Based on the evaluation of dynamic performance for feed drives in machine tools, this paper presents a two-stage tuning method of servo parameters. In the first stage, the evaluation of dynamic performance, parameter ...Based on the evaluation of dynamic performance for feed drives in machine tools, this paper presents a two-stage tuning method of servo parameters. In the first stage, the evaluation of dynamic performance, parameter tuning and optimization on a mechatronic integrated system simulation platform of feed drives are performed. As a result, a servo parameter combination is acquired. In the second stage, the servo parameter combination from the first stage is set and tuned further in a real machine tool whose dynamic performance is measured and evaluated using the cross grid encoder developed by Heidenhain GmbH. A case study shows that this method simplifies the test process effectively and results in a good dynamic performance in a real machine tool.展开更多
大型火力发电厂的协调控制系统CCS(Coordinated Control System)是一个复杂的多变量耦合控制系统。研究了反演算函数在大机组CCS中的设计与实现问题。分析了达拉特发电厂1号机组CCS的特点,为解决火电单元机组CCS的动态非线性和耦合特性...大型火力发电厂的协调控制系统CCS(Coordinated Control System)是一个复杂的多变量耦合控制系统。研究了反演算函数在大机组CCS中的设计与实现问题。分析了达拉特发电厂1号机组CCS的特点,为解决火电单元机组CCS的动态非线性和耦合特性,设计了压力、功率偏差反演算函数的解耦CCS控制回路,引入反演算函数算法用于动态解耦运算,改善了CCS的强耦合及动态非线性特性,改进了CCS适应外界负荷能力差的现状。为补偿锅炉的惯性和迟延,提出了根据前馈的微分作用快速调节燃料量的方法;加入动态超调措施,使一次风风量提前动作。通过现场试投,验证了新协调系统的有效性。系统实际运行曲线验证了控制系统的良好品质。展开更多
Nowadays,grid-connected renewable energy resources have widespread applications in the electricity market.However,providing household consumers with photovoltaic(PV)systems requires bilateral interfaces to exchange en...Nowadays,grid-connected renewable energy resources have widespread applications in the electricity market.However,providing household consumers with photovoltaic(PV)systems requires bilateral interfaces to exchange energy and data.In addition,residential consumers’contribution requires guaranteed privacy and secured data exchange.Dayahead dynamic pricing is one of the incentive-based demand response methods that has substantial effects on the integration of renewable energy resources with smart grids and social welfare.Different metering mechanisms of renewable energy resources such as feed-in tariffs,net metering,and net purchase and sale are important issues in power grid operation planning.In this paper,optimal condition decomposition method is used for dayahead dynamic pricing of grid-connected residential renewable energy resources under different metering mechanisms:feed-intariffs,net metering,and net purchase and sale in conjunction with carbon emission taxes.According to the stochastic nature of consumers’load and PV system products,uncertainties are considered in a two-stage decision-making process.The results demonstrate that the net metering with the satisfaction average of 68%for consumers and 32%for the investigated electric company leads to 28%total load reduction.For the case of net purchase and sale mechanism,a satisfaction average of 15%for consumers and 85%for the electric company results in 11%total load reduction.In feed-in-tariff mechanism,in spite of increased social welfare,load reduction does not take place.展开更多
Properties of enzyme production of a Bacillus subtitles strain （ MSJ-5 ） isolated from soil were studied in the test. Enzyme production reached the peak when MSJ-5 being cultured in fermentation medium for 32 h. 6-1...Properties of enzyme production of a Bacillus subtitles strain （ MSJ-5 ） isolated from soil were studied in the test. Enzyme production reached the peak when MSJ-5 being cultured in fermentation medium for 32 h. 6-1,4-D-mannanase was the main component of crude enzyme solution, test results showed that the optimal reaction temperature of the enzyme was 50 ℃, the optimum reaction pH was 7.0, and the enzyme was stable when pH was 5.0 -7.0. Hydrolysis test re- suits showed that β-1,4-D-mannanase produced by MSJ-5 had significant viscosity reduction effects on Konjak mannan, and the major hydrolysis product was man- nan oligosaecharide. The results indicated that 6-1,4-D-mannanase produced by B. subtilis MSJ-5 had application potential in feed ingredients and functional oligo- saccharides industry.展开更多
