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The nonlinear control of simulator of hexapod parallel mechanism

Journal of Harbin Institute of Technology(New Series) 2010年第3期17卷 393-397页

作者：潘春萍管欣卢颖梁建民 State Key Laboratory of Automobile Dynamic Simulation Jilin University Military Simulation Technology Research Institute Aviation University of Air Force

In order to enhance the innervation fidelity of simulators,a nonlinear controller is developed,which guarantees parallel mechanisms closed loop system global asymptotical stability and the convergence of posture tracking error in Cartesian space. The problems of rapid tracking under the condition of the wide range,nonlinear and variable load are solved. After the nonlinear controller is actually applied to the hexapod parallel mechanisms of simulator,the dynamic-static capabilities of motion system are tested by amplitude-frequency response and posture precision. The experimental results show that the static precision improves ten times and system output amplitude increases and the phase lag reduces with respect to the same input signal in Cartesian space in comparison with the traditional proportional and derivative (i.e. PD) controlling method in joint space. Therefore the nonlinear controller can effectively improve the dynamic-static response performance of the hexapod parallel mechanisms of simulators in Cartesian space.

关键词： simulators hexapod parallel mechanisms dynamics model nonlinear control irmervation＇ s fidelity

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Energy cost and greenhouse gas emissions of a Chinese solar tower power plant

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Procedia Environmental Sciences 2011年 5卷 77-80页

作者： Q. Yang G.Q. Chen Y.H. Zhao B. Chen Z. Li Z.F. Wang State Key Laboratory of Turbulence and Complex Systems College of Engineering Peking University Beijing 100871 China China Hua Dian Corporation Beijing 100035 China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China Key Laboratory of Solar Thermal Energy and Photovoltaic System of Chinese Academy of Sciences Institute of Electrical Engineering P.O. Box 2703 Beijing 100190 China

It is commonly assumed that the application of solar power system can save energy and relief global climate change. Presented in this study is the account of energy performance and greenhouse gas emissions of a planned solar tower power plant in China based on the life cycle analysis method. The conservative estimation of energy cost for the concerned plant is 1.21 times of the electricity output, which is a relatively decent performance amongst power generation technologies. In order to analyze the greenhouse gas performance, a comparison is carried out between the solar tower power plant and conventional coal-fired power plant in China. Results show the application of this solar system obtains a net greenhouse gas emission reduction of 0.31E+06 ton CO2 equivalent, during its operating period of twenty years. It is believed that this successful example can lend solid support to a future wide use of solar power in China.

关键词： Solar tower power plant Electricity generation Energy analysis Greenhouse gas emission

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Optimized inverse kinematics algorithm for onboard craning manipulator

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Nanjing Li Gong Daxue Xuebao/Journal of Nanjing University of Science and Technology 2011年第SUPPL. 1期35卷 49-54页

作者： Ren, Xiao-Lin Li, Yuan-Chun Xu, Jing State Key Laboratory of Automobile Dynamic Simulation Jilin University Changchun 130022 China Department of Communication Engineering Jilin University Changchun 130022 China

To solve the problem of inverse kinematics for 8 DOF onboard craning manipulator in the process of lifting and traversing, the equations of the kinematics model is set up on the basis of assignment description. The kinematics model is analyzed, and a novel algorithm-chaos swarm optimization algorithm(CPSO)is proposed. The new algorithm has the simple implement easity for the global optimization and high computational precision, thereby gaining a set of solutions. simulations show that the present method is effective.

关键词： Manipulators

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Size Distribution of Water Soluble Brown Carbon and Its Light Absorbing Properties

Size Distribution of Water Soluble Brown Carbon and Its Ligh...

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第十八届中国大气环境科学与技术大会

作者： Caiqing Yan Mei Zheng Xiaolu Zhang Jiumeng Liu State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing 100871 China School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta GA School of Earth and A

ze-segregated aerosol samples were collected by Mirco-Orifice Uniform Deposit Impactor (MOUDI) in Atlanta,USA and Beijing,China during summer *** characteristics and size distribution of carbonaceous aerosols especially water soluble brown carbon (light absorbing organic matter with strong wavelength-dependent in UV and UV-Visible ranges) were *** of organic carbon (OC) and water-soluble organic carbon (WSOC) both exhibited bimodal distribution,peaking at coarse mode (3.2 μm) and fine mode (0.56-1 μm).In the fine particle fraction,OC was dominated by WSOC and comprised of significant fraction of light absorbing components.

