Research On Some Theoretical And Technical Problems For Dynamic Combined Environmental Testing

Based on the National High-Tech Research and Development Program "Study on Multi-parameter Combined Environmental Reliability Testing System for Components of Aerospace Devices’", a combined environmental testing (CET) device was designed and some relevant problems of theories and technology were studied.In chapter1, backgrounds of the research and contents of this dissertation were presented. First, the background and significance of CET were introduced. Secondly, the development of CET at home and abroad was presented. Then the recent study status on CET that based on centrifuge was analyzed. At last, the main contents of the dissertation were presented.In chapter2, coupling theory between centrifugal acceleration and temperature field in a closed cavity was studied. First, governing equations of the temperature field were presented and effects of the centrifugal acceleration on the temperature field were analyzed. Then the temperature field with centrifugal acceleration was studied by numerical simulation. At last, experiments were carried out on the CET device, and the effects of the centrifugal acceleration on the temperature field were verified.In chapter3, coupling theory between vibration and temperature field in a closed cavity was studied. First, effects of the temperature field on the dynamic characteristic of the elastic structure were analyzed, and thermal modal analysis of the moving components of the vibration excitor was carried out by numerical method. Secondly, model of heat transfer in a closed cavity was established, and effects of vibration on the heat transfer were analyzed and simulated by numerical method.In chapter4, control of temperature uniformity in the test chamber was studied. First, the MIMO temperature plant was modeled approximately. Then a novel method for control of temperature uniformity was proposed. At last, the control system was simulated by Simulink based on the approximated plant, and experiments were carried out to verify the proposed method.In chapter5, robust control of the vibration excitor was studied. First, considering the centrifugal force and restoring force of the redress system, the plant of the vibration excitor was modeled and uncertainties of its parameters were given. Then the displacement controller was designed based on the mixed sensitivity robust H∞control. At last, the vibration control system was simulated by Simulink, and the tracking performance of the control system was studied.In chapter6, the CET device based on centrifuge was developed. First, the parameters and technical performance of the device were presented. Secondly, the structure of the CET device was designed, including the centrifuge, the vibration excitor and its redress system, the test chamber, the control system, as well as the software. At last, the prototype of the CET device was established and experiments were carried out to generate the combined environment.In chapter7, experiments for a MEMS accelerometer were carried out on the CET device. First, the test system and method of the accelerometer were presented. Then the experiments were carried out, and the effects of different environments on the static and dynamic characteristics of the accelerometer were investigated.In chapter8, achievements of the dissertation were summarized, and the future research was prospected.