Fuzzy Sliding Mode Control for the Vehicle Height and Leveling Adjustment System of an Electronic Air Suspension

The accurate control for the vehicle height and leveling adjustment system of an electronic air suspension(EAS) still is a challenging problem that has not been effectively solved in prior researches. This paper proposes a new adaptive controller to control the vehicle height and to adjust the roll and pitch angles of the vehicle body(leveling control) during the vehicle height adjustment procedures by an EAS system. A nonlinear mechanism model of the full?car vehicle height adjustment system is established to reflect the system dynamic behaviors and to derive the system optimal control law. To deal with the nonlinear characters in the vehicle height and leveling adjustment processes, the nonlinear system model is globally linearized through the state feedback method. On this basis, a fuzzy sliding mode controller(FSMC) is designed to improve the control accuracy of the vehicle height adjustment and to reduce the peak values of the roll and pitch angles of the vehicle body. To verify the effectiveness of the proposed control method more accurately, the full?car EAS system model programmed using AMESim is also given. Then, the co?simulation study of the FSMC performance can be conducted. Finally, actual vehicle tests are performed with a city bus, and the test results illustrate that the vehicle height adjustment performance is effectively guaranteed by the FSMC, and the peak values of the roll and pitch angles of the vehicle body during the vehicle height adjustment procedures are also reduced significantly. This research proposes an effective control methodology for the vehicle height and leveling adjustment system of an EAS, which provides a favorable control performance for the system.

Parameter Method Data Processing for CPⅢ Precise Trigonometric Leveling Network

In view of the limitation of the difference method,the adjustment model of CPⅢprecise trigonometric leveling control network based on the parameter method was proposed in the present paper.The experiment results show that this model has a simple algorithm and high data utilization,avoids the negative influences caused by the correlation among the data acquired from the difference method and its accuracy is improved compared with the difference method.In addition,the strict weight of CPⅢprecise trigonometric leveling control network was also discussed in this paper.The results demonstrate that the ranging error of trigonometric leveling can be neglected when the vertical angle is less than 3 degrees.The accuracy of CPⅢprecise trigonometric leveling control network has not changed significantly before and after strict weight.

Application of Fuzzy Logic Controller to Level Control of Twin-Roll Strip Casting

An intelligent fuzzy-PID controller consisting of fuzzy logic controller and PID controller was developed to control the molten steel level of twin-roll strip caster.Additionally,a feedforward differential PID controller was used for stopper position control in order to avoid differential kick.It is proved by simulation that the proposed intelligent controller is able to obtain zero steady state error asymptotically and the control system is robust due to its fuggy behavior of the controller.

Reservoir-induced landslides and risk control in Three Gorges Project on Yangtze River,China

The Three Gorges region in China was basically a geohazard-prone area prior to construction of the Three Gorges Reservoir （TGR）. After construction of the TGR, the water level was raised from 70 m to 175 m above sea level （ASL）, and annual reservoir regulation has caused a 30-m water level difference after impoundment of the TGR since September 2008. This paper first presents the spatiotemporal distribution of landslides in six periods of 175 m ASL trial impoundments from 2008 to 2014. The results show that the number of landslides sharply decreased from 273 at the initial stage to less than ten at the second stage of impoundment. Based on this, the reservoir-induced landslides in the TGR region can be roughly classified into five failure patterns, i.e. accumulation landslide, dip-slope landslide, reversed bedding landslide, rockfall, and karst breccia landslide. The accumulation landslides and dip-slope landslides account for more than 90%. Taking the Shuping accumulation landslide （a sliding mass volume of 20.7 × 106 m^3） in Zigui County and the Outang dip-slope landslide （a sliding mass volume of about 90 × 106 m^3） in Fengjie County as two typical cases, the mechanisms of reactivation of the two landslides are analyzed. The monitoring data and factor of safety （FOS） calculation show that the accumulation landslide is dominated by water level variation in the reservoir as most part of the mass body is under 175 m ASL, and the dip-slope landslide is controlled by the coupling effect of reservoir water level variation and precipitation as an extensive recharge area of rainfall from the rear and the front mass is below 175 m ASL. The characteristics of landslide-induced impulsive wave hazards after and before reservoir impoundment are studied, and the probability of occurrence of a landslide-induced impulsive wave hazard has increased in the reservoir region. Simulation results of the Ganjingzi landslide in Wushan County indicate the strong relationship between landslide-induced surge and water variation with high potential risk to shipping and residential areas. Regarding reservoir regulation in TGR when using a single index, i.e. 1-d water level variation, water resources are not well utilized, and there is also potential risk of disasters since 2008. In addition, various indices such as 1-d, 5-d, and 10-d water level variations are proposed for reservoir regulation. Finally, taking reservoir-induced landslides in June 2015 for example, the feasibility of the optimizing indices of water level variations is verified.

