Abstract:Based on the traditional PID control law, the flight control laws for attitude control loop of unmanned helicopter are designed using fuzzy control logic.The fuzzy self-tuning PID controller can adapt the parameters of PID controller online, which can improve the controller performance.Utilizing the closed-loop control algorithm simulation in Matlab, the performance of fuzzy self-tuning PID controller is proved to be better than that of the traditional one.Then the hardware in loop is used to verify the proposed controller of this paper, which is based on the ARM STM32 core flight control system.The optimization performance is verified by comparing the zero-state responses of the two controllers with the typical inputs.

Abstract:In this paper, a nonlinear adaptive fault-tolerant control strategy is developed to force an underactuated ship with thruster redundancy to follow a predefined path, despite the presence of unknown system parameters and environmental disturbances induced by wave, wind and ocean current.The techniques involved in the design and analysis include the backstepping, parameter projection techniques and a traverse function.It is shown that with our proposed controller, the reference path can be tracked globally with an arbitrarily small tracking error.Simulation results demonstrate the effectiveness of our proposed controller.

Abstract:In this paper, an active fault tolerant attitude control approach is provided for a flexible spacecraft to accommodate the unknown sensor faults.Firstly, a model-based fault detection and estimation technique is developed into the process behavior by using a virtual filter and an adaptive observer.Secondly, a reconfigurable attitude controller design is developed by combining both adaptive integral sliding mode control and linear matrix inequality technique.Finally, the effectiveness of the proposed fault tolerant scheme has been verified by simulation result on a flexible spacecraft attitude control system with a time varying sensor fault.

Abstract:The input impedance of a constant power load usually behaves as negative incremental impedance characteristic, which may have strong impact on the system stability when it is interacting with the front-end converter in a microgrid.In this paper, an improved sliding mode control (SMC) method is proposed to improve the large signal stability of micro grid system.Firstly, the system uncertainties and external disturbances are considered in the system modeling, which make the control have strong robustness.Then, the adaptive algorithm is introduced in the sliding mode control to estimate the upper bound of the total disturbance, which improves the control accuracy.Finally, a simulation model of a microgrid is established in Matlab/Simulink.The effectiveness of the proposed method is verified by simulation results.

Abstract:Because of the controllable damping characteristics, magnetorheological damper can be used to produce high-quality shock absorber.In recent years, it has been developed in the field of industrial vibration control by combining design with variety of control strategies.Researches show that the fractional model has high accuracy of fitting to the MR damper.In this paper, the viscoelastic properties of the MR damper are described by the fractional model, and the approximate fractional transfer function is obtained by the Oustaloup approximation method.A new model predictive controller is designed based on the quadratic performance index of the output tracking input after the discretization.Finally, the simulation results show that the predictive controller has good dynamic performance and verify the feasibility and stability of the design.

Abstract:Lots of sustainable resources cannot provide continuous and stable energy for their characteristics of intermittent power providing, such as solar, wind, and tidal energy.Gas turbine power generation system demonstrates vast potential as an energy resource, due to its fast response and high efficiency characteristics, making it an ideal alternative source for hybrid renewable energy generation systems.However, its mathematical modeling often leads to complex nonlinear dynamics.Moreover, the most important part is the speed control loop, where traditional PID controllers were always applied.However, the parameters of controllers cannot be adjusted automatically, which will weaken the power system performance.Besides, considering that the actuator fault occurs, traditional controllers cannot guarantee the stability of the system, which may lead to failure of the plants operating.Therefore, by focusing on modeling a simplified single-shaft gas turbine generation system under stand-alone operation, this paper develops a control scheme for speed tracking loop based on the backstepping method.To account for modeling uncertainties and external disturbances, a robust adaptive control, combined with a dynamic surface control, is constructed.Besides, by considering the possibility of actuator faults, a fault tolerant control unit with Nussbaum-type functions is utilized.Finally, simulations verify that the presented controllers ensure high precision of tracking performance.

Abstract:This paper is concerned with the consensus of multi-agent systems with stochastic controller gain variation.Firstly, under the hypothesis that the connected network topology is fixed, undirected and linked, a closed-loop system is obtained that captures the stochastic controller gain variation.By using the Lyapunov stability theory, linear matrix inequality technique and robust control approach, a new sufficient condition is obtained such that consensus error dynamic system is asymptotically stable.Then, after some matrix manipulation, the controller gains are determined by solving a set of linear matrix inequalities.Finally, the effectiveness of the proposed design algorithm is verified by a numerical simulation.

