A Computer-Controlled Polishing Machine

Describes a computer controlled polishing machine utilizing a small polisher with specified movement to figure optical surfces having strict dimensional requirements. The system is especially applicable in figuring aspherical surfaces, beginning with the best fit sphere if the departure from the desired surface is not large. An interferometric measuring system is desiigned to form a closed loop control during processing.

Computer Controlled Polishing of the Off-axis Aspheric Mirrors

In this paper, the manufacturing and testing procedures to make large off-axis aspherical mirrors are presented. The difficulties in polishing and testing for both circular aperture and rectangular aperture mirrors are previewed, and a possible solution is given. The two mirrors have been polished by means of CCOS, and the final accuracy is 25nm rms for 770mm×210mm rectangular mirror and 20nm rms for φ600mm circular mirror. These results just meet the optical tolerances specified by the designer, and the manufacturing and testing procedures presented here show good ability to make the large off-axis aspherical mirrors.

Composite Adaptive Control of Belt Polishing Force for Aero-engine Blade

The existing methods for blade polishing mainly focus on robot polishing and manual grinding.Due to the difficulty in high-precision control of the polishing force,the blade surface precision is very low in robot polishing,in particular,quality of the inlet and exhaust edges can not satisfy the processing requirements.Manual grinding has low efficiency,high labor intensity and unstable processing quality,moreover,the polished surface is vulnerable to burn,and the surface precision and integrity are difficult to ensure.In order to further improve the profile accuracy and surface quality,a pneumatic flexible polishing force-exerting mechanism is designed and a dual-mode switching composite adaptive control(DSCAC) strategy is proposed,which combines Bang-Bang control and model reference adaptive control based on fuzzy neural network(MRACFNN) together.By the mode decision-making mechanism,Bang-Bang control is used to track the control command signal quickly when the actual polishing force is far away from the target value,and MRACFNN is utilized in smaller error ranges to improve the system robustness and control precision.Based on the mathematical model of the force-exerting mechanism,simulation analysis is implemented on DSCAC.Simulation results show that the output polishing force can better track the given signal.Finally,the blade polishing experiments are carried out on the designed polishing equipment.Experimental results show that DSCAC can effectively mitigate the influence of gas compressibility,valve dead-time effect,valve nonlinear flow,cylinder friction,measurement noise and other interference on the control precision of polishing force,which has high control precision,strong robustness,strong anti-interference ability and other advantages compared with MRACFNN.The proposed research achieves high-precision control of the polishing force,effectively improves the blade machining precision and surface consistency,and significantly reduces the surface roughness.

Movement Modeling and Control for Robotic Bonnet Polishing

With the increasing demand for high-precision optical components,bonnet polishing technology is increasingly being used in the polishing process of optical components owing to its high removal efficiency and high surface accuracy.However,it is expensive and difficult to implement dedicated bonnet polishing machine tools,and their processing range is limited.This research combines bonnet polishing technology with industrial robot-assisted processing technology to propose a robotic bonnet polishing control model for large-diameter axisymmetric aspherical optical components.Using the transformation relations of the spatial coordinate system,the transformation relations of the workpiece coordinate system,local coordinate system of the polishing point,and tool coordinate system of the bonnet sphere center are established to obtain the bonnet precession polishing motion model.The polishing trajectory of large-diameter axisymmetric aspherical components and the variation in the linkage angle difference were simulated by adding an efficiency-optimal control strategy to the motion model.The robot motion was simulated in Robostudio to verify the correctness of the precession motion model and control algorithm.Lastly,the robotic bonnet polishing system was successfully applied to the polishing process of the optical components.

Design of Passive Constant‑Force End‑Effector for Robotic Polishing of Optical Reflective Mirrors

Polishing plays an indispensable role in optical processing,especially for large-aperture optical reflective mirrors with freeform surfaces.Robotic polishing requires effective control of the contact force between the robot and the mirror during processing.In order to maintain a constant contact force during polishing,traditional polishing robots rely on closed-loop control of air cylinders,whose performances heavily rely on high-fidelity force sensing and real-time control.This paper proposes to employ a compliant constant-force mechanism in the end-effector of a polishing robot to passively maintain a constant force between the robot and the mirror,thus eliminating the requirement for force sensing and closed-loop control.The compliant constant force mechanism utilizing the second bending mode of fixed-guided compliant beams is adopted and elaborated for the passive end-effector.An end-effector providing a constant contact force of 40 N is designed and prototyped.The polishing experiment shows that the passive constant-force end-effector provides stable contact force between the robot and the mirror with fluctuation within 3.43 N,and achieves RMS(Root Mean Square)lower thanλ/10(λ=632.8 nm)of the polished surface of the largeaperture optical reflective mirror.It is concluded that the constant-force compliant mechanism provides a low-cost and reliable solution for force control in robotic polishing.

