基于STM32恒流恒温超辐射光源系统设计

随着光纤传感、光纤陀螺等技术的飞速发展,超辐射发光二极管(SLD)运用场所也是越来越多,SLD光源的稳定性对光纤传感系统性能有及其重要的影响,为了提高光纤传感的精度设计了一种基于STM32的恒电流恒温度超辐射光源系统。该系统采用了运算放大器作为放大器件的恒流源电路技术方案确保电流稳定性,使用了PID算法确保温度控制电路稳定性,具有良好触摸屏控制的人机界面。文中对超辐射光源系统的硬件和软件进行了具体阐述。测试结果证明,该系统在正常温度下一定工作时间内都能保证SLD输出功率稳定在±0.01d Bm范围内,能够很好符合相关需求。     

三轴一体化光纤陀螺光源驱动技术

根据三轴一体化光纤陀螺共享光源,要求光源能够提供较大的高精度的恒流以满足实际需要.结合SLD(超辐射发光二极管)光源结构特点及其工作原理,采用恒流和温控方案,设计了新的高精度恒流驱动和温度控制系统.经测试结果表明,设计的系统能够在环境温度为-45℃～ 70℃内稳定工作,实现了高精度恒流和温度驱动控制,满足三轴一体化光纤陀螺对光源驱动的要求.     

四通道SLD光源驱动技术研究

为提高SLD光源的检测效率,在SLD光源驱动技术的基础上,研究了四通道SLD光源驱动技术。针对四通道SLD光源驱动可能面临的诸如电源供电、系统体积、面板显示、通道一致性等问题,文中分别给出了相应的处理技术或解决方法,并通过试验对四通道驱动技术的可实现性和可靠性进行了实际验证。研究结果对更多通道SLD光源驱动和类似电路系统的设计提供了参考。     

光纤陀螺用SLD光源全数字控制系统

超辐射发光二极管(SLD)是干涉式光纤陀螺的理想光源,介绍了全数字SLD光源控制系统的硬件构成、控制软件流程及PID算法。测试结果表明,在-20～50℃温度范围内,光功率波动小于0.3%,平均波长的温度漂移为3×10-6/K,此数控方法在光纤陀螺高精度、工程化研究中有良好的应用前景,对其他半导体激光光源的高精度控制具有通用性。     

光纤陀螺用SLD的光功率自动控制的实验研究

光纤陀螺(FOG)所用光源的特性对光纤陀螺的性能有很大的影响,着重介绍半导体光源超辐射二极管(SLD)的特性,以及SLD的稳定性对光纤陀螺的影响。针对环境温度和驱动电流对SLD光功率稳定性的影响,设计光功率控制方案及相应的驱动控制电路。     

光纤陀螺用SLD光源的光功率稳定性研究

SLD光源的稳定性对光纤陀螺的性能有及其重要的影响。为提高光纤陀螺的精度 ,设计了 SLD光源的数字化控制系统 ,采用“恒流 +温控”的方案 ,并引入了数字 PID控制算法 ,大大提高了光源出纤光功率的稳定性。用实验证明了数字方法的控制效果远远好于目前广泛应用的模拟控制方法     

基于SoC单片机的小型化SLD光源数字控制系统设计

为提高光纤陀螺用超辐射发光二极管(SLD)光源的稳定性,实现光源性能检测和评价的灵活性,在光源工程化生产中常采用数字化控制系统对光源进行控制。以SoC单片机C8051F060为控制检测平台,结合高性能TEC控制器ADN8831和数字PID控制算法,设计了新型小型化光源数字控制系统。实验表明,该光源数字化控制系统体积小,精度高,操作灵活,可扩展性强,具有良好的实用价值。     

SLD光源驱动电路的设计与实验研究

分析了超辐射发光二极管(super lum inescent d iode,SLD)光源的驱动原理,给出了一种利用控制驱动电流和温度来稳定光源输出功率的驱动电路,并通过采集反馈电压来监控功率的输出。通过对SLD光源的驱动实验,得到电流与输出功率具有良好的线性关系,输出光功率的稳定度优于0.002dB。     

光波长边沿解调系统的设置问题

可调激光边沿滤波解调系统是光纤光栅检测超声波的重要测试系统。在测试前需对光源的波长进行正确的设置,否则将造成测量结果严重失真。然而由于受到实验假象的影响,光源波长设置值的正确性不易辨别。因此,以静态试验的方式,分析了系统波长设置不准的原因,研究了光源波长的变化对系统工作性能的影响。最后提出正确调试光源波长的注意事项。     

光纤陀螺用SLD光源的控制方法研究

光源控制技术是光纤陀螺技术研究领域的关键技术之一.为进一步提高光源的控制精度,从SLD光源驱动原理出发,提出光源模拟控制与数字控制方案,分析了电路原理,结合实际研究情况,从恒流精度、温控精度及光功率等关键技术指标出发,对两种方案进行比较并给出结论.     

