Xiaoguang Hu

Quaternion switching filter for impulse noise reduction in color image

A novel approach to impulse noise reduction in color image is introduced in this paper. By applying the quaternion unit transform theory, the difference between two color pixels can be represented in the quaternion form. Based on the difference mentioned above, an efficient filter that can switch between the vector median filter (VMF) and the identity filter (no filtering operation) is proposed. Extensive simulation result indicates that the proposed filter achieves a trade-off between noise suppression and detail preservation in both correlated and uncorrelated impulse noise scenarios when compared with other widely used filters. Furthermore, the computational complexity analysis shows that the proposed filter is quite efficient.

Research of on-line monitoring system of the condition of circuit breaker based on ARM and FPGA

To achieve the strict requirements for rapidness of data acquisition and the precision of data transmission during the on-line monitoring system of the condition of circuit breaker, a design approach for real-time data acquisition and remote transmission system base on Field Programmable Gate Arrays(FPGA) and ARM technology is presented. The approach adopts an overall structure of FPGA+ARM + ICC(industrial control compute)and the system has all the functions of sampling, measurement and communication. It can not only monitor on-line temperature, insulation, electric and mechanical parameters of high voltage circuit breaker(HVCB), but communicate with other data acquisition devices and ICC by CAN field bus. The presented device is excellent in the ability of real-timing and high reliability. The accuracy and reliability of the system has been proved through an analysis of the test results and on-the-spot installation and operation.

Research and realization of on-line monitoring system for high voltage circuit breaker based on ZigBee technology

Through designing a terminal device based on the AVR microprocessor, this paper proposes an approach to realize the on-line monitoring control to replace with conventional preventive maintenance. In addition, the mechanism of data transmission is designed also in the terminal device. Aiming at the shortcoming of additional cable that is difficultly lain down in transformer substation, a kind of wireless terminal device is also designed based on JN5121-M02 from Jennic Company. Finally, a control software is developed under the programming environment VC++6.0, so that the system can realize the on-line monitoring control. The designs of hardware and software are discussed in detail in the paper. The system can exchange the data with control center through ZigBee wireless network, so workers can visit the terminal devices in control center. Test results indicate that it is a good solution.

Testing of circuit breakers using coil current characteristics analysis

The paper presents the construction and principle of a designed system for diagnostic testing of high voltage circuit breakers (CB). The diagnostic testing system of circuit breakers is performed by characteristic analysis, and the discrete-time Mallet wavelet transform algorithm is used to process the signal of coil current. The coil current characteristic patterns from circuit breakers (made by ABB Corporation) are acquired, compared and analyzed. The circuit breakers are all tested under the conditions of working fields to ensure the objectivity of the conclusion. The accuracy and reliability of the system has been proved through an analysis of the test results. The serious faults on circuit breakers, including operating mechanism delays and major lubrication problems are detected correctly by the diagnosis system. Thus, the testing process and results performed under realistic conditions demonstrates that the coil current characteristic analysis is a reliable and feasible method for diagnostic testing on circuit breakers.

Research on digital simulation of satellite integrated electronic system

Satellite simulation technology is an effective method to reduce the risk of satellite system application and the production cost. With the satellite electronic system tending to integration and comprehension, it is particularly necessary to do researches on simulation of the satellite integrated electronic system (IES). The paper explains the design ideology of IES digital simulation, builds a simulation framework, introduces the realization of the digital simulation of IES, and develops universal and authentic simulation software. In simulation application level, the paper realizes the function of the real satellite IES and the software has been applied to real satellite testing system.

Research on modeling and simulation of satellite attitude control system

Satellite is a specific product with a 4-H characteristic: high-tech, high-cost, high-benefit and high-risk, which makes satellite difficult to develop. However, simulation technology has the potential to fix the problem. It is highly reliable, non-destructive and can be recycled regardless of the time and space. All the advantages enable the technology to provide an effective way to reduce the cost and risk of satellite production. The paper focuses on the modeling technology which is used for simulating satellite on-orbit performance and dynamic environment, thus it can provide a general simulation framework for test during the development of a satellite.

Electrical equipment fault diagnosis system based on the decomposition products of SF6

This paper presents electrical equipment fault diagnosis system based on the decomposition products of SF6, and makes an introduction of a method that electrical equipment fault diagnosis system of hardware and software implementation. The hardware uses ATmega128 series single-chip platform, and the software uses advanced wavelet neural network fault diagnosis method. To prove the superiority of this algorithm, we make the simulation and comparison with others. A good synergy of hardware and software is used in SF6 electrical equipment fault diagnosis, and analysis of SF6 gas content of decomposition products to judge if the electrical equipment fault happens and to make a fault prediction. In this paper we will introduce the hardware design method and the detailed design of the software just because of strong electromagnetic interference environment and it is very important to the system design, finally by giving the experimental data to prove system reliability and practicality.

Hot-Redundancy CPCI Measurement and Control System Based on Probabilistic Neural Networks

Aiming at the requirements of high reliability and high real time for aerospace measurement and control systems, a solution based on Compact PCI (CPCI) bus for hot-redundancy of hardware structure is proposed. And an advanced fault diagnosis method for checking the faults of cards based on the probabilistic neural networks (PNN) is used in this system. A set of hot-redundancy experimental system platforms are developed to perform experimental verification on device-level hot-redundancy technology. Simulation and experiment results show that the system can realize hot-redundancy.

Design and realization of multi-function serial port with high-speed/large-capacity/asynchronous FIFO

Serial ports, such as RS232, RS422, RS485, and so on, have been more and more applied in industrial instrumentation and automatic devices. In the field of automatic testing, designing a multi-function serial port will create great convenience to workers. Meanwhile, the amount of data becomes larger and larger. In this case, we design the multi-function serial port with high speed and large capacity. However, dedicated high-speed FIFO chip is expensive and has limited capacity. Then we put forward using Field-Programmable Gate Array (FPGA) to control Synchronous Dynamic Random Access Memory (SDRAM) to realize this FIFO. This paper describes the method of using FPGA to design SDRAM controller and multi-function serial port. This design has been applied in multi-function serial interface card.

Design and implementation of time management in simulation and test platform for satellite

Satellite simulation and test platform is used for testing and verifying function and information flow of each satellite subsystem. Time management problems involving the instruction execution time, the simulation speed, the system logic sequence, etc. This paper proposes a method to realize the time management, include changing simulation speed in real time, correcting time of subsystem, broadcasting time code to each subsystem and releasing time report, etc.