The Design Of Motion Attitude Measurement System Of A Product Under Water

The measurement of attitude can provide effective information for navigation andcontrol system. With the growing maturity of MEMS technology, the attitude measurementsystem composed of micro inertial sensors gradually accepted by people of all ages. Themeasuring system whose characters are high integration, small volume, low powerconsumption, has broad application prospects.Based on the comprehensive technology on existing conditions, this paper formulatedthe corresponding measurement scheme according to the characteristics of an underwatermotion. The attitude measurement system designed in this paper is mainly composed of MTI,large range of three axis accelerometer and pressure sensor. MTI is composed of three axisaccelerometer, gyroscope consists of three axis and three axis magnetometer, which measureof the movement of products during the whole process.The large range of three axisaccelerometer is mainly to measure the acceleration value when the product into the waterand in the separation time, and this is because the inner accelerometer scale of MTI is not upto the requirements of measurement at the moment. The attitude angles of the product gotinto and separated in the water can be obtained through the calculation of the shockacceleration plus MTI output angular velocity and magnetic information. Pressure sensor ismainly used to measure the depth of water, then the attitude angle of the product in any depthcan be measured.The hardware design mainly includes the data storage module of MTI, and the collecting,storing and transmitting module of the acceleration and pressure. The digital quantity of MIToutput can be directly written into the SD card which is controlled by single-chipmicrocomputer through RS232bus. The analog quantity exported by accelerometer andpressure sensor should be transformed through the AD7606, stored in the Flash chipK9WBG08U1M and transmitted to PC finally through the USB chip CY7C68013A. Among these, the A/D conversion, Flash storage and USB transmission module are controlled by theFPGA EP2C8Q208C8N. The software design concentrates on the corresponding program andlogic design according to the hardware modules.At last, the whole system is tested on the ground. The experimental results show that themeasurement system can complete functions to measure and store the attitude angle.