Abstract:According to the problem of limited self-adjustment ability of microgrid with distributed energy resource (DER) under islanding operation mode, a control strategy based on backstepping control method is designed, which solves the voltage control problem of DER system in islanding operation mode.Firstly, the system model and the mathematical model of output voltage of islanded DER system are given.Secondly, the controllers are designed by using backstepping control method step by step, and the stability analysis is proved by using the Lyapunov stability theory.Finally, the designed controllers are used to control the output voltage under balanced load and unbalanced load, and the effectiveness of the backstepping controllers is verified by simulation.

Abstract:This paper investigates the dissipative stability analysis and control problem for the two-dimensional (2-D) switched Fornasini-Marchesini local state-space (FMLSS) model.Firstly, the definition of 2-D (T, S, R)-δ-dissipativity is introduced for the 2-D FM systems.Secondly, the sufficient condition to guarantee the asymptotical stability and (T, S, R)-δ-dissipativity of the 2-D switched FM systems is proposed.Then the 2-D (T, S, R)-δ-dissipative state-feedback controller is designed based on the obtained dissipative stability condition and the projection lemma technique.Finally, the effectiveness of the proposed method is illustrated via a numerical example.

Abstract:Renewable energy is playing an increasingly important role in modern agriculture.But some constraints like low efficiency of renewable energy and complex control strategies restrict the development of green farm.The introduction of energy storage components can significantly increase the energy efficiency, and the full use of power grid and time-of-use (TOU) electricity price policy can improve the system's stability and reduce the electricity charge.This paper demonstrates the feasibility of an optimal control strategy in a hybrid power system, designs a set of visual photovoltaic-grid green farm energy monitoring management system based on LabVIEW.The system matches the output power with farm loads by using mixed solar and power grid energy.Simulations and experiments are carried out to prove the system's stability, and the NPV function is used to testify the system's efficiency.

Abstract:The power transformer is an important component of the power system, its safe operation has great influence on the reliable power supply of power system.Therefore, the paper focuses on the method for fault diagnosis of power transformer.The dissolved gas analysis of power transformer is an effective means of diagnosing internal faults of power transformer.The gradient descent principle is a general local optimization algorithm of neural network, which has slow convergence speed in fault diagnosis of power transformer, and is easy to fall into local minimum.While the genetic membrane algorithm has the characteristics of parallel computing, and can be used to effectively prevent neural network from converging to the local optimal solution, and has better fault diagnosis speed.Finally numerical simulations show the effectiveness of the given method.

Abstract:With hardware and software in mobile devices getting more and more powerful, it is now in the spotlight worldwide to study how to combine Augmented Reality(AR) technology with mobile devices.Three-dimensional tracking registration technique is one of the keys in mobile AR.This paper firstly outlines three methods of tracking registration in mobile AR:sensor-based method, machine vision-based method, and hybrid tracking registration, then makes detailed discussion on and inter-comparison between these methods in terms of their characteristics, finally provides summary and outlook for tracking registration technique in mobile AR.

Abstract:Aiming at the problem of holes and false contour in virtual view rendering technology, a new stereo matching algorithm is presented in this paper to obtain dense disparity map to complete the virtual view synthesis.Only two images are required for this method, which are segmented using mean shift algorithm.A good view of the disparity map and an effective interpolation method are basis for successful virtual viewpoint drawing.The weighted multi-window stereo matching method is used to obtain the initial disparity map, and the cross checking is employed to filter false match points and occlusion parts.The obtained dense disparity map is then view interpolated and noise filtered to finish the multiple point virtual view drawing.Experimental results with test images like Tsukuba provided by Middlebury dataset show that the algorithm effectively improves the quality of virtual view images.

Abstract:A field experiment was conducted to investigate the effects of enhanced UV-B radiation on diurnal variations of net photosynthetic rate (P_n), stomata conductance (G_s), intercellular CO₂ concentration(C_i), transpiration rate (T_r), and water use efficiency (E_wu) of peanut leaves at fruiting stage of different peanuts cultivars, so as to provide a basis for screening out high-yield, drought-resistant and UV-B-radiation-resistant peanut varieties.The experiment was designed with two levels of UV-B radiation, natural light (CK) and enhanced UV-B radiation by 20% (E).The results showed that enhanced UV-B radiation inhibit photosynthesis and transpiration of peanuts significantly.The daily average P_n of KaiNong No.49, 64, and 69 declined by 19.4%, 27.8%, and 24.7%, respectively;the daily average G_s decreased by 26.7%, 42.9%, and 28.6%, respectively.Besides, the daily average C_i of KaiNong No.49, 64, and 69 declined by 27.2%, 20.4%, and 23.1%, respectively, and the T_r decreased by 17.8%, 23.3%, and 25.1% respectively.Furthermore, the E_wu reduced by 16.6%, 23.2%, and 23.9% for KaiNong No 49, 64, and 69, respectively.These results indicate that enhanced ultraviolet-B radiation have a restraint effect on these three cultivars, but sensibility differences exist among these peanuts cultivars.Therein, KaiNong No.49 is the least sensitive peanuts cultivar.Therefore, compared with the other two cultivars, KaiNong No.49 shows great advantages in regard to UV-B radio-resistance.

