Flexible Bio-tensegrity Manipulator with Multi-degree of Freedom and Variable Structure

Conventional manipulators with rigid structures and sti ness actuators have poor flexibility,limited obstacle avoidance capability,and constrained workspace.Some developed flexible or soft manipulators in recent years have the characteristics of infinite degrees of freedom,high flexibility,environmental adaptability,and extended manipulation capability.However,these existing manipulators still cannot achieve the shrinking motion and independent control of specified segments like the animals,which hinders their applications.In this paper,a flexible bio-tensegrity manipulator,inspired by the longitudinal and transversal muscles of octopus tentacles,was proposed to mimic the shrinking behavior and achieve the variable motion patterns of each segment.Such proposed manipulator uses the elastic spring as the backbone,which is driven by four cables and has one variable structure mechanism in each segment to achieve the independent control of each segment.The variable structure mechanism innovatively contains seven lock-release states to independently control the bending and shrinking motion of each segment.After the kinematic modeling and analysis,one prototype of such bionic flexible manipulator was built and the open-loop control method was proposed.Some proof-of-concept experiments,including the shrinking motion,bending motion,and variable structure motion,were carried out by controlling the length of four cables and changing the lock-release states of the variable structure mechanism,which validate the feasibility and validity of our proposed prototype.Meanwhile,the experimental results show the flexible manipulator can accomplish the bending and shrinking motion with the relative error less than 6.8%through the simple independent control of each segment using the variable structure mechanism.This proposed manipulator has the features of controllable degree-of-freedom in each segment,which extend their environmental adaptability,and manipulation capability.

Time-Domain Analysis of Body Freedom Flutter Based on 6DOF Equation

The reduced weight and improved efficiency of modern aeronautical structures result in a decreasing separation of frequency ranges of rigid and elastic modes.Particularly,a high-aspect-ratio flexible flying wing is prone to body freedomflutter(BFF),which is a result of coupling of the rigid body short-periodmodewith 1st wing bendingmode.Accurate prediction of the BFF characteristics is helpful to reflect the attitude changes of the vehicle intuitively and design the active flutter suppression control law.Instead of using the rigid body mode,this work simulates the rigid bodymotion of the model by using the six-degree-of-freedom(6DOF)equation.A dynamicmesh generation strategy particularly suitable for BFF simulation of free flying aircraft is developed.An accurate Computational Fluid Dynamics/Computational Structural Dynamics/six-degree-of-freedom equation(CFD/CSD/6DOF)-based BFF prediction method is proposed.Firstly,the time-domain CFD/CSD method is used to calculate the static equilibrium state of the model.Based on this state,the CFD/CSD/6DOF equation is solved in time domain to evaluate the structural response of themodel.Then combinedwith the variable stiffnessmethod,the critical flutter point of the model is obtained.This method is applied to the BFF calculation of a flyingwing model.The calculation results of the BFF characteristics of the model agree well with those fromthe modalmethod andNastran software.Finally,the method is used to analyze the influence factors of BFF.The analysis results show that the flutter speed can be improved by either releasing plunge constraint or moving the center ofmass forward or increasing the pitch inertia.

Degree of Freedom Analysis for Holographic MIMO Based on a Mutual-Coupling-Compliant Channel Model

Degree of freedom(DOF)is a key indicator for spatial multiplexing layers of a wireless channel.Traditionally,the channel of a multiple-input multiple-output(MIMO)half-wavelength dipole array has a DOF that equals the antenna number.However,recent studies suggest that the DOF could be less than the antenna number when strong mutual coupling is considered.We utilize a mutual-coupling-compliant channel model to investigate the DOF of the holographic MIMO(HMIMO)channel and give a upper bound of the DOF with strong mutual coupling.Our numerical simulations demonstrate that a dense array can support more DOF per unit aperture as compared with a half-wavelength MIMO system.

