greater of normal adhesion force because of the larger impact and more overshoot. The faster the unloading speed between the soil surface and the steel sample, the greater of normal adhesion force because of the instantaneous vacuum absorbability in the interface. The greater the amplitude of load, the soil sinkage shows the same wave range of the wave range of normal loads, but there exist a lag of time. Research of working process of soil-engaging components can be simplified as the study of the interaction between soil and bulldozing plate, and bulldozing plate include plane blade and curve blade. Results by analyzing the influence of cutting angle and forward speed to the draft resistance and normal pressure distribution of plane blade show that, the maximum of the normal pressure is on the middle of cutting edge of plane plate, along with remoteness of cutting edge, value of the normal pressure decreases. Value of the normal pressure on the surface of plane blade increases along with the increasing of cutting angle and forward speed. The normal pressure distribution influences the force of each part on the surface of plane blade. Plane blade is considered as a combination of many little plane blades, value of the normal pressure is considered as unchanged if size of plane blade is very little, horizontal and vertical components of draft resistance and slidingresistance are function of the normal pressure, the total force of plane blade is composed by the force of each little plane blade. The performance equation of the adhesion interface system between soil and plane blade is established, and it provides a mathematical model, which is useful in obtaining of the performance equation of the adhesion interface system between soil and curve blade. The surfaces of soil-engaging components is the combination of curve blade and plane blade commonly, study of interaction between soil and curve blade has more signification than that of plane blade. When considering the different parameters and conditions involved in the soil-tool interaction system, it becomes a difficult work to study the interaction between soil and curve blade variously, and it is essential to use numerical simulation instead of physical test to solve this problem. In the same way, curve blade is considered as a combination of many little plane blades with different cutting angle, and the total force of curve blade is the combination of the force of each little plane blade. The research results of plane blade are applied in the numerical simulation of the draft resistance and frictional resistance of curve blade. The BP neural network is used to “learn”results of the numerical simulation to the draft resistance and frictional resistance of curve blade, establishing the performance equation of the adhesion interface system between soil and curve blade, then to simulate the test results of interaction between soil and curve blade. The BP neural network has a structure of 3×10×4, input facts of the BP neural networks are cutting angle, front reversal angle and forward speed, output facts are horizontal and vertical components of draft resistance and sliding resistance. The correctness of the output facts is more than 94%; it means the performance equation of the adhesion interface system has a high forecasting accuracy and favorable generalization ability.更多还原