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A modular cable-driven humanoid arm with anti-parallelogram mechanisms and Bowden cables

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0722-2

摘要: This paper proposes a novel modular cable-driven humanoid arm with anti-parallelogram mechanisms (APMs) and Bowden cables. The lightweight arm realizes the advantage of joint independence and the rational layout of the driving units on the base. First, this paper analyzes the kinematic performance of the APM and uses the rolling motion between two ellipses to approximate a pure-circular-rolling motion. Then, a novel type of one-degree-of-freedom (1-DOF) elbow joint is proposed based on this principle, which is also applied to design the 3-DOF wrist and shoulder joints. Next, Bowden cables are used to connect the joints and their driving units to obtain a modular cable-driven arm with excellent joint independence. After that, both the forward and inverse kinematics of the entire arm are analyzed. Last, a humanoid arm prototype was developed, and the assembly velocity, joint motion performance, joint stiffness, load carrying, typical humanoid arm movements, and repeatability were tested to verify the arm performance.

关键词: modular robotic arm     anti-parallelogram mechanism     Bowden cable     humanoid arm     lightweight joint design    

Lightweight design of an electric bus body structure with analytical target cascading

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0718-y

摘要: Lightweight designs of new-energy vehicles can reduce energy consumption, thereby improving driving mileage. In this study, a lightweight design of a newly developed multi-material electric bus body structure is examined in combination with analytical target cascading (ATC). By proposing an ATC-based two-level optimization strategy, the original lightweight design problem is decomposed into the system level and three subsystem levels. The system-level optimization model is related to mass minimization with all the structural modal frequency constraints, while each subsystem-level optimization model is related to the sub-structural performance objective with sub-structure mass constraints. To enhance the interaction between two-level systems, each subsystem-level objective is reformulated as a penalty-based function coordinated with the system-level objective. To guarantee the accuracy of the model-based analysis, a finite element model is validated through experimental modal test. A sequential quadratic programming algorithm is used to address the defined optimization problem for effective convergence. Compared with the initial design, the total mass is reduced by 49 kg, and the torsional stiffness is increased by 17.5%. In addition, the obtained design is also validated through strength analysis.

关键词: electric vehicle     body in white (BIW)     lightweight     analytical target cascading (ATC)    

Precast steel–UHPC lightweight composite bridge for accelerated bridge construction

Shuwen DENG, Xudong SHAO, Xudong ZHAO, Yang WANG, Yan WANG

《结构与土木工程前沿(英文)》 2021年 第15卷 第2期   页码 364-377 doi: 10.1007/s11709-021-0702-3

摘要: In this study, a fully precast steel–ultrahigh performance concrete (UHPC) lightweight composite bridge (LWCB) was proposed based on Mapu Bridge, aiming at accelerating construction in bridge engineering. Cast-in-place joints are generally the controlling factor of segmental structures. Therefore, an innovative girder-to-girder joint that is suitable for LWCB was developed. A specimen consisting of two prefabricated steel–UHPC composite girder parts and one post-cast joint part was fabricated to determine if the joint can effectively transfer load between girders. The flexural behavior of the specimen under a negative bending moment was explored. Finite element analyses of Mapu Bridge showed that the nominal stress of critical sections could meet the required stress, indicating that the design is reasonable. The fatigue performance of the UHPC deck was assessed based on past research, and results revealed that the fatigue performance could meet the design requirements. Based on the test results, a crack width prediction method for the joint interface, a simplified calculation method for the design moment, and a deflection calculation method for the steel–UHPC composite girder in consideration of the UHPC tensile stiffness effect were presented. Good agreements were achieved between the predicted values and test results.

关键词: accelerated bridge construction     ultrahigh-performance concrete     steel–UHPC composite bridge     UHPC girder-to-girder joint    

Planar jumping with stable landing through foot orientation design and ankle joint control

Qilong YUAN, I-Ming CHEN

《机械工程前沿(英文)》 2012年 第7卷 第2期   页码 100-108 doi: 10.1007/s11465-012-0318-3

摘要:

This paper introduces a method to generate the planar jumping motion for biped robot. In this work, through determining the upper body posture trajectory in the flight phase, the foot landing posture is made to be flat while landing. Together with properly designing the trajectory for local center of gravity and the foot landing velocity, the soft landing trajectory is generated. A controller on the ankle joint is added to avoid significant impact with the ground and stabilize the robot after landing. Jumping motion with stable landing is achieved in a dynamic simulation environment based on this method.

