【作者】 王婷；

【导师】 王东坡；

【作者基本信息】 天津大学 ， 材料加工工程， 2005， 硕士

【摘要】 本教研室研制的采用超声冲击提高焊接接头疲劳性能的技术一经实现就受到了学术界的高度关注,成为研究热点。目前,超声冲击技术由于其执行机构轻巧、噪音小、效率高、成本低且节能等诸多优势,已成为一种理想的焊后改善接头疲劳性能的方法。但目前所使用的模拟电源有着自身无法克服的缺陷。数字化电源控制灵活、易于实现柔性化,可以达到更高的稳定性和控制精度,接口兼容性良好。为了很好地解决模拟电源实时性较差和不可回调的缺点,本课题以DSP(数字信号处理器)为控制核心研制了一套数字化超声冲击电源。本文首先设计了系统的硬件电路,包括DSP的最小系统电路、采样预处理电路、输出信号死区形成电路、恒幅控制电路和显示电路。根据DSP的工作主频和控制系统的精度要求,引入倍频器来减小频率调整步长,以实现高精度控制。在软件编写过程中,根据超声冲击机的工作特点对控制算法进行了改进,确定了最佳扫描区域,同时设置了电流门槛值,从而减轻了频率跟踪的压力。循环跟踪阶段,编写了A/D转换程序、相位差计算程序、PWM生成程序、D/A转换程序和参数显示程序,实现了控制思想。联机试验表明,本文研制的基于DSP的数字化超声冲击电源可以使系统工作在谐振状态,冲击过程稳定。所设计的软硬件系统基本实现了预期功能。更多还原

【Abstract】 Once the technique of improving the fatigue performance of welded joints by ultrasonic peening treatment (UPT) has been realized by this research group, it has been paid fully attention to. As for its advantages of handy equipment, little noise, high efficiency, low cost and energy saving, it has been one of the perfect post-weld treatments for improving the fatigue performance of the joints. However, its analog power supply has the shortage that cannot be overcome.Digital power supply can achieve flexible control, high stability and precision and fine interface compatibility. In order to solve the problem of real-time control and back adjustment of the analog power, in this paper, digital ultrasonic peening power supply whose control system is based on DSP (Digital Signal Processor) has been developed.At first, hardware circuit of the system has been designed, including minimum system of DSP, sampling pretreatment, dead zone formation, constant amplitude control and display circuit. According to the frequency of DSP and the requirement of control precision, frequency multiplier has been used to reduce to adjusting step size. In the software programming, control algorithm is improved according to the characteristic of ultrasonic peening machine. Optimal scan region is settled as well as the threshold of the current, so that it is easier for frequency track. The program includes A/D conversion, phase difference calculation, PWM formation, D/A conversion and numeral display.On-line testing shows that, this digital ultrasonic peening power supply based on DSP can make the system work at the resonance state, and the peening process is stable. Both the hardware and software can achieve the expected function.更多还原