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Efficient Dynamic Locomotion of Quadruped Robot via Adaptive Diagonal Gait

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Journal of Bionic Engineering 2024年第1期21卷 126-136页

作者： Jian Bi Teng Chen Xuewen Rong Guoteng Zhang Guanglin Lu Jingxuan Cao Han Jiang Yibin Li The center for robotics School of Control Science and EngineeringShandong UniversityJi Nan 250000China

Quadruped animals in the nature realize high energy efficiency locomotion by automatically changing their gait at different speeds.Inspired by this character,an efficient adaptive diagonal gait locomotion controller is designed for quadruped robot.A unique gait planning method is proposed in this paper.As the speed of robot varies,the gait cycle time and the proportion of stance and swing phase of each leg are adjusted to form a variety of gaits.The optimal joint torque is calculated by the controller combined with Virtual Model Control(VMC)and Whole-Body Control(WBC)to realize the desired motion.The gait and step frequency of the robot can automatically adapt to the change of speed.Several experiments are done with a quadruped robot made by our laboratory to verify that the gait can change automatically from slow-trotting to flying-trot during the period when speed is from 0 to 4 m/s.The ratio of swing phase is from less than 0.5 to more than 0.5 to realize the running motion with four feet off the ground.Experiments have shown that the controller can indeed consume less energy when robot runs at a wide range of speeds comparing to the basic controller.

关键词： Quadruped robot Gait transition Adaptive gait Energy efficiency

Feedback linearization and equivalent-disturbance compensation control strategy for piezoelectric stage

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Nanotechnology and Precision Engineering 2024年第2期7卷 49-59页

作者： Tao Huang Yingbin Wang Zhihong Luo Huajun Cao Guibao Tao Mingxiang Ling State Key Laboratory of Mechanical Transmissions for Advanced Equipment Chongqing UniversityChongqing 400044China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China Hongdu Aviation Industry Group NanchangJiangxi 330000China robotics and microsystems center Soochow UniversitySuzhou 215123China

Piezoelectric stages use piezoelectric actuators and flexure hinges as driving and amplifying mechanisms,respectively.These systems have high positioning accuracy and high-frequency responses,and they are widely used in various precision/ultra-precision positioning fields.However,the main challenge with these devices is the inherent hysteresis nonlinearity of piezoelectric actuators,which seriously affects the tracking accuracy of a piezoelectric stage.Inspired by this challenge,in this work,we developed a Hammerstein model to describe the hysteresis nonlinearity of a piezoelectric stage.In particular,in our proposed scheme,a feedback-linearization algorithm is used to eliminate the static hysteresis nonlinearity.In addition,a composite controller based on equivalent-disturbance compensation was designed to counteract model uncertainties and external disturbances.An analysis of the stability of a closed-loop system based on this feedback-linearization algorithm and composite controller was performed,and this was followed by extensive comparative experiments using a piezoelectric stage developed in the laboratory.The experimental results confirmed that the feedback-linearization algorithm and the composite controller offer improved linearization and trajectory-tracking performance.

关键词： Piezoelectric stage Hysteresis nonlinearity Feedback linearization Equivalent-disturbance compensation

Recent Developments in Metallic Degradable Micromotors for Biomedical and Environmental Remediation Applications

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Nano-Micro Letters 2024年第3期16卷 1-35页

作者： Sourav Dutta Seungmin Noh Roger Sanchis Gual Xiangzhong Chen Salvador Pané Bradley J.Nelson Hongsoo Choi Department of robotics and Mechatronics Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)Daegu 42988Republic of Korea DGIST‑ETH Microrobotics Research center DGISTDaegu 42988Republic of Korea Multi‑Scale robotics Lab Institute of Robotics and Intelligent SystemsETH Zurich8092 ZurichSwitzerland Institute of Optoelectronics State Key Laboratory of Photovoltaic Science and TechnologyShanghai Frontiers Science Research Base of Intelligent Optoelectronics and PerceptionFudan UniversityShanghai 200433People’s Republic of China

Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fuel-free propulsion,favorable biocompatibility,and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media,efficient cargo delivery and favorable biocompatibility.A noteworthy number of degradable metal-based micromotors employ bubble propulsion,utilizing water as fuel to generate hydrogen bubbles.This novel feature has projected degradable metallic micromotors for active in vivo drug delivery applications.In addition,understanding the degradation mechanism of these micromotors is also a key parameter for their design and performance.Its propulsion efficiency and life span govern the overall performance of a degradable metallic micromotor.Here we review the design and recent advancements of metallic degradable micromotors.Furthermore,we describe the controlled degradation,efficient in vivo drug delivery,and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical applications.Moreover,we discuss micromotors’efficacy in detecting and destroying environmental pollutants.Finally,we address the limitations and future research directions of degradable metallic micromotors.

