Research Of Detergent Concentration Sensor And Intelligent Control For Washing Machine

As people's living standards improve and the pace of work accelerates, washing machines are becoming increasingly important in everyday life. According to statistics of resource development department of the state information center, washing machine water consumption accounts for about one third of household water consumption. 22.47 million washing machines totally were sold in the last year in China. The existing maintain of washing machines is about 210 million units. Therefore, research and innovation for the washing machine, improving the level of intelligent control, enhancing the product's market competitiveness, improving people's living standards, making washing machines more green, health and intelligent have great economic and social significance. This topic has focused on the detection of detergent concentration and intelligent control of washing machines.For the residual detergent in the washing solution is harmful to the human's health, it becomes increasingly important for the detection and control of the detergent concentration. However, it is still a big problem to detect this concentration because of various detergent brands and complex ingredients of detergent. A lot of experiments of different brand detergent such as alkalinity, pH, electric conductivity were conducted, experimental results were summarized, the detergent concentration detection program were compared, selected and determined. Researches indicate that detergent concentration positively relates to the electrical conductivity of the solutions and have a good linear when detergent concentration is among 0~2g/L based on the experiments applying different brand of detergents. In addition, the experimental results show that the conductivity of solutions is almost free from stains. Further, hardware and software are designed and detergent concentration control is implemented according to the detection principle of the detergent concentration so that the measurement accuracy is less than±4%.Market demand and the nonlinear characteristics of washing machine itself make intelligent control algorithms being introduced into the washing machine control system increasingly. Firstly the washing process in the washing machine and intelligent control were introduced in this paper. Intelligent control of detergent concentration sensing device was described with the role of detecting detergent concentration, controlling the amount of water and determining the rinse end point. The application of fuzzy control in the washing machines was discussed and at last the degree and type of dirt were as input variables for the decision of washing time, and forms and problems to be paid attention to were introduced briefly when implemented on general single chips.This issue makes useful explorations for the detection and control of detergent concentration and the fuzzy decision-making of washing machines. Finally, the future work was predicted.