Research For Electrostatic Servo Technology Of The Liquid Floating Rotor Type Micromachined Gyroscope

This paper presents the liquid floated rotor type micro-machined gyroscope byusing the working theory of suspension rotor micro-machined gyroscope, but differentfrom magnetic suspension and electrostatic suspended gyroscope. It adopts magneticdriver to reach a high-speed of rotating in the liquid cavity. The structure has theadvantage, which reduces the electrostatic voltage required by buoyancy of the rotor inthe liquid. In addition, compared to vacuum, resistance of rotor in liquid are larger, butits stability is better. At the same time using ultra thin drag reduction technology canalso reduce the rotor resistance. On the basis of the combination of electrostatic servotechnology, effectively improve the precision and performance. On the basis, thegyroscope combines with electrostatic servo technology and effectively improves theprecision and performance. This paper, from the perspective of the electrostatic servosystem, uses the finite element analysis software simulation, and simulates the workingcondition of the whole system and optimizes the structure of gyro.First of all, this paper introduces a simple overview of all kinds of suspended rotorgyro and this paper makes a detailed introduction of working principle of electrostaticservo system, control circuit and liquidity of the disc rotor, and lists a transfer functionblock diagram of the electrostatic servo system. After having a certain understanding ofthe whole system, it is not hard to see, the disc rotor structure and the controllingelectrode structure of electrostatic servo system plays an important role.Secondly, in order to get a higher precision and more stable suspension system, therelationship which is between rotor radius and rotor height, the angular velocity, therotor angular momentum is calculated and simulated to get the optimal size of rotorradius. This paper takes that the rotor radius is the size of7.5mm. In addition, thecontrolling electrode structure is analyzed. When ratio is0.33between the radius ofcommon electrode and rotor’s, the result reaches the maximum static torque of the rotor.At the same time, to control the electrode using fillet processing, it can reduce thepossibility of breakdown, achieving the goal of optimizing control electrode.Finally, according to the optimized structure of rotor and the control electrode, thecontroller is designed to achieve the effect of the electrostatic servo. This paper firstlyuses advancing-lagging PID algorithm. The algorithm uses low pass filter and caneffectively filter out high frequency noise to improve the performance of the PIDcontroller. Through the finite element analysis, overshoot amount of the controllerreaches7%, the adjusted time is5.3s. However, there is the nonlinear and instability ofsuspension system. So the fuzzy PID controlling algorithm is used in this paper,electrostatic servo system is simulated with Simulink. Compared with the simulation results, the fuzzy PID controller can better and effectively adapt to the nonlinear andcomplexity of a micro-gyroscope. It can quickly adjust rotor to make it back to thebalanced position and has a smaller overshooting time which is0.52s and overshootamount which is6.4%to satisfy indexes of the design.