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Material selection combined with optimal structural design for mechanical parts

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第6期14卷 383-392页

作者： Le-miao QIU Liang-feng SUN Xiao-jian LIU Shu-you ZHANG State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

To reduce the environmental impact of mechanical parts, an approach integrating structural design and material selection was studied. Adding the discrete variable of material, a hybrid optimization model was built with the aim of minimizing environmental impact and based on an ordinary structure optimization model. An optional material set was built by combining measures of qualitative and quantitative screening, while the lifecycle environmental impact of the materials was quantified using the method of Eco-indicator 99. Two groups of structurally optimal solutions were calculated with ideal and negative-ideal materials selected respectively, and then the hybrid model was simplified by comparing the solutions. A material environmental performance index was calculated using an analytic method. By comparing this index for every material in the optional material set, the optimal material can be found and the structural solutions calculated. This method was applied to a dowel bar design process as a case study. The results show that the environmental impact of each material has a significant effect on the optimal structural solution, and it is necessary to study the integration of structural design and material selection.

关键词： Green design Structure optimization Material selection Environmental performance index

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Robust Optimal Output Tracking control of A Midwater Trawl System Based on T-S Fuzzy Nonlinear Model

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China Ocean Engineering 2013年第1期27卷 1-16页

作者：周华陈英龙杨华勇 State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

A robust optimal output tracking control method for a midwater trawl system is investigated based on T-S fuzzy nonlinear model. A simplified nonlinear mathematical model is first employed to represent a midwater trawl system, and then a T-S fuzzy model is adopted to approximate the nonlinear system. Since the strong nonlinearities and the external disturbance of the trawling system, a mixed H2/H∞ fuzzy output tracking control strategy via T-S fuzzy system is proposed to regulate the trawl depth to follow a desired trajectory. The trawl depth can be regulated by adjusting the winch velocity automatically and the tracking error can be minimized according to the robust optimal criterion. In order to validate the proposed control method, a computer simulation is conducted. The simulation results indicate that the proposed fuzzy robust optimal controller make the trawl net rapidly follow the desired trajectory under the model uncertainties and the extemal disturbance caused by wave and current.

关键词： trawl system output tracking robust optimal control Takagi-Sugeno (T-S) fuzzy systems nonlinear systems

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Disturbance observer based position tracking of electro-hydraulic actuator

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Journal of Central South University 2015年第6期22卷 2158-2165页

作者：国凯魏建华田启岩 State Key Laboratory of Fluid Power Transmission and Control (Zhejiang University)

A nonlinear controller based on an extended second-order disturbance observer is presented to track desired position for an electro-hydraulic single-rod actuator in the presence of both external disturbances and parameter uncertainties. The proposed extended second-order disturbance observer deals with not only the external perturbations, but also parameter uncertainties which are commonly regarded as lumped disturbances in previous researches. Besides, the outer position tracking loop is designed with cylinder load pressure as output; and the inner pressure control loop provides the hydraulic actuator the characteristic of a force generator. The stability of the closed-loop system is provided based on Lyapunov theory. The performance of the controller is verified through simulations and experiments. The results demonstrate that the proposed nonlinear position tracking controller, together with the extended second-order disturbance observer, gives an excellent tracking performance in the presence of parameter uncertainties and external disturbance.

关键词： electro-hydraulic system single-rod actuator disturbance observer external disturbance parameter uncertainty

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Investigation on the Radial Micro-motion about Piston of Axial Piston Pump

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Chinese Journal of Mechanical Engineering 2013年第2期26卷 325-333页

作者： XU Bing ZHANG Junhui YANG Huayong ZHANG Bin State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

The limit working parameters and service life of axial piston pump are determined by the carrying ability and lubrication characteristic of its key friction pairs. Therefore, the design and optimization of the key friction pairs are always a key and difficult problem in the research on axial piston pump. In the traditional research on piston/cylinder pair, the assembly relationship of piston and cylinder bore is simplified into ideal cylindrical pair, which can not be used to analyze the influences of radial micro-motion of piston on the distribution characteristics of oil-film thickness and pressure in details. In this paper, based on the lubrication theory of the oil film, a numerical simulation model is built, taking the influences of roughness, elastic deformation of piston and pressure-viscosity effect into consideration. With the simulation model, the dynamic characteristics of the radial micro-motion and pressure distribution are analyzed, and the relationships between radial micro-motion and carrying ability, lubrication condition, and abrasion are discussed. Furthermore, a model pump for pressure distribution measurement of oil film between piston and cylinder bore is designed. The comparison of simulation and experimental results of pressure distribution shows that the simulation model has high accuracy. The experiment and simulation results demonstrate that the pressure distribution has peak values that are much higher than the boundary pressure in the piston chamber due to the radial micro-motion, and the abrasion of piston takes place mainly on the hand close to piston ball. In addition, improvement of manufacturing roundness and straightness of piston and cylinder bore is helpful to improve the carrying ability of piston/cylinder pair. The proposed research provides references for designing piston/cylinder pair, and helps to prolong the service life of axial piston pump.

