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Chatter stability and precision during high-speed ultrasonic vibration cutting of a thin-walled titanium cylinder

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Chinese Journal of Aeronautics 2020年第12期33卷 3535-3549页

作者： Zhenlong PENG deyuan Zhang Xiangyu zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China Institute of Bionic and Micro-Nano Systems Beihang UniversityBeijing 100083China Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing 100083China

Titanium alloys are widely used in the aviation and aerospace industries due to their unique mechanical and physical properties.Specifically,thin-walled titanium(Ti)cylinders have received increasing attention for their applications as rocket engine casings,aircraft landing gear,and aero-engine hollow shaft due to their observed improvement in the thrust-to-weight ratio.However,the conventional cutting(CC)process is not appropriate for thin-walled Ti cylinders due to its low thermal conductivity,high strength,and low stiffness.Instead,high-speed ultrasonic vibration cutting(HUVC)assisted processing has recently proved highly effective for Ti-alloy machining.In this study,HUVC technology is employed to perform external turning of a thinwalled Ti cylinder,which represents a new application of HUVC.First,the kinematics,tool path,and dynamic cutting thickness of HUVC are evaluated.Second,the phenomenon of mode-coupling chatter is analyzed to determine the effects and mechanism of HUVC by establishing a critical cutting thickness model.HUVC can increase the critical cutting thickness and effectively reduce the average cutting force,thus reducing the energy intake of the system.Finally,comparison experiments are conducted between HUVC and CC processes.The results indicate that the diameter error rate is 10%or less for HUVC and 51%for the CC method due to a 40%reduction in the cutting force.In addition,higher machining precision and better surface roughness are achieved during thin-walled Ti cylinder manufacturing using HUVC.

关键词： High-speed machining Minimum chip thickness Mode-coupling Thin-walled cylinder Ultrasonic vibration cutting

A Bionic Starfish Adsorption Crawling Soft Robot

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Journal of Bionic Engineering 2024年第1期21卷 149-165页

作者： Xiangang Huang Chenghao zhang Wenqi Feng Xiangye zhang deyuan Zhang Yanqiang Liu Institute of Bionic and Micro-Nano Systems School of Mechanical Engineering and AutomationBeihang UniversityBeijing 100191China

A variety of soft wall-climbing robots have been developed that can move in certain patterns.Most of these soft robots can only move on conventional surfaces and lack adaptability to complex surfaces.Improving the adaptability of soft robots on complex surfaces is still a challenging problem.To this end,we study the layered structure of the starfish tube foot and the valve flap structure in the water vascular system,and use an ultrasonic stress detector to study the stiffness distribution of the arm structure.Inspired by the motion of the starfish,we present a bionic soft wall-climbing robot,which is driven by two groups of pneumatic feet and achieves body bending through active adaptation layers.We design the structure of the foot to flex to provide driving force,and there are suction cups at the end of the foot to provide suction.The soft foot has a simple structure design,adapts to a variety of surfaces,and does not damage the surface of the substrate.Variable stiffness layers achieve stiffness changes by the principle of line blocking.The Central Pattern Generator theory is introduced to coordinately control the multiple feet of the robot.After experiments,we verify the adaptability of the soft robot to curved surfaces.The research may provide a reference for the design and development of crawling soft robots on complex surfaces.

关键词： Starfish Tube foot Biomimetic robot Soft robot Climbing robot

Bioinspired Functional Surfaces for Medical Devices

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Chinese Journal of Mechanical Engineering 2022年第3期35卷 37-50页

作者： Liwen zhang Guang Liu Yurun Guo Yan Wang deyuan Zhang Huawei Chen School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing 100191China

Medical devices are a major component of precision medicine and play a key role in medical treatment,particularly with the rapid development of minimally invasive surgery and wearable devices.Their tissue contact properties strongly affect device performance and patient health(e.g.,heat coagulation and slipperiness on surgical graspers).However,the design and optimization of these device surfaces are still indistinct and have no supporting principles.Under such conditions,natural surfaces with various unique functions can provide solutions.This review summarizes the current progress in natural functional surfaces for medical devices,including ultra-slipperiness and strong wet attachment.The underlying mechanisms of these surfaces are attributed to their coupling effects and featured micronano structures.Depending on various medical requirements,adaptable designs and fabrication methods have been developed.Additionally,various medical device surfaces have been validated to achieve enhanced contact properties.Based on these studies,a more promising future for medical devices can be achieved for enhanced precision medicine and human health.

