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The distributed parameter model of an Electro-Pneumatic System Actuated by Pneumatic Artificial Muscles with PWM-Based Position Control

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ENERGIES 2024年第14期17卷 3381页

作者： Kotkas, Lyubov Donskoy, Anatolij Zharkovskii, Aleksandr Zhurkin, Nikita Peter Great St Petersburg Polytech Univ World Class Res Ctr Adv Digital Technol Peter Great St St Petersburg 195251 Russia

Today, the analysis and synthesis methods of electro-pneumatic systems with position control actuated by pneumatic artificial muscles (PAMs) are quite well known. In these methods, pneumatic artificial muscle is considered as an object with lumped parameters. However, the PAM is an object with distributed parameters, where the pressure, density, and mass flow rate of gas are varied along the bladder length. Thus, in the case of certain design parameters of the pneumatic artificial muscle and certain frequencies of the supply pressure, resonant gas oscillations affected by the wave processes in the bladder may occur. Thereby, in the PWM-driven PAM-actuated system, certain operation frequencies of the control pneumatic valve can cause oscillations of gas in the bladder and in the connected pipeline. These processes could lead to vibrations of the executive device. To solve this practical problem, a distributed parameter model of the PAM that takes into account the pressure fluctuations in the bladder and in the pipeline was elaborated. Also, in this work, a new method in which the wave processes are described by ordinary differential equations instead of partial differential equations was proposed.

关键词： electro-pneumatic system pneumatic artificial muscle distributed parameter model position control PWM resonant gas oscillations wave processes supply pipeline ordinary differential equations

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Development of a distributed-parameter model for the evaporation system in a supercritical W-shaped boiler

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APPLIED THERMAL ENGINEERING 2014年第1期62卷 123-132页

作者： Zheng Shu Luo Zixue Deng Yanxiang Zhou Huaichun Huazhong Univ Sci & Technol State Key Lab Coal Combust Wuhan 430074 Hubei Peoples R China

In this paper, a distributed parameter model of an evaporation system in a supercritical W-shaped once-through boiler is developed based on the 3-D temperature distribution. The mathematical model was formulated to predict the distributions of the heat flux and the metal-surface temperature while considering a non-uniform distribution of the surface heat transfer and the frictional resistance coefficient. The results show that the heat flux distribution on the front water wall has three high heat flux zones in the W-shaped boiler, and the peak of the heat transfer coefficient moves to the peak of the heat flux gradually with the increment of load at supercritical pressure. The maximum deviation of the metal temperature is nearly 94 degrees C for different loads. This distributed parameter model is fit for the in-situ operating status of the boiler, and it provides a reference for the heat transfer of a supercritical system. (c) 2013 Elsevier Ltd. All rights reserved.

关键词： distributed parameter model Evaporation system Wall temperature Heat flux distribution Supercritical W-shaped boiler

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Force Control of Dual-Manipulator Handling a Flexible Payload Based on distributed parameter model

Force Control of Dual-Manipulator Handling a Flexible Payloa...

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Chinese Automation Congress

作者： Shuyang Liu Yuanchun Li Reza Langari Department of Mechanical Engineering Texas A&M University College Station TX USA

This paper presents an exact dynamic model of a dual-manipulator handling a flexible payload by using Hamilton's principle. On the basis of the distributed parameter model, a force controller is designed via Lyapunov theory. The controller can accomplish the desired contact force between the manipulator and the flexible payload while achieving the given desired link angles, and simultaneously suppressing the vibration of the flexible payload. All the states used in the controller are readily available so that the proposed method is feasible to implement.

关键词： Force control distributed parameter model Flexible payload Lyapunov function

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Fault properties identification scheme for hybrid MTDC system based on LCC signal injection and distributed parameter line model

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IET GENERATION TRANSMISSION & DISTRIBUTION 2023年第16期17卷 3718-3738页

作者： Junjie, Hou Guobing, Song Yanfang, Fan Xinjiang Univ Sch Elect Engn Urumqi Peoples R China Xi An Jiao Tong Univ Sch Elect Engn Xian Peoples R China

A fault properties identification scheme for a hybrid multi-terminal DC (MTDC) system is proposed to improve the power supply reliability in the system recovery stage. Firstly, a current signal injection strategy based on line commutated converter (LCC) is proposed using the fault control capability. Secondly, the difference between the calculated value (CV) and the measured value (MV) of the current signal under permanent and temporary faults is analyzed for the distributed parameter line model. By introducing the dynamic time warping (DWT) algorithm to represent the difference between CV and MV, a fault properties identification scheme for permanent fault identification is constructed. Finally, the proposed scheme for permanent fault location with the distributed parameter model is obtained by introducing the trust region reflection (TRR) algorithm. The simulation results show that the proposed fault properties identification scheme has the function of permanent fault identification and location. The proposed scheme fully considers the effects of fault impedance, sampling rate, noise, and data loss. It can be applied to high voltage DC long-distance transmission lines with LCC.