A Laser Scanner-Stage Synchronized System Supporting the Large-Area Precision Polishing of Additive-Manufactured Metallic Surfaces

This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing demands for high surface quality in metal additive manufacturing.The proposed synchronized control system is composed of a motion decomposition module and an error synthesis module.The experimental results show that stitching errors can be avoided thanks to continuous motion during laser processing.Moreover,in comparison with the existing step-scan method,the processing efficiency of the proposed method is improved by 38.22%and the surface quality of the laser-polished area is significantly enhanced due to a more homogeneous distribution of the laser energy during the material phase change.The proposed synchronized system paves the way for high-speed,high-precision,and large-area laser material processing without stitching errors.

复杂曲面机器人磨抛技术研究现状与趋势展望综述

在航空、能源、交通、军工等国家战略领域中,针对复杂曲面零件的自动化、高质量和高效率磨抛需求,对近年来国内外工业机器人磨抛加工关键技术及集成系统的研究和应用进展进行了综述。首先,从复杂曲面机器人磨抛机理及工艺优化、磨抛运动轨迹规划、磨削力控制等方面总结了复杂曲面机器人磨抛技术的研究成果;然后,介绍了国内外机器人磨抛集成系统应用现状;最后,分析了复杂曲面机器人磨抛技术的主要问题以及发展趋势,为该技术的发展提供了重要的指导和方向。研究结果表明:当前该技术存在的主要问题包括磨抛机理不够清晰,数学模型不够准确,复杂曲面机器人磨抛轨迹规划效率不高,磨抛力的控制仍不够精准等;另外,磨抛工艺参数优化、机器人力位混合控制、机器人高精度标定与误差补偿、基于数字孪生的机器人磨抛在线监控、机器人磨抛细分应用场景等方面的研究和实践将极大地推动机器人磨抛技术的发展和应用。

全口径环形抛光的光学元件面形误差影响因素及其控制

全口径环形抛光是加工大口径平面光学元件的关键技术之一,其瓶颈问题是元件面形的高效高精度控制。通过研究元件面形的影响因素及其控制方法从而提升其确定性控制水平。围绕影响面形误差的运动速度、抛光盘表面形状误差和钝化状态等关键工艺因素,建立基于运动轨迹有效弧长的环形抛光运动学模型,揭示了抛光盘表面开槽槽型对面形误差的影响规律;提出了采用位移传感器以螺旋路径扫描抛光盘表面并通过插值算法生成其形状误差的方法,建立基于小工具的子口径修正方法,实现了抛光盘形状误差的在位定量修正;提出抛光盘表面钝化状态的监测方法,研究了抛光盘表面钝化状态对面形误差的影响规律。结果表明:抛光盘表面开槽采用环形槽时元件表面容易产生环带特征,采用径向槽、方形槽和螺旋槽时元件表面较为匀滑;通过在位定量检测和修正抛光盘形状误差,可显著提升元件的面形精度;随着抛光盘表面的逐渐钝化,元件面形逐渐恶化。在研制的5 m直径大口径环形抛光机床上加工800 mm×400 mm×100 mm平面元件的面形PV值优于λ/6(λ=632.8 nm),提升了元件的面形控制效率和精度。

原子层制造的研究现状与科学挑战

原子层制造是指加工精度达到原子层量级的可控制造技术,包括原子层去除、添加、迁移等。针对信息、能源、航空航天等领域核心零部件超高性能构建的发展需求,通过原子层可控去除制造全频段原子级精度无损表面,并结合原子层增材制造原子级新结构,有望实现特殊功能的有效创成,保证超高性能的安全可靠。另外,后摩尔时代先进芯片的制造工艺将迈入亚纳米物理极限,原子层制造需求贯穿芯片制造工艺的全流程。本文阐述了原子层制造技术的发展需求与研究进展,围绕原子层抛光、原子层沉积/刻蚀、原子层损伤控制、原子层工艺与装备等领域,梳理了原子层制造的发展方向及研究目标,凝练了原子层制造领域未来的关键科学问题及面临的挑战,探讨了前沿研究方向和发展战略。

曲面抛光机器人的模糊自适应阻抗控制

为了使机器人在曲面零件抛光过程中实现精确的力控制,进行了合理的轨迹规划与重力补偿分析,分析了阻抗控制参数对力控制稳态误差的影响。建立了曲面法向上的系统刚度模型,为了使机器人抛光系统在不同系统刚度下能够具有较好的力跟踪性能,提出能够适应系统刚度变化的模糊自适应阻抗控制模型,该模型根据力误差和力误差率,按照一定的模糊规则调整阻抗控制参数,实现了稳定的法向力控制和位置控制。仿真和试验表明,模糊自适应阻抗控制模型力控制的最大误差在±2 N以内,利用该模型抛光的圆柱凹型曲面工件表面轮廓算术平均偏差达到0.035μm,相比传统阻抗控制模型降低了59.7%,抛光质量也得到显著提高。

