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Jerk-limited feedrate scheduling and optimization for five-axis machining using new piecewise linear programming approach

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Science China(Technological Sciences) 2019年第7期62卷 1067-1081页

作者： SUN YuWen CHEN ManSen JIA JinJie LEE Yuan-Shin guo dongming School of Mechanical Engineering Dalian University of Technology Dalian 116024 China Department of Industrial and Systems Engineering North Carolina State University Raleigh NC 27695 USA

In this paper, a new computation method and an optimization algorithm are presented for feedrate scheduling of five-axis machining in compliance with both machine drive limits and process limits. Five-axis machine tool with its ability of controlling tool orientation to follow the sculptured surface contour has been widely used in modern manufacturing industry. Feedrate scheduling serving as a kernel of CNC control system plays a critical role to ensure the required machining accuracy and reliability for five-axis machining. Due to the nonlinear coupling effects of all involved drive axes and the saturation limit of servo motors, the feedrate scheduling for multi-axis machining has long been recognized and remains as a critical challenge for achieving five-axis machine tools’ full capacity and advantage. To solve the nonlinearity nature of the five-axis feedrate scheduling problems, a relaxation mathematical process is presented for relaxing both the drive motors’ physical limitations and the kinematic constraints of five-axis tool motions. Based on the primary optimization variable of feedrate, the presented method analytically linearizes the machining-related constraints, in terms of the machines’ axis velocities, axis accelerations and axis jerks. The nonlinear multi-constrained feedrate scheduling problem is transformed into a manageable linear programming problem. An optimization algorithm is presented to find the optimal feedrate scheduling solution for the five-axis machining problems. Both computer implementation and laboratorial experiment testing by actual machine cutting were conducted and presented in this paper. The experiment results demonstrate that the proposed method can effectively generate efficient feedrate scheduling for five-axis machining with constraints of the machine tool physical constraints and limits. Compared with other existing numerical methods, the proposed method is able to find an accurate analytical solution for the nonlinear constrained five-axis feedrate scheduling problems w

关键词： five-axis machining feedrate scheduling jerk linear programming optimization

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Investigation on the cleaning of KDP ultra-precision surface polished with micro water dissolution machining principle

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Science China(Technological Sciences) 2017年第1期60卷 27-35页

作者： CHEN YuChuan GAO Hang WANG Xu guo dongming TENG XiaoJi Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education School of Mechanical Engineering Dalian University of Technology Dalian 116023 China

A potassium dihydrogen phosphate(KDP) optical crystal was machined to an ultra-precision surface with water-in-oil(W/O) micro emulsion polishing fluid. The micro water dissolution principle utilized in the machining process is discussed, its planarization mechanism is illustrated, and an ultra-precision polished surface with 2.205 nm RMS roughness is obtained. However, a substantial quantity of residual contamination remained on the polished surface after machining. This can seriously impact the optical performance of the crystal, and so it must be removed. Fourier transform infrared(FTIR) spectroscopy was used to conduct an investigation into the composition of the surface residue, and the results showed that the residue was comprised of organic chemicals with hydrocarbon chains and aromatic ether, i.e., mostly the polishing fluid. The cleaning method and the principle on which the KDP ultra precision surface investigation is based are discussed in detail, and the cleaning experiments with selected KDP-compatible organic solvents were then performed. FTIR transmittance spectra measurement and microscopic observations were employed to assess the effects of the cleaning process on the surface of the KDP crystal. The results showed that toluene cleaning achieved the most desirable results. This cleaning method produced a surface roughness of 1.826 nm RMS, which allows the KDP crystal to be applied to subsequent engineering applications.

