Low-speed Maglev Train. In The Gap Sensor Development,

As a new type of transportation vehicle, Middle-Low Speed Maglev Train (MLSM) is suited to the situation of our country which has the broad application prospect, and suspensive gap sensor is very important in the suspension control system. The suspensive gap measurement of MLSM is studied in this dissertation, and the target is design of gap sensor which met the demand of the suspension control system, having integrative structure.To improve linearity and sensitivity of the sensor, the electro and magnetic characteristic of the coil-target when approaching to the detected train trace is analyzed. Using the FEM analyses software Ansys, the equivalent inductance of inductive coils with different shape, area and number of turns is simulated, providing basis for optimization of inductive coil.Temperature stability of eddy current sensor is important research index. Factors that affecting the temp stability of frequency modulated eddy current sensor is analyzed in the dissertation, and corresponding measure is taken separately. Temperature compensation is finished with look-up-table method, which solved the temperature stability problem of output displacement signal.Hardware design based on FPGA is completed, and pipeline style high resolution frequency measurement is fulfilled on a monolithic FPGA chip, which met the demand of control system on sensor's bandwidth. Other functions are also finished, including sensor output linearization, temperature compensation with look-up-table method and so on. Because sensor working conditions are quite complex, sensor performance is affected by various electro and magnetic disturbance through the conduction or the radiation way. EMC test of sensor is introduced. With surge absorb component and multiple-level LC filters, EMI is eliminated.At last, the gap sensor is designed and realized according to the aforesaid results. Through single point suspension experiment, it's proved basically that the gap sensor's technical index is verified, and satisfied experiment result is achieved.