关键词: biped jumping     stable landing control     jumping motion generation    

基于现场可编程门阵列的不同数据路径架构 ANU轻量级密码的设计与实现 Personal View

Vijay DAHIPHALE, Gaurav BANSOD, Ankur ZAMBARE, Narayan PISHAROTY

《信息与电子工程前沿(英文)》 2020年 第21卷 第4期   页码 615-628 doi: 10.1631/FITEE.1800681

摘要: 自物联网(IoT)诞生以来,数据与系统安全一直是开发者关注的重点。由于大多数物联网设备在8位控制器上运行,其容量和计算力有限,因此需要使用轻量级密码在发送端和接收端分别进行加密和解密。提出用于ANU密码硬件实现的新架构,并给出每一架构的相关结果。在相同实施条件下,在4种不同现场可编程门阵列(FPGA)上分别以4位、8位、16位和32位的数据路径尺寸实现ANU密码,并比较每一性能指标。与以往ANU密码架构不同,新架构具有用于高吞吐量和硬件优化的并行替换盒(S盒)。通过不同数据路径设计,在资源极其有限的系统中,ANU密码被证明是实现安全性的最佳选择。

关键词: 轻量级密码;物联网(IoT);嵌入式系统安全;加密;现场可编程门阵列;数据路径设计    

基于人体髋关节转动中心分析的髋关节外骨骼仿生设计 Article

Wei YANG,Can-jun YANG,Ting XU

《信息与电子工程前沿(英文)》 2016年 第17卷 第8期   页码 792-802 doi: 10.1631/FITEE.1500286

摘要: 为了改善外骨骼穿戴舒适性,本文提出了一种基于人机物理交互优化的外骨骼设计方法。该方法通过设计外骨骼髋关节,使其保证人体髋关节运动时外骨骼髋关节转动中心能跟随人体髋关节转动中心的运动轨迹。当人体髋关节运动时,通过实验测量和计算可以得到其转动中心轨迹。本文设计的外骨骼髋关节运动机构能在人体髋关节屈曲/伸展和外展/内收时,保证转动中心都能够包容人体髋关节转动中心运动范围。同时,所设计的外骨骼髋关节被应用到下肢步行康复训练外骨骼中。通过人机接触力实验可知,与传统设计外骨骼髋关节进行相比,本文设计的仿生髋关节外骨骼在髋关节屈曲/伸展和内收/外展时分别可以减小24.1%和76.0%的人机接触力。这一结果证明仿生设计髋关节外骨骼更具穿戴舒适性,更符合人机工程学的设计要求。最后,本文通过建立人机闭式链模型进一步分析了仿生设计对于人体髋关节内力的影响,并验证该设计能减少关节内力作用。

关键词: 髋关节外骨骼;髋关节中心;柔顺关节;人机交互力    

一种具有大工作空间的轻量级力反馈手套 Article

郑宇铠, 王党校, 王子琦, 张昱, 张玉茹, 徐卫良

《工程(英文)》 2018年 第4卷 第6期   页码 869-880 doi: 10.1016/j.eng.2018.10.003

摘要:

在虚拟现实场景中,佩戴力反馈手套是一种有效的增强穿戴者与虚拟物体交互沉浸感的方法。这种手套的设计难点在于需要提供足够大的手指运动工作空间,在模拟自由空间和约束空间交互时提供所需的力反馈感觉,以及确保一个轻量级的结构。本文提出了一种将气动驱动器安装在使用者手背侧的力反馈手套。该手套采用了一种凸轮连杆组合机构,利用带有弯曲滑槽和三个运动副的连杆将阻力从气缸活塞杆传递到指尖。为了得到穿戴者指尖反馈力的一个较大的法向分量,通过分析带有三个运动副的连杆上的力平衡,计算出了滑槽的轮廓。本文研制了质量为245 g 的五指力反馈手套样机,建立了可穿戴的力测量系统,对自由空间和约束空间的力反馈性能进行了定量评价。实验结果表明,该手套在自由空间模拟中平均阻力小于0.1 N,在约束空间模拟中指尖力最大为4 N。实验进一步证实,这种手套能够保证手指的自由移动以及模拟典型的抓取操作手势。