关键词： KDP晶体清洗方法超精密抛光加工原理抛光表面水溶解傅里叶变换红外光谱表面粗糙度

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Implementation strategies for high accuracy grinding of hydrodynamic seal ring with wavy face for reactor coolant pumps

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Science China(Technological Sciences) 2013年第10期56卷 2403-2412页

作者： FENG Guang guo dongming HUO FengWei JIN ZhuJi KANG RenKe Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education Dalian University of Technology

Large size mechanical seals are one of the most important components used in reactor coolant pumps.However,the hydrodynamic seal rings with wavy face are difficult to machine due to their high hardness and high form accuracy demand.In order to solve this difficult problem,a novel four-axis linkage grinding method using a cup wheel to process the hydrodynamic seal rings by line contact was proposed.A preliminary study indicates that the form error of the ground seal ring surface is extremely sensitive to different linkage relations of the four axes.By taking the center height of the cup wheel and the laws of motion along the X-axis,Z-axis,B-axis and C-axis as control variables,their effects on the principle form error of the ground surface are evaluated.Six implementation strategies are proposed to reach lower principle form errors.It is found that the minimal principle form error is only 9.64 nm and hence its influence on the ground seal ring shape can be neglected in designing an ultra-precision grinding machine.In addition,the results indicate that the position accuracy of the X-axis at the microscale is acceptable no matter which implementation strategy is selected.This study is expected to serve as a theoretical basis for design and development of the four-axis ultra-precision grinding machine.

关键词：流体动压冷却剂泵密封环研磨机反应堆波浪形高精度形状误差

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Dynamic characteristics of an intestine capsule robot with variable diameter

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Chinese Science Bulletin 2010年第17期55卷 1813-1821页

作者： ZHANG YongShun JIANG ShengYuan ZHANG XueWen YU HongHai WANG DianLong guo dongming Key Laboratory for Precision & Non-traditional Machining of Ministry of Education of China Dalian University of Technology Dalian 116023 China Mechanical Engineering School Beihua University Jilin 132021 China

This paper proposes an intestine capsule robot with variable diameter. It is driven by external rotating magnetic field and has the function of automatic radial clearance compensation. An external magnetic field generating device and a capsule robot with variable diameter are developed. Radial dynamic balance equation and kinematics equation of the capsule robot traveling inside flexible elasto-wall environment are established, and dynamic characteristics of the capsule robot inside flexible elasto-wall pipe and rigid wall pipe environments are analyzed and compared. Simulations and experiment results show that its dynamic characteristics in both pipes are almost the same. Under the action of radial clearance compensation, fluid dynamic pressure around outer surface of the capsule robot and its propulsion, as well as its adaptability to diameter change range, are significantly improved. Its propulsion and moving speed are controlled by adjusting rotating angular speed of the rotating magnetic field. This innovative capsule robot with radial clearance compensation has a promising prospect for inside intricate gastrointestinal (GI) tract in non-invasive therapy applications.

关键词：动态特性机器人变直径胶囊胃肠动力平衡方程径向间隙旋转磁场

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Characteristics of spatial magnetic torque of an intestine capsule micro robot with a variable diameter

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Science China(Technological Sciences) 2009年第7期52卷 2079-2086页

作者： ZHANG YongShun YUE Ming guo dongming WANG DianLong YU HongHai JIANG ShengYuan ZHANG XueWen Key Laboratory for Precision&Non-traditional Machining of Ministry of Education Dalian University of TechnologyDalian 116024China School of Automotive Engineering Dalian University of TechnologyDalian 116024China Mechanical Engineering School Beihua UniversityJilin 132021China

A drive and control method is put forward for a variable diameter capsule micro robot to screw forward in intestine using magnetic coupling between an inner actuator inside the robot and the rotational magnetic field generated by a rotating outer actuator. The structures of the outer and inner actuators are magnet cylinders with multiple magnetic poles in tegular shape alternating with dissimilar radial magnetization. An universal mathematical model of magnetic torque at eccentric state is established based on the equivalent magnetic charge method, and the characteristics of magnetic torque with respect to structural parameters of actuators are theoretically studied. Experiments show that the driving method features advantages such as powerful magnetic torque, high safety, reliability, etc. The driving ability of the variable diameter capsule micro robot is greatly improved by its automatic radial clearance compensation. The magnetic drive system has a promising prospect of medical applications in intestine.