关键词： Magnesium Zinc Iron Biodegradable microrobot Biomedical Environmental

Hemispherical resonator with low subsurface damage machined by small ball-end fine diamond grinding wheel:A novel grinding technique

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Chinese Journal of Aeronautics 2024年第5期37卷 570-585页

作者： Biao QIN Henan LIU Jian CHENG Jinchuan TIAN Jiangang SUN Zihan ZHOU Chuanzhen MA Mingjun CHEN State Key Laboratory of robotics and System Harbin Institute of TechnologyHarbin 150001China center for Precision Engineering Harbin Institute of TechnologyHarbin 150001China

As for the ultra-precision grinding of the hemispherical fused silica resonator,due to the hard and brittle nature of fused silica,subsurface damage(SSD)is easily generated,which enormously influences the performance of such components.Hence,ultra-precision grinding experiments are carried out to investigate the surface/subsurface quality of the hemispherical resonator machined by the small ball-end fine diamond grinding wheel.The influence of grinding parameters on the surface roughness(SR)and SSD depth of fused silica samples is then analyzed.The experimental results indicate that the SR and SSD depth decreased with the increase of grinding speed and the decrease of feed rate and grinding depth.In addition,based on the material strain rate and the maximum undeformed chip thickness,the effect of grinding parameters on the subsurface damage mechanism of fused silica samples is analyzed.Furthermore,a multi-step ultra-precision grinding technique of the hemispherical resonator is proposed based on the interaction influence between grinding depth and feed rate.Finally,the hemispherical resonator is processed by the proposed grinding technique,and the SR is improved from 454.328 nm to 110.449 nm while the SSD depth is reduced by 94%from 40μm to 2.379μm.The multi-step grinding technique proposed in this paper can guide the fabrication of the hemispherical resonator.

关键词： Fused silica Ultra-precision grinding Hemispherical resonator Subsurface damage Grinding technique

Enabling the transfer matrix method to model serial-parallel compliant mechanisms including curved flexure beams

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International Journal of Mechanical System Dynamics 2024年第1期4卷 48-62页

作者： Mingxiang Ling Lei Yuan Tingjun Zeng Xianmin Zhang robotics and microsystems center Soochow UniversitySoochowChina Guangdong Key Laboratory of Precision Equipment and Manufacturing Technology School of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhouChina

Compliant mechanisms with curved flexure hinges/beams have potential advantages of small spaces,low stress levels,and flexible design parameters,which have attracted considerable attention in precision engineering,metamaterials,robotics,and so forth.However,serial-parallel configurations with curved flexure hinges/beams often lead to a complicated parametric design.Here,the transfer matrix method is enabled for analysis of both the kinetostatics and dynamics of general serial-parallel compliant mechanisms without deriving laborious formulas or combining other modeling methods.Consequently,serial-parallel compliant mechanisms with curved flexure hinges/beams can be modeled in a straightforward manner based on a single transfer matrix of Timoshenko straight beams using a step-by-step procedure.Theoretical and numerical validations on two customized XY nanopositioners comprised of straight and corrugated flexure units confirm the concise modeling process and high prediction accuracy of the presented approach.In conclusion,the present study provides an enhanced transfer matrix modeling approach to streamline the kinetostatic and dynamic analyses of general serial-parallel compliant mechanisms and beam structures,including curved flexure hinges and irregular-shaped rigid bodies.

关键词： compliant mechanisms curved flexure beams transfer matrix method nanopositioner rigid-body dynamics

Micro/nanosystems for controllable drug delivery to the brain

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The Innovation 2024年第1期5卷 139-157页

作者： Mingzhen Tian Zhichao Ma Guang-Zhong Yang Institute of Medical robotics School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Drug delivery to the brain is crucial in the treatment for central nervous system disorders.While significant progress has been made in recent years,there are still major challenges in achieving controllable drug delivery to the brain.Unmet clinical needs arise from various factors,including controlled drug transport,handling large drug doses,methods for crossing biological barriers,the use of imaging guidance,and effective models for analyzing drug delivery.Recent advances in micro/nanosystems have shown promise in addressing some of these challenges.These include the utilization of microfluidic platforms to test and validate the drug delivery process in a controlled and biomimetic setting,the development of novel micro/nanocarriers for large drug loads across the blood-brain barrier,and the implementation of micro-intervention systems for delivering drugs through intraparenchymal or peripheral routes.In this article,we present a review of the latest developments in micro/nanosystems for controllable drug delivery to the brain.We also delve into the relevant diseases,biological barriers,and conventional methods.In addition,we discuss future prospects and the development of emerging robotic micro/nanosystems equipped with directed transportation,real-time image guidance,and closed-loop control.

