Cross-coupling integral adaptive robust posture control of a pneumatic parallel platform

A pneumatic parallel platform driven by an air cylinder and three circumambient pneumatic muscles was considered. Firstly, a mathematical model of the pneumatic servo system was developed for the MIMO nonlinear model-based controller designed. The pneumatic muscles were controlled by three proportional position valves, and the air cylinder was controlled by a proportional pressure valve. As the forward kinematics of this structure had no analytical solution, the control strategy should be designed in joint space. A cross-coupling integral adaptive robust controller(CCIARC) which combined cross-coupling control strategy and traditional adaptive robust control(ARC) theory was developed by back-stepping method to accomplish trajectory tracking control of the parallel platform. The cross-coupling part of the controller stabilized the length error in joint space as well as the synchronization error, and the adaptive robust control part attenuated the adverse effects of modelling error and disturbance. The force character of the pneumatic muscles was difficult to model precisely, so the on-line recursive least square estimation(RLSE) method was employed to modify the model compensation. The projector mapping method was used to condition the RLSE algorithm to bound the parameters estimated. An integral feedback part was added to the traditional robust function to reduce the negative influence of the slow time-varying characteristic of pneumatic muscles and enhance the ability of trajectory tracking. The stability of the controller designed was proved through Laypunov's theory. Various contrast controllers were designed to testify the newly designed components of the CCIARC. Extensive experiments were conducted to illustrate the performance of the controller.

基于遗传算法与Hardy-Cross方法的矿井通风机控制

针对矿井通风机系统控制的复杂问题,提出了一种遗传算法与Hardy-Cross方法相结合的矿井通风控制,强化了其在处理离散变量和非凸搜索空间中寻找全局最优解的能力。通过数学形式化定义问题并结合基尔霍夫定律,确立了通风机网络的优化模型。根据实际用风情况智能调节通风机的供风量,以实现能源节约和安全生产的目标。通过对某煤矿的通风案例深入研究和验证,风扇的配置在优化气流方面表现出了卓越性能。该研究不仅为矿山工程领域提供了新的优化思路和方法,也为通风机系统的管理提供了重要参考。

The Design and Its Application of Cross-Coupled Controller in X-Y Table

In conventional cross-coupled controller design,the method usually ignored the inherent characteristic of time-vary- ing parameters and model uncertainties in system.In this paper,a cross-coupled controller(CCC)using an H~∞control scheme has been proposed to reduce the contouring error for an X-Y table.Furthermore,the proposed CCC design,which is a typical Multi- Input Multi-Output(MIMO)system with linear time varying(LTV)characteristics,has been verified as being internally stable. The simulations are carried on Matlab simulink to verify the proposed method,and the results showed that the proposed method can reduce the contouring error significantly compared with the conventional one.

Effect of mandrel on cross section quality of thin-walled tube numerical controlled bending

The effect of mandrel with the structure of ball and socket on the cross section quality of thin-walled tube numerical controlled(NC) bending was studied by numerical simulation method, combined with theoretical (analysis) and experiment. Influencing factors of the mandrel include the count of mandrel heads, the diameter of mandrel and its position. According to the principle of NC tube bending, quality defects possibly produced in thin-walled tube NC bending process were analyzed and two parameters were proposed in order to describe the cross section quality of thin-walled tube NC bending. According to the geometrical dimension of tube and dies, the range of mandrel protrusion was derived. The finite element model of thin-walled tube NC bending was established based on the DYNAFORM platform, and key technological problems were solved. The model was verified by experiment. The effect of the number of mandrel heads, the diameter of mandrel and the protrusion length of mandrel on the cross section quality of thin-walled tube NC bending was revealed and how to choose mandrel parameters was presented.

Two-qubit and three-qubit controlled gates with cross-Kerr nonlinearity

Schemes for two-qubit and three-qubit controlled gates based on cross-Kerr nonlinearity are proposed in this paper.The probability of the success of these gates can be increased by quantum nondemolition detectors,which are used to judge which paths the signal photons pass through.These schemes are almost deterministic and require no ancilla photon.The advantages of these gates over the existing ones include less resource consumption and a higher probability of success,which make our schemes more feasible with current technology.

The Design and Implementation of Qt-based Cross-platform Video Conferencing Remote Control

In order to overcome the defects of the dedicated video conference remote control, this paper designs and implements a Qt-based cross-platform video conferencing remote control. The remote control not only implements a full range of video conferencing control functions with an easy-to-use visual interface;but also implement cross-platform feature to allow users to use remote control software on their own equipment. It is economic, convenient and stylish for users. This paper mainly describes the design and implementation of remote control system framework and cross-platform features. Finally, the result in the paper shows: This remote control is reliable and easy to use.

