【作者】 张炜；

【导师】 王从军；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2011， 硕士

【摘要】 锻造行业是装备制造业得以发展的基础,特别是大型锻件,其尺寸精度是是保证重大技术装备制造质量的一个重要因素。根据美国能源部的调查,美国锻造行业中的废品率大于15%,其主要原因在于缺乏高温热态锻件的测量技术,而这种情况也同样存在于我国锻造行业,为了有效地减少锻件的废品率,需对热态锻件进行现场测量以控制锻压过程的质量。随着我国在能源电力、航空航天、核电、高速列车、化工冶金、船舶等领域的快速发展,大型锻件的需求也日益增加,高温热态物体在线测量技术研究的经济意义也与日俱增。本文结合十一五国防预研项目的相关光学测量研究,对热态锻件测量技术进行了探索性的研究,以期为控制锻压过程的质量提供有力的支持。本文对国内外相关的热态锻件测量技术进行分析研究之后,采用实验室现有的结构光三维测量系统,在成功地完成了测量系统的内外部参数标定的基础上,针对锻件在制造过程中伴随着高温、高压、锻件表面存在空气波动等特点,设计了合理的图像采集方案,然后根据高温热态测量的特点进行相位误差的分析,选择中值滤波算法对光栅图像进行滤波预处理,减少图像噪声对相位误差的影响,选择五步相移法作为系统的相位计算,降低相移误差和系统非线性响应对相位误差的影响,最后整个测量系统在分别使用四步相移算法和五步相移算法的情况下对待测物体进行测量,通过其三维数据的对比,可以发现五步相移算法提高了系统测量精度。更多还原

【Abstract】 Forging industry is the basis of developing equipment manufacturing industry, especially for large forgings, whose dimensional precision is an important factor to ensure the manufacturing quality of major technical equipment. According to the survey of Department of Energy, rejection rate of forging industry in the United States is more than 15%, mainly due to the lack of measurement techniques about hot forgings, and this situation also exists in Chinese forging industry. The field measurement for hot forging parts to control the quality of forging process is needed, in order to effectively reduce forging rejection rate. As China’s rapid development in energy and power, aerospace, nuclear power, high-speed trains, engineering chemistry and metallurgy, shipping and other fields, the demand for large forgings is growing, so is the economic significance of the research on field measurement techniques of high temperature objects. Connected with the related optical measurement research of the Eleventh Five-Year national defense pre-research item, this paper makes an exploratory study on measurement techniques of hot forgings, with a view to provide strong support for controlling the quality of forging process.After making research on the related techniques of measurement of hot forgings at home and abroad, this paper adopts the current structured light 3D measurement system and design the reasonable image acquisition scheme aiming at the characteristics that forgings in the produce process is accompanied by high temperature、high pressure and the airwaves existing in forging surface, on the basis of successfully finishing the intrinsic and extrinsic parameters calibration of measurement system. Then according to the characteristics of high temperature measurement, it makes analysis of phase error and chooses median filtering algorithm to make filtering preprocess of raster image, reducing the picture noises’influence on phase error, and chooses five-step phase-shifting method as phase computation of the system to reduce the influence of phase displacement error and system’s nonlinear response on phase errors, and finally the whole measurement system measures the objects being measured under the situation of separately using five-step phase-shifting method and five-step phase-shifting method, and through the comparison of their three-dimensional data, the Five-step phase shift algorithm improving measurement precision of the system can be found.更多还原