Research On The Improvement Of Data Collection Equipment In Bus Counting System

The technology of bus passengers automatic counting is the key techniques of intelligent bus system, the accurate, efficient and quick collection and analysis of the number of passengers has a decisive role for establishing reasonable urban bus system, it also has very important significance to establish the main body status of urban public transportation. This paper is based on the large density bus passengers counting system for background, deeply research two reasons cause it’s the acquisition of signal inaccurately, which are infrared interference and switch noise. The research improves the big density bus passengers counting system.The background of this paper is derived from Northeastern University’s the innovation project of national student. It uses the big density bus passengers counting system as context and its data collection equipment as study object. Firstly, I learnt the big density bus passengers counting system. After the deeply understanding of that, I deeply research two reasons cause it’s the acquisition of signal inaccurately, which are infrared interference and switch noise. Then I points out their problems respectively.For the problem of adjacent infrared interference, this paper uses the frequency of its related time share detection technology, in the original processing of the infrared tubes time-sharing system on the basis of sequence scanning, I plus the frequency modulation technology to the system, make the triggered signals be FM radio wave which contains time and frequency relations, and I use the FM frequencies as the center frequency of bandpass filter for filtering and envelope detection, so making the frequency related, and I make each pair of infrared tube and infrared receiving tube has a definite frequency and time relationship, so eliminating the infrared jamming.For the problem of switch noise, this paper makes a detailed analysis of the inverter to the basic circuit and its working principle, and I got the conclusion that the cause of switch noise, after that, according to the working principle of electric circuit, I established the mathematical model of the switch noise, through the analysis of mathematical model. I sum up the factors which influence the generation of the switch noise. For these factors, I devise a circuit, and use genetic algorithm to optimize the correlative parameters. Using these methods to restrain the influence of these factors on the switch noise. At last, I achieve the purpose of noise suppression.