Structure Analysis of Locking Mechanism of Gear-Rack Typed Ship-Lift

Contact nonlinear theory was researched. Contact problem was transformed into optimization problem containing Lagrange multiplier, and unsymmetrical stiffness matrix was transformed into symmetrical stiffness matrix. A finite element analysis （FEA） model defining more than 300 contact pairs for long nut-short screw locking mechanism of a large-scale vertical gear-rack typed ship-lift was built. Using augmented Lagrange method and symmetry algorithm of contact element stiffness, the FEA model was analyzed, and the contact stress of contact interfaces and the von Mises stress of key parts were obtained. The results show that the design of the locking mechanism meets the requirement of engineering, and this method is effective for solving large stole nonlinear contact pairs.

Design and Analysis of Electro-mechanical Hybrid Anti-lock Braking System for Hybrid Electric Vehicle Utilizing Motor Regenerative Braking

Braking on low adhesion-coefficient roads, hybrid electric vehicle＇s motor regenerative torque is switched off to safeguard the normal anti-lock braking system （ABS） fimction. When the ABS control is terminated, the motor regenerative braking is readmitted. Aiming at avoiding permanent cycles from hydraulic anti-lock braking to motor regenerative braking, a novel electro-mechanical hybrid anti-lock braking system using fuzzy logic is designed. Different from the traditional single control structure, this system has a two-layered hierarchical structure, The first layer is responsible for harmonious adjustment or interaction between regenerative system and anti-lock braking system. The second layer is responsible for braking torque distribution and adjustment. The closed-loop simulation model is built. Control strategy and method for coordination between regenerative and anti-lock braking are developed. Simulation braking on low adhesion-coefficient roads with fuzzy logic control and real vehicle braking field test are presented. The results from simulating analysis and experiment show braking performance of the vehicle is perfect, harmonious coordination between regenerative and anti-lock braking function, significant amount of braking energy can be recovered and the proposed control strategy and method are effective.

A novel stiffness optimization model of space telescopic boom based on locking mechanism

The deployable telescopic boom,whose mass and stiffness play crucial roles,is extensively used in the design of space-deployable structures.However,the most existing optimal design that neglects the influence of the locking mechanisms in boom joints cannot raise the whole stiffness while reducing the boom mass.To tackle this challenge,a novel optimization model,which utilizes the arrangement of the locking mechanisms to achieve synchronous improvement of the stiffness and mass,is proposed.The proposed optimization model incorporates a novel joint stiffness model developed based on an equivalent parallel mechanism that enables the consideration of multiple internal stiffness factors of the locking mechanisms and tubes,resulting in more accurate representations of the joint stiffness behavior.Comparative analysis shows that the proposed stiffness model achieves more than at least 11% improved accuracy compared with existing models.Furthermore,case verification shows that the proposed optimization model can improve stiffness while effectively reducing mass,and it is applied in boom optimization design.

An 8-Node Plane Hybrid Element for StructuralMechanics Problems Based on the Hellinger-Reissner Variational Principle

The finite element method (FEM) plays a valuable role in computer modeling and is beneficial to the mechanicaldesign of various structural parts. However, the elements produced by conventional FEM are easily inaccurate andunstable when applied. Therefore, developing new elements within the framework of the generalized variationalprinciple is of great significance. In this paper, an 8-node plane hybrid finite element with 15 parameters (PHQ8-15β) is developed for structural mechanics problems based on the Hellinger-Reissner variational principle.According to the design principle of Pian, 15 unknown parameters are adopted in the selection of stress modes toavoid the zero energy modes.Meanwhile, the stress functions within each element satisfy both the equilibrium andthe compatibility relations of plane stress problems. Subsequently, numerical examples are presented to illustrate theeffectiveness and robustness of the proposed finite element. Numerical results show that various common lockingbehaviors of plane elements can be overcome. The PH-Q8-15β element has excellent performance in all benchmarkproblems, especially for structures with varying cross sections. Furthermore, in bending problems, the reasonablemesh shape of the new element for curved edge structures is analyzed in detail, which can be a useful means toimprove numerical accuracy.