Triad-displaced ULAs configuration for non-circular sources with larger continuous virtual aperture and enhanced degrees of freedom

Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteristics play a significant role in improving the direction-of-arrival(DOA)estimation accuracy.However,most of the existing NULA geometries are primarily applicable to circular sources(CSs),while they limitedly improve the DOF and continuous virtual aperture for noncircular sources(NCSs).Toward this purpose,we present a triaddisplaced ULAs(Tdis-ULAs)configuration for NCS.The TdisULAs structure generally consists of three ULAs,which are appropriately placed.The proposed antenna array approach fully exploits the non-circular characteristics of the sources.Given the same number of elements,the Tdis-ULAs design achieves more DOF and larger hole-free co-array aperture than its sparse array competitors.Advantageously,the number of uniform DOF,optimal distribution of elements among the ULAs,and precise element positions are uniquely determined by the closed-form expressions.Moreover,the proposed array also produces a filled resulting co-array.Numerical simulations are conducted to show the performance advantages of the proposed Tdis-ULAs configuration over its counterpart designs.

Modal identification of multi-degree-of-freedom structures based on intrinsic chirp component decomposition method

Modal parameter identification is a mature technology.However,there are some challenges in its practical applications such as the identification of vibration systems involving closely spaced modes and intensive noise contamination.This paper proposes a new time-frequency method based on intrinsic chirp component decomposition(ICCD)to address these issues.In this method,a redundant Fourier model is used to ameliorate border distortions and improve the accuracy of signal reconstruction.The effectiveness and accuracy of the proposed method are illustrated using three examples:a cantilever beam structure with intensive noise contamination or environmental interference,a four-degree-of-freedom structure with two closely spaced modes,and an impact test on a cantilever rectangular plate.By comparison with the identification method based on the empirical wavelet transform(EWT),it is shown that the presented method is effective,even in a high-noise environment,and the dynamic characteristics of closely spaced modes are accurately determined.

Constrained multi-degree reduction of rational Bézier curves using reparameterization

Applying homogeneous coordinates, we extend a newly appeared algorithm of best constrained multi-degree reduction for polynomial Bezier curves to the algorithms of constrained multi-degree reduction for rational Bezier curves. The idea is introducing two criteria, variance criterion and ratio criterion, for reparameterization of rational Bezier curves, which are used to make uniform the weights of the rational Bezier curves as accordant as possible, and then do multi-degree reduction for each component in homogeneous coordinates. Compared with the two traditional algorithms of ＂cancelling the best linear common divisor＂ and ＂shifted Chebyshev polynomial＂, the two new algorithms presented here using reparameterization have advantages of simplicity and fast computing, being able to preserve high degrees continuity at the end points of the curves, do multi-degree reduction at one time, and have good approximating effect.

Trimming the Degrees of Freedom via a K^(+) Flux Rectifier for Safe and Long‑Life Potassium‑Ion Batteries

High degrees of freedom(DOF)for K^(+)movement in the electrolytes is desirable,because the resulting high ionic conductivity helps improve potassium-ion batteries,yet requiring support from highly free and flammable organic solvent molecules,seriously affecting battery safety.Here,we develop a K^(+)flux rectifier to trim K ion’s DOF to 1 and improve electrochemical properties.Although the ionic conductivity is compromised in the K^(+)flux rectifier,the overall electrochemical performance of PIBs was improved.An oxidation stability improvement from 4.0 to 5.9 V was realized,and the formation of dendrites and the dissolution of organic cathodes were inhibited.Consequently,the K||K cells continuously cycled over 3,700 h;K||Cu cells operated stably over 800 cycles with the Coulombic efficiency exceeding 99%;and K||graphite cells exhibited high-capacity retention over 74.7%after 1,500 cycles.Moreover,the 3,4,9,10-perylenetetracarboxylic diimide organic cathodes operated for more than 2,100 cycles and reached year-scale-cycling time.We fabricated a 2.18 Ah pouch cell with no significant capacity fading observed after 100 cycles.

