Optimal interval type-2 fuzzy fractional order super twisting algorithm: A second order sliding mode controller for fully-actuated and under-actuated nonlinear systems

In this paper, a novel interval type-2 fuzzy fractional order super twisting algorithm (IT2FFOSTA) which is essentially a second order sliding mode controller is presented. The proposed IT2FFOSTA enhances fractional order super twisting algorithm (FOSTA) by taking advantage of an interval type-2 fuzzy fractional order sliding surface (IT2FFOSS) for some classes of fully-actuated and under-actuated nonlinear systems in presence of uncertainty. The FOSTA significantly reduces the amount of chattering and the IT2FFOSS results in decreasing the tracking error, control effort, and chattering level. In order to control under-actuated systems, a hierarchical sliding surface is employed. The multi-tracker optimization algorithm is utilized to adjust the controller’s parameters; this leads to an optimal performance for the IT2FFOSTA. To examine the performance of the IT2FFOSTA, some simulation and experimental tests on three examples of different classes of fully-actuated and under-actuated systems, including ball and plate, inverted pendulum, and ball and beam systems are carried out. The simulation and experimental results demonstrate the superiority of the IT2FFOSTA in reducing the amount of chattering, tracking error, and control effort compared to those of the other control methods.     

管状带式输送机扭转检测装置

通过研究、分析管式输送机发生扭转的原因,在不影响管式输送机正常运转的情况下,设计制造出一种随输送带扭转而转动、并能够测量扭转角度的新型装置,从而实现对管式输送机中间段扭转故障的检测。     

基于滑模的二阶多智能体快速抗扰一致性

针对带有外部未知扰动的二阶多智能体系统的领导—跟随有限时间一致性问题，本文设计出一种带有时变增益的有限时间干扰观测器，用以实现对每个跟随智能体中未知扰动的快速估计，在此基础上，本文结合超螺旋积分滑模控制方法并利用邻居智能体的位置和速度信息设计一种快速抗扰一致性协议，该协议能够保证存在非线性动态的多智能体系统有限时间一致性控制并能抑制抖振现象.同时，利用李亚普诺夫函数进行了稳定性的证明.最后，通过Matlab数值仿真进一步验证了所提出协议的可行性.     

Influence of the rigidity of the steroid core in the structure of chiral dopants on the temperature dependence of cholesteric short pitch

New chiral compounds of the steroid type, namely, 3-alkanoyl- and 3-alkyl derivatives of 16-arylidene estrone, were synthesized and exhibited high helical twisting power (HTP) in nematic liquid crystals E63 and LC-1289. The peculiarities of the molecular structure of chiral compounds (CCs) and their high degree of chirality were discussed. Quite small concentrations of chiral compounds in both nematic solvents were needed to obtain a short-pitch cholesteric helical macrostructure with the selective light reflection in the visible range of the spectrum. The insignificant temperature dependence of the maximum wavelength of the selective light reflection obtained on the whole cholesteric range for all studied liquid crystalline (LC) systems could be related to relatively rigid molecular structure of the chiral compounds. The cholesteric LC mixtures comprising 3-alkanoyl- and 3-alkyl derivatives of 16-arylidene estrone were characterized by the phase stability and the stability of reflective characteristics in time that makes it possible to consider this series of dopants as appropriate for development of bistable cholesteric reflective LC displays.     

Closed loop torque SVM-DTC based on robust super twisting speed controller for induction motor drive with efficiency optimization

This paper presents a space vector modulation (SVM) based Direct Torque Control strategy (DTC) for induction motor (IM) in order to overcome the drawbacks of the classical DTC. SVM can reduce the high torque and flux ripples by preserving a fixed switching frequency. This technique is known by the closed loop torque SVM-DTC. Moreover, the control scheme performance is improved by inserting a second order sliding mode super twisting controller in the outer loop for speed regulation. This nonlinear technique ensures a good dynamic and high robustness against external disturbance. Furthermore, the IM energy optimization is treated in the second objective of this paper. A proposed model based loss minimization strategy is presented for efficiency optimization. This strategy chooses an optimal flux magnitude for each applied load torque. The proposed optimized SVM-DTC algorithm will be investigated by simulation and real time implementation using Matlab/Simulink with real time interface based on dSpace 1104 signal card.     

一种新型粘合力测试方法探讨及其应用

目前,漆包线行业内尚无测试?0.05 mm及以下漆包自粘线粘合力的方法。针对这一情况,本文提出了一种适用于测试微细自粘线热粘合力的方法,即扭绞法。实践证明,该方法在生产中可以快速、简便、准确地测试微细自粘线的热粘合力。     

输送带用钢丝绳生产及技术进步

介绍输送带用钢丝绳的主要生产控制及使用要求。从捻制质量、结构选择、力学性能以及粘合力和镀层质量控制等方面介绍输送带用钢丝绳的生产工艺控制以及各生产工序质量控制的注意事项,指出钢丝绳弯曲疲劳、输送带张紧装置造成胶带张力过大和张力分布不均匀、外力过大、腐蚀、异物损伤以及接头抽丝是输送带用钢丝绳使用过程中断裂的主要原因,保证钢丝绳储存质量和改善钢丝绳接头工艺有助于减少输送带生产过程中的钢丝绳消耗。对输送带用钢丝绳的技术进步做了展望。     

磨耗板的成形工艺与模具设计

以某出口车型转向架上的关键零件导框顶面磨耗板为例,结合车间生产实际,对工艺方法进行了调整,优化了模具结构,解决了零件对称度差、扭曲问题。模具结构合理,满足零件批量生产要求。     

右-右缠绕模范畴M_A~C(Ψ)中的扭曲

主要推广了关于相关Hopf模的扭曲理论到缠绕模上,证明(A,C,Ψ)上的右-右缠绕模范畴MCA(Ψ)同构于(Aτ,C,Ψ)上的右-右缠绕模范畴MACτ(Ψ),从而发展了缠绕模的理论。     

捻向组合对钢丝绳应力分布的影响规律

为揭示捻向组合对钢丝绳股内钢丝应力的影响规律,根据钢丝绳捻制成形理论,以6×19IWS型右同向捻和右交互捻2种钢丝绳为例,利用ANSYS软件建立了钢丝绳的有限元模型,并结合钢丝绳的强度理论,对其进行拉伸载荷下的非线性有限元分析。结果表明,钢丝绳股内侧丝的应力呈空间二次螺旋线形状变化,并且侧丝越靠近外侧,其应力值越大;交互捻钢丝绳应力水平及变化幅度低于同向捻钢丝绳。