Research On Fuzzy Control System Of Sleep Respirator

Obstructive sleep apnea syndrome (OSAS) is the most common sleep breathes obstacle disease, which is a serious potential threat to the mankind's health. At present, the main means to treat OSAS is as follows: operation treatment, medication and respirator being treated to continuous positive airway pressure (CPAP). Because such characteristics as it is remarkable that the respirator has no wounds , curative effect to treat, have already become the first-selected method to treat OSAS now. On the sleep respirator market in the domestic at present, the medium and high-grade goods are produced by the manufacturers of foreign countries. The respirator adopt control algorithms of PID more in the control system.Because the control course of the pressure and flow of respirator is non-linear, the whole system varies with time, If the system adopts the PID control method,it can't get the satisfied result after simplifying the system.This paper combines the fuzzy control theory and single-chip microcomputer technology, and studies the design method to fuzzy controller , and designs the fuzzy controller of respirator. Fuzzy control is a kind of new developing control means on the foundation of fuzzy set theory; it is the result that theory and fuzzy technology and automatic control technology of fuzzy system combined together. The core of fuzzy controls is the usage of a fuzzy set theory, transform the natural language of people's control strategy the control algorithm described for algorithmic language which the computer can accept , the method can not only realize control, can imitate mode of thinking of people can't construct to some mathematics model accuse of target's carrying on effective control. Fig. 1 is a fuzzy control principle diagram. e expresses for the deviation of accurate quantity in the picture; ec expressed for the deviation change of accurate quantity; u is the output of accurate quantity. E, EC are fuzzy deviation and deviation change; C stands for the fuzzy controlling amount. The part with the dotted line frame is a fuzzy controller in the picture. It is constituted by fuzzily, fuzzy rule and fuzzy judgment. Fuzzy control isn't constrained by the mathematics model , but utilizes the fuzzy language, adopts condition sentence model that is made up with sentences, confirming the control rules of every parameter or turning into the fuzzy control form, and is revised repeatedly artificially in the course of debugging actually. Then adopt checking the form and find out the corresponding fuzzy controlling amount in controlling forms through the computer, get the actual control amount to add to the control target again after certain proportion operation finally. The design of the fuzzy controller does not like routine controller which is described by accurate mathematics of adopting differential equation, transmitting function or the state equation etc, but under the jurisdiction of function through defining fuzzy variable, fuzzy set and corresponding one, adopt a group of fuzzy condition sentences to describe the relation of shining upon outputted in introduction. So in the fuzzy control system, it is very important to design and adjust the work of the fuzzy controller. The design of the fuzzy controller includes the following several contents: Fig. 1 fuzzy control principle diagram ·Confirm the input variable of the fuzzy controller and the output variable ·Design the control rule to fuzzy controller ·Set up the fuzzy method and against the fuzzy method ·Choose the input variable of the fuzzy controller and output the parameter of talking about the land and confirming the fuzzy controller of the variable (such as the quantization factor and factor of proportionality) ·Work out the fuzzy application program of the control algorithm ·Choose to the sampling time of the fuzzy control algorithm rationally The detailed introductions to this text regards walking into the electrical machinery as the fuzzy controller design process of controlling the target, and utilizes SIMULINK toolbox and Fuzzy Tools toolbox in MATLAB software, set up the reasoning system and simulation diagram of the system of respirator, and have carried on emulation as Fig. 2 shows. Fig. 2 simulation diagram of the system The usually fuzzy controller has two kinds of composition ways: One kind is used by hardware that the fuzzy logic chip makes up exclusively the fuzzy...