Study On The Noise Field Control Technology In The Multi-parameter-integrated Reliability Testing Environment

In the thesis, the author made some researches and resolutions on the white noise environment simulation testing system in the multi-parameter-integrated and accelerated reliability testing environment, which were associating with the National High Technology Research and Development Program ("863"Program of China), "Study on Multi-parameter-integrated and Accelerated Reliability Testing Environment for the Components in the Airspace Craft".In chapter 1, the purpose and significance of the thesis was presented. Firstly, the significance and research status of multi-parameter-integrated and accelerated reliability Testing environment was introduced, and the developing trends on such research was also presented; then, the research status and generation methods of the white noise environment simulation testing system was presented; at last, the main research content and key techniques of the dissertation was pointed out.In chapter 2, the theoretical analysis and FEM simulation of the noise field in a rectangular chamber under the motivation of flat speakers were elaborated. In this chapter, the coupled model of flat speakers and air-fluid of the rectangular chamber was established by FEM on the basis of acoustics, and the distribution of the noise field influenced by acoustic modes of rectangular chambers which have same volume and different sizes was studied, and also by the Installation locations of flat speakers and sound-absorbing material laid on the internal wall of the rectangular chamber. Such research results could provide guidance on the design of air-tight noise field in a chamber under the motivation of flat speaks.In chapter 3. the generation techniques of white noise and simulation research of the system based on DSP were studied. Firstly, the theory of generating white noise was introduced; then, the white noise waveform generator based on DSP was designed according to the above theory, and was studied through relevant simulation; at last, the white noise control system based on dual DSP and the system software were designed; the test results showed that the white noise waveform generator based on DSP could meet the reauirements of the subiect.In chapter 4, the hardware circuit of the white noise control system was researched. Firstly, the whole framework of the white noise control system was introduced; then, the core components of the hardware circuit design were introduced of the the white noise control system; at last, the combination of the whole system was accomnlished.In chapter 5, the control algorithm of the white noise control system was presented. Firstly, the multiple-input and multiple-output system was introduced, and on this basis the feedforward decoupling controller was designed:then, the feedforward decoupling fuzzy PID control algorithm was designed after the fuzzy PID algorithm was studied; at last, the white noise system was researched by using the feedforward decoupling fuzzy PID control algorithm. The test results showed that this control algorithm of the white noise system based on dual DSP could meet the design requirements of the subject.In chapter 6, the experiments which had only one noise parameter or had multiple parameters were separately studied. Firstly, the impact of other parameters on the noise field in an open-loop control system was analyzed through the change of air pressure and vibration acceleration, also temperature and centrifugal acceleration; at last, the experiments was studied in a closed-loop control system; the experiments results showed that the white noise field could reach the requirements of the subject by using closed-loop control.In chapter 7, the achievement of the dissertation was briefly summarized and the further research work which needs to be done was expected.