A dynamic velocity feed-forward compensation （RBF-NN） dynamic model identification was presented for control （DVFCC） approach with RBF neural network the adaptive trajectory tracking of industrial robots. The prop...A dynamic velocity feed-forward compensation （RBF-NN） dynamic model identification was presented for control （DVFCC） approach with RBF neural network the adaptive trajectory tracking of industrial robots. The proposed control approach combined the advantages of traditional feedback closed-loop position control and computed torque control based on inverse dynamic model. The feed-forward compensator used a nominal robot dynamics as accurate dynamic model and on-line identification with RBF-NN as uncertain part to improve dynamic modeling accu- racy. The proposed compensation was applied as velocity feed-forward by an inverse velocity controller that can con- vert torque signal into velocity in the standard industrial controller. Then, the need for a torque control interface was avoided in the real-time dynamic control of industrial robot. The simulations and experiments were carried out on a gas cutting manipulator. The results show that the proposed control approach can reduce steady-state error, suppress overshoot and enhance tracking accuracy and efficiency in joint space and Cartesian space, especially under high- speed condition.展开更多
The dynamic linear state feedback control problem is addressed for a class of nonlinear systems subject to time-delay.First,using the dynamic change of coordinates,the problem of global state feedback stabilization is...The dynamic linear state feedback control problem is addressed for a class of nonlinear systems subject to time-delay.First,using the dynamic change of coordinates,the problem of global state feedback stabilization is solved for a class of time-delay systems under a type of nonhomogeneous growth conditions.With the aid of an appropriate Lyapunov-Krasovskii functional and the adaptive strategy used in coordinates,the closed-loop system can be globally asymptotically stabilized by the dynamic linear state feedback controller.The growth condition in perturbations are more general than that in the existing results.The correctness of the theoretical results are illustrated with an academic simulation example.展开更多
基金This paper is supported by the Major State Basic Research Development Program of China under Grant No2005CB724101the Key Items Program of International Science and Technology Cooperation of China under Grant No2003DF000021
文摘Based on the evaluation of dynamic performance for feed drives in machine tools, this paper presents a two-stage tuning method of servo parameters. In the first stage, the evaluation of dynamic performance, parameter tuning and optimization on a mechatronic integrated system simulation platform of feed drives are performed. As a result, a servo parameter combination is acquired. In the second stage, the servo parameter combination from the first stage is set and tuned further in a real machine tool whose dynamic performance is measured and evaluated using the cross grid encoder developed by Heidenhain GmbH. A case study shows that this method simplifies the test process effectively and results in a good dynamic performance in a real machine tool.
