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Yifei Zhang,Ming Zhu,Tian Chen,Zewei Zheng 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.1
This paper investigates the distributed formation control problem of multiple stratospheric airships in three-dimensional space with several practical problems, such as relative state constraints, input delay, input saturation and disturbances. An adaptive mixed self-/event-triggered formation control scheme is proposed by combining backstepping control, an adaptation technique and a mixed self-/event-triggered control mechanism. First, a novel relative-error-constraint virtual control law is designed based on the barrier Lyapunov function, which is processed into the desired velocity and angular velocity as the input of the next-step designed controller. Then, an adaptive controller is designed based on a designed adaptive law that is utilized to eliminate the influence of external disturbances, input saturation and input delay. In addition, a mixed self-/event-triggered mechanism is designed in the whole system, involving a self-triggered mechanism in the virtual control law and an event-triggered mechanism in the adaptive controller. All signals in the closed-loop system are proven to be semiglobal, uniform and ultimately bounded, and Zeno behavior is proven to be excluded. Finally, the effectiveness of the proposed method is verified through simulations.
Yifei Cai,Bin Qin,Chun Li,Xiaoqing Si,Jian Cao,Xiaohang Zheng,LIANG QIAO,Junlei Qi 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.120 No.-
Lithium (Li) metal is a promising material for high-energy–density batteries, but it is still plagued byobvious capacity degradation and low average Coulombic efficiency resulting from dendrite Li propagation. One main reason is the electro-mechanic coupled failure of plated Li on the current collector, whichcontributes to non-dense Li deposition on the anode. Transition metal oxides (TMOs) with a conversiontypemechanism have been used directly as the anode materials for lithium ion batteries, which demonstratedbetter electro-mechanical stability than metal Li. Herein, a successive ’’conversion-deposition’’mechanism is ingeniously developed to restrain the generation of dendritic Li. Specifically, a microcrystallineCu2O modified current collector was prepared, in which Li+ are sequentially inserted intoCu2O and deposited in the form of Li metal at successive low potential. A Li-Cu half-cell based on thehybrid mechanism sustains a high Coulombic efficiency of over 99.3 % in up to 800 cycles. This work ingeniouslyinhibits the generation of dendrite Li by incorporating conversion-type materials withdeposition-dissolution type metal Li, which contributes to a novel concept for the design of functionalcurrent collectors for composite Li anodes.
Hu Yifei,Jiang Xin,Huo Guanying,Su Cheng,Zhou Shiwei,Wang Bolun,Li Hexiong,Zheng Zhiming 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.1
Feed rate scheduling is a critical step in computer numerical control machining, as it has a close relationship with machining time and surface quality. It has now become a hot issue in both industry and academia. In this article, we present a novel and complete S-shape-based feed rate scheduling method for three-axis non-uniform rational B-spline (NURBS) tool paths, which can reduce high chord errors and round-off errors, and generate continuous velocity, acceleration, and jerk profile. The proposed feed rate scheduling method consists of three modules: a bidirectional scanning module, a velocity scheduling module, and a round-off error elimination module. The bidirectional scanning module aims to guarantee the continuity of the feed rate at the junctions between successive NURBS blocks, where the chord error, tangential acceleration, and tangential jerk limitations are considered. After the NURBS blocks have been classified into two cases by the previous module, the velocity scheduling module first calculates the actual maximum feed rate. It then generates the feed rate profiles of all NURBS blocks according to the proposed velocity profile. Later, the round-off error elimination module is applied to adjust the actual maximum feed rate so that the total interpolation time becomes an integer multiple of the interpolation period, which leads to the elimination of round-off errors. Finally, benchmarks are conducted to verify the applicability of the proposed method. Compared with the traditional method, the proposed method can save the interpolation time by $4.67$ to $14.26\% $.
Investigation of Different Conduction States on the Performance of NMOS-Based Power Clamp ESD Device
Wei Weipeng,Wang Yang,Chen Xijun,Zheng Yifei,Li Jieyu,Cao Pei,Cao Wenmiao 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3
This article investigates the eff ects of diff erent gate coupling voltage and gate voltage duration on electro-static discharge (ESD) performance of several NMOS-based power rail protection devices. Through simulation and transmission line pulse (TLP) test, it is found that there are two modes in the conduction process of the main clamping NMOS: channel conduction state and parasitic NPN conduction state. Diff erent gate voltage and duration bring the two conduction states diff erent proportions in the whole working process, which give the device very diff erent robustness. The results show that under the condition of small gate voltage and long duration and the condition of large gate voltage and short duration, the device can achieve optimal performance because the trigger voltage can be reduced, and the parasitic NPN can be turned on in time to release most of the current