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The cLVSM:A Novel Compact Linear Variable Stiffness Mechanism Based on Circular Beams

Chinese Journal of Mechanical Engineering 2024年第6期37卷 414-428页

作者： Yixin Shao Yufeng Zhou Di Shi Yanggang Feng Xilun Ding Wuxiang Zhang Advanced Manufacturing Center Ningbo Institute of TechnologyBeihang UniversityNingbo 315800China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China

Variable stiffness mechanisms(VSMs)are a class of compliant mechanisms that can adjust their intrinsic stiffness,which promises to be beneficial in applications needed to interact with the environment,such as collaborative robots,wearable robots,and polishing *** paper presents the design and optimization of a novel linear VSM,called cLVSM,to produce linear motion,conversely to the majority of VSMs designed to perform rotary *** changing the effective length of specially designed circular beams,the cLVSM is capable of continuous stiffness regulation from a minimum value to almost *** from the VSMs which need rotation-to-translation converting mechanisms for stiffness regulation,the stiffness of the proposed design is adjusted by directly rotating the beams without the use of additional mechanisms,which contributes to improving the structural compactness,and reducing the energy loss and error in ***,the beam rotation needed to regulate the stiffness is almost perpendicular to the beam deflection force,which helps to reduce the torque needed for stiffness *** stiffness model of the proposed VSM is developed using the screw theory,and the design parameters are optimized using the genetic *** effectiveness of the mathematical model and the performance of the design are verified by simulation and experiments.

关键词： Variable stiffness Compliant mechanism Stiffness modeling Circular beam Screw theory

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Construction of laser-induced graphene/silver nanowire composite structures for low-strain,high-sensitivity flexible wearable strain sensors

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Science China(Technological Sciences) 2024年第11期67卷 3524-3534页

作者： YANG PingAn ZHAO JingYuan LI Rui ZHOU ZhiHao GUI YinGang SUN RuiXue WU DeCheng WANG XiaoJie School of Automation Chongqing University of Posts and TelecommunicationsChongqing 400065China College of Engineering and Technology Southwest UniversityChongqing 400715China Bio-inspired Robotics and Intelligent Material Laboratory Institute of Advanced Manufacturing TechnologyHefei Institutes of Physical ScienceChinese Academy of SciencesChangzhou 213164China

Sandwich-structured flexible sensors based on graphene have high sensitivity and *** graphene is combined with a flexible substrate in a sandwich structure,the weak bonding between them compromises the sensor's stability and sensitivity at low *** presents challenges in monitoring subtle physiological activities,such as hand bending and pulse *** this purpose,laser-induced graphene(LIG)is proposed to be used to prepare flexible sensors in order to improve the sensitivity and stability of the sensors at low ***(PDMS)with low modulus and polyimide(PI)with rich carbon content are selected as precursor materials for LIG,and graphene is formed through laser ***,silver nanowires(Ag NWs)solution is added to LIG to give the sensor low strain and high sensitivity *** the PI/PDMS ratio is 1:3,the Ag NWs/LIG flexible strain sensor exhibits excellent sensitivity(GF=778.468)over a small strain range(8.76%-11.25%).Meanwhile,the sensor still shows excellent stability after 2000 cycle *** Ag NWs/LIG flexible strain sensor shows good performance when placed on the back of the hand,around the eyes,*** is demonstrated that Ag NWs/LIG flexible strain sensors have good application potential in human physiological activity monitoring,health management and medical fields,and provide a low-strain,high-sensitivity sensor design strategy for flexible wearable devices.