关键词: 力反馈手套     轻量级     大工作空间     气压驱动     虚拟现实    

BORON:面向普适计算的超轻量低功耗加密设计 Article

Gaurav BANSOD,Narayan PISHAROTY,Abhijit PATIL

《信息与电子工程前沿(英文)》 2017年 第18卷 第3期   页码 317-331 doi: 10.1631/FITEE.1500415

摘要: 我们提出一种超轻量,紧凑且低功耗的分组密码:BORON。BORON是一种替换、互换网络,运行于64位纯文本上,支持128位或80位密钥长度。针对128位密钥和80位密钥,BORON的紧凑结构分别需要1939个和1626个等效门(gate equivalents, GE)。BORON包含移位、循环移位和异或操作。其的独特设计有助于在较少的回合内产生大量的活动S-box,从而挫败针对加密的线性或差分攻击。BORON在硬、软件平台上均具有较好的性能。与轻量加密LED相比,BORON具有更低的功耗水平;与现有SP网络加密相比,BORON具有更高的吞吐量。本文还展示了BORON的安全性分析及其作为超轻量紧凑型加密的性能。BORON可适用于将引脚面积和功率耗散作为关键参数的应用。

关键词: 轻量密码;SP网络;分组密码;物联网;加密;嵌入式安全    

Microcellular injection molding process for producing lightweight thermoplastic polyurethane with customizable

Thomas ELLINGHAM, Hrishikesh KHARBAS, Mihai MANITIU, Guenter SCHOLZ, Lih-Sheng TURNG

《机械工程前沿(英文)》 2018年 第13卷 第1期   页码 96-106 doi: 10.1007/s11465-018-0498-6

摘要:

A three-stage molding process involving microcellular injection molding with core retraction and an “out-of-mold” expansion was developed to manufacture thermoplastic polyurethane into lightweight foams of varying local densities, microstructures, and mechanical properties in the same microcellular injection molded part. Two stages of cavity expansion through sequential core retractions and a third expansion in a separate mold at an elevated temperature were carried out. The densities varied from 0.25 to 0.42 g/cm3 (77% to 62% weight reduction). The mechanical properties varied as well. Cyclic compressive strengths and hysteresis loss ratios, together with the microstructures, were characterized and reported.

关键词: thermoplastic polyurethane     microcellular injection molding     cavity expansion     compressive strength     hysteresis loss ratio    

A lightweight authentication scheme with user untraceability

Kuo-Hui YEH

《信息与电子工程前沿(英文)》 2015年 第16卷 第4期   页码 259-271 doi: 10.1631/FITEE.1400232

摘要: With the rapid growth of electronic commerce and associated demands on variants of Internet based applications, application systems providing network resources and business services are in high demand around the world. To guarantee robust security and computational efficiency for service retrieval, a variety of authentication schemes have been proposed. However, most of these schemes have been found to be lacking when subject to a formal security analysis. Recently, Chang (2014) introduced a formally provable secure authentication protocol with the property of user-untraceability. Unfortunately, based on our analysis, the proposed scheme fails to provide the property of user-untraceability as claimed, and is insecure against user impersonation attack, server counterfeit attack, and man-in-the-middle attack. In this paper, we demonstrate the details of these malicious attacks. A security enhanced authentication scheme is proposed to eliminate all identified weaknesses.

关键词: Authentication     Privacy     Security     Smart card     Untraceability    

Analytical algorithms of compressive bending capacity of bolted circumferential joint in metro shield

《结构与土木工程前沿(英文)》   页码 901-914 doi: 10.1007/s11709-023-0915-8

摘要: The integrity and bearing capacity of segment joints in shield tunnels are associated closely with the mechanical properties of the joints. This study focuses on the mechanical characteristics and mechanism of a bolted circumferential joint during the entire bearing process. Simplified analytical algorithms for four stress stages are established to describe the bearing behaviors of the joint under a compressive bending load. A height adjustment coefficient, α, for the outer concrete compression zone is introduced into a simplified analytical model. Factors affecting α are determined, and the degree of influence of these factors is investigated via orthogonal numerical simulations. The numerical results show that α can be specified as approximately 0.2 for most metro shield tunnels in China. Subsequently, a case study is performed to verify the rationality of the simplified theoretical analysis for the segment joint via numerical simulations and experiments. Using the proposed simplified analytical algorithms, a parametric investigation is conducted to discuss the factors affecting the ultimate compressive bending capacity of the joint. The method for optimizing the joint flexural stiffness is clarified. The results of this study can provide a theoretical basis for optimizing the design and prediciting the damage of bolted segment joints in shield tunnels.

