【作者】 关朝亮；

【导师】 戴一帆；

【作者基本信息】 国防科学技术大学 ， 机械工程， 2010， 博士

【摘要】 复杂光学曲面在提高光学系统性能。实现特殊光学特性。减少系统零件数量。减小系统尺寸等方面有许多显而易见的优点。随着光电信息技术的迅猛发展。复杂光学曲面零件的应用领域将十分广阔。复杂光学曲面无疑是非球面光学零件发展和应用的趋势之一。但目前还远未能纳入到现代光学系统的主流当中。问题的重要原因之一就在于复杂光学曲面的超精密制造相当困难。随着机床技术的进步。直线电机驱动、主轴伺服等一系列新技术应用于超精密车床的设计中。使得一种新的基于慢刀伺服技术的超精密车削创成加工成为可能。机床具有主轴伺服的多轴联动功能。刀具可严格按照规划路径相对于工件复杂表面运动。实现各种高精度的复杂曲面加工。本文以慢刀伺服车削技术作为复杂光学曲面的加工手段。对其创成原理、刀具设计、轨迹规划和精度分析等几方面的关键技术开展研究。1、慢刀伺服超精密车削技术原理及关键技术通过对机床结构和创成运动的分析。研究了慢刀伺服车削加工原理。揭示了其与快刀伺服和普通三轴数控加工之间的根本区别。分析指出：直线轴运动性能、先进插补技术以及主轴位置控制是技术关键所在。为研究制约进给驱动性能的关键因素。建立了直线驱动进给系统模型。开展了一系列仿真及实验研究。研究表明进给轴达到高动态、高精度驱动的必要条件是：导轨具有足够的动态刚度。反馈环节量化误差噪声抑制到较低水平。针对复杂曲面数控插补问题。提出了适应加工特点的参数计算方法。将PvT插补技术引入复杂曲面车削。解决了使用线性插补存在的弊端。从伺服轴驱动能力限制和轨迹跟踪精度两个角度分析。得到伺服轴执行能力幅频图。用于确定可加工范围。这些研究为构建慢刀伺服加工平台。正确选择慢刀伺服加工方法奠定了理论基础。2、复杂光学曲面慢刀伺服超精密车削的刀具设计理论刀具设计是指刀具模型的建立和几何参数的确定。运用解析分析方法。得到了切削刃轮廓的空间解析模型。为确定刀具几何参数的合理范围。从复杂曲面面形、加工表面微观形貌、加工表面光学特性以及加工材料等角度。研究了对刀具几何参数的制约关系。复杂曲面每一点处对刀具的限制均不相同。通过对曲面基本方程的分析。推导出代表制约关系的关键矢量。解决了复杂曲面对刀具制约问题。这些工作为复杂曲面慢刀伺服车削加工合理设计刀具提供了理论支撑。3、复杂光学曲面慢刀伺服超精密车削的刀具路径规划理论精确规划刀具路径是复杂曲面车削加工的基本要求。在合理规划刀具接触点轨迹的基础上。采用误差控制的方法离散。提出法向偏置和稳定x轴偏置两种方法补偿刀具切削刃轮廓。结合提出的刀位点修正方法解决前角非零刀具过切与欠切问题。可高效精确获得合理刀具路径。针对刀具路径在曲面边界外的情况。创造性地利用空间曲线插值技术在螺旋曲线上延拓刀位轨迹。实现了刀具路径的平滑过渡。为达到提高复杂光学曲面车削精度的目的。提出了基于刀位点修正的慢刀伺服车削误差补偿算法。利用数据滤波方法或Zemike重构方法。从加工误差中分离出需要补偿的误差分量。对刀具路径进行修正后再次加工。可实现特定面形误差成分的补偿。这些研究为生成高质量的数控程序。拓展加工范围。提高加工精度提供了理论指导。4、慢刀伺服超精密车削的精度建模与仿真分析加工过程定量分析包含几何仿真和误差分析两个相互联系的重要方面。用z-map矢量表达曲面。以刀位点间隔作为仿真步长。通过坐标变换和拟合算法获得刀刃轮廓扫描曲面。讨论了矢量与NuRBS曲面交点的求解方法。对z-map矢量进行更新。解决了慢刀伺服车削的几何仿真问题。针对各种误差源的影响。详细研究了误差特征矩阵。以多体系统理论推导了包含误差因素的成形函数。解决了仿真分析误差影响的问题。精度仿真、预测、分析系统的建立为深入认识慢刀伺服车削机理。开展精度分析。预测加工结果等提供了有力手段。5、复杂光学曲面慢刀伺服超精密车削实验复杂光学曲面加工实验用于所述理论的全面验证。离轴抛物面镜的加工主要体现了以仿真分析为指导。解决刀具对中误差对面形精度的影响；在凹球面反射镜阵列加工中。主要体现了刀具路径规划方式对伺服轴动态性能的不同要求；在波前校正眼镜加工中。主要验证了加工、检测、修正、再加工循环对提高面形精度的作用；螺旋相位板、连续相位板的加工主要体现了慢刀伺服技术在解决传统工艺难题方面的优势。从上述几方面入手。探讨了如何利用慢刀伺服超精密车削技术实现复杂光学曲面高精度加工。研究成果对慢刀伺服车削加工机床的建立具有指导作用。对复杂曲面慢刀伺服车削加工具有技术支撑作用。更多还原

