According to the specific application, the loops are adjusted. The classical four loops include: amplitude control loop, frequency control loop, orthotropic control loop and rate control loop. The amplitude control loops and frequency control loops usually work together to make the mode shape stable. The orthotropic control loops and rate control loops work together. The orthotropic control loops are responsible for adjusting the mode shape and suppressing frequency cracking, and the rate control loops are responsible for extracting the input angular rate [7,12�C14]. In real applications, Coriolis vibratory gyros that use a second order derivative linear variable structure and classical four-loop control method cannot effectively estimate variable structure arguments.

Many scholars have designed the control loops of these kinds of gyros with adaptive theory, sliding mode variable structure control theory and any other modern control theories to solve the problem [15�C17]. However, the inconveniences that using advanced control methods brings are the high requirement for signal calculating systems and the difficulty of operating the system. In practical engineering, studying the advanced control method is still ongoing and does not have detailed product application information.Combining traditional vibratory gyros’ electrical designing ideas with the characteristics of gyros, the article designs a circuit system of a BVG, including the driving components, detecting components and control loops. The BVG works in the force balance mode and uses classical four-loop control to make the mode shape stabilized.

In chapter two, the BVG’s working principle is described and the equivalent dynamic model is given. In chapter three, the whole design plan Brefeldin_A of the BVG for the signals’ characteristics is given. Chapter four studies the circuit system’s driving components, detecting components and control loops, discusses theory analysis, simulation verification and experimental testing and gives the detailed design and analysis process. In chapter five, an experiment is done to test the BVG’s circuit system, to extract the input angular rate effectively and to prove its effectiveness and practicality.2.?Overview of Bell-Shaped Vibratory Angular Rate GyroThe BVG is a kind of axisymmetric shell resonator gyroscope inspired by the traditional Chinese bell, and the core component is a bell-shaped resonator-like Chinese traditional bell. It uses the piezoelectric elements stuck to the resonator’s wall to detect the standing waves’ precession to calculate the input angular rate.2.1.