The Piezoelectric Gyro Bias Temperature Drift Compensation Study

Piezoelectric gyro is an important inertial sensor, and has been widely used in the applications of military aviation and civilian automobile. As the essential element of inertial measurement system, the error of piezoelectric gyro affects the accuracy and performance of the system directly. The bias of piezoelectric gyro is very sensitive to environmental change, especially temperature change, and the relationship of bias and temperature is non-linear. The paper researches the reason why the static bias of piezoelectric gyro drift severely with temperature, and establishes a mathematics model of piezoelectric gyro, and employs hardware method and software method to compensate temperature error.The primary researches include:1.Introduction of the configuration and the basic theory of piezoelectric gyro. The main factors of temperature affection on piezoelectric gyro are analyzed from the design of the gyro.2.Reseach of methods of temperature control, thermistors, and hardware and software compensation. The principles of several compensation method and their circuit design are studied.3.Design of compensation system of bias temperature drift using the hardware method and software method. A diode function is used to compensate the bias error, and the function is analyzed and deduced in 4 quadrants with 8 formulas. The method of least square is used to estimate remaining error of the residual modification in the software model, and the calculation is completed in MCU. A multi-channel data sampling and analysis system is designed to sample the data of gyro temperature drift. The hardware of the system consists of sampling control unit, digital multimeter, computer and power source, and the software of the system is developed based on Visual C++6.0. In this system, parallel interface of the computer and sampling-control unit can choose different channels, and the communication is accomplished by RS232 serial interface of computer. Sampling of gyro data is accomplished by the HP45501A digital multimeter. The non-linear relation between gyro bias and temperature change is calibrated with analog circuit combining with digital compensation. The result of experiment shows the method can decrease the bias error of gyro and improve the accuracy of gyro.