关键词： variable diameter capsule robot, Radial offset distance Magnetic torque, Equivalent magnetic charge method

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NOVEL METHOD SOLVING NUMERICAL INSTABILITIES IN TOPOLOGY OPTIMIZATION

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Chinese Journal of Mechanical Engineering 2002年第1期15卷 22-26页

作者： guo dongming Wang Xiaoming Liu Zhenyu Department of Mechanical Engineering，Dalian University of Technology， Dalian 116023，China Department of Mehanical Engineering Dalian University of Technology Dalian 116023

Numerical instabilities are often encountered in FE solution of continuumtopology optimization. The essence of the numerical instabilities is given from the inverse partialdifferential equation (PDE) point of view. On the basis of the strict mathematical theory, a novelmethod, named as window filter and multi-grid method, which solves the numerical instabilities, isproposed. Convergent analyses and a numerical example are presented.

关键词： Topology optimization Gaussian windows Checkerboard pattern

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铜表面脉冲电化学射流加工的定域性和粗糙度分析

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机械工程学报 2022年第7期58卷 258-266页

作者：王可周平闫英张超郭东明大连理工大学精密与特种加工教育部重点试验室大连116024

电化学射流加工(Jet-ECM)是一种用于表面微细结构加工的超精密加工方法。但是,Jet-ECM加工的定域性不足,表面质量不高,无法满足高精度表面加工的需求。采用合理的电解液和脉冲电源参数可以提高电化学加工的精度和表面质量,但单纯基于试... 详细信息

电化学射流加工(Jet-ECM)是一种用于表面微细结构加工的超精密加工方法。但是,Jet-ECM加工的定域性不足,表面质量不高,无法满足高精度表面加工的需求。采用合理的电解液和脉冲电源参数可以提高电化学加工的精度和表面质量,但单纯基于试错的方法获得合理参数的难度极大。根据电化学反应和双电层的基本原理,将Jet-ECM系统等效为RC电路,用于指导脉冲Jet-ECM加工参数的选择。研究结果显示,磷酸基电解液Jet-ECM中采用脉冲电源能有效减少过切,提高铜表面加工的定域性,当加工电压为6.5 V时,采用10 kHz,50%占空比的脉冲电源相比直流电源定域性提高36%。降低加工电压和占空比也可有效提高加工定域性。但表面质量和定域性的变化趋势相反,降低加工电压和占空比不利于工件表面黏膜层的形成,降低了表面质量。本研究有助于进一步明确Jet-ECM加工中的电化学去除机理,提高无应力加工方法的加工精度,为Jet-ECM在工业中的进一步应用提供了指导。

关键词：电化学射流加工脉冲电源双电层定域性表面质量

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Evaluation of antibody responses in healthy individuals receiving SARS-CoV-2 inactivated vaccines

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生物安全与健康(英文) 2024年第3期6卷 153-164页

作者： Liu Ziyu Cai Liyan Xing Man Qiao Nan Liu Jiaojiao Li Xuejun Zhang Chiyu Tang Naijun Xu Zhelong guo Yingying Lu Renfei Zhou dongming Department of Pathogen Biology School of Basic Medical Sciences Tianjin Medical University Tianjin China Physical examination center Affiliated Nantong Hospital of Nantong University Nantong China Shanghai Public Health Clinical Center Fudan University Shanghai China Department of Occupational and Environmental Health School of Public Health Tianjin Medical University Tianjin China Clinical Laboratory Affiliated Nantong Hospital of Nantong University Nantong China