A NEW METHOD FOR SOLUTING TRANSIENT RESPONSE OF GENERALLY VISCOUS DAMPING MULTI-DEGREE SYSTEM

By means of the theory of composite-modality,the superposition principle of the vibra-tion mode of the linear system,and the analytical method of the original coordinate,a mathematical model of transient response to any stimulus for generally viscous damping multi-degree system was established.This method not only solves the problem of the transient response of displacement,but also calculates the transient response of the elastic force or the elastic couple of the system.

Freedom EVO全自动酶联免疫前处理仪故障分析

全自动酶联免疫前处理是一种高自动化酶免诊断分析仪,用于检验科各类样品的液体处理工作。仪器在正常保养的情况下,由于标本量巨大、项目繁多,运行过程中不可避免地会出现故障。以Freedom EVO全自动酶联免疫前处理为例,分析总结使用过程中出现的常见故障及解决方法,以尽快解决故障,提高检验质量和工作效率,确保设备长期有效的运行,供操作及维护人员参考。

The Kinematics Performance of Self-Propelled Full Freedom Filament in Wakes of Flow around Cylinder

In vortex streets, the kinematics performance of self-propelled full freedom filament is closely related to the length and the position of filaments in the flow field. In this paper, the changes of passive propulsion velocity and pressure of full-degree-of-freedom filaments after cylindrical wake were analyzed by 15 sets of experiments when the length and position of filaments were changed. The results show that the propulsive velocity of the filament, it approximately increases first and then decreases with the filament length increasing, and the further away from the center of the cylinder, the smaller the propulsive velocity of the filament. In addition, the longer the filament length and the further it is from the center of the cylinder, the lower the pressure around the filament. Experiments show that filaments without energy input can obtain energy from the surrounding flow field to maintain self-propelled motion. Studying the influence of length and position on the kinematics of filaments is helpful to provide a reference for revealing the hydrodynamic mechanism on passive propulsion process and developing low resistance energy harvesting device in swimming fish movement.

The Prisoner of“Freedom”:Cultural Displacement of Santosh in Naipaul’s In a Free State

In a Free State is a post-colonial novel written by Naipaul.“One out of Many”is one of the stories in this novel to explore the freedom of the culturally rootless.The protagonist,Santosh,lives under the collision between the Indian culture and American culture.In the“crevice”of two different cultures,he is deeply involved in the tumultuous and painful process of cultural displacement.His behaviors in cultural displacement can be divided into three stages.Firstly,he has experienced a“cultural shock”after his arrival in Washington,D.C.as a new comer.Secondly,after being fully exposed to the host culture and American style,he has experienced assimilation and absorption to be like an American.Finally when he escapes from his employer and chooses his own way of living,he finds that he is not free at all because he is confronted with an awkward cultural dilemma:he can neither return to his past life;nor can he aspire to a better future.The anxiety about the dislocation causes misery for his fate.As a result,he becomes a prisoner in an unfamiliar culture,and his“freedom”can only be a rootless“freedom”.

The Conflict and Balance Between Intellectual Property Rights and Public Freedom of Information in the“Anti-circumvention Clause”

There is a long-standing conflict between intellectual property rights and public freedom of information.The continuous development of the“anti-circumvention clause”has caused the conflict to intensify.As a basic human right,freedom of information is being gradually eroded by the expansion of intellectual property rights.The existing research mainly carries on the right balance from the negative protection path,but the positive protection path is more advantageous to realizing the public freedom of information and alleviates the conflict between the two kinds of rights.In practice,there are some problems in the application of the anti-circumvention clause,such as the legality of the aim,the division of the protected part,and the determination of the circumvention.This is mainly due to the lack of restrictions on technical measures,the failure to distinguish between“copyright protection”and“contact control”,and the offside and absence of administrative bodies in practice.We should protect public freedom of information by distinguishing the two measures of copyright protection and contact control and the two torts of access and use,increasing the restrictive conditions for the use of technical protection measures,and changing the functions of administrative supervision agencies.

