Advanced Materials Research Vols. 139-141

Abstract: Various information and communication technologies have been introduced to conventional construction methodologies to make them more advanced. Although these advanced methodologies are often referred to as “Intelligent construction” or “Smart construction” in Japan, we call them “Precision construction” here to make their purpose clearer. Precision construction generally has two different functions. One is to support machine control and the other is to support the flexible decision making of the on-site engineers. This paper introduces the present conditions and the foresight of precision construction in Japan.

Abstract: In the centrifuge of the multi-parameter combined environmental testing device, the three-phase induction motor could not be started directly at the frequency of 50Hz due to the large moment of inertia of the centrifuge rotor. Therefore, large torque output of the three-phase induction motor was required at low frequencies. And the specimen needed stepless rotational speed adjustment (40-130r/min). A set of frequency control system was developed based on vector control with PG, inverter and LabVIEW to solve these problems. The principle of the centrifuge was present. The principles of vector control with PG of three-phase induction motor were analyzed. Based on the mechanical characteristic of three-phase induction motor, vector control with PG was employed in the system. The system control software based on LabVIEW was presented, which realized stepless speed adjustment of the centrifuge on a computer. Experimental results show that the developed system could realize the stepless regulation of the specimen’s centrifugal acceleration.

Abstract: The model of speed control system plays an important role in power system stability studies, the non-linear properties prevent us from getting accurate mechanism model. In this paper, the radial basis function neural network with self-structuring and fast convergence is used in the modeling of steam turbine speed control system in the modeling process, also, this paper presents a method which combines particle swarm optimization algorithm and least-squares algorithm for the neural network’s training, it has the property of high accuracy and fast convergence, after training, the proposed model and related training algorithm are verified by the test data of one power plant, it has proved that the neural network can be used in the modeling of the speed control system for the power system stability studies.

Abstract: A kind of multi-input and multi-output network control system with multiple independent control loops is examined in this paper. The controller of each control loop is connected with the sensor and actuator by a network and each control loop has a different sampling period. The whole mathematical model of this kind of networked control system is set up when the maximum network-induced delay is smaller than one sampling period. And the sufficient condition subject to the asymptotic stability of this kind of networked control system is derived based on the theorem for estimation of feature value deduced from perturbation theory. The research results of this paper have significance in the analysis and design of this kind of networked control system or a similar networked control system.

Abstract: Considering that conventional AC de-icing method has many shortcomings such as complicated braking operation and difficult arrangement for power operation modes, we propose the new AC de-icing technology using capacitor compensation. On this basis, a novel regulative capacitor series-wound compensating AC de-icing equipment is developed, which works through controlling the line current to be within the permitted range in order to melt the ice. By the unique design mechanism of changing the series-parallel connection modes of capacitor combination and capacitor number for each combination, this equipment can make reasonable compensation for transmission line of arbitrary length within 40 km. Field test at JiLi 220kV substation of Hunan province manifests that this new-style AC de-icing equipment has remarkable effect with low energy consumption, simple operation and low engineering cost, thus has bright prospects of engineering application.

Abstract: Limiting the short-circuit current effectively is of great importance to keep the safe and steady running of the power system. A novel fault current limiter (FCL) on the basis of a high speed switch and a triggered vacuum switch (TVS) is presented. The high speed switch is used to break the short-circuit current of the power system. The TVS is used to discharge the precharged pulse capacitor so as to rapidly extinguish the arc in the high speed switch and to realize the active transfer of the short-circuit current. A resistor is used to limit the short-circuit current. The parameters of the FCL for the 10 kV power system are designed and a FCL apparatus is fabricated. An onsite experiment of the FCL apparatus is performed in an actual transmission line of a substation. The FCL apparatus operates normally and achieves the expected current limiting effect.

Abstract: Masks are widely used in different industries, for example, traditional metal industry, hospitals or semiconductor industry. Quality is a critical issue in mask industry as it is related to public health and safety. Traditional quality practices for manufacturing process have some limitations in implementing them in mask industries. This paper aims to investigate the suitability of Six Sigma quality control method for the manufacturing process in the mask industry to provide high quality products, enhancing the process capacity, reducing the defects and the returned goods arising in a selected mask manufacturing company. This paper suggests that modifications necessary in Six Sigma method for effective implementation in mask industry.

Abstract: Gaussian Process (GP) is a new learning method on nonlinear system modeling. The most common way of model training is conjugate gradient method, but this method should compute Heisenberg matrix which needs much computing resource. It is not a suitable training method for online learning algorithm. There is one online learning algorithm of GP which is named sparse online GP now. This algorithm has constraint to the training data sets. In order to satisfy the real-time modeling without the limit of the training data sets, an online algorithm of GP based on adaptive natural gradient (ANG) is proposed in this paper. The algorithm is applied in Continuous Stirred Tank Reactor (CSTR) modeling and the sparse online GP is also applied in CSTR modeling for comparison. Obtained from the simulation results, the algorithm is effective and has higher Accuracy compared with the sparse online GP algorithm.

Abstract: Dual-bypass MIG welding (DB-GMAW) is a new kind of high speed MIG welding with three arcs. In order to monitor the weld process and control it, a high speed weld system of DB-GMAW was built. The system was run by LabVIEW programs, including getting data of system and control output signals. The test result of system showed that all equipments could be used in the same time. Beside images of weld pool and arc, the weld voltages and currents of every part had been acquired. The signals of bypass current and weld speed also had been input TIG welding sources and worktable motor successfully. Meanwhile, the high speed weld formation had a good quality, and all of these established the closed-loop control of high speed DB-GMAW.

Abstract: On the foundation of the analysis of the working mechanism of the GL160C continuously variable transmission (CVT), the mathematical model of the axial clamping force of the driving and driven pulleys are constructed. The relationship between the pressure of the driving and driven cylinders and the speed ratio of the CVT are derived while the CVT is transmitting the unit torque. The control method of the axial clamping force between the driving and driven pulleys, the control model of the CVT speed ratio are given. The following conclusions are drawn from the bench test and integral vehicle test: the acceleration performance and the stability of the speed ratio of the GL160C CVT are good, the power output is stable and reliable, the controller could achieve every functional requirement, all of which could guarantee that the output of the engine could run as the designed ideal dynamic curve and the ideal economical curve.