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Electromagnetic three-dimensional vibration energy harvester based on an oblique cross-spring vibrator structure

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Science China Technological Sciences 2025年第1期 189-206页

作者： Yaohui AN Yimin FAN Kefan XU Yuhao che. Yewei ZHANG liqun che. School of Science Harbin Institute of Technology College of Aerospace Engineering Shenyang Aerospace University

This paper presents an electromagnetic three-dimensional vibration energy harvesting device that uses an oblique cross-spring vibrator structure to collect low-frequency vibration energy. The oblique cross-spring structure allowed the center vibrator to vibrate in any direction. Together with six-directional coils, this configuration senses and harvests environmental vibrations across all directions and levels. First, the dynamics of the oblique cross-spring vibrator structure were analyzed and a finite element simulation was performed for the magnet arrangement and mode shape of the structure. A prototype is designed,fabricated, and experimentally verified. The results showed that the efficiency of the three-dimensional energy output was higher under the same excitation, which was 2.7 times higher than that of the unidirectional output. The unidirectional output power with load is 0.94 mW at 11 Hz under 0.3 g base excitation. The highest total output power of the prototype was 50 mW when it was fixed to the leg at a running speed of 8 km/h. Consequently, the energy harvesting sche.e proposed in this study has a considerable low-frequency output effect, which provides a novel means of improving the electrical performance of energy harvesting systems for self-powered IoT and sensor devices.

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Attitude Control of Spherical Liquid-Filled Spacecraft Based on High-Order Fully Actuated System Approache.

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Journal of Systems Science & Complexity 2022年第2期35卷 471-480页

作者： XIAO Fuzheng che. liqun School of Science Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

The attitude of spherical liquid-filled spacecraft is controlled based on the high-order fully actuated system *** rigid-fluid coupling dynamic equation can be established in terms of the Euler angles of the spacecraft and the angular velocities of the liquid *** to the dynamic equation,three kinds of input selections are *** the case of one control input,the dynamic equation is transformed into the third-order or the second-order differential equations of the Euler angle by the high-order fully actuated system *** a control law is designed to track the *** effectiveness of the control law is demonstrated by numerical simulations.

关键词： Attitude control high-order fully actuated system approache. spherical liquid-filled spacecraft

Quadratic forms connected with Fourier coefficients of Maass cusp forms

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Frontiers of Mathematics in China 2015年第5期10卷 1101-1112页

作者： liqun HU Department of Mathematics Shandong University Jinan 250100 China Department of Mathematics: Nanchang Universityl Nanchang 33{)031 China

For the normalized Fourier coefficients of Maass cusp forms λ（n） and the normalized Fourier coefficients of holomorphic cusp forms a（n）, we give the bound of

关键词： Circle method Fourier coefficients of Maass cusp forms quadraticform exponential sum

县域中等职业教育高质量发展的价值诉求、社会逻辑与实践路径

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教育与职业 2025年第1期 23-30页

作者：郑立群王忠英和震山东省教育科学研究院山东师范大学职业技术教育研究院山东济南250002 济南职业学院山东济南250014 北京师范大学国家职业教育研究院北京100875 北京师范大学职成所北京100875

以社会学理论视角为切入点,运用社会构成的经济、政治、社会交往、精神文化“四要素”分析框架进行系统分析可知,中等职业教育高质量发展要立足县域经济统筹发展,助力县域政治生态稳定,满足县域社会美好生活需要,创设县域良好文化环境... 详细信息

以社会学理论视角为切入点,运用社会构成的经济、政治、社会交往、精神文化“四要素”分析框架进行系统分析可知,中等职业教育高质量发展要立足县域经济统筹发展,助力县域政治生态稳定,满足县域社会美好生活需要,创设县域良好文化环境。由此,从中等职业教育的发展理念、区域特色、功能定位、条件保障等方面寻求路径突破,提出推动县域中等职业教育“技能化”发展、“区域化”发展、“多元化”发展、“长效化”发展,从而为实现我国县域中等职业教育高质量发展提供理论支撑与政策依据。

关键词：县域社会高质量发展中等职业教育社会逻辑实践路径

Optimal reorientation of underactuated spacecraft using genetic algorithm with wavelet approximation

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Acta Mechanica Sinica 2009年第4期25卷 547-553页

作者： Xinsheng Ge liqun che. College of Mechanical & Electrical Engineering Beijing Information Science & Technology University 100192 Beijing China Department of Mechanical Shanghai University 200072 Shanghai China

The optimal attitude control of an underactuated spacecraft is investigated in this paper. The flywheels of the spacecraft can somehow only provide control inputs in two independent directions. The dynamic equations are formulated for the spacecraft under a nonholonomic constraint resulting from the constant time-rate of the total angular momentum of the system. The reorientation of such underactuated spacecraft is transformed into an optimal control problem. A genetic algorithm is proposed to derive the control laws of the two flywheels angle velocity inputs. The control laws are approximated by the discrete orthogonal wavelets. The numerical simulations indicate that the genetic algorithm with the wavelet approximation is an effective approach to deal with the optimal reorientation of underactuated spacecraft.

