Study On Extreme Environment Simulating Instrument And Control Strategy In High Temperature High Pressure Deep Sea

The discovery of hydrothermal system in seafloor is of great significance to theresearch on geology, geochemistry and life science, etc. Especially, during theresearch on bio-mineralization process and the origin of life, many new phenomenawere discovered. Those discoveries have become great challenges to conventionaltheories. However, due to the particularity of extreme environment in seafloor, it wasdifficult to observe and investigate hydrothermal system on the spot. Therefore, tomeet the demand of carrying out relative experiments on land, it is very necessary toestablish an extreme environment simulation system in lab. The investigation onhydrothermal is one of the most important task in ocean exploration, and has got rapidprogress in many aspects. In order to go deep into the research on the precioussamples taken from extreme environment, relative equipment is indispensable thenthe development of simulating instruments is inevitable.At present, the instruments made in china cannot meet the special demand ofextreme environment research, and advanced similar instrument in the world alsohave many defects. Therefore, new simulating techniques and instruments need to bedeveloped to meet the demands of scientific research. This paper was aim to meet theparticular demand of extreme environment research, and carried out research inaspects as following:1. Research on extreme environment simulating system development. Environmentaround submarine hydrothermal is an extreme environment with characteristics ashigh temperature and high pressure, high corrosion and easy contamination. In thispaper we developed a high-temperature and high-pressure resistant reaction kettle,which was made of titanium for its bio-friendly nature and optimal corrosion resistantability. The mechanical part as well as temperature and pressure control circuit of thesimulating system also was developed to establish extreme environment simulatinginstrument's hardware platform.2. Research on temperature control. Successful temperature control assures forsuccessful experiments. Lapsus in temperature control will result in deviation evenmisleading conduct in research. Here, we built a temperature system model, andanalyzed the big lag link existed in the system which affected overshoot in classiccontrol policy. As Smith predictor has obvious advance in eliminating the negativeinfluence of lag link, we adapted two layers of closed-loop smith predictor to adjustthe negative influence of two big lag link in the model. Finally, we control thetemperature system precisely.3. Research on high-precision pressure detection and pressure control.High-precision pressure detection is an important technique to guarantee the oceanexplore going on well. When in high temperature environment, ordinarysilicon-pressure sensor would intensify the leakage between strain resistance andsilicon wafer, which caused the sensor destroyed then, cannot work. In this paper, wedesigned a titanium pressure sensor that works well even in extreme environment.The reliability and validity of the experiment result is depended on the controlprecision of pressure. In this paper, we also built a pressure system model, and analyzed the nonlinear link existed in the model. The gradient-variating iterationlearning control algorithm was designed, which could be used in nonlinear systemsconformed to certain paradigm. This algorithm had successfully controlled thepressure system rapidly, steadily and precisely.4. Research on instrument-oriented software framework model. This software isobvious different to custom softwares, because of its high demands in real-timereaction and high-reliability, and low demands in resource efficiency. In this paper, weimported the idea to divide the system into modules and layers structure, built theinstrument-oriented software framework model, and improved the reliability andfacility of the new system and the code reuse efficiency.Main innovations as follows:1. Developed the gradient-variation iteration learning control algorithm to improve thecontrol precision of the pressure system.2. Designed a titanium pressure sensor applied to extreme environment, andenhanced the detection precision by mulriple linear interpolation algorithm.3. Designed the instrument-oriented software framework model to impove theefficiency and reliability of software developing.