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High sensitivity MEMS vibration sensors based on LiNbO3 ferroelectric single-crystal films

Ceramics International 2025年第16期51卷 21810-21819页

作者： Zhang, Huiyi Li, Xiaohuang Qiao, Xiaojun Wei, Huifen Bi, Kaixi Hou, Xiaojuan Mu, Jiliang He, Jian Chou, Xiujian Geng, Wenping Science and Technology on Electronic Test and Measurement Laboratory North University of China Taiyuan030051 China Shanxi Provincial Key Laboratory of Advanced Manufacturing Technology North University of China Taiyuan030051 China

Piezoelectric vibration accelerometers with higher sensitivity and wider working range are extremely desirable regarding vibration monitoring. Limited by the inherent frequency of sensors and environmental protection, conventional piezoelectric sensors are unable to detect vibration signals in wide frequency and high acceleration environments. The sensor proposed in this paper is capable of achieving passive test work by collecting vibration signals from the external environment and utilising the force-electric conversion capability of the piezoelectric effect to achieve the sensor's detection of the environment. Herein, LiNbO3-based single-crystal film piezoelectric vibration sensors based on cantilever beams structure are proposed with enhanced operating bandwidth and high sensitivity. The fork-finger electrodes collection method effectively improves the output charges efficiency. Vibration experiments are conducted at high acceleration environment over wide frequency from 20 to 2400 Hz where the charge sensitivity of sensors can reach 10.336 pC/g @ f = 2400 Hz. Subsequently, the charge sensitivity was calculated by cluster analysis algorithm for random vibration environments and compared with the charge performance of sinusoidal signals showing little deviation. The repeatability error of sensors is maintained within 3.4 % for multiple measurements. The results show that cantilever beams model based on fork-finger electrodes provides a new structural design and charges collection method for highly sensitive and eco-friendly piezoelectric vibration devices operating in complex vibration environments. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Cantilever beams

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Design and Optimization Analysis of an Adaptive Knee Exoskeleton

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Chinese Journal of Mechanical Engineering 2024年第5期37卷 387-408页

作者： Xinhua Yang Sheng Guo Peiyi Wang Yifan Wu Lianzheng Niu Duxin Liu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control TechnologyMinistry of EducationBeijing Jiaotong UniversityBeijing 100044China

To solve the problem of undesired relative motion of human-machine interaction positions caused by misalignment of the human-machine joints rotation axis of the knee exoskeleton,this study designed an adaptive knee exoskeleton based on a gear-link mechanism(GLM)by considering the human body as a component of the exoskeleton ***,the concept of the wearable area(WA)was proposed,which transformed the operation of aligning the exoskeleton rotation axis with the human knee joint rotation axis into a"face alignment point"in the sagittal plane,reducing the difficulty of aligning the human-machine joint rotation *** the kinematic analysis of GLM,the phenomenon of instantaneous movement of the central axis of the human knee joint was *** on the kinematic model,the WA,velocity transfer ratio,and initial position static stiffness of GLM were *** NSGA-II optimization algorithm was used to optimize the size parameters of GLM,which increased the WA by 18.4%,the average velocity transfer ratio by 4.98%,and the average initial position static stiffness by 6.01%.Finally,the ability of the exoskeleton to absorb movement displacement(MD)was verified through simulation,and the good human-machine kinematic compatibility of the exoskeleton was verified through wearable tests conducted on the initial mechanism principle prototype.

关键词： Adaptive knee exoskeleton Gear-link mechanism Wearable area Optimization Simulation

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Tracked robot with underactuated tension-driven RRP transformable mechanism:ideas and design

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Frontiers of Mechanical Engineering 2024年第1期19卷 85-104页

作者： Ran XU Chao LIU School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control Technology(Ministry of Education)Beijing Jiaotong UniversityBeijing 100044China

Robots with transformable tracked mechanisms are widely used in complex terrains because of their high adaptability,and many studies on novel locomotion mechanisms have been conducted to make them able to climb higher *** underactuated transformable mechanisms for tracked robots could decrease the number of actuators used while maintaining the flexibility and obstacle-crossing capability of these robots,and increasing their cost ***,the underactuated tracked robots have appreciable research *** this paper,a novel tracked robot with a newly proposed underactuated revolute‒revolute‒prismatic(RRP)transformable mechanism,which is inspired by the sit-up actions of humans,was *** newly proposed tracked robot has only two actuators installed on the track pulleys for moving and does not need extra actuators for ***,it could concentrate the track belt’s tension toward one side,and the unbalanced tension would drive the linkage mechanisms to change its *** this method,the proposed underactuated design could change its external shape to create support points with the terrain and move its center of mass actively at the same time while climbing obstacles or crossing other kinds of terrains,thus greatly improving the climbing capability of the *** geometry and kinematic relationships of the robot and the crossing strategies for three kinds of typical obstacles are *** the basis of such crossing motions,the parameters of links in the robot are designed to make sure the robot has sufficient stability while climbing ***-crossing dynamic simulations were run and analyzed to prove the feasibility of the robot.A prototype was built and *** show that the proposed robot could climb platforms with heights up to 33.3%of the robot’s length or cross gaps with widths up to 43.5%of the robot’s length.