关键词： axial piston pump piston/cylinder pair micro motion carrying ability

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Adaptive fuzzy integral sliding mode pressure control for cutter feeding system of trench cutter

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Journal of Central South University 2016年第12期23卷 3302-3311页

作者：田启岩魏建华方锦辉国凯 State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

A nonlinear pressure controller was presented to track desired feeding pressure for the cutter feeding system(CFS) of trench cutter(TC) in the presence of unknown external *** feeding pressure control of CFS is subjected to unknown load characteristics of rock or soil; in addition,the geological condition is *** to the complex load characteristics of rock or soil,the feeding velocity of TC is related to geological *** is worse,its dynamic model is subjected to uncertainties and its function is *** deal with the particular characteristics of CFS,a novel adaptive fuzzy integral sliding mode control(AFISMC) was designed for feeding pressure control of CFS,which combines the robust characteristics of an integral sliding mode controller and the adaptive adjusting characteristics of an adaptive fuzzy *** AFISMC feeding pressure controller is synthesized using the backstepping *** stability of the overall closed-loop system consisting of the adaptive fuzzy inference system,integral sliding mode controller and the cutter feeding system is proved using Lyapunov *** are conducted on a TC test bench with the AFISMC under different operating *** experimental results demonstrate that the proposed AFISMC feeding pressure controller for CFS gives a superior and robust pressure tracking performance with maximum pressure tracking error within ?0.3 MPa.

关键词： electro-hydraulic system cutter feeding system feeding pressure control adaptive fuzzy integral sliding mode control

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Product Modular Design Incorporating Preventive Maintenance Issues

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Chinese Journal of Mechanical Engineering 2016年第2期29卷 406-420页

作者： GAO Yicong FENG Yixiong TAN Jianrong State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

Traditional modular design methods lead to product maintenance problems, because the module form of a system is created according to either the function requirements or the manufacturing considerations. For solving these problems, a new modular design method is proposed with the considerations of not only the traditional function related attributes, but also the maintenance related ones. First, modularity parameters and modularity scenarios for product modularity are defined. Then the reliability and economic assessment models of product modularity strategies are formulated with the introduction of the effective working age of modules. A mathematical model used to evaluate the difference among the modules of the product so that the optimal module of the product can be established. After that, a multi-objective optimization problem based on metrics for preventive maintenance interval different degrees and preventive maintenance economics is formulated for modular optimization. Multi-objective GA is utilized to rapidly approximate the Pareto set of optimal modularity strategy trade-offs between preventive maintenance cost and preventive maintenance interval difference degree. Finally, a coordinate CNC boring machine is adopted to depict the process of product modularity. In addition, two factorial design experiments based on the modularity parameters are constructed and analyzed. These experiments investigate the impacts of these parameters on the optimal modularity strategies and the structure of module. The research proposes a new modular design method, which may help to improve the maintainability of product in modular design.

关键词： modular design modularity strategy preventive maintenance optimization design

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Inertia Market:Mechanism Design and Its Impact on Generation Mix

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Journal of Modern power Systems and Clean Energy 2023年第3期11卷 744-756页

作者： Jingwei Hu Zheng Yan Xiaoyuan Xu Sijie Chen Key Laboratory of Control of Power Transmission and Conversion Ministry of Educationand Shanghai Non-Carbon Energy Conversion and Utilization InstituteShanghai Jiao Tong UniversityShanghai 200240China

Increasing penetration of renewable energy generation poses a challenge to power system inertia *** is vital to provide long-term incentive signals to induce a generation mix with adequate inertia ***,existing literature rarely studies inertia incentive mechanisms or considers inertia constraints when making generation investment ***,we propose an inertia market to quantify the value of inertia and to remunerate inertia *** examine the impacts of the inertia market on generation mix,we then propose a stochastic bilevel generation investment equilibrium model that depicts a multi-leader and multi-follower Stackelberg *** lower level of the model considers the proposed inertia market,along with the energy,reserve,and capacity *** upper level considers multiple profit-maximizing strategic producers,and each producer is able to build gas-fired generators,wind generators,and energy *** experiments demonstrate that a generation mix with adequate inertia supply can be induced with the proposed inertia market whereas there can be inertia shortage without the inertia ***,considering carbon taxes,it is more cost-competitive to invest in wind resources with virtual inertia facilities than to substitute wind resources by thermal ***,the introduction of an inertia market does not significantly reduce wind generation shares but boosts virtual inertia facility *** findings imply a future power system powered by fully decarbonized power resources with adequate inertia.