The Main Biological Hazards in Animal Biosafety Level 2 Facilities and Strategies for Control

Concern about the biological hazards involved in microbiological research, especially research involving laboratory animals, has increased in recent years. Working in an animal biosafety level 2 facility （ABSL-2）, commonly used for research on infectious diseases, poses various biological hazards. Here, the regulations and standards related to laboratory biosafety in China are introduced, the potential biological hazards present in ABSL-2 facilities are analyzed, and a series of strategies to control the hazards are presented.

Non-Linear Tank Level Control for Industrial Applications

Tank level control is ubiquitous in industry. The focus of this paper is on accurate liquid level control in single tank systems which can be actuated continuously and modulation of the level setpoint is also required, for example in cascade control loops or supervisory Model Predictive Control (MPC) applications. To avoid common problems encountered when using fixed gain or adaptive/gain scheduled schemes, an accurate technique based around feedback linearization and Proportional Integral (PI) control is introduced. This simple controller can maintain linear performance over the full operating range of a uniform tank. As will be demonstrated, the implementation overhead compared to a regular PI controller is negligible, making it ideal for industrial implementation. Implementation details and parameter identification for adaptive implementation are discussed. Simulations coupled with experimental results using a large-scale laboratory level control system using commercial industrial control equipment validate the approach, and illustrate its effectiveness for both level tracking and disturbance rejection.

Primary Function of Microcontroller EM78P458 and Research on Applications of Its ADC on Chip

The build-in structure of microcontroller EM78P458 and its application in supervising the water level of solar water heater are introduced. The circuit and the flow chart of AD conversion program are depicted. In the end, the design of assembly language program about the AD conversion is introduced.

Effect of Rural Sewage Irrigation Regime on Water-Nitrogen Utilization and Crop Growth of Paddy Rice in Southern China

Reclaimed water irrigation has become an effective mean to alleviate the contradiction between water availability and its consumption worldwide.In this study,three types of irrigation water sources(rural sewage’s primary treated water R1 and secondary treated water R2,and river water R3)meeting the requirements of water quality for farmland irrigation were selected,and three types of irrigation water levels(low water levelW1 of 0–80 mm,medium water level W2 of 0–100 mm,and high water level W3 of 0–150 mm)were adopted to carry out research on the influence mechanismS of different irrigation water sources and water levels on water and nitrogen use and crop growth in paddy field.The water quantity indicators(irrigation times and irrigation volume),soil ammonium nitrogen(NH4+-N)and nitrate nitrogen(NO3−-N),rice yield indicators(thousand-grain weight,the number of grains per spike,and the number of effective spikes),and quality indicators(the amount of protein,amylose,vitamin C,nitrate and nitrite content)of rice were measured.The results showed that,the average irrigation volume under W3 was 2.4 and 1.9 times of that under W1 and W2,respectively.Compared with R3,the peak consumption of rice was lagged behind under R1 and R2,and the nitrogen form in 0–40 cm soil layers under rural sewage irrigation was mainly NH4+-N.The changes of NO3−-N and NH4+-N in the 0–40 cm soil layer showed the trend of declining and then increasing.The water level control only had a significant effect on the change of NO3−-N in the 60–80 cm soil layer.Both irrigation water use efficiency and crop water use efficiency were gradually reduced with the increase of field water level control.The nitrogen utilization efficiency under rural sewage irrigation was significantly higher than that under R3.Compared with the R3,rural sewage irrigation could significantly increase the yield of rice,and as the field water level rose,the effect of yield promotion was more obvious.It was noteworthy that the grain of rice under R1 monitored the low nitrate and nitrite content,but no nitrate and nitrite was discovered under R2 and R3.Therefore,reasonable rural sewage irrigation(R2)and medium water level(W2)were beneficial to improve nitrogen utilization efficiency,crop yield and crop quality promotion.

Hybrid Level of Detail Algorithm for Real-Time Rendering of Large-Scale Terrain

Hybrid level of detail （LOD） （HLOD） algorithm based on discrete LOD and continuous LOD is presented for real-time rendering of large-scale terrains. There are n HLOD models created off-line, which form a pyramid with n layers. Each of these models contains countless versions of the model at various levels of detail. When rendering, the corresponding models in some layer will be chosen. As the viewer＇s moves, either the continuous LOD algorithm will be applied to the selected models, or the visible models in another layer will be selected. An experiment on a triangular irregular network（TIN） terrain model was performed respectively using discrete LOD, continuous LOD and HLOD. The experimental results show that the HLOD algorithm exceeds the other two kinds of LOD in frame rate without reduction of terrain＇s fidelity.

Algorithm of Dynamic Operation Process of Hydraulic Automatically Operated Canals with Constant-Downstream Level Gates

On the basis of analysis the governing process of downstream water level gates AVIO and AVIS, a mathematical model for simulation of dynamic operation process of hydraulically automated irrigation canals instalIed with AVIO and AVIS gates is presented, the main point of this rnathematical model is firstly applying a set of unsteady flow equations （St. Venant equations here） and treating the condition of gate movement as its dynamic boundary, and then deeoupling this interaction of gate movement with the change of canal flow. In this process, it is necessary to give the gateg open-loop transfer function whose input is water level deviation and output is gate discharge. The result of this simulation for a practical reach has shown it has satisfactory accuracy.

