The Implementation Of A Measuring Instrument For Levitation GAP Of High Temperature Superconducting Maglev Vehicle

When high temperature superconducting maglev vehicle is running, the levitation gap must be detected quickly. To do that, a suitable distance measuring sensor is needed.There is a strong magnetic field around the rail, aimed at this point, a few kinds of distance measuring sensors including ultrasonic sensor, eddy current sensor and photo-electricity sensor are analyzed. At last, CMOS image sensor is chosen to measure the distance because of its low cost.Using two laser LEDs and the theory of forming an image by convex lens, we can compute the levtation gap if know distance of two laser dot's images under the condition of the distance of two laser dots is not changed at anytime.The System was divided five sub modules, they are imaging module, data processing module, control module, comunication module and I/O module. After all modules were designed and debugging finished, the whole instrument was assembled, debugged.In the text, the hardware and software of the system are expounded detailedly and all theory fig, part of program list are given. The test result show that the instrument can measure distance from 45mm to 70mm, the resolving power is 0.25mm. It can measure four times every second. The cost of the instrument is about 500 yuan.But there are some defects. First, the resolving power is too low. Second , the speed of measuring is not high. Third, the software of communication is not finished. If high resolving power image sensor and high speed processor were used, those defects can be conquered, but the cost of the instrument will rise.