关键词： distributed parameter model fault properties identification scheme hybrid multi-terminal DC system signal injection of line commutated converter

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Global nonlinear distributed-parameter model of parametrically excited piezoelectric energy harvesters

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NONLINEAR DYNAMICS 2012年第2期67卷 1147-1160页

作者： Abdelkefi, A. Nayfeh, A. H. Hajj, M. R. Virginia Tech Blacksburg VA 24060 USA

A global nonlinear distributed-parameter model for a piezoelectric energy harvester under parametric excitation is developed. The harvester consists of a unimorph piezoelectric cantilever beam with a tip mass. The derived model accounts for geometric, inertia, piezoelectric, and fluid drag nonlinearities. A reduced-order model is derived by using the Euler-Lagrange principle and Gauss law and implementing a Galerkin discretization. The method of multiple scales is used to obtain analytical expressions for the tip deflection, output voltage, and harvested power near the first principal parametric resonance. The effects of the nonlinear piezoelectric coefficients, the quadratic damping, and the excitation amplitude on the output voltage and harvested electrical power are quantified. The results show that a one-mode approximation in the Galerkin approach is not sufficient to evaluate the performance of the harvester. Furthermore, the nonlinear piezoelectric coefficients have an important influence on the harvester's behavior in terms of softening or hardening. Depending on the excitation frequency, it is determined that, for small values of the quadratic damping, there is an overhang associated with a subcritical pitchfork bifurcation.

关键词： Piezoelectric material Energy harvesting distributed parameter model Nonlinear analysis Method of multiple scales

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Design and performance of an adaptive-stiffness rocking structure for enhanced seismic resilience

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JOURNAL OF BUILDING ENGINEERING 2025年 103卷

作者： Wu, Dayang Meng, Hao Xing, Lili Qingdao Univ Technol Coll Civil Engn Qingdao 266520 Peoples R China

The rocking structure is widely recognized for its excellent seismic resilience, including damagefree performance. However, it still faces challenges, such as low energy dissipation efficiency and significant higher-mode effects, which hinder its ability to simultaneously control displacement and force responses. To address these issues, this paper proposes the adaptive-stiffness rocking structure (ASRS) by integrating the adaptive stiffness mechanism with the rocking and energy dissipation mechanisms, thereby enhancing energy dissipation efficiency. This integration also effectively mitigates the influence of higher-mode effects, such as acceleration and shear forces. In this study, the ASRS's non-proportional damping distributed parameter model and the distributed transfer function method (DTFM) are used to solve the dynamic equations. The dynamic characteristics, including frequency and damping ratio, are derived, and parametric equations for the modal damping ratio are obtained via curve fitting. The inter-story drift ratio (IDR) design spectrum of the ASRS is calculated using the modal decomposition response spectrum method. Based on this, the preliminary design and performance assessment of the ASRS are conducted. The results show that the ASRS effectively reduces dynamic responses, such as IDR, acceleration, and shear force, by leveraging the combined action of the adaptive stiffness and energy dissipation mechanisms. Furthermore, the IDR design spectrum enables an efficient preliminary design of the ASRS.

关键词： Rocking structure Adaptive stiffness Energy dissipation distributed parameter model Inter-story drift ratio spectrum Design method

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distributed parameter modeling and optimal control of the oxidation rate in the iron removal process

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JOURNAL OF PROCESS CONTROL 2018年 61卷 47-57页

作者： Xie, Shiwen Xie, Yongfang Yang, Chunhua Gui, Weihua Wang, Yalin Cent S Univ Sch Informat Sci & Engn Changsha 410083 Hunan Peoples R China

