Advanced Materials Research Vols. 317-319

Abstract: A novel concept to estimate the shape of inner hole in course of honing is presented in this paper. Based on analysis of machining condition, five sections measuring model is established in process pneumatic measurement system for inner hole honing. It used matrix algorithms to simplify judging process about inner hole shape. And it improves the accuracy of machining area in inner hole. The method and principle are elaborated in this article. Program module was designed and written for experiment. And the experimental data show that the measuring model is feasible.

Abstract: In this work, a nonlinear system fault detection approach based on tangent space distance locally linear embedding (TLLE) is proposed. In the algorithm, tangent space distance is introduced to LLE, which overcomes the shortcoming of original LLE method based on Euclidean distance. It can satisfy the requirement of locally linear much better and so can express the I/O mapping quality better than classical method. Simulation results are given to demonstrate the effectiveness of the fault detection algorithm based on TLLE method.

Abstract: Carry on unattended substation at the voltage of 220kV and the following is a technological innovation which having the profound influence to the current power supply system, is also the most important technology safeguard measure of the downsizing for efficiency in the power supply system. Along with the development of modern communication technology, computer technology, network technology, automatic control technology, image technology, monitoring technology and weak electricity integration technology, we had already realized the image and the sound signal's digitization, the audio and video signal's processing and the long-distance transmission. To the substation, besides the remote measurement, the remote signaling, the remote control, and the remote regulating functions which have already realized, the remote monitoring has also increased which called “five remote”. The “five remote” caused unattended substation become the reality and give a higher request to the information management and the intellectualization simultaneously. According to many years unattended substation's operational guidance experience, I proposed my ideas about the information management and the intellectualization of unattended substation, I hope that it is helpful to the promotion of the unattended substation.

Abstract: The metro train operation curve reflected the relations between the speed and the location of the train. The energy conservation and the time saving were mainly considered in the conventional metro train operation curve simulation. The metro train traction algorithm was studied and the actual train operation rules were followed to establish the genetic algorithm for optimizing the operation curve of the section, and consider the comfortableness of the section and the actual train operation curve. By stimulating, comparing and analyzing, the train operation curve was created with three elements of energy saving, time saving and comfortableness.

Abstract: The key to accomplish transient liquid phase bonding in the atmosphere is to control bonding temperature, holding time and compressive pressure. The measurement and control system was independently developed based on an industrial computer and I/O cards. The output of a medium frequency power supply and the opening degree of a proportional relief valve were regulated to control bonding temperature and compressive pressure. Improved PID algorithm was presented, and the temperature precision in steady stage reached ± 0.1%. The system is applied to TLP bond steel pipes successfully.

Abstract: The overcurrent fault characters in underground cable distribution networks is analyzed, the symmetry current fault protection based on phase-sensitive detection, the asymmetrical current fault protection based on negative sequence current detection and the overload current fault protection based on the amplitude current are designed. The protection system was tested and the result shows that signal can accurately reflect the type of fault and fault parameters. It has been realized intelligent current protection through automatic identify fault type by PLC and has been applied to mine flameproof and intrinsically safety load control centre. Practice shows that the mine's intelligent current protection system is realiable and will be of great applied value in mining industry.

Abstract: To solve the traffic congestion control problem on oversaturated network, the total delay is classified into two parts: the feeding delay and the non-feeding delay, and the control problem is formulated as a conflicted multi-objective control problem. The simultaneous control of multiple objectives is different from single objective control in that there is no unique solution to multi-objective control problems(MOPs). Multi-objective control usually involves many conflicting and incompatible objectives, therefore, a set of optimal trade-off solutions known as the Pareto-optimal solutions is required. Based on this background, a modified compatible control algorithm(MOCC) hunting for suboptimal and feasible region as the control aim rather than precise optimal point is proposed in this paper to solve the conflicted oversaturated traffic network control problem. Since it is impossible to avoid the inaccurate system model and input disturbance, the controller of the proposed multi-objective compatible control strategy is designed based on feedback control structure. Besides, considering the difference between control problem and optimization problem, user's preference are incorporated into multi-objective compatible control algorithm to guide the search direction. The proposed preference based compatible optimization control algorithm(PMOCC) is used to solve the oversaturated traffic network control problem in a core area of eleven junctions under the simulation environment. It is proved that the proposed compatible optimization control algorithm can handle the oversaturated traffic network control problem effectively than the fixed time control method.

Abstract: With the natural gas widely used in the modern industry and daily life, gas safety issues become prominent. An air-tight property detector based on the principle of direct pressure with the C8051F350 MCU as the core is designed in this paper. It is controlled by the main and auxiliary systems in the form of hierarchical, and it is more flexible in detecting. The pressure is measured by the high accuracy differential pressure transmitter and the 24-bit A/D converter is used to deal with the small signals. The temperature compensation algorithm is introduced to improve the detection accuracy. As the uncertainty analysis shows that the experimental data meet the requirements.

Abstract: A kind of gain scheduling control is designed for Buck converter. The small signal model of the Buck converter is translated into the Linear Parameter-Varying (LPV) dynamic equation with the load and the line voltage as the scheduled parameters. Based on it, the closed-loop system poles assignment is taken to the specific area with gain scheduled state feedback via linear matrix inequalities (LMIs) technique, the gain scheduled state feedback is designed to regulate the duty cycle of the switch conduction. Compared with robust state feedback control, it has better disturbance rejection performance.

Abstract: In this work, we apply iterative learning method to address the traffic density control problem in a macroscopic level freeway environment with ramp metering. The second-order traffic flow model is firstly formulated. Then traffic density is selected as the control variable in place of traffic occupancy. Based on the traffic flow model and in conjunction with nonlinear feedback theory, an iterative learning based traffic density controller is designed. Finally, the iterative learning based feedback controller is simulated in Matlab software. Simulation results show that this method has good dynamic and steady-state performance, and can achieve an almost perfect tracking performance.