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Pseudo-rigid-body Model for Corrugated Cantilever Beam Used in Compliant Mechanisms

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Chinese Journal of Mechanical Engineering 2014年第1期27卷 122-129页

作者： wang nianfeng LIANG Xiaohe ZHANG Xianmin Guangdong Province Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University

Common compliant joints generally have limited range of motion, reduced fatigue life and high stress concentration. To overcome these shortcomings, periodically corrugated cantilever beam is applied to design compliant joints. Basic corrugated beam unit is modeled by using pseudo-rigid-body method. The trajectory and deformation behavior of periodically corrugated cantilever beam are estimated by the transformation of coordinate and superposition of the deformation of corrugated beam units. Finite element analysis（FEA） is carried out on corrugated cantilever beam to estimate the accuracy of the pseudo-rigid-body model. Results show that the kinetostatic behaviors obtained by this method, which has a relative error less than 6%, has good applicability and corrugated cantilever beam has the characteristics of a large range of motion and high mechanical strength. The corrugated cantilever beam is then applied to design a flexible rotational joint to obtain a larger angle output. The paper proposes a pseudo-rigid-body model for corrugated cantilever beam and designed a flexible rotational joint with large angle output.

关键词： corrugated beam pseudo rigid body method compliant mechanisms

Design and Myoelectric Control of an Anthropomorphic Prosthetic Hand

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Journal of Bionic Engineering 2017年第1期14卷 47-59页

作者： nianfeng wang Kunyi Lao Xianmin Zhang Guangdong Province Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology Guangzhou 510640 China

This paper presents an anthropomorphic prosthetic hand using flexure hinges, which is controlled by the surface electromyography （sEMG） signals from 2 electrodes only. The prosthetic hand has compact structure with 5 fingers and 4 Degree of Freedoms （DoFs） driven by 4 independent actuators. Helical springs are used as elastic joints and the joints of each finger are coupled by tendons. The myoelectric control system which can classify 8 prehensile hand gestures is built. Pattern recognition is employed where Mean Absolute Value （MAV）, Variance （VAR）, the fourth-order Autoregressive （AR） coefficient and Sample Entropy （SE） are chosen as the optimal feature set and Linear Discriminant Analysis （LDA） is utilized to reduce the dimension. A decision of hand gestures is generated by LDA classifier after the current projected feature set and the previous one are ＂pre-smoothed＂, and then the final decision is obtained when the current decision and previous decisions are ＂post-smoothed＂ from the decisions flow. The prosthetic hand can perform prehensile postures for activities of daily living and carry objects under the control of EMG signals.

关键词： electromyography anthropomorphic prosthetic hand myoelectric control pattern recognition prehensile gestures

Spring-Joint Method for Topology Optimization of Planar Passive Compliant Mechanisms

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Chinese Journal of Mechanical Engineering 2013年第6期26卷 1063-1072页

作者： JIN Mohui ZHANG Xianmin ZHU Benliang wang nianfeng Guangdong Provincial Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology

There is seldom approach developed for the initial topology design of flexure-based compliant mechanisms. The most commonly-used approaches, which start with an existing rigid-body mechanism, do not consider the performances between different topologies. Moreover, they rely heavily on the rigid-body topology, therefore limit the diversity of compliant mechanisms topology. To obtain the optimal initial topology of such mechanisms directly from problem specifications without referencing to the existing mechanism topologies, a spring-joint method is presented for a restricted class of the serial passive flexure-based compliant mechanisms, which are the building blocks of parallel compliant mechanisms. The topology of the compliant mechanisms is represented by a serial spring-joint mechanism（SSJM） that is a traditional rigid-body mechanism with a torsional spring acting on each joint, and is described by position vectors of the spring-joints. A simplified compliance matrix, determined by the position vectors, is used to characterize the tip of the SSJM kinematically, and is optimized to ensure the desired freedoms of the compliant mechanisms during optimization. The topology optimization problem is formulated as finding out the optimal position of the spring-joints in a blank design domain with an objective function derived from the simplified compliance matrix. In design examples, syntheses of the compliant mechanisms with both single freedom and two decoupled freedoms are presented to illustrate the proposed method. The proposed method provides a new way for the initial design of flexure-based compliant mechanisms.