Generally, the iron removal process is modelled as a lumped parameter system that does not provide information about the distribution of reactants in the steady state. In this paper, we investigate the distributed parameter model and control for the iron removal process. By analyzing the process properties, we study the mass balance over a differential volume element, and the spatiotemporal distributions of the Fe2+, Fe3+ and H+ concentrations are derived by partial differential equations. An optimization problem is constructed to estimate the unknown parameters. Then, an optimal control problem for the oxidation rate of the ferrous ions in the steady state is proposed to achieve process requirements that have the lowest cost of oxygen and zinc oxide and obtain high goethite quality. To eliminate the impact from inevitable disturbances, an expert-based correction mechanism is constructed to compensate for the optimal control when the outlet ferrous ion concentrations are out of the desired range. Finally, the simulation results demonstrate the good performance of distributed parameter model. Industrial experiments demonstrate the satisfactory control performance of the optimal control strategy. Regarding manual operation and PI control, the control strategy increased the qualified ratio of the #4 reactor outlet Fe2+ concentrations by 8.4% and 3.4%, respectively. Additionally, on average 17760 m(3) of oxygen and 109.68 t of zinc oxide per month were saved compared to manual operation. The mass percent of iron in the goethite increased from 34.31% (manual operation) and 35.12% (PI control) to 35.83%. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： distributed parameter model parameter estimation Optimal control Expert-based correction Iron removal process

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distributed parameter modelING AND THERMAL ANALYSIS OF A SPIRAL WATER WALL IN A SUPERCRITICAL BOILER

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THERMAL SCIENCE 2013年第5期17卷 1337-1342页

作者： Zheng, Shu Luo, Zixue Zhou, Huaichun Huazhong Univ Sci & Technol State Key Lab Coal Combust Wuhan 430074 Peoples R China

In this paper, a distributed parameter model for the evaporation system of a supercritical spiral water wall boiler is developed based on a 3-D temperature field. The mathematical method is formulated for predicting the heat flux and the metal-surface temperature. The results show that the influence of the heat flux distribution is more obvious than that of the heat transfer coefficient distribution in the spiral water wall tube, and the peak of the heat transfer coefficient decreases with an increment of supercritical pressure. This distributed parameter model can be used for a 600 MW supercritical-pressure power plant.

关键词： distributed parameter model evaporation system supercritical boiler spiral water wall

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distributed parameter modeling for prefabricated wall-frame system assembled by horizontal and vertical connection

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RESULTS IN ENGINEERING 2022年 16卷

作者： Jiang, Hongbo Cui, Hengwei Deng, Luyun Cao, Dafu Ge, Wenjie Chen, Kongyang Zhao, Jianchen Sun, Jian Yangzhou Univ Coll Civil Sci & Engn Yangzhou Peoples R China Jiangsu Yangzhou Technician Coll Yangzhou Peoples R China Suzhou Elect Power Design Inst Co Ltd Suzhou Peoples R China Southeast Univ Key Lab Concrete Prestressed Concrete Struct Minist Educ Nanjing Peoples R China

distributed parameter model (also referred to as continuum model) is commonly used to analyze the behavior of conventional frame-shear wall structure. In recent decades, extensive research has been published and proved the well-controlled seismic performance of wall-frame system, beyond which some researchers applied the continuous philosophy to the analysis of specified wall-frame systems. This paper extends the distributed parameter model to a general distributed parameter model, and corresponding closed-form solutions for three typical load cases are derived, verified, and parametric analyzed. The model in this paper unifies the three nondimensional parameters into one model and parameterizes the relative stiffness between wall, frame, vertical connection, and horizontal connection. Additionally, the proposed model can analyze the system with various horizontal connection (hinged/fixed/semi-rigid) as well as vertical connection (dampers/coupling links). Further, the shear demand of frame retrofitted by resilient wall, a new retrofit has been constructed lately, is theoretically studied using the proposed model. Results shows that the shear demand of frame at upper floor levers may increase after retrofitting.

关键词： Wall-frame system distributed parameter model Closed-form solution Seismic retrofit Semi-rigid connection

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Iterative learning consensus tracking control for distributed parameter models multi-agent with disturbance 31

Iterative learning consensus tracking control for distribute...

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31st Chinese Control And Decision Conference (CCDC)

作者： Huang, Qingnan Wang, Cun Dai, Xisheng Guangxi Univ Sci & Technol Sch Elect & Informat Engn Liuzhou 545006 Peoples R China Guangxi Higher Educ Inst Key Lab Ind Proc Intelligent Control Technol Liuzhou 545006 Peoples R China

ISBN: (纸本)9781728101057

In this paper, we study the consensus tracking for a class of distributed parameter models multi-agent systems. Taking into account the presence of disturbance in the system, using knowledge between neighboring agents, the virtual leader technology is introduced. A distributed P-type iterative learning control protocol is proposed. When the ILC law is applied to the system, the consensus tracking error between any two agents under the sense of L-2 norm can converge to zero after a sufficient number of iterations in a finite time interval. Finally, simulation examples demonstrate the effectiveness of the method.

关键词： Iterative learning control distributed parameter model multi-agent systems disturbance consensus tracking

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