公序良俗在情人遗赠纠纷中的适用——基于私法与基本权利冲突理论的二元视角

遗赠是否违背公序良俗应以遗赠本身为审查对象,而不能以遗赠以外之事实为断。同时,情人遗赠行为是否违背公序良俗,尤应考察当事人一方遗赠的动机是否是将性奉献与经济上的对待给付联结起来,抑或是存在其他更值得尊重的动机。但在私法视角下,情人遗赠的效力,总是呈现出完全有效或完全无效的形态。而在基本权利冲突与权衡的视角下,各基本权利相互较量各自在具体个案中的分量,此种权衡和较量之结果体现在法律行为效力上,即既非完全有效亦非完全无效,而是在两者间存在多种可能性,因而更能适应个案中的具体情况,也更具灵活性。

高校学术权力的异化表征与归正路径

学术权力既是高校办学自主权的重要内容,也是大学组织的基础权力。然而,当前我国高校学术权力的异化现象较为严重,这种异化的负向力量会降低公众对于学术权力的心理预期,进而影响高校治学管理和学术研究顺利运行。高校学术权力异化主要表现在高校学术权力主体异化、高校学术权力活动异化、高校学术权力配置异化及高校学术权力监督异化等方面,高校学术主体道德失范、政府过多干预高校学术管理、高校学术权力行政化色彩和高校学术权力法律地位缺乏独立是造成高校学术权力异化的主要归因。回归高校学术权力的本真要义,应进一步规范高校学术权力主体行为、明确高校学术权力运行规则、协调高校“学术”与“行政”权力关系及健全高校学术权力监督机制。

宪法视野下的婚检制度变革与完善——基于《民法典》第1053条告知义务的履行

《民法典》第1053条对禁婚疾病传统作出重大调整,成为新时代背景下婚检制度设计的重要法律依据。在婚姻宪法保护框架下,“婚姻自由—私人告知—自愿婚检”的传统思路忽略了比“婚姻自由保护”更为根本的“婚姻传统功能保护”。婚姻的公共性及解决相关司法实践难题的客观需要,使得婚检融入履行环节成为可能。从《宪法》到《民法典》再到《婚姻登记条例》,民法典时代婚检制度设计应沿循“婚姻保护—法定告知—弱强制婚检”设计思路,采取“程序强制+形式审查”模式,即当事人于婚前相互告知专业健康检查结论,婚姻登记机关仅要求当事人填写知晓声明并进行必要口头提示而不对告知内容及其真实性进行实质审查。

基于改进麻雀优化PID的波浪补偿控制方法

随着海上风电“十四五”规划的不断推动,在深远海域对兆瓦级大功率海上风机的需求量随之增加,其规模也在不断扩大。但是,在吊运、安装等海上工作过程中,复杂海浪对船舶产生的持续影响导致风机安装的精度和效率大幅下降,甚至会对人员安全以及财产造成重大损失。在深远海域复杂海况下对工程船舶进行有效的波浪补偿,可提供稳定的作业环境以保证精准高效地完成各项工作,因此,本文提出了一种基于改进麻雀优化PID的波浪补偿控制方法并将其应用于Stewart补偿平台。首先,建立波浪补偿平台动力学以及运动学反解模型,并设计正解模型迭代求解算法。随后,使用PID进行波浪补偿控制,并通过麻雀搜索算法优化参数。接着,采用Circle混沌映射对其进行初始化分布,以解决初始化不均匀的问题;并采用动态自适应加权、柯西突变以及反向学习以提升算法全局寻优能力。最后,生成4~6级海况下的某工程船运动数据作为系统输入,利用MATLAB和Simulink软件平台搭建模型进行补偿控制验证,并在Stewart硬件平台上做补偿试验。结果表明,改进麻雀搜索算法具有较快的收敛速度、较高的精度和更好的寻优能力,优化后的PID控制方法更适合用于复杂海况下波浪补偿平台的控制优化,可为大功率海上风机安装的补偿平台控制系统设计提供参考。

