Advanced Materials Research Vols. 383-390

Abstract: Data reconciliation is based on spatial redundancy to adjust process data to improve the quality of measurement corruption due to measurement noise. However, the presence of gross errors can severely bias the reconciled results. Robust estimators can significantly reduce the effect of gross errors and yield less biased results. In this paper, a method is proposed to solve the robust data reconciliation problem. By using the proposed method, the robust estimator problem can be transformed into least squares estimator problem which leads to the convenience in computation. Simulation results for a linear process verify the efficiency of the proposed method.

Abstract: The traditional method applying to solve continuous variable optimization problems is not suit for flume structural optimization design with hybrid discrete variable. According to the mathematical model of structural optimum design of the prestressed U-shell flumes, differential evolution (DE) algorithm was introduced to flume structural optimization design. In order to improve the population’s diversity and the ability of escaping from the local optimum, a self-adapting crossover probability factor was presented. Furthermore, a chaotic sequence based on logistic map was employed to self-adaptively adjust mutation factor based on linear crossover, which can improve the convergence of DE algorithm. Dynamic penalty function, to transform the constrained problem to unconstrained one, was employed. The result shows that, compared with the original design scheme, the optimization design scheme can greatly reduce the amount of prestressed reinforcement. The construction cost of both the flume and the whole project can be reduced accordingly.

Abstract: The system provide some convenient to the teaching and administration of academics, and achieves network management in teaching course-choosing. Combining with ASP.NET language is used in client layer, SQL SERVER2000 database is used as the background database. The object oriented C# language is adopted in ASP.NET so that the problems of portability and upgrade are resolved.

Abstract: In order to eliminate the friction of the feed system in NC Machine Tools, this paper presented a novel direct magnetic levitation permanent magnet linear motor. First, the structure and magnetic levitation theory of the direct magnetic levitation motor were discussed. Second, on the basis of the motor magnetic hierarchical model, the expression of the magnetic field and the electromagnetic force was derived by the virtual displacement method. Finally, no-load magnetic field, load air-gap flux density and the electromagnetic force of the motor were simulated by using Ansoft Maxwell 2D software. The results of simulation test indicated that using direct magnetic levitation permanent magnet linear synchronous motor can realize the friction-free feed of NC Machine Tools.

Abstract: In order to improve the generated energy of PV array and adding the utilization ration of solar energy, the photovoltaic tracking system adapts electro-optical tracking techniques which making the solar panels always perpendicular to sunlight. This paper mainly introduces the basic structure of photovoltaic automatic tracking system and the control strategy of the stepper motor. The theories of cerebellum model articulation controller and conventional PID control are also described. And combined with the characteristics of PID control, the compound control based on the cerebellum model articulation controller and conventional PID was applied to photovoltaic automatic tracking system and compared with fuzzy PID control algorithm. The simulation result shows that the cerebellum model articulation controller and conventional PID parallel control algorithm has the advantage of small overshoot, high robustness, fast response, high control accuracy, and so on.

Abstract: A novel photoelectric sensor based on differential method and position sensitive detector for refractive index (RI) measurement is proposed. In the paper, we systematically proposed an electro-optical measurement principle, built a mathematical model, and designed the structure of sensing probe; through detail calculation, key parameters of the refractometer are determined, simulation results showed that resolution reaches order of 10^-6, preliminary experiment also verified the feasibility of the design.

Abstract: The computer simulations during hammer forging process for Inconel 718 were conducted, and the temperature, strain and stress evolution were obtained and analyzed. Rebound takes place right after the ram goes up and this may have a significant effect on the temperature distribution and the reduction of friction. The simulated results can be helpful to predict further microstructure of forged product and the service life of the die.

Abstract: Active disturbance rejection control technology and its application to trajectory tracking control of a linear actuator are presented in this paper. Working principle of each part of this control technology is given, and parameter tuning method is discussed which helps control engineers to use this technology well. In order to test the performance of active disturbance rejection control technology, a sinusoidal trajectory tracking control system of a linear actuator is constructed. Simulation and experimental results show that the introduced control technology can achieve small tracking error at low velocity where friction is the main disturbance. Active disturbance rejection control technology provides a good choice for control engineers in actual industry applications with its simple structure, convenience to use and excellent performance.

Abstract: Magnesium alloys have high specific strength, specific stiffness, excellent thermal conductivity and casting properties, which have a great prospects development in the industry, However, its low plasticity and ductility limited its application. Magnesium matrix composites can effectively improve its performance. Magnesium alloy die-casting is the main forming process, the conventional high-pressure die-casting (HPDC) defects in multi-cavity type, easy to volume gas, non-heat-treated. Compared with HPDC, the rheo-diecasting (RDC) process has been greatly developed for near-net shape components. In this paper, Mg2Si /AM60 composites is fabricated by in-situ synthesis and semi-solid magnesium matrix composites which are rheoformed in the die-casting machine are prepared by mechanical stirring. The results indicate that the microstructure of composites is non-dendritic and Chinese script type Mg2Si are fine distributed. The fundamental morphology of microstructure by HPDC is dendrite and liquid-phase distributed between dendrite irregularly. The RDC samples have close-to-zero porosity, less segregation, the most of semi-solid of microstructure in rheo-diecasting is spherical or as-spherical structure.

Abstract: A new approach for vector spatial data Fusion based on Topological Relationship is presented. The constraints in map conflation are first derived, and the coordinates displacements of the conflated objects are then obtained by topological correlation computation. The results of the map conflation test show that the proposed method has a high precision and better ability to maintain the characteristics of the conflated objects compared with the exist methods.