一种采用Lock-Free同步机制的数据结构的研究

随着多核芯片在嵌入式实时系统中的广泛应用,采用传统锁机制对共享数据的访问会引起死锁、优先级翻转以及CPU饥饿现象,进而会影响系统整体性能的发挥,严重时还会导致不可估量的损失发生.为此,针对Skiplist的共享数据结构提出了一种Lock-Free的同步机制方法,对该方法的线性一致性进行了证明,并将其应用于混合关键任务的共享优先级调度队列中.经过实验,该方法在吞吐量、核利用率以及平均响应时间方面优于传统的基于锁机制的方法,有效地提升了多核运行的效率.

基于改进公证人机制的跨链隐私共享研究

近年来,随着区块链技术的不断发展,安全问题也随之出现.例如,链上隐私数据泄露和隐私数据跨链交互等.针对上述问题,提出一种基于改进公证人机制的跨链隐私共享模型.首先,设计一种基于门限代理重加密的跨链数据共享机制,该机制规定公证人节点需要质押一定量代币,跨链发起者需要提供一定量的跨链奖励,诚实公证人节点获取代币奖励,恶意公证人节点扣除一定量质押金给与发起者.该机制有效降低公证人节点为恶意节点的可能性;然后,设计一种基于哈希锁和默克尔树的代币锁定机制,确保跨链发起者和公证人节点在互不信任的前提下实现数据可信跨链;最后,实验结果和理论研究证明,所提模型公证人节点恶意攻击概率低、恶意攻击成本高,且所用算法在加解密效率方面优于其他比较方案.

Dynamic behaviors of rockslides subjected to brittle failure of locked segments

Locked segments are recognized as a critical role that controls the stability of rock slopes but remain an unclear and challenging problem with respect to their role incorporated into the failure mechanism.In order to study the effect of the locked segments on the initial failure process of rockslides,thirty-six groups of locked segment specimens with three different lithologies were prepared,direct shear tests were carried out to obtain the accelerations caused by brittle failure of the locked segment specimens.Experiment results showed that the maximum accelerations caused by the brittle failure of locked segment specimens was 2.91 g in the horizontal direction,and 3.18 g in the vertical direction.We took the Wangjiayan rockslide in 2008 Wenchuan earthquake as an example,the critical balance condition of the sliding mass under combined effect of gravity and accelerations induced by brittle failure of locked segment was analyzed,which indicated that the initial failure process of the Wangjiayan rockslides was notably influenced by the existence of the locked segment.The departure acceleration and direction of the Wangjiayan rockslide were proposed.The study results can provide a new insight into the understanding of the initial failure mechanism of rockslides with locked segments.

The two-way feedback and passing-way of human body

Two-way feedback of human body was published in 1992. The sensation of two-way feedback of body is a special system of human reaction, which maintains and regulates symmetry and balance of human body. The human two-way feedback reacts to human health. For human overall health and delay decrepitude, it is necessary to pay attention to the stimulations (passive acceptance and initiative interventions) and relevant influences in human body and the stimulative effect. In this paper, the experimental research of stimulation and an example of two-way feedback in human body are given. And lay a foundation of prevention, medical treatment and hygiene of human overall health.

基于气动控制的蜡模成型实验装置设计与应用

针对手动式蜡模成型实验装置操作耗费人力且锁紧效率低,不便于操作的问题,设计了气动控制的蜡模成型实验装置,以气压为动力源,增设模具快速拆装和锁模机构,实现了气压自动压注的效果。实验表明:设计的气动蜡模成型实验装置成型的蜡模效果好,模具拆装和锁模效率比手动驱动方式提高了近3倍;将该装置应用在实验教学中,提高了学生实验参与度,实验反馈效果好。

含有球面4R环路锁定模式的球面7R机构模式变换分析

具有运动和锁定模式的机构在变换为特定锁定模式位形后,可满足特定工况下的刚度需求。通过在球面4R机构连杆上,设置处于折叠位形的球面3R运动链,设计了一类具有锁定模式的双环球面7R机构。分析球面4R机构连杆曲线的几何特征,通过算例验证了球面4R机构连杆曲线方程的正确性。使用旋量理论分析球面4R环路处于奇异位形下连杆的瞬时转动轴线,确定了球面4R环路中连杆的瞬时转动轴线与球面3R运动链轴线共面,为机构模式变换必要条件。将球面4R环路作为广义转动副,对双环球面7R机构加速度进行分析,得到了球面4R机构环路连杆曲线尖点对应机构位形下,连杆瞬面切线与球面3R运动链轴线共面,为机构模式变换必要条件。结果表明,该类球面7 R机构具有锁定模式,通过旋量理论分析球面4R机构环路连杆的瞬时运动旋量,可确定机构运动模式变换位形。对于分析设计满足运动和锁定生产作业变换需求的多模式机构,具有参考价值。

