Research On The Self-feedback System Of The Gyro Based On The Double MCU

As an all-weather and self-orientation fine measuring instrument, gyro-theodolite is widely used in surveying and mapping, military, aerospace, etc. At present, the foreign gyro technology is very advanced, and has been seeking to achieve automatic north-seeking measurement of the gyro, but the majority of the domestic gyro theodolite needs manual intervention to complete the north-seeking. Therefore, the study of the automatic and"a key north-seeking"gyro theodolite is a very important significance.A high-efficiency north-seeking algorithm is proposed in terms of gyro principle and some common north-seeking algorithm, and the feedback control system based on the double MCU system is designed. The main research contents of the paper are as follows:1. The error compensation multi-stepping rough north-seeking method based on trend forecast is put forward. The main MCU real-time collects the movement information of the gyro cursor, and delivers the data to the PC by USB, and then PC calculates the result of the north-seeking with the algorithm of the error compensation multi-stepping rough north-seeking method based on trend forecast and gets the predicted result N1 and the compensation point N′by the compensation function ;then the actual result(N1+ N′) is sent to the main MCU ;At last the main MCU control the turntable to rotate the appropriate location.2. The double MCU system is designed and completed, and the asynchronous serial communication between the two MCU is achieved. The stepper motor is triggered by the slave MCU and automatically delegates, while the main MCU real-time collects and monitors the movement information of the gyro cursor, and uploads the data to the PC via USB to calculate the result. And then the result is conveyed to the main MCU to control the turntable to rotate according to the result. This can be completed the process of the north-seeking after several the above process.3. The self-feedback control of the north-seeking system is designed and implemented. First, the function relation between the initial position of the gyro cursor and the half off position is established; secondly, the feedback signal between the double MCU system-half off position is determined. During the process of the gyro downing, the main MCU constantly checks the changes of the cursor, when the change of the cursor meets the function, which represents the gyro arriving the half off position; then the main MCU delivers the feedback signal to the slave MCU to make the stepper motor stop. The system not only increases the quality of the gyro downing, but also effectively controls the gyro swing within the effective range.4. The software programming of the feedback system is completed, and the effectiveness and stability of the system is verified by experiments. Through rough north-seeking experiments in many orientations, it is proved that the north-seeking time of the system is within 4 min; in different initial azimuth, the max average of the north-seeking error is about 15′35″,the maximum of the standard deviation is about 5′35″,which greatly improves the rough north-seeking speed and accuracy.