| There are such deficiencies as poor stability, more tendency to roll in traditional unloading ways. To resolve this problem, the funnel unloading train with a bottom door is a good choice.The automatic unloading train with a bottom door has been a trend nowadays. And its unloading control system is based on the position of the train, which makes the issue of location a key point. Radio Frequency Identification(RFID) is a proper and decent technology to solve this problem because of its characteristics of being non-contact, wider recognition scope, strong penetrability and anti-interference capability. In this paper, passive RFID is applied to the location and identification of funnel unloading trains. Currently, there are lots of location ways for unloading trains, such as magnet, active wheel detector, infrared sensor, ultrasonic sensor, GPS and so on, all of which cannot identify the train. Moreover, there are certain shortcomings of these ways like inaccurate location and limited environmental suitability. Using RFID for identification and location is a new method, which integrates communication, identification and location and contains the advantages of strong anti-interference capability, high reliability and locating accuracy. There are two types of RFID: active RFID and passive RFID. Active RFID has already been employed in practical application system nowadays. However, it cannot be applied in a host of occasions because the active tag is limited with power supply. The funnel unloading train adopts mechanical collision switch door mechanism, which would control the collision rod according to the station layout. If we adopt active tags to solve this problem, a large number of location tags will be used in proper parts of the train and there will be certain difficulties in power supply. Thus passive RFID will be discussed and applied to automatic unloading system in this paper. Therefore, this paper will explore passive RFID positioning technology. The technique is applied to the bottom and open the door automatically dump truck unloading systems. This article is designed to study passive RFID location technique and unloading control strategy which contains five parts:1. Background. This part contains the reason for choosing this topic, research status of unloading train, and application status of position measurement technology and RFID.2. This part mainly elaborates the composition and operating principles of RFID system, the comparison and characteristics of active RFID and passive RFID, the main technological difficulty of location and its solutions.3. The design for the location system of the funnel unloading train. This part analyzes the traditional locating scheme and designs the positioning system for passive RFID and the train journey localization algorithm research, including ranging location algorithm, the non-ranging location algorithm.4. The structure and control strategy of the whole system. Combining theory and unloading train positioning method, the overall control system structure design and layout and explained each part of the system functions and rational installation of the various parts of the positioning system.5. The key technology experiments and simulations. This part analyzes the issue of energy transfer between the reader and electronic label and the key impacting indicator of RSSI; Builds RSSI log-normal model simulation. Through experimental platform, this paper carries out locating experiment on the passive RFID system which simulates the movement of the train. In this experiment, the locating accuracy should be within ±8.2cm and adopts proper installation method for tags and readers to make it completely meet the needs of unloading system. |
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