关键词： Bioinspired functional surfaces Medical devices Wet attachment Interfacial liquid Micro-nano structures Wearable devices

Segment-wise learning control for trajectory tracking of robot manipulators under iteration-dependent periods

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Science China(Information Sciences) 2024年第3期67卷 155-166页

作者： Fan zhang deyuan MENG Kaiquan CAI The Seventh Research Division Beihang University School of Automation Science and Electrical Engineering Beihang University School of Electronics and Information Engineering Beihang University

This paper is concerned with the amplitude boundedness problem of adaptive iterative learning control(AILC) for robot manipulators operating with iteration-dependent periods. By introducing virtual memory slots for storing historical data, a practical AILC method is proposed to achieve the segmentwise learning. This method requires less memory storage for historical information of previous iterations,especially in comparison with that of the conventional AILC methods using point-wise learning strategies.It is shown that not only the energy boundedness but also the amplitude boundedness of estimates and inputs of practical AILC can be guaranteed. Moreover, the practical AILC method can achieve the perfect tracking objective regardless of iteration-dependent periods when the robot manipulators have a persistent full learning property. In addition, a solution to the visual manipulator platform is provided and deployed based on Coppeliasim and Matlab, which helps to show the amplitude boundedness of learning results and the perfect tracking performances of the proposed practical AILC method for robot manipulators.

关键词： amplitude boundedness iteration-dependent period iterative learning control robot manipulator segment-wise virtual memory slot

Applications of bioinspired approaches and challenges inmedical devices

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Bio-Design and Manufacturing 2021年第1期4卷 146-148页

作者： Huawei Chen Yi zhang Liwen zhang Xilun Ding deyuan Zhang School of Mechanical Engineering and Automation Beihang UniversityBeijingChina Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijingChina

Urgent requirements of medical devices Precision medicine has gradually become a development strategy in many countries and attracted worldwide attention in recent years due to the increasing concerns in public health.Although the definition of precision medicine has less or more difference from the viewpoints of different fields,the demands on the properties of medical devices or medical materials involving biocompatibility and anti-thrombosis are gradually growingmuch more diverse and much more urgent than ever[1].This trend brings up many new research topics about materials,mechanical systems and sensors to develop advanced medical devices.How to design and on-demand fabricate the bio-materials,bio-interface and bio-systems to meet the urgent demands of medical devices is still a challenge for us.

关键词： interface urgent viewpoint

Robust Optimization-Based Iterative Learning Control for Nonlinear Systems With Nonrepetitive Uncertainties

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IEEE/CAA Journal of Automatica Sinica 2021年第5期8卷 1001-1014页

作者： deyuan Meng Jingyao zhang the Seventh Research Division Beihang University(BUAA)Beijing 100191 the School of Automation Science and Electrical Engineering Beihang University(BUAA)Beijing 100191

This paper aims to solve the robust iterative learning control(ILC)problems for nonlinear time-varying systems in the presence of nonrepetitive uncertainties.A new optimization-based method is proposed to design and analyze adaptive ILC,for which robust convergence analysis via a contraction mapping approach is realized by leveraging properties of substochastic matrices.It is shown that robust tracking tasks can be realized for optimization-based adaptive ILC,where the boundedness of system trajectories and estimated parameters can be ensured,regardless of unknown time-varying nonlinearities and nonrepetitive uncertainties.Two simulation tests,especially implemented for an injection molding process,demonstrate the effectiveness of our robust optimization-based ILC results.