大型连续绿茶精制加工生产线研发

茶叶加工技术与装备是茶叶产业发展的基础,对行业发展起着举足轻重的作用。为实现绿茶加工机械自动化生产,设计了大型连续绿茶精制加工生产线,阐述了该生产线系统结构、主要生产环节及安装调试应用。基于PLC控制的大型连续绿茶精制加工生产线,主要由鲜叶上料输送机、大型滚筒杀青机、冷却回潮机、四机协同联动式揉捻机组、并列连续预烘干机组、储料仓、计量分料装置、茶叶炒干与抛光机组、筛分装置、风选装置及配套的测控系统等组成。针对绿茶加工工艺的各个环节,采用模块化设计,根据茶叶加工企业的厂房实际情况,灵活安装组线,满足企业个性化需求。基于模糊PID温度控制的大型滚筒杀青机双模糊控制技术,解决了传统杀青温度与时间无法实现精确控制的难点问题。采用链式刮板输送智能加料装置与多机联动协同连续揉捻控制技术,实现多机协同联动式自动加料连续揉捻,边进料边揉捻,揉捻均匀度高。生产线上杀青机、理条机和烘干机各环节温度采用模糊PID控制,解决了茶叶加工温度、投叶量与杀青、理条、烘干时间实时配合的问题,输入不同等级、不同重量的鲜叶可输出相适应的杀青温度和时间,实现对茶叶生产过程的精确控制,减少人为因素的干扰,实现绿茶的智能化生产。近年来,生产线用户遍布皖、苏、浙、云、贵、川、豫、湘、鄂和陕等10多个省份200余家茶叶生产企业。该生产线的推广应用,实现了茶叶规模化生产,保证了茶叶品质,对茶产业发展具有重要意义。

基于变刚度复杂曲面模糊路径策略的飞机座舱自动化磨抛

飞机座舱罩作为典型的复杂曲面弱刚性薄壁零件,是军用与民用飞机的重要部件,其安全与否直接关系到飞机和飞行员的安全。针对飞机座舱盖研磨抛光过程的曲面形状复杂以及刚性弱等问题,本文基于机器人自动化磨抛系统提出了一种基于自适应阻抗控制策略的复杂曲面模糊路径的生成方法,并对磨抛过程的接触力进行建模与分析,引进主被动相结合的磨抛方法,对某型飞机座舱盖进行了仿真及磨抛试验分析。试验结果表明,所提出的主被动相结合的磨抛方法结合自适应阻抗控制策略能较好的适应复杂曲面模糊路径的磨抛过程,力控制精度可达±1N;提出的复杂曲面模糊路径能够满足某型飞机座舱罩的自动化磨抛工艺需求,在保证磨抛结果一致性的同时提高了磨抛效率。

基于变参数阻抗控制的机器人恒力打磨研究

面向机器人恒力打磨需求,文章设计了阻抗参数在线调整与离线优化的自适应阻抗控制算法,实现了打磨力控制。自适应阻抗控制算法将刚度参数作为时变参数,根据打磨接触力实时在线调整,以消除打磨过程中的稳态误差。针对阻尼参数和惯性参数难以整定的问题,以降低系统超调量和调整时间作为优化目标,采用改进粒子群算法进行阻抗参数离线优化。进行了机器人恒力打磨仿真,仿真结果表明,该方法可以综合改善机器人的恒力控制性能。开展了机器人恒力打磨实验,实验结果表明,该方法可以有效地提高机器人打磨表面质量。

面向复杂曲面力控抛光的变阻抗控制研究

针对复杂曲面的力控抛光任务中同时控制刀具进给速度与接触力困难的问题,分析了在刀具期望进给速度与接触力方向时变场景下基于经典力位混合方法的柔顺控制算法难以控制的原因,提出了一种新的基于时变力位混合框架及自适应导纳控制的柔顺控制算法。使用工件轮廓曲率实时修正力位混合框架,减小进给速度与接触力控制之间的耦合影响,并使用接触力误差与力位混合框架修正速度来自适应调整导纳控制的阻尼参数。仿真验证了所提算法可解决传统算法在时变力位跟踪时的接触力不收敛问题,且所提自适应策略可进一步降低超过80%的接触力跟踪误差。