单点锁紧装置后基座模块化更换虚拟建造分析

针对FPSO单点系泊系统锁紧装置插板和局部结构因反复焊修导致的焊接裂纹问题,提出一种模块化更换方案,以提高焊接质量、结构可靠性和现场施工效率。采用模块化更换方法,通过热弹塑性数值模拟评估单点锁紧装置后基座更换过程中的焊接变形,优化焊接顺序和坡口设计,以控制焊接过程中的变形和残余应力。同时,考虑模块边界设计和不同模块类型的特殊需求,以适应FPSO单点舱复杂结构的多样性。模拟结果显示,优化后的模块化更换方案实现了焊接变形的最小化,有效控制了焊接变形,保证了后基座模块化更换的装配精度,确保了与安装平面误差在可控范围内。模块化更换方案是一种有效的解决FPSO单点锁紧装置插板和局部结构焊接裂纹问题的方法,为后续相关在线维修或坞修提供参考。

基于充气薄膜的可展开帆板结构设计

充气薄膜结构具有质量轻、收纳比高的优势。通过理论分析及实验验证的方法,得到了充气薄膜管承载力矩与充气内压、管道内径、展开程度之间的映射关系。进一步通过“厚度包边”法处理二级展开帆板的厚度问题,设计了转动锁定、转动-滑移锁定、搭接锁定连接结构,提出薄膜管驱动的二级可展开矩形帆板、圆形帆板以及百叶窗式矩形帆板三种大尺度可展开帆板结构形式,并进行展开状态的模态仿真,对比其模态振型。本设计可为大尺度充气可展开结构形式提供参考。

高精度小型经纬仪转轴锁紧机构结构设计

随着光测设备对机动化、小型化的需求增多,受系统空间限制,原大型经纬仪的转轴锁紧机构复杂,占用空间大,加工难度大,并不适用小型经纬仪转轴锁紧。本文根据项目特点设计了小型经纬仪转轴锁紧结构,具有稳定性高、结构简单、加工难度小、占用空间小等特点,可以实现经纬仪在任意角度的转轴锁紧,实现凝视功能。其中对锁紧机构的组成与工作原理进行了详细的介绍与阐述,经过计算选择核心零件的材料,实践结果表明了该结构的合理性。

变电所门的设计要点简析

梳理变电所门的主要作用和设置要点;介绍变电所门的常见的“机械锁”和“门禁”两种形式的管理方式;结合气体灭火系统的特点,分别对两种管理方式下变电所的外门和相邻变电所之间双向开启弹簧门的特点进行分析,提出一种验证灭火剂喷射时能否顶开变电所门的公式,并结合气体灭火系统的要求提出合理建议;最后,分析低压柜长度对门设置的影响并提出建议。

路由器安全防护锁盖注射模设计

针对某路由器安全防护锁盖设计了1副两板注射模,模具中设计了双斜导柱驱动的四向抽芯复合滑块机构,机构使用2根斜导柱驱动1个滑块实施抽芯,滑块在抽芯过程中由4个小滑块带动4个镶件在4个方向上实施同步抽芯,解决了塑件局部区域多个特征多向抽芯脱模机构的难题。

面向空间望远镜在轨组装的主镜接口设计

针对大型空间望远镜在轨组装需求增加及其主镜接口设计的关键技术问题,采用一种基于圆柱凸轮机构的对接接口锁紧机构设计。通过对机构关键零件的设计与校核,进行了望远镜模块对接锁紧过程的容差分析,并利用ANSYS软件对机构的承载能力进行了分析及校核。对于圆柱凸轮锁紧机构从动件运动加速度过大,不适合直接用于望远镜模块锁紧机构的问题,采用统一函数法对圆柱凸轮锁紧机构的曲线槽进行了优化设计,确定了基于改进余弦等速运动规律的曲线槽设计方案,并验证了该方案的优越性。最后,通过7自由度机械臂系统进行了望远镜主镜地面模拟组装实验,验证了所设计接口的对接锁紧和释放功能的有效性。