文摘大型火力发电厂的协调控制系统CCS(Coordinated Control System)是一个复杂的多变量耦合控制系统。研究了反演算函数在大机组CCS中的设计与实现问题。分析了达拉特发电厂1号机组CCS的特点,为解决火电单元机组CCS的动态非线性和耦合特性,设计了压力、功率偏差反演算函数的解耦CCS控制回路,引入反演算函数算法用于动态解耦运算,改善了CCS的强耦合及动态非线性特性,改进了CCS适应外界负荷能力差的现状。为补偿锅炉的惯性和迟延,提出了根据前馈的微分作用快速调节燃料量的方法;加入动态超调措施,使一次风风量提前动作。通过现场试投,验证了新协调系统的有效性。系统实际运行曲线验证了控制系统的良好品质。
文摘Nowadays,grid-connected renewable energy resources have widespread applications in the electricity market.However,providing household consumers with photovoltaic(PV)systems requires bilateral interfaces to exchange energy and data.In addition,residential consumers’contribution requires guaranteed privacy and secured data exchange.Dayahead dynamic pricing is one of the incentive-based demand response methods that has substantial effects on the integration of renewable energy resources with smart grids and social welfare.Different metering mechanisms of renewable energy resources such as feed-in tariffs,net metering,and net purchase and sale are important issues in power grid operation planning.In this paper,optimal condition decomposition method is used for dayahead dynamic pricing of grid-connected residential renewable energy resources under different metering mechanisms:feed-intariffs,net metering,and net purchase and sale in conjunction with carbon emission taxes.According to the stochastic nature of consumers’load and PV system products,uncertainties are considered in a two-stage decision-making process.The results demonstrate that the net metering with the satisfaction average of 68%for consumers and 32%for the investigated electric company leads to 28%total load reduction.For the case of net purchase and sale mechanism,a satisfaction average of 15%for consumers and 85%for the electric company results in 11%total load reduction.In feed-in-tariff mechanism,in spite of increased social welfare,load reduction does not take place.
基金Supported by National Public Welfare Industry(Agriculture)Scientific Special Project(201203001)Shandong Agricultural Sciences Youth Fund Project(2014QNM21)Shandong Independent Innovation Achievements Special(2013ZHZX2A0402)
文摘Properties of enzyme production of a Bacillus subtitles strain （ MSJ-5 ） isolated from soil were studied in the test. Enzyme production reached the peak when MSJ-5 being cultured in fermentation medium for 32 h. 6-1,4-D-mannanase was the main component of crude enzyme solution, test results showed that the optimal reaction temperature of the enzyme was 50 ℃, the optimum reaction pH was 7.0, and the enzyme was stable when pH was 5.0 -7.0. Hydrolysis test re- suits showed that β-1,4-D-mannanase produced by MSJ-5 had significant viscosity reduction effects on Konjak mannan, and the major hydrolysis product was man- nan oligosaecharide. The results indicated that 6-1,4-D-mannanase produced by B. subtilis MSJ-5 had application potential in feed ingredients and functional oligo- saccharides industry.
文摘A dynamic velocity feed-forward compensation （RBF-NN） dynamic model identification was presented for control （DVFCC） approach with RBF neural network the adaptive trajectory tracking of industrial robots. The proposed control approach combined the advantages of traditional feedback closed-loop position control and computed torque control based on inverse dynamic model. The feed-forward compensator used a nominal robot dynamics as accurate dynamic model and on-line identification with RBF-NN as uncertain part to improve dynamic modeling accu- racy. The proposed compensation was applied as velocity feed-forward by an inverse velocity controller that can con- vert torque signal into velocity in the standard industrial controller. Then, the need for a torque control interface was avoided in the real-time dynamic control of industrial robot. The simulations and experiments were carried out on a gas cutting manipulator. The results show that the proposed control approach can reduce steady-state error, suppress overshoot and enhance tracking accuracy and efficiency in joint space and Cartesian space, especially under high- speed condition.
基金supported by US National Science Foundation under Grant No.HRD-0932339the National Natural Science Foundation of China under Grant Nos.61374038,61374050,61273119,61174076+1 种基金the Natural Science Foundation of Jiangsu Province of China under Grant No.BK2011253Research Fund for the Doctoral Program of Higher Education of China under Grant No.20110092110021
文摘The dynamic linear state feedback control problem is addressed for a class of nonlinear systems subject to time-delay.First,using the dynamic change of coordinates,the problem of global state feedback stabilization is solved for a class of time-delay systems under a type of nonhomogeneous growth conditions.With the aid of an appropriate Lyapunov-Krasovskii functional and the adaptive strategy used in coordinates,the closed-loop system can be globally asymptotically stabilized by the dynamic linear state feedback controller.The growth condition in perturbations are more general than that in the existing results.The correctness of the theoretical results are illustrated with an academic simulation example.
