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Near-perfect replication on amorphous alloys through active force modulation based on machine learning/neural network parameter prediction

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science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 181-191页

作者： Senkuan Meng Zheng Wang Ruisong Zhu Ruijie Liu Jiang Ma Lina Hu Weihua Wang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) School of Materials Science and Engineering Shandong University College of Mechatronics and control engineering Shenzhen University Songshan Lake Materials Laboratory Institute of Physics Chinese Academy of Sciences

As a microforming technique, micro/nano-structural replication possesses advantages of high precision and efficiency. With the remarkable superplasticity in the supercooled liquid region, amorphous alloys or metallic glasses(MGs) are regarded as ideal materials for miniature fabrication. However, due to the intrinsic metastable nature of supercooled liquids, the design of imprinting processes for MGs poses a challenge. In the past, process parameters have largely relied on trial-and-error *** this work, a low-frequency active force modulation system is employed to apply a stable, precise, and real-time feedback stress field for imprinting of MG samples. Low-frequency vibrations can facilitate the filling of microstructures on the template surface by reducing the effective viscosity of the supercooled liquid. With the dataset composed of orthogonal experiments, a machine learning strategy based on back-propagation(BP) neural networks was utilized to construct a 3D parameter space for temperature, stress, and time, and to predict the corresponding filling ratio. Furthermore, the optimal combination of imprinting process parameters was identified, and its filling ratio was experimentally validated to reach as high as 0.94. The near-perfect replication of microstructures confirms the superiority of the active force modulation system and the data-driven strategy of machine learning-assisted parameter design. At the same time, this one-step microforming process provides a new approach to addressing the accuracy-cost trade-off dilemma in precision manufacturing.

关键词： metallic glass amorphous alloy microforming imprinting machine learning

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A high precision visual localization sensor and its working methodology for an indoor mobile robot

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Frontiers of Information Technology & Electronic engineering 2016年第4期17卷 365-374页

作者： Feng-yu ZHOU Xian-feng YUAN Yang YANG Zhi-fei JIANG Chen-lei ZHOU school of control science and engineering Shandong University school of Information science and engineering Shandong University

To overcome the shortcomings of existing robot localization sensors, such as low accuracy and poor robustness, a high precision visual localization system based on infrared-reflective artificial markers is designed and illustrated in detail in this paper. First, the hardware system of the localization sensor is developed. Secondly, we design a novel kind of infrared-reflective artificial marker whose characteristics can be extracted by the acquisition and processing of the infrared image. In addition, a confidence calculation method for marker identification is proposed to obtain the probabilistic localization results. Finally, the autonomous localization of the robot is achieved by calculating the relative pose relation between the robot and the artificial marker based on the perspective-3-point(P3P) visual localization algorithm. Numerous experiments and practical applications show that the designed localization sensor system is immune to the interferences of the illumination and observation angle changes. The precision of the sensor is ±1.94 cm for position localization and ±1.64° for angle localization. Therefore, it satisfies perfectly the requirements of localization precision for an indoor mobile robot.

关键词： Mobile robot Localization sensor Visual localization Infrared-reflective marker Embedded system

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维普期刊数据库

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Gradient control and synchronization of Julia sets

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Chinese Physics B 2008年第2期17卷 543-549页

作者：张永平刘树堂 school of control science and engineering Shandong University

This paper firstly introduces the control methods to fractals and give the definition of synchronization of Julia sets between two different systems. Especially, the gradient control method is taken on the classic Julia sets of complex quadratic polynomial Zn＋1 = zn^2＋ c, which realizes its Julia sets control and synchronization. The simulations illustrate the effectiveness of the method.

关键词： Julia set gradient control synchronization

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Adaptive output-feedback tracking for nonlinear systems with unknown control direction and generic inverse dynamics

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science China(Information sciences) 2022年第8期65卷 134-149页

作者： Yuan WANG Yungang LIU school of control science and engineering Shandong University

This paper studies adaptive output-feedback tracking for a class of typical uncertain nonlinear systems. In the context of unknown control direction, a generic uncertainty encountered inevitably in practice is adequately taken into consideration, i.e., the ISpS(input-to-state practically stable) inverse dynamics acting as the dynamic differences between the real plants and the models. Besides, the systems in question also permit two critical ingredients, i.e., unmeasured-state dependent nonlinearities and arbitrary functionof-output growth on unknown system nonlinearities. The three ingredients together largely challenge the feasibility/availability of practical tracking by means of output feedback. Nevertheless, a new control strategy is proposed by flexibly integrating the dynamic compensation based on Nussbaum-type gain, backstepping design technique together with the refined pseudo-sign and pseudo-dead-zone functions that were introduced for the first time in our previous studies. The two refined functions, which are sufficiently smooth, can moderately avoid the use of smooth domination/treatment in control design and can potentially render the attained control strategy tighter and less conservative. Moreover, to keep the order of the closed-loop system at a low level, an n-dimensional filter with a dynamic high gain is delicately devised instead of a2 n-dimensional one used in the relevant literature. It turns out that the proposed adaptive output-feedback controller is capable of guaranteeing the global boundedness of all states of the resulting closed-loop system,while steering the system tracking error to enter, in finite time, a prescribed λ-neighborhood of the origin and keeping it inside thereafter. A simulation example is provided to demonstrate the proposed approach.

