The Study And Accomplishment Of The Speed And Relative Location Detection Sensor For Low Speed Maglev Train

The technology of speed and location detection is one of the key technologies of low speed maglev train. It provides speed and location signals for ground control center and other systems in maglev train to carry out traction, braking and operation control. Based on engineering application, and taking the CMS04 maglev train developed by National University of Defense Technology as the application object, this paper accomplishes the design and realization of a new speed detection and relative location sensor to realize high-precision LSD for maglev train. This sensor overcomes the defect of the inductive proximity switch which is sensitive to detecting distance, and eliminates the influence of detecting distance and train body vibration on the measurement results. Thus is promising in engineering application. The main jobs done in this thesis are as follows:(1). A new speed and relative location detection scheme which uses first difference to detect the inductance values of two adjacent coils for high-precision LSD is proposed by analyzing the defects of the inductive proximity switch. Based on this, in order to improve detection sensitivity, enhance noise immunity and avoid misjudgments, a further detection method applying second difference to the inductance of three adjacent coils is proposed which enhances the sensor's availability.(2). On the basis of theoretical derivation, the finite element software is applied to simulate and verify the effect of turn number, wire diameter, detecting distance, the distance between exciting coil and detecting coil on the detecting coil. The detecting coil which is suitable for the new sensor is designed and entwined(3). According to the performance requirements of the speed and relative location detection system of"sensor-counting method"for low speed maglev train, the exciting circuit, the power amplifier circuit, the demodulation circuit and the digital processing circuit are analyzed and designed. Finally, a test sensor system is accomplished.(4). The new sensor is calibrated though calibration table and its location detection function is tested in different operation conditions which are simulated by calibration table.The availability of the new speed and relative location detection sensor is verified by ground simulated experiment. The test results show that the properties of the new sensor satisfy the design requirements.