关键词： mechanical design tracked robot underactuated mechanisms RRP mechanism obstacle crossing strategy

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FATIGUE DAMAGE EVOLUTION ANALYSIS OF DRIVE SHAFT CONSIDERING RESIDUAL STRESS AND HARDNESS GRADIENT 10

FATIGUE DAMAGE EVOLUTION ANALYSIS OF DRIVE SHAFT CONSIDERING...

引用

10th International Symposium on Test Automation and Instrumentation, ISTAI 2024

作者： Yang, Li Wang, Liyong Li, Le Zheng, Xinhui Chang, Shuyuan Key Laboratory of Advanced Manufacturing Technology Beijing University of Technology Affiliation name of department and organisation Beijing China The Ministry of Education Key Laboratory of Modem Measurement and Control Technology Beijing Information Science & Technology University Beijing China

ISBN: (纸本)9781837242672

The service environment of the transmission shaft is complex, and it is frequently subjected to impact load. Impact fatigue is the main cause of its fatigue failure. In this study, a fatigue damage evolution analysis method of transmission shaft considering residual stress and hardness gradient is proposed under the framework of damage irreversible thermodynamics. Firstly, combined with the wave theory, the wave effect of impact stress wave is analyzed, the evolution equation of stress wave fluctuation behavior is established, and the evolution law of stress and strain field under the action of stress wave is analyzed. Then, based on the irreversible thermodynamic framework of damage, the thermodynamic state potential and dissipation potential of the damage process are studied, and the coupling characteristics of the damage evolution dynamic response and the intrinsic damage dissipation of the damaged material are analyzed. The damage evolution model of fatigue performance degradation considering residual stress and hardness gradient is established to identify the critical condition of intrinsic damage dissipation and describe the fatigue damage failure behavior. Finally, the cohesive element of the coupled damage constitutive is defined to simulate the damage evolution behavior of the substructure, and the influence of residual stress and hardness gradient on the damage evolution is explored. The results show that different initial crack forms have an important influence on the stress wave propagation behavior. The existence of residual tensile stress accelerates the process of fatigue damage accumulation, and the improvement of surface hardness can improve the fatigue resistance of the body. © The Institution of Engineering & technology 2024.

关键词： Fatigue damage

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Path Tracking controller Design of Automated Parking Systems via NMPC with an Instructible Solution

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 353-367页

作者： Liang Chen Zhaobo Qin Manjiang Hu Yougang Bian Xiaoyan Peng State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China Wuxi Intelligent Control Research Institute of Hunan University Wuxi 214115China

Parking difficulties have become a social issue that people have to *** parking system is practicable for quick par operations without a driver which can also greatly reduces the probability of parking *** paper proposes a Lyapunov-based nonlinear model predictive controller embedding an instructable solution which is generated by the modified rear-wheel feedback method(RF-LNMPC)in order to improve the overall path tracking accuracy in parking ***,A discrete-time RF-LNMPC considering the position and attitude of the parking vehicle is proposed to increase the success rate of automated parking ***,the RF-LNMPC problem with a multi-objective cost function is solved by the Interior-Point Optimization,of which the iterative initial values are described as the instructable solutions calculated by combining modified rear-wheel feedback to improve the performance of local optimal ***,the details on the computation of the terminal constraint and terminal cost for the linear time-varying case is *** closed-loop stability is verified via Lyapunov techniques by considering the terminal constraint and terminal cost ***,the proposed RF-LNMPC is implemented on a selfdriving Lincoln MKZ platform and the experiment results have shown improved performance in parallel and vertical parking *** Monte Carlo analysis also demonstrates good stability and repeatability of the proposed method which can be applied in practical use in the near future.