Inactivated coronavirus disease 2019 (COVID-19) vaccines such as CoronaVac and BBIBP-CorV have been widely used in China. However, more investigation is still needed to understand antibodies'' duration and effectiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants in the real world. In this study, 575 participants who had been vaccinated with two or three doses of the inactivated vaccine were recruited. Serum samples were collected and tested for anti-spike IgG and neutralizing antibodies against SARS-CoV-2 (original strain, Dela, and Omicron). Unsurprisingly, a third dose of the vaccine significantly enhanced antibody responses against SARS-CoV-2 and its variants. However, despite a booster dose, the neutralizing antibody levels against Omicron, particularly the BA.5.2 subvariant, remained low. There was no sex bias, but an age bias was observed. Notably, the predominant IgG subclass antibodies were IgG1 and IgG2, with a much lower level of IgG4. After the booster shot, the ratio of IgG4 to IgG1 significantly increased. The observation of IgG1 to the IgG4 class switch after repeated inactivated vaccinations underscores the importance of continuous monitoring of subclass antibody responses. Further clinical investigations are required to understand the implications of this class switch for optimizing immunization strategies.

关键词： Variant of concern (VOC) Inactivated vaccines Serological study IgG subclasses Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

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原子级制造的关键基础科学问题

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中国科学基金 2024年第1期38卷 86-98页

作者：雒建斌郭东明杨华勇叶鑫钱林茂居冰峰姜澜邵金友张振宇陈磊陈远流胡洁李祥明冯俊元韩伟娜谭新峰解国新赖一楠苗鸿雁王岐东清华大学高端装备界面科学与技术全国重点实验室北京100084 大连理工大学高性能精密制造全国重点实验室大连116024 浙江大学流体动力基础件与机电系统全国重点实验室杭州310027 国家自然科学基金委员会工程与材料科学部北京100085 西南交通大学机械工程学院成都610031 北京理工大学机械与车辆学院北京100081 西安交通大学精密微纳制造技术全国重点实验室西安710049

人类的制造技术逐步向原子级推进,原子作为化学反应中的最小粒子,虽然它可以分成更小的原子核、电子等,但是从制造的角度看,原子级制造可以说是人类制造的最底层技术,也是继微纳制造之后新的制造范式,可将制造精度以及产品性能推向极致... 详细信息

人类的制造技术逐步向原子级推进,原子作为化学反应中的最小粒子,虽然它可以分成更小的原子核、电子等,但是从制造的角度看,原子级制造可以说是人类制造的最底层技术,也是继微纳制造之后新的制造范式,可将制造精度以及产品性能推向极致水平,代表着人类对物质世界认知和制造能力发展的新阶段,是引领未来产业变革发展的战略性技术,也是保障国家安全和推动国计民生重大装备跨代升级的重要前沿方向。本文基于第330期双清论坛总结了原子级制造的研究现状、发展趋势及机遇挑战,凝练出未来5~10年原子级制造的焦点问题和亟需解决的关键科学问题,探讨了相关领域的前沿发展方向和科学基金资助战略。

关键词：原子级制造原子层制造团簇与器件制造原子级精度制造原子级测量与表征学科交叉

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高性能精密制造

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中国机械工程 2018年第7期29卷 757-765页

作者：郭东明大连理工大学精密与特种加工教育部重点实验室大连116024

高性能制造是高端装备和产品的关键零部件以性能精准保证为目标的几何和性能一体化制造,体现了由几何尺寸及公差要求为主的传统制造向高性能要求为主的先进制造的跃升。从制造的现状、需求和发展趋势出发,阐明了高性能零件的内涵、高性... 详细信息

高性能制造是高端装备和产品的关键零部件以性能精准保证为目标的几何和性能一体化制造,体现了由几何尺寸及公差要求为主的传统制造向高性能要求为主的先进制造的跃升。从制造的现状、需求和发展趋势出发,阐明了高性能零件的内涵、高性能制造的特点、面临的问题及其分类体系,并结合实例给予了深入分析和说明,为高端装备中一大批关键零部件的精密制造难题提供了可行的解决策略和途径。

关键词：高性能制造难加工材料超高精度跨尺度表面层结构功能一体化

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