【Abstract】 Freeform surfaces can be used in optical systems to achieve novel functions, improve performances, reduce size, and decrease the cost of various products. Therefore, optical freeform surfaces find applications in the fields of optics, medicine, fiber communication, life science, aerospace etc. Freeform optics has become the key element of quantitative light technology, which is becoming increasingly important in various fields. However, designers are reluctant to utilize freeform surfaces due to the complexity and uncertainty of their fabrication. Slow Slide Servo is a novel machining process capable of generating freeform optical surfaces or rotationally non-symmetric surfaces at high levels of accuracy. In order to achieve high accuracy optical complex surface by using Slow Tool Servo turning, the major research efforts include the following points.1. The theory of Slow Tool Servo turning and key technologies. A systematic introduction of the theory of Slow Tool Servo turning is first given by analyzing machine architecture and movements. By comparing with some other conventional technologies, the key technologies are high dynamic feed drive system, advanced interpolation technology and position control spindle technology. Then, the research emphasis on the performance of feed drive system and curve interpolation algorithm. Several aspects are discussed to improve the motion accuracy and control performance of feed drive system. PVT interpolation algorithm is introduced to Slow Tool Servo turning to overcome inherit drawback of conventional interpolation algorithm. In order to estimate the machining scope and accuracy, study on the machining capacity of Slow Tool Servo turning.2. The design theory of tool geometry parameters in ultra-precision Slow Tool Servo turning complex optical surface. Based on the requirements of slow tool servo, two types of tool are designed and analytic geometry models of cutting edge are built. A geometrical approach is introduced to formulate the relationship between tool tip and complex surface. By virtue of surface analytic method, the problem is solved efficiently, combined with the NURBS representation of complex surface. Experiments are carried out to validate solving algorithm. In addition, the relation models between tool shape and roughness, optical property and materials are built.3. The programming theory of tool path in ultra-precision Slow Tool Servo turning complex optical surface. In the basic design algorithm of complex optical surface slow tool servo turning, firstly study on the tool contact path design method and accuracy control skills of discrete process. Then, cutting edge compensation problem is considered. Two algorithms (normal direction compensation method and keeping X steady method) are proposed to avoid interfaces between surface and tool tip of zero rake angle. A tool path correct algorithm is developed to overcome over cutting and lack cutting due to non-zero rake angel. With regard to the calculate problem of tool path outer of surface region, space curve interpolation algorithm and surface continuation methods are proposed. In order to improve the manchining accuracy, error compensation algorithm is studied base on the tool path correction.4. The error model and simulation algorithm of Slow Tool Servo turning. Base on the discrete vector intersection, geometry simulation algorithm of slow tool servo turning is constructed. Then, major error sources and its transformations in complex surface turning are analyzed. An error model of slow tool servo turning is built base on multi-body theory. Experiments are carried out to validate simulation algorithm and error model.5. Finally, plentiful experiments are performed on a variety of complex optical surfaces including off-axis parabolic, array lenses, wave front correcting glass, spiral phase plate, continuous phase plate and so on. The successful machining results prove the validity and advantages of the proposed algorithms and the proposed process improvements.更多还原