关键词： brown carbon light absorption size distribution Beijing Atlanta

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Integrated vehicle chassis control of active steering and active braking using the inverse Nyquist array method

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Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (Engineering and Technology Edition) 2011年第SUPPL. 2期41卷 41-46页

作者： Zhu, Bing Ren, Lu-Quan Zhao, Jian Li, You-De Key Laboratory of Bionic Engineering of Ministry of Education Jilin University Changchun 130022 China State Key Laboratory of Automotive Simulation and Control Jilin University Changchun 130022 China

The characteristic of the target vehicle equipped with both of the two active control systems was analyzed;an integrated vehicle chassis controller was designed using the inverse Nyquist array method, to pre-compensate and dynamic compensate the vehicle system respectively;the framework of the integrated chassis control system was established to coordinate the subsystems. A typical case was simulated on the co-simulation platform with MATLAB and AMESim, the results showed that the integrated vehicle chassis controller based on the inverse Nyquist array method can coordinate the active steering system and active brake system, and improves the vehicle handling and stability performance effectively.

关键词： controllers

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Integrated water resource security evaluation of Beijing based on GRA and TOPSIS

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中国高等学校学术文摘·地球科学 2010年第3期4卷 357-362页

作者： Jing DAI Jing QI Jingjing CHI Shaoqing CHEN Jin YANG Liping JU Bin CHEN State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China State Key Laboratory of Turbulence and Complex Systems Peking University Beijing 100871 China

Security evaluation has become a hot topic in the research field of water resource management. In this paper, we established a novel water resource security indicator system based on the Pressure-Status-Response (PSR) framework using gray relation analysis (GRA) and technique for order preference by similarity to ideal solution (TOPSIS). A case study of Beijing from 1996 to 2007 was conducted to verify the evaluation system. Results showed that the gray relative closeness degrees of water resource security to the positive ideal solution were low, with the least one of 0.360 in 1999 and the largest one of 0.527 in 2007, implying that Beijing was facing severer challenges with water resources during the concerned time. Also, the analysis of water resource security indicated that the pressure of water resource was constantly increasing. Finally, factor analysis was employed to calculate the gray relation degrees of evaluating indices with the ideal solutions so as to reveal the relativity of water resource security of Beijing, which may contribute to a better understanding of the urban water resource management and regulation.

关键词： water resource security grey relation analysis (GRA) technique for order preference by similarity to ideal solution (TOPSIS) factor analysis

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Transient interaction of HVAC and HVDC in converterer station in HVDC, I: Electromagnetic transient model of equipments in DC side

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Gaodianya Jishu/High Voltage Engineering 2011年第2期37卷 395-403页

作者： Chen, Shui-Ming Yu, Zhan-Qing Xie, Hai-Bin Huang, Lu-Lu State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

Huge interconnected power grids are formed in AC and DC power systems in China. The nanoseconds, microseconds, milliseconds electromagnetic transient due to AC and DC system operation and fault, the DC converter valve movement, the load generated by changes interact in the AC and DC interconnected system, impairing AC and DC power systems, especially leading to the commutation of DC system failures and atresia such serious incidents. Consequently, a theoretical analysis was combined with a test method to establish an over ground network, considering DC electrical networks, control systems and underground grounding system of the full-wave process of the UHV system, Finally, converter transformer was modeled with UMEC model, and transmission line was modeled with J-Marti frequency dependent model;moreover, valve was modeled with transistor, RLC circuit, and other units including DC controller, and DC filter and AC filter were modeled with RLC circuit. The broadband characteristics of electromagnetic transient models of key units in DC sides for the analysis of AC and DC interconnected system were also analyzed.

