The Application Of The Digital Rebalance Technique In Gyroscope

Dynamically tuned gyroscope(DTG) is one of the most widely used gyros in inertial navigation systems,and it is suitable for mass production,due to its simple structure, low cost and easy processing and assembly. DTG used in strapdown system must work in the closed-loop state,so rebalance loop or force feedback loop is critical.It is not only measuring circuit,but also control loop,whose accuracy can directly affect the accuracy of the gyroscope,and even the reliability of the whole inertial navigation system.There are two types of force feedback loop currently, analog force feedback loop and digital force feedback loop. In this paper, we select digital force feedback loop instead of analog force feedback loop, in view of its poor thermal stability and large quantization error and nonlinearity error. The main contents here include several aspects as following:1. Analyzing the structure and working principle of dynamically tuned gyroscope in detail, according to the actual condition of gyroscope, which be maked a detailed introduction about the structure of torquer and signal device, and due to the cause of manufacturing process, given such error of gyroscope gimbal ring, the drive shaft, rotor and torquer corresponding solution.2. Investigating the coupling case of gyroscope according to DTG's dynamic model,and giving a design method of the control decoupling and output decoupling by using diagonal matrix decoupling method in pulse force feedback loop.3. Studying the structural features of analog force feedback loop and digital force feedback loop,and determining the solution on dual-width-modulated circuit.4. According to the output from signal device is so weak and which be contained a lot of noise. according to the digital rebalance loop technique requirements, given the signal preprocessing module, phase sensitive demodulation module, modulus conversion module and low pass filtering module and other related auxiliary circuit.5. By using the type of TMS320F2812 DSP chip and the type of AD7656 digital converter module, given data collection and processing circuits of the digital rebalance loop system.6. Obtaining a design method of realizing related hardware circuit in digital force feedback loop in this issue via analyzing the characteristics of digital force feedback loop with properties of gyroscope.7. Based on the hardware design of digital rebalance circuit, given the peripherals interrupt function module, the data acquisition module and related software programs.