关键词： Underactuated spacecraft Reorientation Attitude control Genetic algorithm Wavelet

Standard Dual Quaternion Optimization and Its Applications in Hand-Eye Calibration and SLAM

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Communications on Applied Mathematics and Computation 2023年第4期5卷 1469-1483页

作者： liqun Qi Department of Mathematics School of ScienceHangzhou Dianzi UniversityHangzhou310018ZhejiangChina Department of Applied Mathematics The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

Several common dual quaternion functions,such as the power function,the magnitude function,the 2-norm function,and the kth largest eigenvalue of a dual quaternion Hermitian matrix,are standard dual quaternion functions,i.e.,the standard parts of their function values depend upon only the standard parts of their dual quaternion ***,the sum,product,minimum,maximum,and composite functions of two standard dual functions,the logarithm and the exponential of standard unit dual quaternion functions,are still standard dual quaternion *** the other hand,the dual quaternion optimization problem,where objective and constraint function values are dual numbers but variables are dual quaternions,naturally arises from *** show that to solve an equality constrained dual quaternion optimization(EQDQO)problem,we only need to solve two quaternion optimization *** the involved dual quaternion functions are all standard,the optimization problem is called a standard dual quaternion optimization problem,and some better results ***,we show that the dual quaternion optimization problems arising from the hand-eye calibration problem and the simultaneous localization and mapping(SLAM)problem are equality constrained standard dual quaternion optimization problems.

关键词： Standard dual quaternion functions Dual quaternion optimization Quaternion optimization Hand-eye calibration Simultaneous localization and mapping(SLAM)

A piezoelectric energy harvester based on internal resonance

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Acta Mechanica Sinica 2015年第2期31卷 223-228页

作者： liqun che. Wenan Jiang Department of Mechanics Shanghai University Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University

A vibration-based energy harvester is essentially a resonator working in a limited frequency *** increase the working frequency range is a challenging *** paper reveals a novel possibility for enhancing energy harvesting via internal *** internal resonance energy harvester is *** excitation is successively assumed as the Gaussian white noise,the colored noise defined by a second-order filter,the narrow-band noise,and exponentially correlated *** corresponding averaged root-meansquare output voltages are *** results demonstrate that the internal resonance increases the operating bandwidth and the output voltage.

关键词： Vibration energy harvesting Internal resonance Stochastic excitations

Outer synchronization of uncertain small-world networks via adaptive sliding mode control

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Applied Mathematics and Mechanics(English Edition) 2015年第3期36卷 319-328页

作者： Shuang LIU liqun che. Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Department of Mechanics Shanghai University Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University

The outer synchronization of irregular coupled complex networks is inves- tigated with nonidentical topological structures. The switching gain is estimated by an adaptive technique, and a sliding mode controller is designed to satisfy the sliding con- dition. The outer synchronization between two irregular coupled complex networks with different initial conditions is implemented via the designed controllers with the corre- sponding parameter update laws. The chaos synchronization of two small-world networks consisting of N uncertain identical Lorenz systems is achieved to demonstrate the appli- cations of the proposed approach.

关键词： adaptive synchronization sliding mode control Lyapunov stability small- world network

Vibration of an Axially Moving String Supported by a Viscoelastic Foundation

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Acta Mechanica Solida Sinica 2016年第3期29卷 221-231页

作者： Haijuan Zhang liqun che. Shanghai Institute of Applied Mathematics and Mechanics Shanghai University School of Mechanical Engineering Anhui University of Technology Department of Mechanics Shanghai University Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University

The transverse vibration of an axially moving string supported by a viscoelastic foundation is analysed using the complex modal method. The equation of motion is developed using the generalized Hamilton principle. The exact closed-form solution of eigenvalues and eigen- functions are obtained. The governing equation is represented in a canonical state space form defined by two matrix differential operators, and the eigenfunctions and adjoint eigenfunctions are proved to be orthogonal with respect to each operator. This orthogonality is applied so that the response to arbitrary external excitations and initial conditions can be expressed in modal expansion. Numerical examples are presented to validate the proposed approach.

关键词： axially moving string viscoelastic foundation complex modal analysis