Song Jiancheng

A Low-Cost Calibration Strategy for Measurement-While-Drilling System

The measurement-while-drilling (MWD) system is mainly used to draw borehole trajectory in a coal mine. However, its measurement error directly demonstrates a deviation between the drawing locus and the actual path. Thus, it is imperative to effectively compensate the error in advance. In this study, the traditional-integrated error model is adopted and a low-cost calibration strategy, namely an incomplete calibration strategy, is proposed. In this strategy, the ellipsoid-fitting method is quoted to determine the combined bias and orthogonalize the coordinate frame of the triaxial accelerometer, and a new plane-fitting method is exploited to align the orthogonal accelerometer coordinate frame with the body coordinate frame of the MWD system; meanwhile, the theoretical basis is also stated with the simulation verification of MATLAB. Besides this, the scalar product constant method is finally employed to acquire the error model of the triaxial magnetometer on the condition of the previously calibrated accelerometer coordinate system. In the end, the newly designed calibration strategy was experimentally tested with the MWD prototype developed by ourselves. The results reveal that the strategy can not only be implemented without the help of other expensive auxiliary equipment but also has good performance in attitude reconstruction

Design and realization of power quality monitoring system based on B/S model

With the development and application of Web technology, the power quality (PQ) monitoring system is providing a new application platform for large-scale information share. It will simultaneously increase efficiency while greatly decreasing workload. The software with three-tire B/S (Browser/Server) structure needs to administer only the server, so all the clients are just the browsers and do not need any maintenance. In this paper, the three-tier system structure model of PQ monitoring system, the structure of the application servers and the data exchange standards PQDIF (PQ date interchange format) are discussed. The GUI of the Application Server and the PQDIF file in XML are also given.

Reduction of load model based on perturbation method

This paper describes the concept of the multi-time scales in math and derives a integrated typical model that represented by the induction motor. Then the system is separated to some subsystems in different scales for the purpose of reducing the order of the model. Finally the perturbed models for induction motor are developed, implemented and tested on the one-machine infinite-bus system. The dynamic performances of the perturbed models are compared with the full models as well as the simple models which completely neglect fast transients during simulations. From the simulation results it is seen that the perturbation technique is reasonable.

The intelligent fault modeling of induction motor

The study of early intelligent obstacle diagnosis for large-sized mechanical equipment is of momentous social significance and far-reaching economic importance. The equipment directly influences production safety for enterprises, and concern economic efficiencies. So it is very important for the induction motor to guarantee non-failure work time and the whole cutting process without fault. The early-term fault and in-time diagnosis, however, is the most basic prerequisite for the amount ahead of schedule of maintenance.

The Early Fault Diagnosis Method of Induce Motor Based on Gray Prediction Nerve Network

It makes diagnosis of induce motor very complex that it’s fault omens and feature is non-linear. It is more difficult to get earlier period fault information and realize function reflection between information and running state. As the knowledge limitation and parameter change in running of induce motor, the gray prediction combined with the nerve network is used to predict feature parameter and future running state.