关键词： Adaptive iterative learning control(ILC) nonlinear time-varying system robust convergence substochastic matrix

Structural and Mechanical Characterization ofAtrina Pectinata and Freshwater Mussel Shells

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Journal of Bionic Engineering 2015年第2期12卷 276-284页

作者： Jianlu Lv Yonggang Jiang deyuan Zhang School of Mechanical Engineering and Automation Beihang University Xueyuan Road No. 37 Haidian District Beij'ing 1 00191 China International Research Institute for Multidisciplinary Science Beihang University Xueyuan Road No. 37 Haidian District Belling 100191 China

The microstructures ofAtrina pectinata and freshwater mussel shells are investigated by optical microscopy and scanning electron microscopy. The mechanical properties of these shells are characterized by nanoindentation and three-point bending tests. Results show that both shells possess a prismatic microstructure mainly composed of columnar crystals and an organic matrix. The fracture toughness of the prismatic structure of Atrina pectinata and freshwater mussel are approximately 1.15 MPa.m1/2 and 0.87 MPa.m1/2, respectively, while the fracture toughness of natural calcite is approximately 0.2 MPa.m1/2. Calculated results from indentations agree with those obtained from the three-point bending tests. The columnar crystal material shows excellent fracture toughness due to grain refinement. In addition, the organic matrix of the prismatic layer can arrest cracks, and thereby improves the fracture toughness.

关键词： shell prismatic fracture toughness organic matrix crack

The Prey Capture Mechanism of Micro Structure on the Sarracenia Judith Hindle Inner Surface

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Journal of Bionic Engineering 2018年第1期15卷 34-41页

作者： Yang Gan Huawel Chen Tong Ran Pengfei zhang deyuan Zhang School of Mechanical Engineering and Automation Beihang University Beijing 1 O0191 China

Low friction surface has attracted considerable attention due to its potential application in various fields. As a typical carnivorous plant, Sarracenia Judith Hindle possesses unique slippery surface to capture prey especially in wet environment. In order to make clear the low friction mechanism, structural characterization was carried out and unique inclined micro-thorn structure was found on the inner wall surface. Micro-droplets harvest on the surface of the micro-thorn was discovered via the observation in wet environment. Friction force measurement was conducted by sliding the ants＇ footpad on the inner surface and polymer replica surfaces, which demonstrated that the friction force decreases on those surfaces in wet environment or inward direction. Further analysis manifested that the slippery inner surface grown with hierarchical micro-thorn structure leads to the friction decrease, and that is the fundamental mechanism for prey capture and retention in the pitcher of carnivorous plant Sarracenia Judith Hindle.

关键词： prey capture hierarchical microstructure Sarracenia low friction surface anisotropic structure

Resilient observer-based event-triggered control for cyber-physical systems under asynchronous denial-of-service attacks

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Science China(Information Sciences) 2022年第4期65卷 182-196页

作者： Yifang zhang Zheng-Guang WU Zongze WU deyuan MENG State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang University School of Automation Guangdong University of Technology Seventh Research Division Beihang University (BUAA) School of Automation Science and Electrical Engineering Beihang University (BUAA)

We develop the resilient observer-based event-triggered control update strategy in this paper.It is utilized to achieve the input-to-state stability(ISS) of cyber-physical systems(CPSs) when there is an asynchronous denial-of-service(DoS) attack, which is launched by malicious adversaries both on measurement channel and control channel in a random attack strategy. To estimate the unmeasurable states while saving the limited networked bandwidth, an H∞observer-based event-triggered control scheme is first designed to guarantee the ISS of CPSs with economic communication. Moreover, the occurrence of Zeno behavior can be eliminated by providing the existence of a lower positive bound of any two inter-event times. Then, a recursive model of asynchronous DoS attacks is introduced. A resilient control update strategy is proposed and further analyzed to derive the stability criterion of CPSs. At last, a numerical simulation example is given to demonstrate the effectiveness of the introduced control update policy.

关键词： cyber-physical systems input-to-state stability asynchronous DoS attacks $H_\infty~$ observer event-triggered control