关键词： nonlinear systems ISpS inverse dynamics unknown control direction practical output tracking global output feedback adaptive compensation

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Adaptive control of nonlinear systems with severe uncertainties in the input powers

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science China(Information sciences) 2021年第1期64卷 227-238页

作者： Linzhen YU Yungang LIU Yongchao MAN school of control science and engineering Shandong University

In this study, we discuss global adaptive stabilization for a class of uncertain nonlinear *** input powers of the system are unknown, and the upper bound and the nonzero lower bound are not known in advance. This suggests that the system suffers from severe uncertainties with respect to the input powers when compared with the related literature, which would considerably challenge the control design. The switching-based strategy can compensate for severe system uncertainties, especially new types of uncertainties, including those associated with the input powers. Herein, a switching adaptive controller is successfully designed to ensure that the resulting closed-loop system states are globally bounded and ultimately converge to the origin(the equilibrium point). The proposed controller is extended to the systems with unknown control directions by redefining the involved switching sequences. A simulation example demonstrates the effectiveness of the proposed switching adaptive controller.

关键词： nonlinear systems severe uncertainties global stabilization unknown input powers switching adaptive control

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H_∞ FILTERING FOR CONTINUOUS-TIME SYSTEMS WITH POINTWISE TIME-VARYING DELAY

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Journal of Systems science & Complexity 2012年第1期25卷 90-104页

作者： Wei WANG Huanshui ZHANG school of control science and engineering Shandong University

The problem of H∞ filtering for continuous-time systems with pointwise time-varying delay is investigated in this paper. By applying an innovation analysis in Krein space, a necessary and sufficient condition for the existence of an H∞ filter is derived in two methods： One is the partial differential equation approach, the other is the reorganized innovation analysis approach. The former gives a solution to the proposed H∞ filtering problem in terms of the solution of a partial differential equation with boundary conditions. The later gives an analytical solution to the proposed H∞ filtering problem in terms of the solutions of Riccati and matrix differential equations.

关键词： Continuous-time systems H∞ filtering partial differential equations pointwise timevarying delay reorganized innovation analysis Riccati differential equations.

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Modified projective synchronization with complex scaling factors of uncertain real chaos and complex chaos

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Chinese Physics B 2013年第12期22卷 141-151页

作者：张芳芳刘树堂余卫勇 College of control science and engineering Shandong University

To increase the variety and security of communication, we present the definitions of modified projective synchronization with complex scaling factors （CMPS） of real chaotic systems and complex chaotic systems, where complex scaling factors establish a link between real chaos and complex chaos. Considering all situations of unknown parameters and pseudo-gradient condition, we design adaptive CMPS schemes based on the speed-gradient method for the real drive chaotic system and complex response chaotic system and for the complex drive chaotic system and the real response chaotic system, respectively. The convergence factors and dynamical control strength are added to regulate the convergence speed and increase robustness. Numerical simulations verify the feasibility and effectiveness of the presented schemes.

关键词： modified projective synchronization complex scaling factors complex chaotic systems speed-gradient method

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Stackelberg Game Approach to Mixed H2/H∞ Problem for Continuous-Time System

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Journal of Systems science & Complexity 2019年第5期32卷 1324-1339页

作者： LI Xiaoqian WANG Wei XU Juanjuan ZHANG Huanshui school of control science and engineering Shandong University

This paper studies the mixed H2/H∞ control for continuous-time linear dynamic *** applying Stackelberg game approach, the control input is treated as the leader and the disturbance is treated as the follower, respectively. Under standard assumptions and maximum principle, a necessary and sufficient existence condition which is based on three decoupled Riccati equations is *** expression of controllers and solutions to forward backward differential equations(FBDES)are obtained by homogeneous analysis of variables. A numerical example is finally given to verify the efficiency of the proposed approach.

关键词： Continuous-time case mixed H2/H∞ control open-loop controller Stackelberg game approach

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Observer-based distributed consensus for nonlinear multi-agent systems with limited data rate

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science China(Information sciences) 2022年第9期65卷 191-205页

作者： Jing ZHANG Shuai LIU Xianfu ZHANG school of control science and engineering Shandong University

In this paper, we investigate the observer-based distributed consensus problem for nonlinear multi-agent systems with a limited data rate. We assume that each agent displays strict-feedback nonlinear dynamics. An observer is constructed to estimate the system states as they cannot be directly *** quantizers and logarithmic quantizers are considered in communication channels among agents and observer-based distributed control protocols are proposed for each agent. For the uniform quantizer, theδ-asymptotic distributed consensus, with δ being the resolution of the quantizer, can be achieved under the proposed control protocol, i.e., the consensus errors tend to zero as δ approaches zero. For the logarithmic quantizer, the asymptotic consensus can be achieved. The simulation results reveal the conclusion.

关键词： nonlinear multi-agent systems uniform quantizer logarithmic quantizer dynamic gain $\delta$-asymptotic distributed consensus

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Global practical tracking via adaptive outputfeedback for uncertain nonlinear systems with generalized control coefficients

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science China(Information sciences) 2016年第1期59卷 188-200页

作者： Shaoli JIN Yungang LIU school of control science and engineering Shandong University

This paper investigates the global practical tracking via adaptive output-feedback for a class of uncertain nonlinear systems with generalized control coefficients. Notably, the system in question has the function-of-output control coefficients and the serious unknowns in the system and the reference signal, and hence is essentially different from the existing closely related literature. To solve the global practical tracking,a high-gain observer is first introduced to reconstruct the unmeasurable system states, and then an adaptive output-feedback controller is designed. It is worth emphasizing that the gains in the designed observer and controller are functions of time and output, for which a novel updating law of the high-gain is introduced to overcome the additional system nonlinearities and the serious unknowns mentioned above. The designed controller is shown such that all the states of the closed-loop system are globally bounded, and furthermore,tracking error will be ultimately prescribed sufficiently small. A numerical simulation is provided to demonstrate the effectiveness of the proposed approach.

关键词： uncertain nonlinear systems function-of-output control coefficients global practical tracking dynamical high-gain adaptive output-feedback

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