Conical tank level control using fractional order PID controllers： a simulated and experimental study

In this paper, simulated and experimental results on the conical tank level control are presented. PI/PID controllers of integer order （IO） as well as of fractional order （FO） are studied and compared. The tuning parameters are obtained first by using root locus （RL） and Ziegler and Nichols methods, for comparison purposes. Next, particle swarm optimization （PSO） is employed to determine the optimal controllers＇ parameters using as fitness function the integral of the absolute value of tracking error （IAE）. From the experimental results it is concluded that PI/FOPI are the controllers presenting the lowest IAE indexes, whereas PID/FOPID controllers present the lowest energy consumption by the control signal.

Analysis and Design of Scaling Optimal GPM-PID Control with Application to Liquid Level Control

In this paper, a new analysis and design method for proportional-integrative-derivative （PID） tuning is proposed based on controller scaling analysis. Integral of time absolute error （ITAE） index is minimized for specified gain and phase margins （GPM） constraints, so that the transient performance and robustness are both satisfied. The requirements on gain and phase margins are ingeniously formulated by real part constraints （RPC） and imaginary part constraints （IPC）. This set of new constraints is simply related with three parameters and decoupling of the remaining four unknowns, including three controller parameters and the gain margin, in the nonlinear and coupled characteristic equation simultaneously. The formulas of the optimal GPM-PID are derived based on controller scaling analysis. Finally, this method is applied to liquid level control of coke fractionation tower, which demonstrate that the proposed method provides better disturbance rejection and robust tracking performance than some commonly used PID tuning methods.

Level 2 Automatic Control System of LF

Research on level 2 control system of 100 tons LF furnace was carried out. According to the principle of energy conservation and principle of mass conservation, the LF temperature prediction model and the composition prediction model were established. At the same time, the set value calculated by heating model and addition model could be sent to PLC. The results show that the technical indexes of LF furnace level 2 control system reach the demand and the system realizes automatic control.

Dynamic model identification of a real-time simple level control system

Using a relay feedback approach,mathematical expressions for identification of real-time level control system in transfer function form are proposed in this paper.An ideal relay with hysteresis is feedback to a simple level control system for the generation of sustained oscillations.Subsequently,limit cycle information is utilised in deduced expressions for the estimation of unknown system parameters.Using describing function analysis,the gain of an ideal relay with hysteresis is approximated to yield simple mathematical expressions.Typical examples from literature are considered to show the effectiveness of the proposed identification scheme.Yokogawa distributed control system:CENTUM CS 3000 is considered as a platform for the realisation of both relay feedback and Ziegler-Nichols(ZN)method.The accuracy of derived transfer function models is compared with a model derived from ZN method and thereafter demonstrated through frequency response plots which illustrate the experimental validation of the identified real-time process model.

Double regularization control based on level set evolution for tablet packaging image segmentation

This paper proposes a novel double regular- ization control （DRC） method which is used for tablet packaging image segmentation. Since the intensities of tablet packaging images are inhomogenous, it is difficult to make image segmentation. Compared to methods based on level set, the proposed DRC method has some advantages for tablet packaging image segmentation. The local re- gional control term and the rectangle initialization contour are first employed in this method to quickly segment un- even grayscale images and accelerate the curve evolution rate. Gaussian filter operator and the convolution calcula- tion are then adopted to remove the effects of texture noises in image segmentation. The developed penalty energy function, as regularization term, increases the constrained conditions based on the gradient flow conditions. Since the potential function is embedded into the level set of evo- lution equations and the image contour evolutions are bi- laterally extended, the proposed method further improves the accuracy of image contours. Experimental studies show that the DRC method greatly improves the computational efficiency and numerical accuracy, and achieves better results for image contour segmentation compared to other level set methods.

Prediction of the future flood severity in plain river network region based on numerical model: A case study

Suzhou is one of China＇s most developed regions, located in the eastern part of the Yangtze Delta. Due to its location and river features, it may at a high risk of flood under the climate change background in the future. In order to investigate the flood response to the extreme scenario in this region, 1-D hydrodynamic model with real-time operations of sluices and pumps is established. The rain-runoff processes of the urban and rural areas are simulated by two lumped hydrologic models, respectively. Indicators for a quantitative assessment of the flood severity in this region are proposed. The results indicate that the existing flood control system could prevent the Suzhou Downtown from inundation in the future. The difficulty of draining the Taihu Lake floods should be given attention to avoid the flood hazard. The modelling approach based on the in-bank model and the evaluation parameters could be effective for the flood severity estimation in the plain river network catchment. The insights from this study of the possible future extreme flood events may assist the policy making and the flood control planning.