Research On Accuracy Loss Tracing And Prediction Model Of Measurement System

"Science is based on measurement", the level of measurement technology is the important evaluation standard for technology development of a country. With the development of science and technology, opto-electronic technology, sensing technology, CAT, image display technology and modern signal processing technology, etc., have wide application in precise instrument, which promotes the rapid development of design, manufacturing, and the accuracy of measurement. Development of science and technology is the drive force and source of promoting accuracy and the improvement of instrument accuracy has provided new material condition and research measure for science and technology development.With the increasing development of science and technology, precise engineering has a increasingly high demand for accuracy. In order to reliably guarantee the accuracy and realize the goal of low cost, the measure of increasing the accuracy of equipment is not suitable. Adopting the low-cost theory of modern accuracy guarantee and technology has become the field of hot research in and out of China. Meanwhile, accuracy theory is one of the basic theories guiding product design, manufacturing and measurement. Making full use of accuracy theory to guide product design and manufacture is the basis and shortcut to create the favorable and the measure to increase the product level and competitiveness. Applying accuracy theory to design, manufacture and measurement is the specific measure to strengthen the country and enterprises, and the effective method to ensure and improve the product quality.Even if the influences of environment factors are not considered, the accuracy of measuring system, especially with mechanical structure, will decrease in the process of actual use. Moreover, the influence of each inner unit of the system on the total accuracy loss is different.This project is from higher university doctor subject special research foundation project "Uniform design theory and technology basis research of dynamic measuring system based on accuracy loss"(No. 20040359011) and part of NSFC (50675057) .Main content and work of this paper include the following aspects:1. Based on whole-system dynamic accuracy theory, aim at the limitations of traditional modeling methods, studying the whole-system dynamic error modeling theory, this modeling method and theory consider sufficiently the information about insider buildup units of measurement system, so the built model can reflect the change of actual measuring system along with time.2. Based on whole-system dynamic error modeling method and theory, studying the theory and method of dynamic accuracy loss decomposition and tracing, using bill belt signal reconstruction improvement arithmetic to decompose the accuracy loss signal of emulational system, obtain the frequency components of the insider structural units. Model parameters are estimated by BP NN to build accuracy loss function model of each insider cells, so the signals decomposing are achieved. Using the error characteristic of each insider structural units and the systemic whole error model, the signals tracing are achieved.3. Researching weight and weight function theory of dynamic accuracy loss, accuracy loss of each insider unit and their influence on total accuracy loss of the system can be determined by using weight and weight function in the accuracy loss diagnosis. The unit having a large weight and weight function of accuracy loss has a large influence on total accuracy loss of the system.4. Researching the prediction model of dynamic accuracy loss, using this model can achieve real time forecast of accuracy loss about measurement system, and it provide theoretical basis for systemic real time error correcting and compensating.5. A set of accuracy loss experiment system is developed according to the actual research. Accelerating experiment is carried out by using dynamic measurement experimental system (not changing using condition of the hundredth meter). Change of total output error during different measuring periods of the hundredth meter is grasped, so obtain the total accuracy loss law of the system; using experimental results, whole-system dynamic error modeling method and theory, the theory and method of dynamic accuracy loss decomposition and tracing, total accuracy loss of hundredth meter is effectively decomposed and traced, obtain five effective hefts. And using theory of accuracy loss model-building predication, their prediction models of accuracy loss are built Using weight and weight function theory of dynamic accuracy loss, accuracy loss weight of each main insider unit are built.In this paper, dynamic measuring accuracy theory are deepened. Whole-system dynamic error modeling method and theory, accuracy loss decomposition and tracing theory, weight and weight function of accuracy loss research the method of increasing accuracy of measuring system from the root of accuracy loss. Source of accuracy loss of measuring system can be known through the result of decomposition and tracing, which can effectively improve the accuracy of measuring system, and provide theoretical basis for optimizing research of accuracy loss and optimum design theory. Accuracy loss model of actual measurement system can be built by the theory and method of accuracy loss model building predication. Therefore, accuracy of measuring system can be increased effectively by using error correction theory and method, or other theory and method.