The System Of Freshness Storage By The Reduced Pressure Gas Adjustment Based On The Fuzzy Control

Along with the unceasing development of the facility horticulture level in our country, the outputs of the fruit and vegetable grow continually. However, the output growth of the fruit and vegetable also have many new questions, the serious lag technology of fruit and vegetable storage and processing has become an important factor which restricts the development of fruit and vegetable. That the fruits and vegetables are rotten deteriorated seriously after recovery causes the fruit growers vegetable growers bumper crop but not abundant harvest, and it will greatly injury the enthusiasm of the growers to develop the fruits and vegetables industry .Therefore, how to store the gardening products and maintain freshness is the major problem which our country urgently needs to solve, and this problem receives more and more people to take generally.The paper analyzed the existing domestic and overseas way to maintain freshness , studied the using scope and the effect of each kind way to maintain freshness , proposed a method about hypobaric-controlled atmosphere storage with comparison,and analysised the methord in detail. The paper contains the following several aspects:Firstly, the paper used the theory of the controlled atmosphere and hypobaric storage , proposed a method about hypobaric-controlled atmosphere storage,namely has used the principle of the hypobaric storage ,and used the vacuum pump as the installment to control the oxygen density in the storehouse, simultaneously it used the knowledge about the Controlled Atmosphere storage and controlled the temperature, the relative humidity, the oxygen density content, the carbon dioxide density content as well as the ethylene density content and so on in the storehouse .The paper has studied influence to the effect of the fruits and vegetables preservation by the factors about temperature, relative humidity, oxygen density content, carbon dioxide density content and ethylene density content , and had determined control quantity of the hypobaric-controlled atmosphere storage in this foundation: temperature, relative humidity, oxygen, carbon dioxide and ethylene density.Secondly, the paper has designed a automatic monitoring and controlling system which takes the integrated circuit AT89C51 in series of MCS-51 as the control core , designed a system composed of the 8-bit A/D converter chip ADC0809, the programmable I/O expand 27256 , the watch-dog chip MAX183L and 8-bit D/A converter chip DAC0832 and 8×8 keyboard, 8-bit 7 section of LED monitors composed to maintain freshness the storehouse survey, the demonstration and the control system, and has given the interface about chip-microcomputer connected to each part, and has compiled procedures about data acquisition , keyboard control and displays by using the MCS-51 series assembly language. Thirdly, the paper used the principle of the fuzzy control, studied the fuzzy control rules table about the control quantity of the hypobaric-controlled Atmosphere storage: Temperature, relative humidity, oxygen, carbon dioxide and ethylene density , and has carried on the simulation to this fuzzy control rules by using the MATLAB ,and proved this method rationality and the feasibility.Simultaneously the paper also has given the assembly language design of control rule table about the ethylene .The design of the controlled atmosphere and hypobaric storage besed on fuzzy control studied in this paper has provided certain theory instruction and the design which are supported for the research and development of preserving and storing techniques , enhanced the fresh keeping property of fruit and vegetable , and had a certain practical and theoretical value to how to realise it on the general platform.