Digital Design On Controller Of High Precision North-Seeking Instrument

The north-seeking instrument was a kind of inertial instrument. By gyro and accelerator, it measureed the angular speed of Earth rotation and the acceleration of gravity, then the angle between the reference axis of carrier and the true north was resolved through computations. After that, rotating the sensitive axis of the gyro to point the true north, the instrument was working in the azimuth mode to constantly display azimuth angle of the carrier. In this paper, the finding north theory was introduced in detail, and presented a whole scheme on north-seeking system. At the same time, the theory of azimuth instrument was discussed.This paper introduced us all parts and working principle of the system, and the key parts in signal collection and pretreatment were discussed. On the basic of system's model, the closed loops such as gyro rebalance, platform system in serving mode , were researched using classical PID control theory according to requirements. Through 'tustin' transforming, the digital controllers were designed. The simulation results showed their advantage.It used DSP and FPGA as hardware electric circuit core, DSP used TI Corporation C2000 series chip F2812, at present, it was one of the most formidable DSP chips in the control domain. On the component integrated the rich peripheral, it provided the good platform for the motor control, this paper designed the DSP related hardware electric circuit as well as its software procedure.Finally, it gave the test data of the north-seeking instrument, including duplication, high temperature, low temperature and so on, through these experimental proof, it showed the accurate of the system hardware and software algorithm as well as digitized control superiority.