关键词: shield tunnel     segment joint     joint structural model     failure mechanism    

Influence of construction-induced damage on the degradation of freeze–thawed lightweight cellular concrete

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 781-792 doi: 10.1007/s11709-021-0733-9

摘要: During the construction of lightweight cellular concrete (LCC), material damage frequently occurs, causing the degradation and deterioration of the mechanical performance, durability, and subgrade quality of LCC. The construction-induced damage can be more significant than those from the service environment of LCC, such as freeze–thaw (F–T) action in cold regions. However, the effect of construction-induced damage on LCC during F–T cycles is often ignored and the deterioration mechanisms are not yet clarified. In this study, we investigated the factors causing damage during construction using a sample preparation method established to simulate the damage in the laboratory setting. We conducted F–T cycle tests and microstructural characterization to study the effect of microstructural damage on the overall strength of LCC with different water contents under F–T actions. We established the relationship between the pore-area ratio and F–T cycle times, pore-area ratio, and strength, as well as the F–T cycle times and strength under different damage forms. The damage evolution is provided with the rationality of the damage equation, verified by comparing the measured and predicted damage variables. This study would serve as a guide for the construction and performance of LCC in cold regions.

关键词: lightweight cellular concrete     construction-induced damage     freeze-thaw action     microstructure     degradation mechanism    

Design considerations and experimental studies on semi-active smart pin joint

Yancheng LI, Jianchun LI, Bijan SAMALI, Jiong WANG,

《机械工程前沿(英文)》 2009年 第4卷 第4期   页码 363-370 doi: 10.1007/s11465-009-0074-1

摘要: Hostile dynamic loadings such as severe wind storms, earthquakes, and sudden impacts can cause severe damage to many civil engineering structures. An intelligent structural system equipped with smart structural members that are controllable in real-time is an effective solution to structural damage and failure during such situations. Civil intelligent structures with controllable properties to adapt to any changes due to dynamic loadings can lead to effective protection of structures and their occupants. In this paper, design and testing of a semi-active magnetorheological (MR) pin joint, in which the moment resistance can be controlled in real-time by altering the magnetic field, is reported with the view of using it as a potential candidate for smart members in the development of intelligent structures. Design of prototype smart pin joints includes theoretical analysis related to the radius of the rotary plate, the property of MR fluids and the gap between the rotary plate and the casing based on the requirements of the dynamics of MR pin joints. FEM analysis was deployed to study the distribution of the magnetic field along the gap. It is found, from the theoretical analysis and experimental verification, that the MR pin joint with a diameter of 180 mm can produce a torque of up to 30 Nm, which meets requirements for semi-active members in a multi-storey prototype building model in the next stage of research and development.

关键词: magnetorheological (MR) fluids     smart pin joint     design consideration    

Analysis and design of steel-concrete composite sandwich systems subjected to extreme loads

Kazi Md Abu SOHEL, Jat Yuen Richard LIEW, Min Hong ZHANG

《结构与土木工程前沿(英文)》 2011年 第5卷 第3期   页码 278-293 doi: 10.1007/s11709-011-0120-z

摘要: This paper presents the design guide based on analytical, numerical and experimental investigation of Steel-concrete-steel (SCS) sandwich structural members comprising a lightweight concrete core with density ranged from 1300 to 1445 kg/m subjected to static, impact and blast loads. The performance of lightweight sandwich members is also compared with similar members with normal weight concrete core and ultra high strength concrete core ( = 180 MPa). Novel J-hook shear connectors were invented to prevent the separation of face plates from the concrete core under extreme loads and their uses are not restricted by the concrete core thickness. Flexural and punching are the primary modes of failure under static point load. Impact test results show that the SCS sandwich panels with the J-hook connectors are capable of resisting impact load with less damage in comparison than equivalent stiffened steel plate panels. Blast tests with 100 kg TNT were performed on SCS sandwich specimens to investigate the key parameters that affect the blast resistance of SCS sandwich structure. Plastic yield line method is proposed to predict the plastic capacity and post peak large deflection of the sandwich plates. Finally, an energy balanced model is developed to analyze the global behavior of SCS sandwich panels subjected to dynamic load.