关键词： Automated parking Path tracking controller Nonlinear model predictive control Monte Carlo analysis

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Performance Analysis of a Hexagon Rolling Mechanism with Single Degree of Freedom

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Journal of Mechanisms and Robotics 2025年第8期17卷 081001页

作者： Zhang, Qianqian Li, Yezhuo Yan, Shaoze Yao, Yan-An Department of Mechanical Engineering Tsinghua University Beijing100084 China School of Mechanical Electronic and Control Engineering Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control Technology Beijing Jiaotong University Beijing100044 China

This article presents a comprehensive performance analysis of the step-climbing and passive rolling modes of a hexagon rolling mechanism with single-degree-of-freedom, based on its structural characteristics and the constraints of centroid stability. First, a step-climbing model, incorporating motion parameters and support distance parameters, is established by leveraging the symmetrical posture movement characteristics of the hexagon rolling mechanism. Building on this foundation, the impact of each parameter on the mechanism's step-climbing ability is thoroughly analyzed, and the maximum height achievable during step climbing is also examined. Subsequently, the existence and sufficient conditions for the hexagon rolling mechanism to achieve passive rolling are analyzed using the centroid fluctuation curve and its slope curves. The analysis results indicate that, due to its unique coupling structure design, the hexagon rolling mechanism possesses a passive rolling capability that is not available in conventional planar linkage mechanisms. Finally, the correctness of the theoretical model is validated through both simulation and prototype experiments. Copyright © 2025 by ASME.

关键词： Degrees of freedom (mechanics)

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Vibration control of the Rail Grinding Vehicle with Abrasive Belt Based on Structural Optimization and Lightweight Design

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 311-337页

作者： Wengang Fan Shuai Zhang Zhiwei Wu Yi Liu Jiangnan Yu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control TechnologyMinistry of EducationBeijing 100044China China Railway Materials Operation and Maintenance Technology Co. LtdBeijing 100036China

As a new grinding and maintenance technology,rail belt grinding shows significant advantages in many applications The dynamic characteristics of the rail belt grinding vehicle largely determines its grinding performance and service *** order to explore the vibration control method of the rail grinding vehicle with abrasive belt,the vibration response changes in structural optimization and lightweight design are respectively analyzed through transient response and random vibration simulations in this ***,the transient response simulation analysis of the rail grinding vehicle with abrasive belt is carried out under operating conditions and non-operating ***,the vibration control of the grinding vehicle is implemented by setting vibration isolation elements,optimizing the structure,and increasing ***,in order to further explore the dynamic characteristics of the rail grinding vehicle,the random vibration simulation analysis of the grinding vehicle is carried out under the condition of the horizontal irregularity of the American AAR6 ***,by replacing the Q235 steel frame material with 7075 aluminum alloy and LA43M magnesium alloy,both vibration control and lightweight design can be achieved *** results of transient dynamic response analysis show that the acceleration of most positions in the two working conditions exceeds the standard value in GB/T 17426-1998 *** optimizing the structure of the grinding vehicle in three ways,the average vibration acceleration of the whole car is reduced by about 55.1%from 15.6 m/s^(2) to 7.0 m/s^(2).The results of random vibration analysis show that the grinding vehicle with Q235 steel frame does not meet the safety conditions of 3σ.By changing frame material,the maximum vibration stress of the vehicle can be reduced from 240.7 MPa to 160.0 MPa and the weight of the grinding vehicle is reduced by about 21.7%from 1500 kg to 1175 *** modal analysis results indic

关键词： Vibration control Dynamic characteristics Structural optimization Lightweight design Modal analysis

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Trajectory tracking control of autonomous heavy-duty mining dump trucks with uncertain dynamic characteristics

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Science China(Information Sciences) 2023年第10期66卷 246-262页

作者： Liang CHEN Zhaobo QIN Manjiang HU Hongbo GAO Yougang BIAN Biao XU Xiaoyan PENG State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Wuxi Intelligent Control Research Institute of Hunan University Department of Automation University of Science and Technology of China

The proportion of mines using autonomous mining trucks is still very low at present. To promote the development of intelligent mining, it is urgent to proceed with the drive-by-wire modification to common mining trucks and design a motion control algorithm considering uncertain dynamic *** paper proposes a trajectory tracking control method for autonomous heavy-duty mining dump trucks(AHMDTs) with uncertain dynamic characteristics. In this method, a driving/braking force compensation algorithm based on an inverse dynamic model is designed to guarantee accurate longitudinal control with less control gain tuning. Using road curvatures, a modified rear-wheel position feedback control method is proposed to deal with reverse-path tracking, which can simultaneously reduce the lateral error and yaw angle error. A modified Stanley controller considering the collaborative preview based on speed and curvature is constructed to achieve accurate path tracking in the forward gear. Moreover, the proposed method focuses on the practice of trajectory tracking control in an open-pit mine condition with the adverse effects caused by uncertain vehicle dynamics, huge variable load, and large actuator lag. Real vehicle tests show that the proposed methodology can control AHMDTs with a low tracking error.