Safety Assessment of Closed-Loop Level Crossing Control Systems by Means of STAMP(Systems-Theoretic Accident Model and Processes)

There have been a large number of accidents at level crossings of railways and this has been considered to be a significant issue to be solved for the realization of safe and stable railway transport.A conventional level crossing control system is characterized by the use of two types of electronic train detectors;one detects a train approaching to a level crossing section and the other then detects the train having left the level crossing.By contrast,closed-loop level crossing control systems in which level crossing control equipment and train-borne equipment communicate with each other have been advocated and are expected to serve as an effective solution to the abovementioned issue.This paper describes the following three types of closed-loop level crossing control systems:decentralized level crossing control system,fully-centralized comprehensive level crossing control system and fully-centralized individual level crossing control system.This paper then assesses the safety of these systems in comparison to the conventional level crossing control system.For the purpose of the assessment of their safety,a new accident analysis model called STAMP(systems theoretic accident model and processes)that is suitable for software intensive systems is used to clarify the advantage of the proposed three types of level crossing control systems in terms of safety.

Design and Simulation of an Audio Signal Alerting and Automatic Control System

A large part of our daily lives is spent with audio information. Massive obstacles are frequently presented by the colossal amounts of acoustic information and the incredibly quick processing times. This results in the need for applications and methodologies that are capable of automatically analyzing these contents. These technologies can be applied in automatic contentanalysis and emergency response systems. Breaks in manual communication usually occur in emergencies leading to accidents and equipment damage. The audio signal does a good job by sending a signal underground, which warrants action from an emergency management team at the surface. This paper, therefore, seeks to design and simulate an audio signal alerting and automatic control system using Unity Pro XL to substitute manual communication of emergencies and manual control of equipment. Sound data were trained using the neural network technique of machine learning. The metrics used are Fast Fourier transform magnitude, zero crossing rate, root mean square, and percentage error. Sounds were detected with an error of approximately 17%;thus, the system can detect sounds with an accuracy of 83%. With more data training, the system can detect sounds with minimal or no error. The paper, therefore, has critical policy implications about communication, safety, and health for underground mine.

基于数字孪生的交叉筛智能控制技术研究现状

交叉式细粒滚轴筛是一种适用于湿黏细粒煤的干法深度筛分设备。总结了普通滚轴筛和交叉筛的研究现状和局限性,提出了推进交叉筛智能控制技术研究的观点。综述了数字孪生技术在煤矿行业的应用案例,分析了数字孪生技术在煤矿无人化生产、远程控制和安全高效运行方面具备的潜力和价值。基于此,提出了开展基于数字孪生的交叉筛智能控制技术的研究,实现对交叉筛运行过程控制、状态监测等功能,提高交叉筛的智能化发展水平。

基于一阶线性自抗扰控制器的同步磁阻电机无速度传感器控制

同步磁阻电机在实现无速度传感器控制时出现交叉耦合效应,导致dq轴电感随着电流发生非线性变化,转速环使用传统PI控制器已无法满足系统较强的抗扰性能和较高的转子位置估计精度。为了改善此问题,该文提出一阶线性自抗扰控制器的同步磁阻电机无速度传感器控制策略,利用其机械运动状态方程,将同步磁阻电机的交叉耦合效应及负载扰动变化视为扰动。首先通过扩张状态观测器对负载扰动快速观测并进行前馈补偿,以此来提高系统抗扰性;其次利用静止实验法,得到dq轴磁链与电流的非线性函数模型,将该模型运用至磁链观测器中,以减小交叉耦合效应,提高转子位置估计精度;最后在1.5 kW的同步磁阻电机对拖加载实验平台上进行实验,验证了该控制方案的有效性。

跨境电商产业政策对出口开放度的影响:来自合成控制法的证据

跨境电商作为数字经济时代的一种贸易新业态,是否有助于缓解当前逆全球化背景下中国外循环面临的挑战值得关注。文章以2012年和2013年实施的跨境贸易电子商务服务试点作为准实验,运用合成控制法进行了反事实分析,以此来识别跨境电商产业政策对试点城市出口开放度的因果效应,并在此基础上进一步从理论和实证的角度揭示了跨境电商产业政策对试点城市出口开放度的影响机制。研究结果表明,跨境电商产业政策显著促进了试点城市的出口开放度,这一结论通过了一系列稳健性检验;机制分析表明,跨境电商产业政策对试点城市出口开放度的影响主要是通过降低试点城市贸易成本这一渠道产生的。基于上述分析,文章最后针对性地提出了相关政策建议。