基于四阶矩法车削颤振可靠性研究*

再生颤振是影响加工质量、加速刀具磨损、刀具破坏的主要原因。以车削加工为研究对象,针对具有不确定参数的车削加工颤振预测问题,研究车削加工系统结构动态特性参数具有随机特性的情况下颤振可靠性建模及求解问题。定义车削加工过程不出现颤振的概率为颤振可靠度,建立车削加工系统可靠性模型,研究四阶矩法求解可靠度的问题,提出利用颤振可靠性叶瓣图方法进行颤振预测。通过模态试验对一车床进行频响函数测试,采用四阶矩法计算获得了颤振可靠度,并与蒙特卡洛法获得的可靠度相比较。结果表明四阶矩法计算获得的可靠度与蒙特卡洛仿真结果一致性很好,但是四阶矩法计算精度高而且计算耗时远小于蒙特卡洛法。进行颤振可靠性切削试验,通过观察振纹和分析噪声功率谱识别颤振,对典型参数进行验证,试验结果与分析结果一致。     

基于有限元分析的滚齿SLD构建

针对稳定性耳垂线图(SLD)应用于滚齿颤振预测时存在动力学参数获取困难、切削深度难以确定等问题,建立了考虑滚刀刀杆柔性的三维滚齿系统动力学模型,通过滚刀极限切屑厚度与轴向进给量的关系计算滚齿系统动力学参数,并在此基础上绘制出滚齿SLD。设计了滚齿颤振实验方案,通过采集的实验数据分析平稳切削与颤振切削振动的特征量,确定颤振频率及颤振主体,证实了所建立的动力学模型及SLD的有效性。所提方法为滚齿工艺颤振预测、切削参数选取提供了一种新手段。     

Chatter and dynamic cutting force prediction in high-speed ball end milling

Machine tool chatter is a serious problem which deteriorates surface quality of machined parts and increases tool wear, noise, and even causes tool failure. In the present paper, machine tool chatter has been studied and a stability lobe diagram (SLD) has been developed for a two degrees of freedom system to identify stable and unstable zones using zeroth order approximation method. A dynamic cutting force model has been modeled in tangential and radial directions using regenerative uncut chip thickness. Uncut chip thickness has been modeled using trochoidal path traced by the cutting edge of the tool. Dynamic cutting force coefficients have been determined based on the average force method. Several experiments have been performed at different feed rates and axial depths of cut to determine the dynamic cutting force coefficients and have been used for predicting SLD. Several other experiments have been performed to validate the feasibility and effectiveness of the developed SLD. It is found that the proposed method is quite efficient in predicting the SLD. The cutting forces in stable and unstable cutting zone are in well agreement with the experimental cutting forces.     

Modeling and Analytical Solution of Chatter Stability for T-slot Milling

T-slot milling is one of the most common milling processes in industry. Despite recent advances in machining technology, productivity of T-slot milling is usually limited due to the process limitations such as high cutting forces and stability. If cutting conditions are not selected properly the process may result in the poor surface finish of the workpiece and the potential damage to the machine tool. Currently, the predication of chatter stability and determination of optimal cutting conditions based on the modeling of T-slot milling process is an effective way to improve the material removal rate(MRR) of a T-slot milling operation. Based on the geometrical model of the T-slot cutter, the dynamic cutting force model was presented in which the average directional cutting force coefficients were obtained by means of numerical approach, and leads to an analytical determination of stability lobes diagram(SLD) on the axial depth of cut. A new kind of SLD on the radial depth of cut was also created to satisfy the special requirement of T-slot milling. Thereafter, a dynamic simulation model of T-slot milling was implemented using Matlab software. In order to verify the effectiveness of the approach, the transfer functions of a typical cutting system in a vertical CNC machining center were measured in both feed and normal directions by an instrumented hammer and accelerators. Dynamic simulations were conducted to obtain the predicated SLD under specified cutting conditions with both the proposed model and CutPro?. Meanwhile, a set of cutting trials were conducted to reveal whether the cutting process under specified cutting conditions is stable or not. Both the simulation comparison and experimental verification demonstrated that the satisfactory coincidence between the simulated, the predicted and the experimental results. The chatter-free T-slot milling with higher MRR can be achieved under the cutting conditions determined according to the SLD simulation.     

Dual-beam stealth laser dicing based on electrically tunable lens

In this paper, we present the development of a high-speed dual-beam stealth laser dicing (D-SLD) method for processing semiconductor wafers based on electrically tunable lenses (ETLs). An SLD system utilizes a laser beam to dice a wafer by inducing interior defects without modifying the surface characteristics of a wafer, thereby presenting significant advantages over conventional dicing methods, e.g., blade dicing or laser ablation. Currently, the throughput of SLD is limited by the serial scanning process; in addition, wafer misalignment and the warpage effects together deteriorate the dicing quality and yield and demand high-cost multi-axis precision stages. To address the issue, we parallelize the dicing process by splitting the laser focus into two foci, where the laser intensity at different depths are automatically adjusted to achieve optimal dicing condition. By combining the height sensor and ETLs, each laser focus, i.e., laser scan lines, can be rapidly controlled axially to compensate the wafer curvature and misalignment errors in real time, leading to substantially improved precision (kerf width < 2 μm) and speed, demonstrated by our experimental results. The new dual-beam laser dicing system presents an effective solution for high-speed wafer dicing as well as other important engineering applications, e.g., fabrication of micro-devices and optical components.