关键词： vehicle control trajectory tracking control driving/braking force compensation rear-wheel position feedback

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Thickness measurement of Single-Mode Fiber Coating Layer Based on Forward Brillouin Scattering

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IEEE Sensors Journal 2025年第11期25卷 19332-19340页

作者： Zhang, Yongqi Wang, Tao Liu, Yijia Liu, Li Zhang, Mingjiang Taiyuan University of Technology Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education College of Physics and Optoelectronic Engineering Taiyuan030024 China Taiyuan University of Technology Shanxi Key Laboratory of Precision Measurement Physics The College of Physics and Optoelectronic Engineering Taiyuan030024 China

The coating layer is essential for protecting and applying optical fibers. Nowadays, the thickness measurement of the coating layer relies on point measurement schemes, such as the side-looking light distribution method and mechanical method. However, there are some problems with the above methods, such as the tradeoff between resolution and field of view (FOV), the cutting of the measurement position, and the long measurement time. To overcome these problems, we propose a new method based on forward Brillouin scattering (FBS), which measures the coating layer thickness of single mode fibers (SMFs). The physical properties of the transverse acoustic field involved in FBS make it possible to measure the thickness of the fiber coating. The corresponding relationship between the transverse acoustic mode frequency and the diameter of the coating layer can be calculated. The coating layer thickness can be measured with high precision by measuring the frequency spectrum of FBS corresponding to multiple transverse acoustic modes at a given temperature. In the verification experiment, three types of SMF coated with polyimide are used as the sensing fiber to measure the thickness of the coating layer at multiple temperatures. The experimental results show that the error in the coating layer thickness obtained is less than 0.05 μm. To the best of our knowledge, this is the first demonstration of nondestructive, high-precision monitoring of fiber coating thickness. © 2025 IEEE.

关键词： Acoustic field measurement

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An integrated micromachined flexible ultrasonicinductive sensor for pipe contaminant multiparameter detection

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Microsystems & Nanoengineering 2024年第4期10卷 271-283页

作者： Zheng Yuan Xiaoyu Wu Zhikang Li Jiawei Yuan Yihe Zhao Zixuan Li Shaohui Qin Qi Ma Xuan Shi Zilong Zhao Jiazhu Li Shiwang Zhang Weixuan Jing Xiaozhang Wang Libo Zhao State Key Laboratory for Manufacturing Systems Engineering International Joint Laboratory for Micro/Nano Manufacturing and Measurement TechnologiesXi’an Jiaotong University(Yantai)Research Institute for Intelligent Sensing Technology and SystemXi’an Jiaotong UniversityXi’an 710049China School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Instrument Science and Technology Xi’an Jiaotong UniversityXi’an 710049China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 265503China

Pipe contaminant detection holds considerable importance within various industries,such as the aviation,maritime,medicine,and other pertinent *** capability is beneficial for forecasting equipment potential failures,ascertaining operational situations,timely maintenance,and lifespan ***,the majority of existing methods operate offline,and the detectable parameters online are relatively *** constraint hampers real-time on-site detection and comprehensive assessments of equipment *** address these challenges,this paper proposes a sensing method that integrates an ultrasonic unit and an electromagnetic inductive unit for the real-time detection of diverse contaminants and flow rates within a *** ultrasonic unit comprises a flexible transducer patch fabricated through micromachining technology,which can not only make installation easier but also focus the sound ***,the sensing unit incorporates three symmetrical solenoid *** a comprehensive analysis of ultrasonic and induction signals,the proposed method can be used to effectively discriminate magnetic metal particles(e.g.,iron),nonmagnetic metal particles(e.g.,copper),nonmetallic particles(e.g.,ceramics),and *** inclusive categorization encompasses nearly all types of contaminants that may be present in a ***,the fluid velocity can be determined through the ultrasonic Doppler frequency *** efficacy of the proposed detection principle has been validated by mathematical models and finite element *** contaminants with diverse velocities were systematically tested within a 14mm diameter *** experimental results demonstrate that the proposed sensor can effectively detect contaminants within the 0.5−3mm range,accurately distinguish contaminant types,and measure flow velocity.

关键词： inductive holds ultrasonic

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