企业数据跨境流动的风险防控研究

随着大数据经济的发展,数据已经成为各国竞相争夺的数字资源。通过分析企业数据的内涵及特征,根据我国企业数据跨境流动现状,探讨了企业面临的内部数据合规管理体系不完善、数据监管机构不明确等难题。目前许多国家就数据跨境流动提出了解决方案,在此基础上通过建立系统性跨境数据流动法律规范体系、加强国际合作等方式、设置独立的数据监管机构,提升我国数字企业核心竞争力,降低开拓境外市场的合规风险。

永磁直线电机驱动XY平台精密轮廓跟踪控制

为了减少高速进给率条件下轮廓跟踪过程中产生的轮廓误差,提出了一种将PDFF位置控制器与模糊交叉耦合控制器相结合的控制策略。首先,通过调节前馈增益,PDFF位置控制器可以综合利用PDF控制和PI控制的优点;其次,基于自由曲线轮廓误差模型来计算轮廓误差,并且提出一种以两轴的位置跟踪误差以及轮廓误差为输入的模糊交叉耦合器来减少轮廓跟踪过程中产生的轮廓误差;最后,空载与负载实验结果表明,与传统的交叉耦合结构相比,该方法在高速进给率条件下可以有效降低XY平台的轮廓误差,并且可以提高轮廓跟踪系统的鲁棒性。

董事高管责任保险与会计信息质量——基于党组织参与治理的替代或互补效应

以国务院在2020年10月出台的《关于进一步提高上市公司质量的意见》政策为研究契机,选取我国2010—2021年A股上市公司为样本,采用双向固定效应模型,在研究董事高管责任保险对会计信息质量治理作用的基础上,研究党组织参与公司治理是替代还是互补董事高管责任保险发挥这一治理效应,以及剖析其传导效应和企业异质性效应。研究结果表明:董事高管责任保险对企业会计信息质量有治理效应,且“双向进入”式党组织参与治理会提升董事高管责任保险对会计信息质量的治理效应,即存在互补效应;而“交叉任职”式党组织参与治理抑制董事高管责任保险对会计信息质量的治理效应,即替代效应。进一步分析研究表明:董事高管责任保险会通过促进企业创新和提高内部控制质量对会计信息质量发挥治理效应,并在媒体关注度或盈利能力越高的企业中这种治理效应更好。上述研究结果不仅从新视角拓展会计信息质量影响因素的研究,而且丰富董事高管责任保险和党组织参与公司治理的单独及联合治理效果,并为政府、企业等相关利益者在实践中发掘董事高管责任保险的积极作用和提高会计信息质量提供了有益的实践启示。

基于模糊交叉熵与TOPSIS的碳审计风险评估

审计在促进“双碳”目标实现的过程中发挥着重要的监督与评价作用,有效规范了企业的碳排放行为,推动了企业生产方式的绿色转型。当前,我国的碳审计发展尚处起步阶段,存在着诸如制度不健全、碳数据核算困难、碳审计人才缺乏等一系列问题,多种因素的叠加使得碳审计工作面临着极大的风险与挑战。在文献梳理的基础上,本文依托传统风险导向审计理论,首先从环境风险、固有风险、控制风险、检查风险四个层面建立碳审计风险评估指标体系;其次,借助模糊交叉熵和TOPSIS算法构架新型的碳审计风险评估模型,探索碳审计风险评估模型的运行步骤,明晰风险评估模型中的决策方案排序策略;再次,通过对特定案例的深入分析,阐释模糊交叉熵和TOPSIS风险评估模型在碳审计风险评估中的具体应用流程,全方位探究风险评估模型中各类运算结果的分析方法;最后,针对碳审计所面临的各种风险,相应地从碳审计模式设计、双碳大数据中心构建、人才队伍建设三个方面提出管理碳审计检查风险的措施与建议。有关研究思路和结论能够为审计组织如何发现碳审计存在的关键风险因素、衡量碳审计风险水平、评价和控制碳审计风险提供理论支持。