关键词： compliant mechanism synthesis topology optimization spring-joint

Advances in dielectric elastomer actuation technology

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Science China(Technological Sciences) 2018年第10期61卷 1512-1527页

作者： wang nianfeng CUI ChaoYu GUO Hao CHEN BiCheng ZHANG XianMin Guangdong Provincial Key Laboratory of Precision Equipment and Manufacturing Technology South China University of Technology

Dielectric elastomer actuators(DEAs) have attracted much interest over the past decades due to the inherent flexibility, large strain, high efficiency, high energy density, and fast response of the material, which are known as one of the most promising candidates for artificial muscle. In this paper, we first introduce the actuation principle and electromechanical modeling approaches of dielectric elastomers(DEs). Then, the performance of different DEs material and existing compliant electrodes that are widely utilized for DEAs are presented. We also highlight the compatibility of DEs, which is suitable for a variety of actuator designs and applications. Lastly, we summarize the challenges and future development in terms of electromechanical modeling, improvement of materials including compliant electrodes and dielectric elastomer, designs and applications of novel dielectric elastomer actuators.

关键词： dielectric elastomer electromechanical modeling compliant electrodes actuator

Modular crawling robots using soft pneumatic actuators

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Frontiers of Mechanical Engineering 2021年第1期16卷 163-175页

作者： nianfeng wang Bicheng CHEN Xiandong GE Xianmin ZHANG Wenbin wang Guangdong Key Laboratory of Precision Equipment and Manufacturing Technology School of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhou 510640China School of Mechanical and Electrical Engineering Shenzhen PolytechnicShenzhen 518055China

Crawling robots have elicited much attention in recent years due to their stable and efficient *** this work,several crawling robots are developed using two types of soft pneumatic actuators(SPAs),namely,an axial elongation SPA and a dual bending *** constraining the deformation of the elastomeric chamber,the SPAs realize their prescribed motions,and the deformations subjected to pressures are characterized with numerical *** are performed for verification,and the results show good *** SPAs are fabricated by casting and developed into crawling robots with 3D-printing *** schemes are presented,and crawling tests are *** speeds predicted by the numerical models agree well with the speeds in the experiments.

关键词： soft robot soft pneumatic actuator kinematic model crawling robot modular design

Multi-objective Topology Optimization of Thermo-mechanical Compliant Mechanisms

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Chinese Journal of Mechanical Engineering 2011年第6期24卷 1123-1129页

作者： LI Dongmei ZHANG Xianmin GUAN Yisheng ZHANG Hong wang nianfeng School of Mechanical andAutomotive Engineering South China University of Technology Guangzhou 510640 China Guangdong Polytechnic Normal University Guangzhou 510665 China School of Computing Science University of Alberta Edmonton AB Canada

The material characteristics of a structure will change with temperature variation,and will induce stress within the ***,the optimal design for the topology of compliant mechanisms is mainly performed in single physical ***,when compliant mechanisms work in high temperature environments,their displacement outputs are generated not only by mechanical load,but also by the temperature variation which may become the prominent ***,the influence of temperature must be considered in the *** this paper,a novel optimization method for multi-objective topology of thermo-mechanical compliant mechanisms is ***,the thermal field is analyzed with finite-element method,where the thermal strain is taken into account in the constitutive relation,and the equivalent nodal thermal load is derived with the principle of virtual *** the thermal load is converted into physical loads in elastic field,and the control equation of the thermo-mechanical compliant mechanism is ***,the mathematical model of the multi-objective topology optimization is built by incorporating both the flexibility and ***,the coupling sensitivity function and the sensitivity analysis equations of thermal steady-state response are ***,optimality criteria algorithm is employed to obtain numerical solution of the multi-objective topology *** examples show that the compliant mechanisms have better performance and are more applicable if the temperature effect is taken into account in the design *** presented modeling and analysis methods provide a new idea and an effective approach to topology optimization of compliant mechanisms in electrothermic coupling field and multiphysics fields.