关键词： flexible strain sensors high sensitivity strain range Ag NWs laser-induced graphene

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Strain sensor on a chip for quantifying the magnitudes of tensile stress on cells

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Microsystems & Nanoengineering 2024年第3期10卷 305-315页

作者： Yuyin Zhang Yue Wang Hongze Yin Jiahao Wang Na Liu Songyi Zhong Long Li Quan Zhang Tao Yue School of Mechatronics Engineering and Automation Shanghai UniversityShanghaiChina School of Future Technology Shanghai UniversityShanghaiChina Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province School of Mechanical EngineeringZhejiang UniversityHangzhouChina Shanghai Key Laboratory of Intelligent Manufacturing and Robotics Shanghai UniversityShanghaiChina Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghaiChina

During cardiac development,mechanotransduction from the in vivo microenvironment modulates cardiomyocyte growth in terms of the number,area,and arrangement ***,the response of cells to different degrees of mechanical stimuli is ***-on-a-chip,as a platform for investigating mechanical stress stimuli in cellular mimicry of the in vivo microenvironment,is limited by the lack of ability to accurately quantify externally induced ***,previous technology lacks the integration of external stimuli and feedback sensors in microfluidic platforms to obtain and apply precise amounts of external ***,we designed a cell stretching platform with an in-situ *** in-situ liquid metal sensors can accurately measure the mechanical stimulation caused by the deformation of the vacuum cavity exerted on *** platform was applied to human cardiomyocytes(AC16)under cyclic strain(5%,10%,15%,20 and 25%),and we found that cyclic strain promoted cell growth induced the arrangement of cells on the membrane to gradually unify,and stabilized the cells at 15%amplitude,which was even more effective after 3 days of *** platform’s precise control and measurement of mechanical forces can be used to establish more accurate in vitro microenvironmental models for disease modeling and therapeutic research.

关键词： stress deformation arrangement

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Analysis and Verification on Buckling Mechanism of Spatial Tow Steering in Automated Fiber Placement

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Chinese Journal of Mechanical Engineering 2024年第5期37卷 424-438页

作者： Minghui Yi Fei Liu Baoning Chang Yingdan Zhu Xilun Ding Wuxiang Zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Advanced Manufacturing Center Ningbo Institute of TechnologyBeihang UniversityNingbo 315100China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China

Automated fiber placement(AFP)enables the efficient and precise fabrication of complex-shaped aerospace composite structures with lightweight and high-performance ***,due to the excessive compression on the inner edge of the tow placed along the curved trajectory,the resulting defects represented by buckling and wrinkles in spatial tow steering can induce poor manufacturing accuracy and quality degradation of *** this paper,a theoretical model of tow buckling based on the first-order shear deformation laminate theory,linear elastic adhesion interface and Hertz compaction contact theory is proposed to analyze the formation mechanism of the wrinkles and predict the formation of defects by solving the critical radius of the trajectory,and finite element analysis involving the cohesive zone modeling(CZM)is innovated to simulate the local buckling state of the steered tow in ***,numerical parametric studies and experimental results indicate that mechanical properties and geometric parameters of the prepreg,the curvature of the placement trajectory and critical process parameters have a significant impact on buckling formation,and optimization of process parameters can achieve effective suppression of placement *** research proposes a theoretical modeling method for tow buckling,and conducts in-depth research on defect formation and suppression methods based on finite element simulation and placement experiments.

关键词： Automated fiber placement Spatial tow steering Buckling mechanism Process optimization

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Effect of Tine Shaped Furrow Opener on Dry Soil Using Discrete Element Modelling

Effect of Tine Shaped Furrow Opener on Dry Soil Using Discre...

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2023 International Conference on robotics and automation in Industry, ICRAI 2023

作者： Mohiz, Abdul Nasir, Fazal E. Shah, Kamran University of Engineering & Technology Department of Mechatronics Engineering Peshawar Pakistan Advanced Robotics & Automation Lab National Center of Robotics & Automation Peshawar Pakistan

ISBN: (纸本)9781665464727

Tillage of the soil is the most important consideration when it comes to the implementation of agricultural practices. Increases in crop yield has been achieved through a variety of agricultural practices thanks to the discoveries of various agricultural experts. The planting process is the one that has the greatest impact on the crop's overall health. The hull can be more precisely prepared for the seed-planting trench with the assistance of furrows. A variety of furrow openers are currently undergoing the implantation process. Studying dynamic systems that are discontinuous in nature can be done with the help of discrete element modelling. The simulation of a tine-shaped furrow opener using the EDEM package software was carried out for three different speeds. When the speed of an object increases, so does the force it exerts on it. Additionally, the length of an object has an effect on the force it exerts. Additionally, taken into consideration were the profiles that were generated in the soil. To carry out statistical validation of the results analysis of variation (ANOVA) was done. The results provided a basis for calculating a confidence level of 95%. For the furrow openers, it was suggested that a speed of 0.495 meters per second, which is equivalent to 1.76 kilometers per hour, be used. © 2023 IEEE.

