【作者】 刘童玲；

【导师】 胡兵；

【作者基本信息】 华中科技大学 ， 物理电子学， 2007， 硕士

【摘要】 在激光加工领域,激光标刻的应用范围不断扩大,对激光标刻的精度要求也不断提高。本文主要研究一种激光功率适时控制算法及其软件实现。本文首先对激光标刻系统中的振镜特性以及一些常见的标刻误差如:开、关激光延迟、跳转延迟和拐角延迟误差进行了深入研究。虽然通过设置合理的延迟时间可以消除上述延迟误差,但在拐角区域内仍然存在有深度标刻现象。因此我们考虑采用一种参数控制的方式,通过适时改变功率的大小来消除误差,并建立了以实现恒激光能量累积为目标的参数匹配计算机控制模型。模型分析表明,要保证激光标刻的质量,就必须保证激光功率与扫描速度之间的正比关系。在具体的算法实现中需要考虑系统硬件是否具有速度反馈机制:有速度反馈系统中,通常反馈回的是振镜的角速度信号,本文通过对双振镜扫描系统的光路进行研究,给出振镜角速度与扫描速度的换算方法;而对一般系统的算法实现中,关键是要确定标刻矢量段中的变速区域,本文在仔细分析振镜运转规律后,给出了矢量段中加减速区域内的插补点数量以及在这些点上对应的扫描速度。最后,对本激光控制系统的响应性能进行了理论分析,并采用MatLab软件对标刻矢量上的能量分布进行了数值仿真,结果表明本算法能很好的解决深度标刻问题。更多还原

【Abstract】 In the laser processing, laser marking has been applied to many fields, the demand of marker’s precision is also increasing. In this thesis, the algorithm and realizing method of programming for timely control of laser power is presented.Characteristics of galvanometer and some kinds of marking error such as error of pline start and end delay、off vector delay and interseg delay are analyzed in this thesis. Although errors mentioned above can be corrected by setting delay time, overmark still appears at the corner between two connected polylines. In order to timely control of laser power, a parameter-matching computer-controlling model is established to obtain constant accumulative energy in the stuff. According to the analysis of the model, the proportional relationship between laser power and scanning velocity is the necessary qualification to get good quality of marking . Two imaginable situations must be considered: the hardware system has or not have the mechanism of velocity signal feedback. In the feedback system, generally, we only get the angular velocity of galvanometer, a transform method is given in the thesis which can be used to transform angular velocity into scan velocity. In the system without velocity signal, it is most important to make sure the segments at the marking polyline where the scan velocity is changing. The number of points and corresponding velocity in speedup/ speed-down segments can be obtained through the analysis in this thesis.At last, the performance of the laser controlling system is inspected by the theory analysis, and the distributing of energy on the marking polyline is simulated using Matlab software. The results show that the algorithm can solve the overmark problem quite well.更多还原