关键词： Generation mix generation investment equilibrium inertia market Stackelberg game virtual inertia

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Position, Singularity and Workspace Analysis of 3-PSR-O Spatial Parallel Manipulator

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Chinese Journal of Mechanical Engineering 2015年第3期28卷 437-450页

作者： SHAO Jiejie CHEN Wenyu FU Xin State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

Although the parallel mechanisms have the advantages of high accuracy, velocity, stiffness, and payload capacity, the shortcomings of the space utilization and workspace limit the applications in the confined space. A novel 3 degrees of freedom spatial parallel manipulator 3-PSR-O（prismatic-spherical-revolute） is proposed, which possesses a compact architecture and extended workspace while maintaining the inherent advantages of the parallel mechanisms. The direct-inverse position, singularity and workspace are investigated. The mapping method is adopted in the position analysis, and the closed form solution is derived in the form of a six order equation. The singularity analysis of the mechanism is also carried out based on the geometrical constraints, including six singularity boundaries. A feature boundary, which is independent of the prismatic joints＇ stroke limit, is obtained by integrating the six singularity boundaries. According to the formation of the reachable workspace, a concept of basic workspace is also introduced and presented in the analytical way. By demarcating the basic workspace along the central height with the feature boundary, the reachable workspace can be derived and analyzed more efficiently. Finally, a comparative study on the space utilization between the 3-PSP parallel mechanism and the new mechanism is also presented. The area of feature boundary of the new mechanism is about 140% of the 3-PSP parallel mechanism, while its installation radius is only 1/2 of the 3-PSP parallel mechanism. The proposed parallel mechanism shows great space utilization, and is ideally suited for applications in confined space occasions such as immersion lithography, nano-imprint etc.

关键词： spatial-planar parallel mechanism direct-inverse position analysis reachable workspace basic workspace feature boundary

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C-Vine Pair Copula Based Wind power Correlation Modelling in Probabilistic Small Signal Stability Analysis

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IEEE/CAA Journal of Automatica Sinica 2020年第4期7卷 1154-1160页

作者： Jin Xu Wei Wu keyou Wang Guojie Li the Key Laboratory of Control of Power Transmission and Conversion Ministry of EducationDepartment of Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The increasing integration of wind power generation brings more uncertainty into the power system. Since the correlation may have a notable influence on the power system,the output powers of wind farms are generally considered as correlated random variables in uncertainty analysis. In this paper, the C-vine pair copula theory is introduced to describe the complicated dependence of multidimensional wind power injection, and samples obeying this dependence structure are generated. Monte Carlo simulation is performed to analyze the small signal stability of a test system. The probabilistic stability under different correlation models and different operating conditions scenarios is investigated. The results indicate that the probabilistic small signal stability analysis adopting pair copula model is more accurate and stable than other dependence models under different conditions.

关键词： Monte Carlo simulation pair copula small signal stability wind power correlation

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Hierarchical and Classified Aggregation Method with Embedded Regulation Targets for Regulation Capability of Distributed Energy Resources

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Dianli Xitong Zidonghua/Automation of Electric power Systems 2025年第9期49卷 84-95页

作者： Yang, Yilong Fan, Shuai Cai, Siye Gu, Xiaoxu Huang, Renke He, Guangyu Key Laboratory of Control of Power Transmission and Conversion Ministry of Education Shanghai Jiao Tong University Shanghai200240 China Shanghai Non-carbon Energy Conversion and Utilization Institute Shanghai200240 China State Grid Shanghai Jiading Electric Power Company Shanghai201800 China Global Institute of Future Technology Shanghai Jiao Tong University Shanghai200240 China

Exploiting and aggregating the regulation capability of the demand-side distributed energy resources (DERs) is an important basis for realizing the interaction between source and load in new power system. Existing research typically uses generic models to characterize the aggregated regulation capabilities of different types of DERs at different network levels. Since the regulation targets are not included during aggregation process, it is difficult to achieve high solution efficiency and accuracy, and may even result in conservative estimation of regulation ranges or partially unachievable outcomes, limiting the effective utilization of DERs in the actual scheduling. Therefore, a hierarchical and classified aggregation method with embedded regulation targets for regulation capability of DERs is proposed. Firstly, for the same type of resources, an inner approximation method based on similar polyhedra is adopted to complete the aggregation. Secondly, for different types of resources,the time-coupling characteristics of the aggregated output power are characterized by introducing the target shape constraint, and the optimization model of vector aggregation along the target curve is constructed to achieve the optimization of the aggregation accuracy in the target direction. In addition, to address cross-node aggregation scenarios, a power flow model based on the second-order cone relaxation is employed to satisfy the network constraints. Finally, numerical experiment results demonstrate that, compared with the traditional aggregation methods, the proposed method can significantly improve computational efficiency and enhance the accuracy of aggregation for different types and nodes of resources, while ensuring the practical executability of aggregation results. © 2025 Automation of Electric power Systems Press. All rights reserved.

关键词： Numerical methods

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