关键词： Tillage

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Identification of FIR systems under difference-driven scheduled quantized observations

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Control Theory and technology 2024年第2期22卷 163-172页

作者： Dong Liang Ruizhe Jia Fengwei Jing Yong Song Jin Guo School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of Knowledge Automation for Industrial Processes Ministry of EducationBeijing100083China National Engineering Research Center for Advanced Rolling and Intelligent Manufacturing University of Science and Technology BeijingBeijing100083China

In networked system identification,how to effectively use communication resources and improve convergence speed is the focus of ***,there is an inherent contradiction between the two *** this paper,the event-driven communication is used to save communication resources for the identification of finite impulse response systems,and the input design is carried out to meet the requirements of convergence ***,a difference-driven communication is ***,the performance of the communication mechanism is analyzed,and the calculation method of its communication rate is *** that,according to the communication rate and the convergence rate of the identification algorithm,the input design problem is transformed into a constrained optimization problem,and the algorithm for finding the optimal solution is *** addition,considering the case that the output is quantized by multiple thresholds,the way to calculate its communication rate is given and the influence of threshold number on communication rate is ***,the effectiveness of the algorithm is verified by simulation.

关键词： System identification FIR system Difference-driven Quantized observation

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Design and Development of IoT Based Weather and Air Quality Monitoring Station

Design and Development of IoT Based Weather and Air Quality ...

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2023 International Conference on robotics and automation in Industry, ICRAI 2023

作者： Haris, Muhammad Ubaid, Bilal Bibi, Uzma Said, Ameer Us Saqib, Syed Najm Khan, Shahbaz Tufail, Muhammad Advanced Robotics and Automation Lab National Center of Robotics and Automation Peshawar Pakistan University of Engineering and Technology Department of Mechatronics Engineering Peshawar Pakistan Institute of Manufacturing Engineering Management University of Engineering and Applied Sciences Swat Swat Pakistan

ISBN: (纸本)9781665464727

This paper presents the Design and Development of IoT Based Weather and Air Quality Monitoring stations that provide weather-related information for agriculture, and aviation climate forecasting purposes. The prototype is made up of an outdoor unit that consistently monitors numerous climatic variables such as temperature, humidity, barometric pressure, wind speed, wind direction, rainfall, and air quality using sensors with high accuracy. The air quality index(AQI) is also calculated using the sensors values which tell us whether the atmosphere is safe or polluted. ESP32(Microcontroller) which has a WiFi module is used to gather and send the sensor data through the Internet of things (IoT) to a ThingSpeak channel (IoT cloud), an internet platform where the data is saved, analyzed and read the data remotely. The weather station makes use of photovoltaic power and a rechargeable lead-acid battery to sustain the system. This paper also discusses the obvious strengths and shortcomings of the system and suggests plausible upgrades to assist the system in obtaining higher and long-term performance. © 2023 IEEE.

关键词： Internet of things

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Real-Time Plant Recognition and Crop Row Navigation for Autonomous Precision Agricultural Sprayer Robot

Real-Time Plant Recognition and Crop Row Navigation for Auto...