关键词： equipped doses barriers

蚯蚓直线运动的三轴地面反作用力:测量、分析和对机器人建模的影响

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Acta Mechanica Sinica 2024年第2期40卷 1-14页

作者：方虹斌师瑞徐鉴 Institute of AI and robotics State Key Laboratory of Medical NeurobiologyMOE Engineering Research Center of AI&RoboticsFudan UniversityShanghai200433China

蚯蚓在狭窄受限环境中具有良好的移动性,但其在运动过程中与地面的三轴反作用力还未被深入研究.本文探讨了蚯蚓在直线运动过程中的三轴地反力特征及其对机器人建模的影响.具体地,本研究设计了一个基于应变片的三轴微型测力板来测量蚯蚓(... 详细信息

蚯蚓在狭窄受限环境中具有良好的移动性,但其在运动过程中与地面的三轴反作用力还未被深入研究.本文探讨了蚯蚓在直线运动过程中的三轴地反力特征及其对机器人建模的影响.具体地,本研究设计了一个基于应变片的三轴微型测力板来测量蚯蚓(P.guillelmi)在直线运动时的三轴地反力.通过建立地反力的时间历程与运动视频的对应关系,将蚯蚓的周期性运动划分为三个阶段,并从蚯蚓身体变形的角度解析了地反力在三个阶段的力学特征.本研究还对蚯蚓的地反力特征进行了统计分析,并建立了蚯蚓直线运动过程的阻力系数模型.以此为基础,本文还提出了与机器人节段/单元变形相关的阻力系数模型,为离散型和连续型仿蚯蚓机器人的动力学建模提供基础.本研究首次对蚯蚓运动过程中的mN级三轴地反力进行了测量、分析和建模,研究结果对蚯蚓运动生物力学、仿蚯蚓移动机器人设计和机器人-环境接触界面调控等具有重要的指导意义.

关键词：移动机器人直线运动运动视频运动生物力学应变片周期性运动环境接触界面调控

Type Synthesis of Self-Alignment Parallel Ankle Rehabilitation Robot with Suitable Passive Degrees of Freedom

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 160-175页

作者： Ya Liu Wenjuan Lu Dabao Fan Weijian Tan Bo Hu Daxing Zeng School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China Dongguan Engineering Technology Research center for Parallel Robot Dongguan 523808China The DGUT Innovation center of robotics and Intelligent Equipment Dongguan 523808China

The current parallel ankle rehabilitation robot(ARR)suffers from the problem of difficult real-time alignment of the human-robot joint center of rotation,which may lead to secondary injuries to the patient.This study investigates type synthesis of a parallel self-alignment ankle rehabilitation robot(PSAARR)based on the kinematic characteristics of ankle joint rotation center drift from the perspective of introducing"suitable passive degrees of freedom(DOF)"with a suitable number and form.First,the self-alignment principle of parallel ARR was proposed by deriving conditions for transforming a human-robot closed chain(HRCC)formed by an ARR and human body into a kinematic suitable constrained system and introducing conditions of"decoupled"and"less limb".Second,the relationship between the self-alignment principle and actuation wrenches(twists)of PSAARR was analyzed with the velocity Jacobian matrix as a"bridge".Subsequently,the type synthesis conditions of PSAARR were proposed.Third,a PSAARR synthesis method was proposed based on the screw theory and type of PSAARR synthesis conducted.Finally,an HRCC kinematic model was established to verify the self-alignment capability of the PSAARR.In this study,93 types of PSAARR limb structures were synthesized and the self-alignment capability of a human-robot joint axis was verified through kinematic analysis,which provides a theoretical basis for the design of such an ARR.

关键词： Ankle rehabilitation robot Self-alignment Parallel mechanism Type synthesis Screw theory

Damage evolution and removal behaviors of GaN crystals involved in double-grits grinding

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International Journal of Extreme Manufacturing 2024年第2期6卷 469-484页

作者： Chen Li Yuxiu Hu Zongze Wei Chongjun Wu Yunfeng Peng Feihu Zhang Yanquan Geng State Key Laboratory of robotics and System(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China Key Laboratory of microsystems and Microstructures Manufacturing(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China College of Mechanical Engineering Donghua UniversityShanghai 201620People’s Republic of China Department of Mechanical and Electrical Engineering Xiamen UniversityXiamen 361005People’s Republic of China

Elucidating the complex interactions between the work material and abrasives during grinding of gallium nitride(GaN)single crystals is an active and challenging research area.In this study,molecular dynamics simulations were performed on double-grits interacted grinding of GaN crystals;and the grinding force,coefficient of friction,stress distribution,plastic damage behaviors,and abrasive damage were systematically investigated.The results demonstrated that the interacted distance in both radial and transverse directions achieved better grinding quality than that in only one direction.The grinding force,grinding induced stress,subsurface damage depth,and abrasive wear increase as the transverse interacted distance increases.However,there was no clear correlation between the interaction distance and the number of atoms in the phase transition and dislocation length.Appropriate interacted distances between abrasives can decrease grinding force,coefficient of friction,grinding induced stress,subsurface damage depth,and abrasive wear during the grinding process.The results of grinding tests combined with cross-sectional transmission electron micrographs validated the simulated damage results,i.***.amorphous atoms,high-pressure phase transition,dislocations,stacking faults,and lattice distortions.The results of this study will deepen our understanding of damage accumulation and material removal resulting from coupling between abrasives during grinding and can be used to develop a feasible approach to the wheel design of ordered abrasives.

关键词： grinding double-grits molecular dynamics damage material removal gallium nitride