空间可重复机械锁紧及电磁解锁机构设计与分析

针对空间航天器锁紧装置驱动链长、占用物理空间大的问题,结合摩擦自锁理论,设计了空间可重复机械锁紧及电磁解锁机构,利用多种有限元分析软件分别研究了机构的机械承载性能和电磁学性能。结果表明,在轴向最大锁紧承载工况下,锁紧珠与压板、顶杆、锁紧器外壳间的接触力随时间增加而线性增大,满足力的传递性准则和平衡准则,主要承载部件顶杆和锁紧珠所受的等效应力和变形量与时间呈线性关系,最大等效应力远小于材料的屈服极限强度,装置处于小变形范围。当线圈通入额定电流时,由于电阻发热效应,等电流密度的线圈内部出现稳定的欧姆损耗,电磁解锁装置内部近似为匀强磁场,铁芯的磁聚作用增强了端面的磁感应强度。对设计的空间可重复机械锁紧及电磁解锁机构进行样机制造,并进行原理验证,为空间在轨对接接口的可重复锁紧机构设计和分析提供理论参考。

双叉戟状空间自锁吸能系统设计及吸能性能研究

自锁吸能系统可无需外加约束而避免元件在冲击荷载下的横向飞溅,具有广阔的应用前景。然而,已有自锁吸能系统大都只在特定方向具有自锁稳定性,构型复杂且造价昂贵,或截面形状特殊,不便拆装,制约了应用和推广。为此,该文提出了一种新型的多向自锁能量吸收系统,由具有双叉戟状横截面的薄壁管组成,拆装方式灵活便捷。当系统受冲击时,管件的管槽限制了相邻主体管的位移,使管件系统在空间多个方向的冲击载荷下,均可实现自锁,并且充分变形,稳定吸能。通过有限元分析,系统考察了双叉戟单管的几何参数效应以及阵列轮廓尺寸对系统吸能特性的影响。相较于已有的自锁系统,该文发展的双叉戟自锁吸能系统具有更优异的吸能特性。

悬挂式轨道梁与道岔梁间锁定补偿机构

[目的]为了补偿悬挂式单轨交通系统中移动式道岔在轨道梁与道岔梁接口之间预留的转辙安全缝隙,实现道岔转辙到位的可靠锁定,提高列车通过岔区时的安全性及旅客舒适度,提出一种梁间锁定补偿一体化机构,即锁定与补偿功能共用一处动力源,实现道岔转辙到位后先锁定再补偿的时序要求。[方法]介绍了悬挂式单轨道岔的应用现状及主要存在的问题,并对其应用场景进行了分析;介绍了悬挂式轨道梁与道岔梁的梁间锁定补偿机构的设计组成,并对该机构的运动工作原理进行了分析。[结果及结论]所提锁定补偿机构整体外形结构尺寸紧凑,能够满足悬挂式单轨移动式道岔梁与轨道梁之间狭小的安装空间。该机构通过一体化连杆的空间布局设计实现了梁间的可靠锁定、道岔梁与轨道梁间的接缝补偿,以及满足了锁定与补偿两处功能先锁定再补偿的时序要求。

Design of a Novel Exoskeleton with Passive Magnetic Spring Self-locking and Spine Lateral Balancing

This paper proposes a new upper-limb exoskeleton to reduce worker physical strain.The proposed design is based on a novel PRRRP(P-Prismatic;R-Revolute)kinematic chain with 5 passive Degrees of Freedom(DoF).Utilizing a magnetic spring,the proposed mechanism includes a specially designed locking mechanism that maintains any desired task posture.The proposed exoskeleton incorporates a balancing mechanism to alleviate discomfort and spinal torsional effects also helping in limb weight relief.This paper reports specific models and simulations to demonstrate the feasibility and effectiveness of the proposed design.An experimental characterization is performed to validate the performance of the mechanism in terms of forces and physical strain during a specific application consisting of ceiling-surface drilling tasks.The obtained results preliminarily validate the engineering feasibility and effectiveness of the proposed exoskeleton in the intended operation task thereby requiring the user to exert significantly less force than when not wearing it.