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2023 International Conference on robotics and automation in Industry, ICRAI 2023

作者： Nasir, Fazal Haris, Muhammad Khan, Bilawal Tufail, Muhammad Khan, Muhammad Tahir Dong, Zhang National Center of Robotics and Automation Advanced Robotics and Automation Lab Peshawar Pakistan University of Engineering and Technology Department of Mechatronics Engineering Peshawar Pakistan Jinan China

ISBN: (纸本)9781665464727

This paper presents a vision-based selective spraying technique for an autonomous agricultural sprayer robot. In traditional methods, excessive chemical spraying cause deleterious effects on human health, environment and becomes uneconomical. In order to reduce the agrochemical wastage encounters in a broadcast spraying, a selective plant spraying method is used for crop chemical treatment. The sensor-based approach assisted with YOLOv7 model is deployed on a custom designed robot for recognizing and localizing the lettuce plants in field. The PID-based pressure controller is designed that minimizes the undesirable fluctuations cause by the opening/closing of solenoid-valve-nozzles (SVNs) during spraying. Thus the nozzle's spraying quality is maintained by keeping the pressure constant to a desired value. A visual servoing scheme for row tracking is presented that uses the detected plant's spatial features. The robustness of the visual-based navigation is validated in the real field experiments. © 2023 IEEE.

关键词： Crops

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Design and Implementation of Model Predictive Control (MPC) Based Pressure Regulation System for a Precision Agricultural Sprayer

Design and Implementation of Model Predictive Control (MPC) ...

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2023 International Conference on robotics and automation in Industry, ICRAI 2023

作者： Khan, Adrees Nasir, Fazal Tufail, Muhammad Haris, Muhammad Khan, Muhammad Tahir Dong, Zhang University of Engineering and Technology Department of Mechatronics Engineering Peshawar Pakistan Advanced Robotics and Automation Lab National Center of Robotics and Automation Peshawar Pakistan Jinan China

ISBN: (纸本)9781665464727

Model Predictive Control (MPC) is a control scheme that involves predicting the future behavior of a system and optimizing control actions to accomplish the desired objective. In this study, we develop an intelligent control algorithm, based on MPC to regulate the target pressure in variable-rate agriculture sprayer robots. Modeling and simulation steps of the spraying system are developed using MATLAB/Simulink environment, before passing to the description of the MPC algorithm. Real-time implementation of the MPC algorithm was conducted on an Arduino Mega 2560 controller board by using Simulink Support Package for Arduino Hardware in MATLAB/Simulink to experimentally validate the preliminary results of simulations. The work evaluates MPC to regulate the pressure in the system and compares the results with a traditional PID control system. Moreover, MPC is a novel method for nonlinear system control that achieves zero steady-state error, low transient response, and reduces peak overshoot compared to the results obtained with a PID controller, thereby reducing the waste of chemicals, and minimizing the toxicology and environmental risk. © 2023 IEEE.

关键词： Model predictive control

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Isotope effect on the Casimir force

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Science China(Physics,Mechanics & Astronomy) 2023年第10期66卷 131-137页

作者： Lanyi Xie Fuwei Yang Bai Song Department of Energy and Resources Engineering Peking UniversityBejing 100871China Center for Nano and Micro Mechanics Tsinghua UniversityBejing 100084China Department of Advanced Manufacturing and Robotics Peking UniversityBejing 100871China Beijing Innovation Center for Engineering Science and Advanced Technology Peking UniversityBeijing 100871China

Isotopic dependence of the Casimir force is key to probing new physics and pushing novel technologies at the micro and nanoscale, but is largely unexplored. In 2002, an isotope effect of 10^(-4) was estimated for metals—orders of magnitude beyond the experimental resolution. Here, by employing the Lifshitz theory, we reveal a significant isotope effect of over 10^(-1) for polar dielectrics. This effect arises from the isotope-mass-induced line shift of the zone-center optical phonons and is insensitive to the linewidth. We perform numerical analyses on both the imaginary and real-frequency axes, and derive analytical formulas for predicting the isotope effect. The three-orders-of-magnitude difference between polar dielectrics and metals arises from the distinct isotopic dependence of the phonon and plasma frequencies. Our work opens up a new avenue for engineering forces at small scales and may also facilitate the quest for the fifth force of nature.

关键词： isotope effect Casimir force polar dielectric phonon line shift plasma frequency

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