自由的实现:黑格尔与马克思

自由的实现是黑格尔和马克思思想的共同主题,也是二者的分歧所在。在《法哲学原理》中,黑格尔批判了法国大革命“绝对自由”的原则,试图以理性国家统一普遍与特殊,调和个体与共同体之间的矛盾,最终实现私人领域和公共领域的统一。在一个有机共同体中实现具体的自由,这一点成为后来马克思共产主义观念的理论起点,也构成后者的原则高度。不同的是,马克思敏锐地发现了黑格尔理性国家的问题,把对市民社会的批判推进到政治经济学批判中,进而在哲学批判、政治经济学批判以及各种形式的社会主义理论及其现实运动的批判这一总体性的视野中为黑格尔的伦理自由找到了一条通达现实的道路——共产主义及其现实运动。因此,作为观念与现实的统一,马克思的共产主义就在根本上超越了黑格尔的理性国家,是自由的真正实现,即人类解放。

营商环境法治化三维论

市场秩序稳定公平、规则透明公开、法治公正、投资可预期的营商环境,是投资主体实现投资自由便利制度的核心价值所现。推进政府职能新定位,强化“放管服”,放宽市场主体准入等,是优化营商环境的基本环节。自由度是主体最活跃的动力源和策源地,政府确保“中立地位”,促进主体公平竞争和实施反垄断,维护所有市场主体都享有平等、自由、公平竞争机制。便利度是彰显政府向市场主体提供快速实现自由度的便捷化、快捷化和效率化的社会效应程度,核心在于强化市场主体获得从商活动权利能力的快捷、简便、高效行为状态等。创新度是市场主体实现自由度与便利度融合发展处于动态的追求状态,显现了优化营商环境持续创新的法治动力。政府干预与市场调节有机协同调控,做大主体自由度,提升主体更多便利度,促进营商环境的持续创新优化。自由、便利与创新,已成为优化营商环境的路径选择,创新成为优化营商环境的否定之否定规律。自由度、便利度与创新度的辩证关系价值,成为引导探寻优化营商环境的立足点、突破点和发力点。

基于双自由度转台的全向空间单目视觉室内定位测量方法

针对传统单目视觉测量系统测量视场有限的问题,本文提出一种基于双自由度旋转平台的全向空间单目视觉测量方法。首先,对双自由度旋转平台的转轴参数进行标定,用副相机拍摄固定在双自由度转台上的棋盘格标定板,提取棋盘格角点的位置坐标,并将其转化到同一相机坐标系下。利用PCA(主成分分析)平面拟合得到初始位置转轴参数中的方向向量,使用空间最小二乘圆拟合方法得到初始位置下转轴参数中的位置参数。然后,通过转台转动的角度以及罗德里格斯公式将不同位置下相机获取的数据进行坐标系统一,实现水平和竖直方向全向空间下的目标测量。最后,通过高精度激光测距仪验证了本方法的测量精度,并通过与双目视觉测量系统、wMPS测量系统进行比对实验,验证了本方法的全向空间测量能力。实验结果表明,本方法测量精度基本达到双目视觉测量系统水平,但测量范围远大于双目视觉测量,可以满足全向空间测量要求。

罗马法复兴与近代欧洲的自由主义传统

自由主义是一个近现代的概念,但也有古代渊源。古代罗马的法律观、人性观、政治观中都具有近代自由主义的元素,这些古老的思想通过罗马法的复兴运动重新回到了中世纪,给社会带来了深刻的变革。16—18世纪罗马法复兴的新浪潮更是直接促进了古典自由主义的诞生。17世纪以来,古典自由主义学者基于前述研究成果论述了自由主义的人性观、财产观与法治观,构建了西方的自由主义传统。回顾自由主义的发展历史,可以发现罗马法的复兴既是自由主义连续发展的关键,也给予了自由主义新风格。它不仅是学术上的复古运动,同时也对西方社会变革产生了深远的影响。