两桥臂交叉解耦不平衡控制策略研究

由于非不平衡控制策略中没有考虑线电压和相电流的相角差,造成三相电网的有功、无功电流无法完全补偿。为了解决这一问题,根据电压电流相角差,推导出单相补偿器中无功参考补偿电流与负载电流的关系,提出一种两桥臂交叉解耦不平衡控制策略,利用多变量滤波器和交叉解耦双复系数滤波器优化锁相环,精确锁定三相不平衡电网的电压频率和相位,对2个单相背靠背变换器的无功电流分别控制,进而利用两桥臂变换器补偿三相不平衡无功。实验结果验证了所提两桥臂交叉解耦不平衡控制策略,可抑制三相有功不平衡及补偿三相不平衡无功,将三相电流的不平衡度从150.0%降低至2.6%,三相电网功率因数从0.257提升至0.997,减少了三相无功补偿器的开关管个数。

刑事跨境电子数据取证的困境与破解

刑事跨境电子数据获取是治理跨境网络犯罪的关键环节。我国现行国际刑事司法协助取证制度难以实现对境外电子数据便捷、高效获取的目的,而单边跨境远程取证制度和向网络服务提供者调取电子数据制度又易产生司法主权方面的争议。国际上对构建何种跨境电子数据取证制度形成了“数据存储地”和“数据控制者”两种模式。从维护本国数据主权的国家利益出发,我国应采用“数据存储地”模式,从四个方面完善刑事跨境电子数据取证制度。一是简化国际刑事司法协助取证制度,实现跨境电子数据取证的便捷、高效;二是在比例原则下借由“危难或危急情况”“权利人授权的行为”“存储地不明”三种例外情况的取证路径,灵活开展单边跨境远程取证;三是以保存加协助的方式向网络服务提供者调取电子数据;四是依法认可非官方提供的电子数据。

环境案件跨区管辖制度的理论基础与可行性路径

当前环境案件跨区管辖制度改革并不彻底,限于被动回应型逻辑的改革举措存在着顾此失彼等诸多问题,因此进一步深化改革必须破除对策式思维、强调管辖制度自身的内在规律。从管辖制度的本质出发,英美法系国家提出的实际控制理论是管辖权分配的基本原理,具有普适性。借助这一理论工具分析各地环境案件跨区管辖模式,可知当前改革所面临诸多问题的根源都在于环境跨区管辖权未能实现对环境要素的实际控制以及缺乏权源基础。从实际控制理论出发,结合我国管辖制度以及环境司法审判资源等具体实际,环境案件跨区管辖制度的进一步完善应当坚持以生态功能区为标准划分环境案件司法辖区,分别以一般性地方法院与专门环境法院实现对省域内、跨省环境案件的跨区管辖。

面向2G~5G通信的双频双极化基站天线设计

为满足多种通信制式融合的无线通信需求,提出一款覆盖2G、3G、LTE、Sub-6 GHz波段的交叉偶极子基站天线。2对呈±45°正交的偶极子用以实现天线的双极化特性,辐射单元中的扇形内环、钻石状的外环分别对应天线要实现的低频以及高频波段,可以通过对内环以及外环结构参数的调整实现对2个频段的独立控制。天线上方的寄生贴片用以优化天线阻抗匹配。通过制作实物,测得天线在2个频段分别具有49.9%(1.70~2.80 GHz)和19.2%(3.20~3.88 GHz)的相对带宽,隔离度整体优于20 dB,主视轴的交叉极化比优于21 dB,2个波段的半功率波束宽分别为66°±5°、78°±6°。与已有研究比较,该天线结构简单,在交叉极化和增益方面具有显著优势。

独立充放时序SIDO开关变换器电流型变频控制技术

单电感双输出(single-inductor dual-output,SIDO)开关变换器工作在共享充放时序下存在电感电流纹波大、输出支路间交叉影响严重以及电路参数宽范围变化下控制电路不能正常工作等问题.为此,提出一种独立充放时序电流型变频控制(current-mode variable frequency control,C-VF)技术.首先,具体描述变换器在连续导电模式(continuous conduction mode,CCM)下的工作原理,并推导主电路开环传递函数;进一步构建闭环小信号模型,推导闭环交叉阻抗,详细分析不同输出电压及负载电流下变换器的交叉影响特性;最后,通过仿真和实验进行验证.研究表明:相较于共享充放时序,独立充放时序C-VF CCM SIDO buck变换器减小了交叉影响,改善了负载瞬态响应性能;当两支路负载电压不等时,减轻某一支路负载可以降低该支路的交叉影响;当两支路输出电压相同但负载不同时,重载支路对轻载支路的交叉影响更小.