Abstract:Based on the daily temperature data of Yunnan province during 1960 to 2009, the rice chilling process was extracted and graded for recent 50 years according to the operating guideline of rice chilling damage in period of head sprouting and anthesis in Yunnan province.The frequency distribution of rice chilling damage in each decade was drawn by ArcGIS, then the chilling damage strength characteristics was studied geographically.The methods of linear trend and cumulative anomaly curve were used to reveal the evolution features of rice chilling damage in period of head sprouting and anthesis in Yunnan province in recent 50 years.Results showed that the rice chilling damage mainly occurred in Zhaotong, Qujing and Baoshan's Longling county, with Zhaotong as the most injured city.Generally, the total days of rice chilling damage showed a decreasing trend for the past 50 years.However, analysis of the ratio of stations with rice chilling vs.total stations and cumulative anomaly curve indicated that the 1970s had rice chilling damage with the largest range and the highest frequency, while the 1990s had the least rice chilling damage, then chillings occurred intensively in years after 2000, and eventually decreased in 2008.

Abstract:In order to control the eutrophication, some artificial control measures were employed in Nanjing's Xuanwu Lake, including dredging and diluting with diversion works, controlling algae bloom, and aquatic population restoration.The lake water quality before and after these measures were compared using monitoring data.Results show that the dredging and diluting could reduce the concentration of pollutants in sediments and alleviate the eutrophication temporarily, yet the nutrient salt contents in the lake were not distinctly reduced.In the short term, control measure of algal blooms could effectively inhibit the cyanobacterial bloom, improve water quality and restore the aquatic population, thus is an effective way to control eutrophication in emergency conditions.While the water quality was improved distinctly during the aquatic population recovery stage, compared with that in previous years, indicating the aquatic population restoration is a sustainable and effective method for the lake management and eutrophication control.

Abstract:The rapid statistic of the efficiency of meteorological data transferring has become a pressing need for information center of Beijing Meteorological Bureau.In order to improve the transferring efficiency of meteorological data, an algorithm was designed based on MapReduce model for statistics of the arriving ratio and timely rate of meteorological data.The algorithm was then realized on Hadoop platform and comparative experiments were done using text file and Sequence File as input source data.Results show that the MapReduce-based algorithm performs better with Sequence File data.Compared with traditional statistic processes, the proposed algorithm is high in effectiveness and simple in process flow, thus is feasible and applicable for statistic of meteorological data transferring efficiency.

Abstract:Based on the climate simulations from 8 CMIP5 (Coupled Model Intercomparison Project Phase 5) models, their simulation capabilities for air temperature in Guizhou have been examined by using Taylor diagram for period of 1986-2005.Future changes in extreme temperature events under the RCPs (Representative Concentration Pathways) scenarios with the simple multi-model ensemble method are presented for the 21st century over Guizhou.Results show that the simple multi-model ensemble method from the 8 CMIP5 modes can well simulate the spatial distribution of daily average temperature, daily minimum temperature and daily maximum temperature, which are necessary to compute the indexes of extreme temperature events.Project results show that in the 21st century, Guizhou's maximum temperature days (SU), values of extreme minimum temperature (TNN), and days of growing season length (GSL) are likely to increase;while the frost days (FD) are likely to decrease;moreover, the increasing and decreasing trends are more obvious with more gas emission.Relative to period of 1986-2005, the linear variation trends of Guizhou's SU, TNN, FD and GSL during 2006-2099 are likely to be 8.06-1.30 d/(10 a), 0.49-0.07℃/(10 a), -4.99-0.97 d/(10 a), and 3.33-0.04 d/(10 a), respectively, under the RCPs scenarios.

Abstract:Wind energy is to play a larger role in providing electricity to industrial and domestic consumers in Hubei province.Yet there is no provincial wind data management platform in Hubei, which is an obstacle for scientific decision-making and quick examination & approval of wind energy development projects.Therefore a provincial wind energy information management platform is proposed in this paper based on GIS technology.Basic information at provincial level including wind observation data, wind energy resources assessment report, wind farm power generation, geographic information, high resolution digital elevation and remote sensing images, are combined with meteorological data, wind energy resources numerical simulation data and power dispatching data, to realize functions including progress tracking of wind power projects, management of wind observation data, query of wind energy resources distribution, etc.Then the MapGIS is employed to analyze and mine the information, with purpose to assist scientific decision-making and development of wind energy projects.