基于无模型自适应算法的磁流变液水分控制

磁流变抛光是一种去除效率稳定、无亚表面损伤的超精密加工工艺,然而,在抛光过程中,磁流变液的水分损失会改变抛光工具的特性,从而影响去除函数的稳定性。现有的水分控制策略受到磁流变液循环系统大时延、时变扰动的影响,导致水分含量存在周期性波动,使去除函数发生周期时变,进而影响加工质量与精度。本研究建立了磁流变液循环系统的传递函数模型,开展了系统特性分析,并据此设计了基于全格式动态线性化的无模型自适应控制算法,该算法能够实现非线性系统的参数自适应控制,有效抑制因时变扰动和时延引起的水分波动,为抛光过程中水分含量的稳定控制提供了一种简单有效、适用性强的控制策略。实验结果显示,采用FFDL-MFAC控制算法时,磁流变液水分波动的峰谷值(Peak-valley Value,PV)仅为0.06%,相较于使用PID减少了40%,误差绝对值的积分(Integral value of Absolute Er‐ror,IAE)减少了58.1%。有效提升了抛光过程中磁流变液水分含量的稳定性。

机器人打磨系统力控补偿优化算法研究

针对目前打磨机器人在复杂环境中不能兼具磨削精度和顺应性等问题,提出了一种基于算法优化的机器人打磨系统力控补偿方法。首先,阐述了机器人打磨系统的力学特性及力控优化算法原理;然后搭建了实验系统,进行了机器人容许响应范围及主动柔顺恒力磨削实验,最后,采用扩展Kalman滤波算法、最小二乘拟合算法和粒子滤波算法优化打磨力的实时补偿值,并对比了各算法的补偿效果。实验结果表明,通过力控补偿功能,在20 mm内可实现100%对系统结构误差的补偿;与设定期望打磨力比较,平均相对误差为5.44%;利用扩展Kalman滤波算法、最小二乘拟合算法和粒子滤波算法优化后平均误差分别降低至1.20%、1.24%和1.64%。拓展优化机器人协同力控系统的实时力/位补偿功能,将有助于提高机器人打磨系统的精度和稳定性,为机器人技术的发展提供理论依据和技术支持。

基于机器视觉的人防门智能打磨系统

针对人工识别易出错、清理效率低、打磨环境恶劣等难题,基于机器视觉原理结合双机械臂研制一种人防门智能打磨系统,其中视觉系统主要由1台视觉控制器VC3300和2台500万像素相机构成。通过视觉系统识别工件的顶点坐标,建立待打磨坐标系与顶点坐标系的映射关系,解决塞焊孔位置及埋弧焊位置难以有效识别、数据难以高效协同、高精度打磨难以实现的难题。实验结果表明:此视觉系统能够有效保证较高的定位准确率和精度,整体工序相较于人工提速33.3%,打磨后焊点的平均高度0.115 mm,满足实际工业生产需求,具有较好的实用价值。

基于功率键合图理论的陶瓷磨抛力控执行器的建模与仿真研究

为提高磨抛机器人末端恒力执行器在不同工况下的位置跟踪和接触力跟踪性能,并减小力位切换控制时的执行器位移误差和接触力误差,文中运用功率键合图法对机器人末端执行器进行建模,并提出一种滑膜模糊阻抗力位切换控制策略,在AMESim软件中对恒力执行器进行动态仿真并搭建实验验证平台进行验证,实验结果表明:该控制策略可以使机器人末端力控执行器具有更好的力位跟踪性能,同时可以减小力位切换控制时的力位跟踪误差。

基于OCC的汽车智能打磨机器人控制系统构建与应用

为了实现汽车压铸件的高效低冲击打磨生产,基于Open CASCADE(OCC)软件平台开发了汽车智能打磨机器人控制系统,该系统结构分为用户界面层、算法层、数据结构层和三维核心层4层,主要由运动仿真、三维显示仿真、轨迹规划与优化、后置代码以及动力学仿真等5大模块构成,内含多种插补算法和轨迹优化算法,可实现高效低冲击轨迹的规划与优化。将系统应用于汽车发动机的打磨仿真模拟,结果表明,系统可以在利用时间-冲击优化轨迹时,保持打磨轨迹的平稳性,减少对于打磨机器人关节的冲击,还可以提升33%的加工效率,系统确保了汽车构件打磨加工过程的平稳性和效率性。

自动化研磨技术在机械抛光精加工中的实践

随着我国现代工业化水平的不断提高,自动化研磨技术在机械抛光精加工领域的应用成为工业制造业发展的重要趋势。自动化研磨技术是一种结合信息化、智能化与自动化控制的新型工艺,融合了磨削过程控制、表面质量检测与机器人设计等多项技术内容,在机械抛光精加工过程中主要应用于表面抛光、精密研磨以及工艺优化等领域,推动了机械制造系统的进一步优化升级,实现了对机械设备的高效精细加工。基于此,简要概述自动化研磨技术的内涵,分析机械抛光精加工中的自动化研磨技术,提出自动化研磨技术在机械抛光精加工中的实践应用,以推进工业制造产业的智能化和精细化发展。