Applied Mechanics and Materials Vols. 789-790

Abstract: Microcontrollers are widely used in industrial world, and almost all kind of devices were based on microcontroller to achieve high flexibility and abilities. All microcontrollers have nonvolatile and volatile memories to execute the software. During the running, microcontroller calculates many variables and records them to any non-volatile memory to use later. After re-energizing, microcontroller takes the data calculated before the power off and executes the program. In case of any electrical writing error or any power loss during the writing procedure, un-written memory blocks or any un-written data leads to malfunctions. Proposed method uses a gray code based signed two memory blocks to secure the memory reserved for data. Microcontroller uses these memory blocks in alternately. Even if microcontroller has no any real-time ability, gray code provides a guarantee which block is written in last. For every re-starting microcontroller dos not lose the data. In case of any reading problem during the starting, microcontroller has two chances to decide the action. One is to start with default values and the other is to start with the previous data. This study is tested at elevator applications not to lose position and vital values.

Abstract: In this paper, we address the design of a controller that accomplishes stabilization and reference tracking at various flight conditions by using linear helicopter models. The suggested controller is in the form of an H-infinity gain-scheduler, and is used for stabilization and reference tracking for the 4 axis (heave, pitch, roll and yaw) autopilot. Based on the linear models given for the Puma helicopter, an approximate affine parameter dependent model has been built. Then, a linear parameter dependent controller is synthesized which stabilizes the affine parameter dependent helicopter model. By doing so, a single controller achieves stabilization and reference tracking of a family of linear models by scheduling the controller gains based on the online measurement of the scheduling parameter, which is the forward velocity. Moreover, the affine parameter dependent controller is fitted into the linear models. It is observed that this single parameter dependent controller successfully stabilizes a family of linear helicopter model at different forward flight conditions.

Abstract: Static Var Compensator (SVC) is one of FACTS devices which is used in power systems in order to have a better voltage quality. The fluctuations of voltage and current of the grid connected to electric arc furnace causes power quality problems in the network. SVC, as a fast reactive power control equipment, plays an important role in improving the voltage profile and the transient dynamics of the system arising from the nature of the arc. In this paper the effect of implementing SVC in Mobarakeh Steel Company, for mitigating the voltage transient of power system which is connected to an electric arc furnace, is studied. Then the coefficients of the SVC PI controller are optimized using genetic algorithm and the simulation results are presented.

Abstract: HIRFL-CSRm is a heavy ion synchrotron, named the main Cooling Storage Ring of Heavy Ion Research Facility of Lanzhou. Its role is to cool and accumulate the injected low energy ion beam, and then accelerate to high energy and extract. So, requirements for performance and safety of the magnet which directly affect the intensity and stability of ion beam is very high. This paper mainly state temperature monitoring and interlocking protection for the dipole magnets of HIRFL-CSRm to protect magnets, reduce the economic loss, and ultimately ensure safe running of HIRFL.

Abstract: The purpose of this study is to develop a remote mobile monitoring and control system for manufacturing factory by using the cloud computing technology and information and communication (ICT) technology. In conjunction with the cloud and ICT technologies and mobile devices, modern manufacturing systems can be integrated to promote competitive strength to transmit the information and control commands toward the remote monitoring systems instantly via mobile devices. In such a way, this remote system could enhance the efficiency of information flow and the competitive strength and add unknown value to industries. This study adopts the cloud and ICT technologies as the main communication media to develop a remote monitoring and control system with smart mobile devices. The results of this study show the successful integration of the intelligent mobile devices and cloud networks for manufacturing system.

Abstract: In this paper the analysis of a General Electric Wind Turbine Control Model (GEWTCM) and comparison with a Generic Wind Turbine Control Model (GWTCM) is presented. The analysis is performed for the GEWTCM stationary state. Based on the analysis, a systematic method for the GEWTCM initializations as well as a methodology for calculation of the GEWTCM operating point in steady state are presented. It has been shown that, due to lack of limiting of the pitch controller and pitch compensation, uniqueness of solution for initial and steady state values of all GEWTCM state variables are ensured except for the state variables of the pitch controller and pitch compensation. Conclusions from the analysis can help in the implementation of the wind turbine control model in power system dynamic simulation software packages in applications with variable wind speed.

Abstract: The problem of a control system efficiency increasing for nonlinear plant control is considered. It is shown that proposed neural tuner based on neural networks is an efficient approach to solve the problem of PID-controller parameters online tuning. The backpropagation method is used to train the network. This method is modified by adding a rule base containing conditions on choosing learning rate for neurons. Experiments are made for plant models with various parameters values (with a time constant about 10³ seconds and 10¹ seconds). The required quality for each transient is determined. The system with the neural tuner allows to achieve 10% decreasing of the amount of time and 9% of energy-savings in comparison with the conventional PID-controller.

Abstract: The preparation of concrete mixtures can be tailored to provide wide range of mechanical and durability properties as well as to meet the design specifications of the structure. This paper discusses the potential use of recycled concrete aggregate in the production of high strength concrete. The effect of other processing parameters such as aggregate replacement ratio, type of admixture and slump height on the compressive strength and water absorption rate of different concrete mixes were investigated. The fabrication of high strength concrete was done by machine-mixing of the aggregates, cement and admixture in accordance with ASTM C192, utilizing the Taguchi design to derive the concrete mixtures. Using the 10% recycled fine aggregate with Mira P99 admixture and slump height of 4-6 inches showed an optimum condition and yielded a predicted maximum compressive strength at around 8400 psi. The failure mode of the concrete after compression test was generally shear fracture type. For the water absorption rate, only the admixture had a significant effect. Surface morphology of the fractured concrete surface revealed that utilizing recycled concrete aggregate resulted to a porous surface morphology compared to the natural aggregate.

Abstract: This study presents experiments conducted in an environmental wind tunnel using physical models to quantify the airflow field around array of buildings of two different heights. A complex airflow pattern was developed around the buildings. In addition, the tall buildings increased the turbulence level around the short buildings. Combining short and tall buildings increased the spatially averaged velocity and standard deviation around the short buildings by 25% compared to the velocity and standard deviation around buildings of the same height. Thus, the proposed buildings arrangement and spacing proved to be effective in improving the wind environment around the buildings.

Abstract: In this work, identification of rebar radius for a single steel reinforcement buried in a concrete member was investigated. A method based on electromagnetic penetrating radar was proposed. The principle of this method consists of working with adequate high frequency antennas that emit short pulses and measure the reflected echoes from the discontinuities present inside the medium. Image post-processing of the obtained B-scan radargrams enabled to extract essential information which has facilitated the derivation of a correlation formula to estimate the rebar radius. Predictions made by this formula were found to achieve better accuracy than previously known methods.