中文摘要：

通过定义超声回波相关时频特征量，提出基于超声回波时频特征量的焊点质量自动评价方法。通过数据统计分析，建立了便于在线自动检测的量化焊点质量评价标准，实现了汽车点焊质量的自动化评价。实际检测效果表明，基于该方法的检测系统能够快速有效地自动识别八种焊点质量类型，能够初步运用于汽车点焊质量的在线自动检测。

英文摘要：

A spot welding quality automatic evaluation methodology was proposed by defining the time-frequency characteristics of ultrasonic echo, and a spot welding quality evaluation criterion was built, which was convenient for online automatic detection by data statistical analysis. Finally, vehicle spot welding quality was evaluated automatically. Practical test results indicate the detecting system based on the proposed method can automatically identify eight types of spot welding quality quickly and effectively, so this system may preliminarily apply to online automatic detection of spot welding quality.