关键词： compliant mechanisms topology optimization thermo-mechanical coupling multi-objective coupling sensitivity

基于并行策略的多材料柔顺机构多目标拓扑优化

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机械工程学报 2016年第19期52卷 1-8页

作者：张宪民胡凯王念峰张斌华南理工大学机械与汽车工程学院广州510640 上海交通大学机械与动力工程学院上海200240

多材料柔顺机构能够让设计者充分利用各种材料的优良属性,在力,位移,以及能量转移等方面获得更大的设计自由度,因而受到重视。针对受到广泛研究的柔顺机构,结合多目标拓扑优化的方法,提出相应的基于并行策略的求解模型。该方法的核心是... 详细信息

多材料柔顺机构能够让设计者充分利用各种材料的优良属性,在力,位移,以及能量转移等方面获得更大的设计自由度,因而受到重视。针对受到广泛研究的柔顺机构,结合多目标拓扑优化的方法,提出相应的基于并行策略的求解模型。该方法的核心是将一个复杂的多材料多目标问题离散成为单材料子问题,然后并行求解,再根据整体目标的需要,对所有子问题的解进行调整以得到原始问题的解。针对多目标情形,提出新的材料与输出目标关系,从而在将多材料问题离散成单材料子问题的同时,也将多目标问题离散成单目标子问题。对所有的单材料单目标子问题采用各向同性材料的刚度插值-惩罚法并行独立求解。以上方法有其独特优势:在理论和实践上都比较简单,可以处理任意多种材料,可以避免零碎的拓扑结构因而有利于制造。通过算例说明了此方法的有效性。研究结果表明,该方法在某些输出需要特定材料的设计场合更具优势。

关键词：拓扑优化柔顺机构多目标优化多材料

三种两自由度柔顺精密定位平台的性能对比与分析

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机械工程学报 2018年第13期54卷 102-109页

作者：王念峰张志远张宪民梁晓合华南理工大学机械与汽车工程学院

针对传统的缺口型和直片型柔性铰链平台行程不足的特点,设计了一种波纹簧片型柔性铰链,并在此基础上设计了由电磁驱动的两自由度柔顺精密定位平台。基于波纹簧片型、缺口型和直片型柔性铰链平台的特点建立有限元模型分析了这三种平台的... 详细信息

针对传统的缺口型和直片型柔性铰链平台行程不足的特点,设计了一种波纹簧片型柔性铰链,并在此基础上设计了由电磁驱动的两自由度柔顺精密定位平台。基于波纹簧片型、缺口型和直片型柔性铰链平台的特点建立有限元模型分析了这三种平台的静态和模态性能,包括行程,固有频率等。利用电磁驱动作为定位平台的输入驱动,综合对比了三种平台的实际行程,耦合位移,重复定位精度等性能,验证了有限元分析的正确性。结果表明,相比于缺口型和直片型柔性铰链平台,基于波纹簧片型柔性铰链的两自由度柔顺精密定位平台具有行程大,定位精度高的特点,对于柔顺精密定位平台的研究具有重要的参考价值。

关键词：波纹簧片电磁驱动有限元分析

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桥梁主墩承台大体积混凝土温度控制技术研究

建筑结构 2023年第S02期53卷 1450-1453页

作者：王年丰陈云锋中交三公局第一工程有限公司北京100011

为提高某独塔斜拉桥主墩承台大体积混凝土施工质量,对大体积混凝土承台建筑温度控制技术开展研究,现场采用分布式光纤及冷却水管布置监测与控制大体积混凝土的温度;结合MIDAS/Civil建立三维有限元模型,分析承台施工过程的温度场及应力场... 详细信息

为提高某独塔斜拉桥主墩承台大体积混凝土施工质量,对大体积混凝土承台建筑温度控制技术开展研究,现场采用分布式光纤及冷却水管布置监测与控制大体积混凝土的温度;结合MIDAS/Civil建立三维有限元模型,分析承台施工过程的温度场及应力场,揭示大体积混凝土底板施工过程的温度场分布规律,从而指导实际施工过程的温度控制。

关键词：桥梁主墩承台大体积混凝土温度控制技术