含运动副间隙平面连杆机构运动时变可靠性研究

发布时间：2019-05-07 08:44

【摘要】：随着现代科技的发展,机械不断地向高速、轻质、重载,高精度方向发展。机构运动精度已成为影响机械产品质量的重要因素。通常影响机构运动精度的因素有构件几何公差、运动副间隙、构件的受力受热变形、构件的材料和机构运动输入波动等。本文以平面连杆为研究对象,对考虑尺寸公差、运动副间隙和结构误差的平面四杆机构进行了机构运动精度可靠性分析。本文给出了机构运动精度的一般理论,同时采用环路矢量微分法建立了含间隙平面连杆机构运动精度模型。基于前面机构运动精度模型采用一次二阶矩法对机构运动精度可靠性进行了瞬时及时变可靠性分析。为了检验本文所采用解析法的正确性,本文给出了蒙特卡洛方法结果进行对照。然后对考虑结构误差的平面连杆机构的机构运动精度可靠性处理,本文提出等效误差模型的方法将其转换为不含结构误差的机构进行求解,该方法揭示了结构误差对机构运动精度可靠性的作用机理。将解析法与蒙特卡洛方法结果对比,验证了本文所采用的随机模型、机构运动精度模型和机构运动精度可靠性理论是合理有效的。
[Abstract]:With the development of modern science and technology, machinery continues to develop in the direction of high speed, light weight, heavy load and high precision. Mechanism motion accuracy has become an important factor affecting the quality of mechanical products. Generally, the factors that affect the kinematic accuracy of the mechanism include the geometric tolerance of the component, the clearance of the moving pair, the thermal deformation of the component under force, the fluctuation of the material and the motion input of the mechanism and so on. In this paper, the reliability analysis of kinematic accuracy of planar four-bar mechanism considering dimensional tolerance, clearance of kinematic pair and structural error is carried out with planar connecting rod as the research object. In this paper, the general theory of the kinematic accuracy of the mechanism is given, and the kinematic accuracy model of the planar linkage with clearance is established by using the loop vector differential method. Based on the motion accuracy model of the front mechanism, the reliability of the kinematic accuracy of the mechanism is analyzed by means of the first order second moment method, and the instantaneous and time varying reliability analysis is carried out. In order to verify the correctness of the analytical method used in this paper, the results of Monte Carlo method are compared. Then, to deal with the reliability of the kinematic accuracy of the planar linkage mechanism considering the structural error, the equivalent error model is proposed in this paper, which can be transformed into a mechanism without structural error to solve the problem. This method reveals the mechanism of the effect of structural error on the reliability of the kinematic accuracy of the mechanism. The results of the analytical method and Monte Carlo method are compared to verify that the stochastic model, the kinematic accuracy model of the mechanism and the reliability theory of the kinematic accuracy of the mechanism are reasonable and effective.
【学位授予单位】：西华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH112

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