关键词： controllers

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Transient interaction of HVAC and HVDC in converter station in HVDC, II: Equivalence circuit in AC side and steady-state debugging

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Gaodianya Jishu/High Voltage Engineering 2011年第3期37卷 537-547页

作者： Chen, Shui-Ming Huang, Lu-Lu Xie, Hai-Bin Yu, Zhan-Qing State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

The interaction of nanoseconds, microseconds, milliseconds electromagnetic transients due to AC-DC system operation and fault, the DC converter valve movement, the load generated by changes in the interaction of AC-DC interconnected system electromagnetic transient, can pose a hazard on AC and DC power systems, in particular, lead to the commutation of DC system failures and artesian such serious incidents. Combining theoretical analysis with test, we can establish the analysis method of electromagnetic transient of the full-wave process of the UHV system based on AC-DC interconnected system, control systems, and underground grounding system, and focus on the equivalence circuit of AC side network with the Ward method of equivalency under many operation modes and steady-state debugging for the analysis of AC-DC interconnected system, so as to lay the foundation for the interaction of electromagnetic transient.

关键词： Timing circuits

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Transient interaction of HVAC and HVDC in converter station in HVDC, IV: Effects of DC sides on AC sides

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Gaodianya Jishu/High Voltage Engineering 2011年第7期37卷 1590-1597页

作者： Chen, Shui-Ming Yu, Zhan-Qing Huang, Lu-Lu Xie, Hai-Bin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

China AC-DC power systems are interconnected to form a huge power grid. The nanoseconds, microseconds, milliseconds electromagnetic transient were generated due to AC-DC system operation and fault, the DC converter valve movement, the load generated by changes in the interaction of AC-DC interconnected system electromagnetic transient, which can pose a hazard on AC and DC power systems, in particular, can lead to the commutation of DC system failures and atresia such serious incidents. Based on the broadband characteristics model which can accurately reflect the existing AC-DC interconnected system electromagnetic transient characteristics of the key components, we applied the PSCAD/EMTDC platform to establish a computational model, and revealed DC side electromagnetic transient interaction on AC side. The results show that the DC system has little effect on AC system electromagnetic transient, In various types of failures, the overvoltage produced at side of 750 kV, 330 kV lines and bus are in the allowable range.

关键词： HVDC power transmission

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Reinvestigation of the Henry's law constant for hydrogen peroxide with temperature and acidity variation

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Journal of Environmental Sciences 2010年第4期22卷 570-574页

作者： Daoming Huang,Zhongming Chen The state key laboratory of Environmental simulation and Pollution control,College of Environmental Sciences and Engineering,Peking University,Beijing 100871,China. [a] The State Key Laboratory of Environmental Simulation Pollution Control College of Environmental Sciences Engineering Peking University Beijing 100871 China

Hydrogen peroxide is not only an important oxidant in itself; it also serves as both sink and temporary reservoir for other important oxidants including HOx （OH and HO2） radicals and O3 in the atmosphere. Its partitioning between gas and aqueous phases in the atmosphere, usually described by its Henry＇s law constant （KH）, significantly influences its role in atmospheric processes. Large discrepancies between the KH values reported in previous work, however, have created uncertainty for atmospheric modelers. Based on our newly developed online instrumentation, we have re-determined the temperature and acidity dependence of KH for hydrogen peroxide at an air pressure of （0.960 ± 0.013） atm （1 atm = 1.01325 × 10^5 Pa）. The results indicated that the temperature dependence of KH for hydrogen peroxide fits to the Van＇t Hoff equation form, expressed as lnKH = a/T - b, and a = -△H/R, where KH is in M/atm （M is mol/L）, T is in degrees Kelvin, R is the ideal gas constant, and AH is the standard heat of solution. For acidity dependence, results demonstrated that the KH value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level （from pH 7 to pH 1）. Combining the dependence of both temperature and acidity, the obtained a and b were 7024 ± 138 and 11.97 ± 0.48, respectively, AH was （58.40 ± 1.15） kJ/（***）, and the uncertainties represent σ. Our determined KH values for hydrogen peroxide will therefore be of great use in atmospheric models.

关键词： hydrogen peroxide Henry＇s law constant atmosphere acidity

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