Simulation And Experiment Of Nongyroscopic Inertial Measurement Unit

It is significant to obtain the data of ballistic flight, which can accelerate theresearch course and improve the performance of weapon. Axial acceleration ofprojectile loading instruments can reach several hundred thousand g while launching.In order to ensure the instruments work normally after the projectile flies off themuzzle, the sensors must have the ability to resist high shock and vibration. At present,the precision and drift of micro gyroscope are not meet specifications and it is hard toobtain right gyroscope with resisting high shock. On the other hand the microaccelerometer is satisfying. Under this condition, a new gyroscope free micro inertialmeasurement (GFMIMU) scheme, is brought forward for the measurement ofprojectile movement parameters. Correlative theory research work and simulationhave been done. Based on it, the sample of GFMIMU is manufactured, and half sizehardware-in-the-loop simulation is carried out. The results show the validity of thescheme. All the work done in this dissertation provides a helpful attempt of theapplication of GFMIMU. In the end, three new inertial measurement units arepresented for the attitude of high rotation body that suffers slight shock and they arecompared through simulation.Main research work can be summed up the following five aspects:(1) Based on the body with self-rotation, specific force equations at centroid areprovided, which resolve the problem of error caused by ignoring the distance betweencenter of GFMIMU and centroid of the body, when the body has large angular rate.(2) A GFMIMU scheme with redundancy using twelve accelerometers ispresented. The error formulas of angular rate and velocity for body centroid areprovided on the basis of error transfer theory, which are helpful to selectaccelerometers and build the measurement system. In order to enhance the angularrate calculation precision, the data fusion algorithms, including hypothesis test theoryand weighting average method, are used to calculate the angular rate of GFMIMU.And corresponding simulations are given.(3) Real-time data acquisition system of GFMIMU is designed. SPIcommunication software is programmed, and debugging is done on it. It has builtfoundation for the real-time calculation of body movement parameters. The GFMIMUstructure is designed and manufactured. Transient analysis on the mechanical structureis done during the projectile launching with the finite element analysis softwareANSYS. The mechanical structure is verified and suggestions for furtherimprovement of the structural dynamic properties are proposed.(4) The error sources of GFMIMU are analyzed. The effect to measurementaccuracy caused by the accelerometer location error is discussed in detail and relevantcompensation method is presented. Parameters in the static mathematical model areidentified based on the data of tumbling test. The validity of the scheme is verified byhalf size hardware-in-loop simulation.(5) Three new inertial measurement units are presented for the attitude of highrotation body that suffers slight shock and they are compared through simulation.Some results are showed.