关键词: blast load     composite structure     impact load     lightweight concrete     sandwich plate     J-hook connector    

A novel approach to preparing ultra-lightweight ceramsite with a large amount of fly ash

Sen Liu, Congren Yang, Wei Liu, Longsheng Yi, Wenqing Qin

《环境科学与工程前沿(英文)》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1241-1

摘要: •Ultra-lightweight ceramsite is prepared with 80% fly ash. •SiO2, Al2O3, and flux contents significantly influence the performance of ceramsite. •The expansion of ceramsite is caused by the formation of a dense glaze and gas. •The bulk density of ultra-lightweight ceramsite is only 340 kg/m3. The disposal of fly ash has become a serious problem in China due to its rapid increase in volume in recent years. The most common method of fly ash disposal is solidification-stabilization-landfill, and the most common reuse is low-value-added building materials. A novel processing method for preparing ultra-lightweight ceramsite with fly ash was developed. The results show that the optimal parameters for preparation of ultra-lightweight ceramsite are as follows: mass ratio of fly ash:kaolin:diatomite= 80:15:5, preheating temperature of 800°C, preheating time of 5 min, sintering temperature of 1220°C, and sintering time of 10 min. The expansion agent is perlite, at 10 wt.% addition. Finally, a ceramsite with bulk density of 340 kg/m3, particle density of 0.68 g/cm3, and cylinder compressive strength of 1.02 MPa was obtained. Because of its low density and high porosity, ultra-lightweight ceramsite has excellent thermal insulation performance, and its strength is generally low, so it is usually used in the production of thermal insulation concrete and its products. The formation of a liquid-phase component on the surface, and generation of a gas phase inside ceramsite during the sintering process, make it possible to control the production of the suitable liquid phase and gas in this system, resulting in an optimization of the expansion behavior and microstructure of ceramsite. These characteristics show the feasibility of industrial applications of fly ash for the production of ultra-lightweight ceramsite, which could not only produce economic benefits, but also conserve land resources and protect the environment.

关键词: Fly ash     Ultra-lightweight ceramsite     Expansion mechanism     Sintering process    

标题 作者 时间 类型 操作

A modular cable-driven humanoid arm with anti-parallelogram mechanisms and Bowden cables

期刊论文

Lightweight design of an electric bus body structure with analytical target cascading

期刊论文

Precast steel–UHPC lightweight composite bridge for accelerated bridge construction

Shuwen DENG, Xudong SHAO, Xudong ZHAO, Yang WANG, Yan WANG

期刊论文

Planar jumping with stable landing through foot orientation design and ankle joint control

Qilong YUAN, I-Ming CHEN

期刊论文

基于现场可编程门阵列的不同数据路径架构 ANU轻量级密码的设计与实现

Vijay DAHIPHALE, Gaurav BANSOD, Ankur ZAMBARE, Narayan PISHAROTY

期刊论文

基于人体髋关节转动中心分析的髋关节外骨骼仿生设计

Wei YANG,Can-jun YANG,Ting XU

期刊论文

一种具有大工作空间的轻量级力反馈手套

郑宇铠, 王党校, 王子琦, 张昱, 张玉茹, 徐卫良

期刊论文

BORON:面向普适计算的超轻量低功耗加密设计

Gaurav BANSOD,Narayan PISHAROTY,Abhijit PATIL

期刊论文

Microcellular injection molding process for producing lightweight thermoplastic polyurethane with customizable

Thomas ELLINGHAM, Hrishikesh KHARBAS, Mihai MANITIU, Guenter SCHOLZ, Lih-Sheng TURNG

期刊论文

A lightweight authentication scheme with user untraceability

Kuo-Hui YEH

期刊论文

Analytical algorithms of compressive bending capacity of bolted circumferential joint in metro shield

期刊论文

Influence of construction-induced damage on the degradation of freeze–thawed lightweight cellular concrete

期刊论文

Design considerations and experimental studies on semi-active smart pin joint

Yancheng LI, Jianchun LI, Bijan SAMALI, Jiong WANG,

期刊论文

Analysis and design of steel-concrete composite sandwich systems subjected to extreme loads

Kazi Md Abu SOHEL, Jat Yuen Richard LIEW, Min Hong ZHANG

期刊论文

A novel approach to preparing ultra-lightweight ceramsite with a large amount of fly ash

Sen Liu, Congren Yang, Wei Liu, Longsheng Yi, Wenqing Qin

期刊论文